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Multifocal versus monofocal intraocular lenses after cataract extraction

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Abstract

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Background

Good unaided distance visual acuity (VA) is now a realistic expectation following cataract surgery and intraocular lens (IOL) implantation. Near vision, however, still requires additional refractive power, usually in the form of reading glasses. Multiple optic (multifocal) IOLs are available which claim to allow good vision at a range of distances. It is unclear whether this benefit outweighs the optical compromises inherent in multifocal IOLs.

Objectives

To assess the visual effects of multifocal IOLs in comparison with the current standard treatment of monofocal lens implantation.

Search methods

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 5), Ovid MEDLINE, Ovid MEDLINE In‐Process and Other Non‐Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2016), Embase (January 1980 to June 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 13 June 2016.

Selection criteria

All randomised controlled trials comparing a multifocal IOL of any type with a monofocal IOL as control were included. Both unilateral and bilateral implantation trials were included. We also considered trials comparing multifocal IOLs with "monovision" whereby one eye is corrected for distance vision and one eye corrected for near vision.

Data collection and analysis

We used standard methodological procedures expected by Cochrane. We assessed the 'certainty' of the evidence using GRADE.

Main results

We found 20 eligible trials that enrolled 2230 people with data available on 2061 people (3194 eyes). These trials were conducted in Europe (13), China (three), USA (one), Middle East (one), India (one) and one multicentre study in Europe and the USA. Most of these trials compared multifocal with monofocal lenses; two trials compared multifocal lenses with monovision. There was considerable variety in the make and model of lenses implanted. Overall we considered the trials at risk of performance and detection bias because it was difficult to mask participants and outcome assessors. It was also difficult to assess the role of reporting bias.

There was moderate‐certainty evidence that the distance acuity achieved with multifocal lenses was not different to that achieved with monofocal lenses (unaided VA worse than 6/6: pooled RR 0.96, 95% confidence interval (CI) 0.89 to 1.03; eyes = 682; studies = 8). People receiving multifocal lenses may achieve better near vision (RR for unaided near VA worse than J3/J4 was 0.20, 95% CI 0.07 to 0.58; eyes = 782; studies = 8). We judged this to be low‐certainty evidence because of risk of bias in the included studies and high heterogeneity (I2 = 93%) although all included studies favoured multifocal lenses with respect to this outcome.

People receiving multifocal lenses may be less spectacle dependent (RR 0.63, 95% CI 0.55 to 0.73; eyes = 1000; studies = 10). We judged this to be low‐certainty evidence because of risk of bias and evidence of publication bias (skewed funnel plot). There was also high heterogeneity (I2 = 67%) but all studies favoured multifocal lenses. We did not additionally downgrade for this.

Adverse subjective visual phenomena were more prevalent and more troublesome in participants with a multifocal IOL compared with monofocals (RR for glare 1.41, 95% CI 1.03 to 1.93; eyes = 544; studies = 7, low‐certainty evidence and RR for haloes 3.58, 95% CI 1.99 to 6.46; eyes = 662; studies = 7; moderate‐certainty evidence).

Two studies compared multifocal lenses with monovision. There was no evidence for any important differences in distance VA between the groups (mean difference (MD) 0.02 logMAR, 95% CI ‐0.02 to 0.06; eyes = 186; studies = 1), unaided intermediate VA (MD 0.07 logMAR, 95% CI 0.04 to 0.10; eyes = 181; studies = 1) and unaided near VA (MD ‐0.04, 95% CI ‐0.08 to 0.00; eyes = 186; studies = 1) compared with people receiving monovision. People receiving multifocal lenses were less likely to be spectacle dependent (RR 0.40, 95% CI 0.30 to 0.53; eyes = 262; studies = 2) but more likely to report problems with glare (RR 1.41, 95% CI 1.14 to 1.73; eyes = 187; studies = 1) compared with people receiving monovision. In one study, the investigators noted that more people in the multifocal group underwent IOL exchange in the first year after surgery (6 participants with multifocal vs 0 participants with monovision).

Authors' conclusions

Multifocal IOLs are effective at improving near vision relative to monofocal IOLs although there is uncertainty as to the size of the effect. Whether that improvement outweighs the adverse effects of multifocal IOLs, such as glare and haloes, will vary between people. Motivation to achieve spectacle independence is likely to be the deciding factor.

PICOs

Population
Intervention
Comparison
Outcome

The PICO model is widely used and taught in evidence-based health care as a strategy for formulating questions and search strategies and for characterizing clinical studies or meta-analyses. PICO stands for four different potential components of a clinical question: Patient, Population or Problem; Intervention; Comparison; Outcome.

See more on using PICO in the Cochrane Handbook.

Plain language summary

Multifocal versus monofocal intraocular lenses for people having cataract surgery

What is the aim of this review?

The aim of this Cochrane Review was to assess the effects of multifocal compared with monofocal intraocular lenses after cataract extraction. Cochrane researchers collected and analysed all relevant studies to answer this question and found 20 studies.

Key messages

The review shows that people who have a multifocal intraocular lens after their cataract is removed may be less likely to need additional spectacles. However, they may experience more visual problems, such as glare or haloes (rings around lights), compared with people who have monofocal lenses.

What was studied in the review?

As people get older, sometimes the lens of the eye becomes cloudy leading to loss of vision. The cloudy lens is known as a 'cataract'. The cataract can be removed and a replacement lens put in its place. Usually the replacement lens has one 'point of focus'. This means that a person's vision after cataract surgery is either good for distance vision (driving, watching television) or good for near vision (reading, sewing) but not good for both. This standard lens is known as a 'monofocal' lens. People who get a monofocal lens will need to use spectacles for either distance or, more usually, for near vision.

To address this problem, new lenses have been developed that provide two or more points of focus. These are known as 'multifocal' lenses. These are designed to reduce the need for spectacles. People with multifocal lenses may have more vision problems such as glare and seeing haloes. Another option is to put a different monofocal lens in each eye: one with a focus for near vision and one with a focus for distance vision. This is known as 'monovision'.

What are the main results of the review?

The Cochrane researchers found 20 relevant studies that were mainly conducted in Europe and North America (15 studies); three studies were conducted in China and one study each in the Middle East and India. Eighteen studies compared multifocal with monofocal lenses and two studies compared multifocal lenses with monovision.

The Cochrane researchers assessed how certain the evidence is for each review finding. They looked for factors that can make the evidence less certain, such as problems with the way the studies were done, very small studies, and inconsistent findings across studies. They also looked for factors that can make the evidence more certain, including very large effects. They graded each finding as very low, low, moderate or high certainty

The review shows that:

• People with multifocal lenses probably have distance vision that is not very different to the distance vision of people who have standard monofocal lenses after cataract extraction (moderate‐certainty evidence). However, people with multifocal lenses may have better near vision and may be less likely to need spectacles compared with people with monofocal lenses (low‐certainty evidence).

• People who have multifocal lenses may be more likely to experience haloes and glare compared with people who have monofocal lenses (low‐certainty evidence).

• People receiving multifocal lenses had similar distance vision and near vision compared with people receiving monovision but reported less spectacle dependence. People with multifocal lenses reported more problems with glare and haloes compared with people with monovision.

How up‐to‐date is this review?

The Cochrane researchers searched for studies that had been published up to 13 June 2016.

Authors' conclusions

Implications for practice

Multifocal intraocular lenses may result in better near vision without any adverse effect on distance acuity. Spectacle dependence is less likely with use of these intraocular lenses when compared to the standard practice of monofocal implantation.

Whether the improvement in unaided near vision and increased incidence of spectacle independence are sufficient to outweigh the experience of glare and haloes is a matter for each person to decide. The final choice is likely to depend on a person's motivation to be free of spectacles, guided by realistic expectations as to the likelihood of achieving this aim and understanding of the compromises involved.

Implications for research

This review has highlighted the need for a core set of outcome measures in trials comparing multifocal and monofocal lenses. Standardised outcome reporting for visual acuity is required to be able to pool data and draw robust conclusions. Ideally these outcomes should be based on validated measures, particularly for the more subjective outcomes, and include the views of people who have had cataract surgery.

The search for alternative strategies to achieve spectacle independence, such as monovision, trifocal and accommodating intraocular lenses, should continue.

Summary of findings

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Summary of findings for the main comparison. Multifocal compared to monofocal intraocular lenses after cataract extraction

Multifocal compared to monofocal intraocular lenses after cataract extraction

Patient or population: people with cataract
Settings: eye hospital
Intervention: multifocal intraocular lens
Comparison: monofocal intraocular lens

Outcomes

Illustrative comparative risks* (95% CI)

Relative effect
(95% CI)

No of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

Monofocal intraocular lens

Multifocal intraocular lens

Unaided distance visual acuity worse than 6/6

Follow‐up: 6 weeks to 18 months

800 per 1000

768 per 1000
(712 to 824)

RR 0.96

(0.89 to 1.03)

682
(8 studies)

⊕⊕⊕⊝
Moderate1

Corrected distance visual acuity worse than 6/6

Follow‐up: 6 weeks to 18 months

See comment

⊕⊝⊝⊝
Very low1,2, 3

Substantial inconsistency I2 = 54%. Individual study RR ranged from 0.2 (95% CI 0.03 to 1.56) to 1.50 (0.63 to 3.59).

Unaided near visual acuity worse than J3/J4
Follow‐up: 6 weeks to 18 months

570 per 1000

114 per 1000

(40 to 330)

RR 0.20

(0.07 to 0.58)

782
(8 studies)

⊕⊕⊝⊝
Low1,3

Substantial inconsistency I2 = 93% but all individual study results in direction favouring multifocal IOLs. Individual study RR ranged from 0.02 (0.00 to 0.31) to 0.73 (0.54 to 0.97)

Spectacle dependence

Follow‐up: 6 weeks to 18 months

880 per 1000

554 per 1000 (484 to 642)

RR 0.63

(0.55 to 0.73)

1000
(10 studies)

⊕⊕⊝⊝
Low1,4

Substantial inconsistency I2 = 67% but all individual study results favoured multifocal IOLs. Individual study RR ranged from 0.35 (0.21 to 0.57) to 0.79 (0.61 to 1.03)

Participant‐reported outcomes: quality of life or visual function

See comment

435

(4 studies)

⊕⊝⊝⊝

Very low1,2, 3

On average most people in both groups achieved high scores on VF‐7/VF‐14 questionnaires but inconsistent comparative results between the 2 groups.

Participant‐reported outcomes: glare

Follow‐up: 6 weeks to 18 months

180 per 1000

254 per 1000
(185 to 347)

RR 1.41

(1.03 to 1.93)

544

(7 studies)

⊕⊕⊝⊝
Low1,2

Participant‐reported outcomes: haloes

Follow‐up: 6 weeks to 18 months

80 per 1000

286 per 1000 (159 to 517)

RR 3.58

(1.99 to 6.46)

662

(7 studies)

⊕⊕⊕⊝
Moderate1

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; IOL: intraocular lens; RR: risk ratio.

GRADE Working Group grades of evidence
High certainty: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate certainty: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low certainty: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low certainty: We are very uncertain about the estimate.

1 Downgraded for risk of bias (‐1): masking of participants and outcome assessors difficult in these trials; reporting bias unclear.

2 Downgraded for imprecision (‐1): wide confidence intervals.

3 Downgraded for inconsistency (‐1): I2 > 50%.

4 Downgraded for publication bias (‐1): asymmetric funnel plot.

Background

Description of the condition

Cataract, defined as the presence of visually impairing lens opacity in one or both eyes, is present in 30% of people aged 65 years and over in the UK (Desai 1999). Around 400,000 cataract extractions were performed in England in the year 2014 to 2015 (Department of Health 2015).

People with cataract usually present with one or more of the following symptoms: gradual reduction in visual acuity (VA), glare, change in glasses prescription and change in colour appreciation. The diagnosis may be made by the person's general practitioner or optometrist followed by referral to an ophthalmic surgeon for confirmation of the diagnosis and management. Many people with treatable visual impairment from cataract do not access health services (Desai 1999).

Description of the intervention

Cataracts causing only mild symptoms may not need treatment, while changes in glasses prescription due to cataract may simply be managed by the provision of new glasses. Where these options are inadequate the only treatment available is surgical extraction of the cataract. This is routinely accompanied by implantation of an intraocular lens (IOL) to replace the focusing power of the natural lens.

Current techniques of cataract surgery and IOL implantation allow accurate prediction of postoperative refraction. Existing standards of best‐corrected postoperative VA (Desai 1993) are being replaced by an expectation of good uncorrected distance acuity. This has been driven partly by the change from cataract surgery using a large (10 mm) incision to small incision (2 mm to 4 mm) phacoemulsification surgery. This change is generally perceived to offer greater predictability of refractive outcomes, a necessary pre‐requisite for good VA without the need for glasses. Cochrane systematic reviews comparing surgical approaches have been published (Ang 2012; Riaz 2013; de Silva 2014).

Because standard IOLs have a fixed refractive power the focal length is also fixed (monofocal). This means that most people will require a reading addition to their distance glasses prescription (Javitt 1997). While most people undergoing cataract surgery may be happy to use reading glasses, a proportion are likely to seek good unaided near vision as well as distance vision. The need for reading glasses for near vision is unlikely to be considered an important issue at present in low‐income countries where the burden of blindness due to cataract is so high.

How the intervention might work

One approach to improve near VA is to modify the IOL. There are no IOLs currently available that can change shape during accommodation in the manner of the natural crystalline lens. A fixed‐shape optic IOL could theoretically provide near vision if attempted accommodation resulted in forward displacement of the IOL. Efforts to design an IOL using this principle have so far been unsuccessful (Legeais 1999).

An IOL can also provide near and distance vision if both powers are present within the optical zone. This has been attempted using diffractive optics or with zones of differing refractive power. Both types of IOL divide light up to focus at two (bifocal) or more (multifocal) points so that the person can focus on objects at more than one distance from them. IOLs of both types are currently commercially available.

Optical evaluation of multifocal IOLs has been performed in detail. Exact figures vary with the IOL tested but essentially a two‐ to three‐fold increase in the depth of field is achieved at the expense of a 50% reduction in the contrast of the retinal image (Holladay 1990; Lang 1993). Clinical evaluation of a multifocal IOL is less clear‐cut. Several large studies, including non‐randomised comparisons with monofocal IOLs, have indicated that the quality of vision with bifocal and multifocal IOLs is good (Gimbel 1991; Knorz 1993; Lindstrom 1993; Steinert 1999). The key question to be answered is whether the optical trade‐off inherent in a multifocal IOL results in better or worse visual function compared to a monofocal IOL. Objective (Desai 1993) and subjective (Desai 1996) improvement in vision following cataract surgery with monofocal IOL implantation is so high that any study lacking a randomised control group as a comparator will be relatively uninformative.

Why it is important to do this review

There is an extensive body of published data on both monofocal and multifocal IOLs describing largely successful outcomes. To draw some conclusions regarding the relative merits of the different IOL types we undertook a systematic review of the best quality data (that from randomised controlled trials).

Objectives

To assess the visual effects of multifocal IOLs in comparison with the current standard treatment of monofocal lens implantation.

Methods

Criteria for considering studies for this review

Types of studies

We included randomised controlled trials.

Types of participants

We included trials in which participants were undergoing cataract surgery and IOL implantation in one or both eyes. There were no restrictions on race, gender or ocular comorbidity. We excluded trials that included participants with paediatric cataract (onset prior to age 16 years).

Types of interventions

We included trials in which any type of diffractive or refractive multifocal IOL was compared with monofocal IOL implantation.

In the current update 2016 we considered two comparisons. This was a protocol amendment (see Differences between protocol and review for further explanation).

  • Multifocal IOLs versus monofocal IOLs.

  • Multifocal IOLs versus monovision.

Types of outcome measures

Outcome data were collected at the longest time postoperatively that was available in each study.

We revised the outcomes for the update in 2016 (see Differences between protocol and review).

Primary outcomes

  • Distance, intermediate and near VA (unaided and corrected).

    • We used the cut‐point of worse than 6/6 for distance VA (20/20, logMAR score > 0) as 6/6 vision is usually considered normal VA. We used the cut‐point of worse than J3/J4 (Jaegar cards) or equivalent for near VA.

    • We also considered VA as a continuous variable where it was reported in logMAR units.

  • Spectacle dependence as reported by the participant.

Secondary outcomes

  • Contrast sensitivity (contrast is the difference between the brightness of an image and its background divided by the total brightness of image plus background. Contrast sensitivity is the inverse of target contrast threshold).

  • Participant‐reported outcomes including:

    • quality of life or visual function as measured by validated instruments;

    • informal (non‐validated) subjective assessment of visual function;

    • participant satisfaction;

    • glare (glare occurs when a light source other than the target image illuminates the retina, resulting in reduced contrast. Scatter of light from the glare source by the optics of an IOL may cause unequal glare between participants);

    • other optical aberrations including halos.

  • Resource use and costs.

Adverse effects

  • Any other adverse effects or complications as reported in trial reports.

Search methods for identification of studies

Electronic searches

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 5), Ovid MEDLINE, Ovid MEDLINE In‐Process and Other Non‐Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2016), Embase (January 1980 to June 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 13 June 2016.

See: Appendices for details of search strategies for CENTRAL (Appendix 1), MEDLINE (Appendix 2), Embase (Appendix 3), ISRCTN (Appendix 4), ClinicalTrials.gov (Appendix 5) and the ICTRP (Appendix 6).

Searching other resources

We searched the reference lists of relevant articles and Martin Leyland's personal database of trials. For the first version of the review we contacted investigators of included studies and the manufacturers of multifocal IOL (Acute Care; Spectrum Ophthalmics; Storz Ophthalmics; Bausch & Lomb Surgical Ltd (UK); Alcon Laboratories Ltd; Pharmacia & Upjohn; Rayner Intraocular Lenses Ltd) for details of additional published and unpublished trials. We did not do this for subsequent updates.

Data collection and analysis

Selection of studies

Two review authors working independently examined the titles and abstracts from the electronic searches. We obtained the full paper of any trial that appeared to fit the inclusion criteria. We assessed full copies according to the definitions in the Criteria for considering studies for this review. We only assessed trials meeting these criteria for risk of bias.

Data extraction and management

For the update 2016, partly because we had revised the outcomes but also because we needed to incorporate more information as a result of the updated methodological expectations of Cochrane Reviews (MECIR 2013), we extracted the data for all trials again using a piloted customised data extraction template in web‐based review management software (Covidence 2016). Review author pairs extracted data independently (JE/VK/MZ) and a third review author (SdeS) adjudicated discrepancies as needed. We imported data directly from Covidence into Review Manager 5 (RevMan 2014), which was checked by one review author (JE).

Assessment of risk of bias in included studies

Review author pairs (JE/VK/MZ) independently assessed risk of bias in Covidence using Cochrane's tool for assessing risk of bias (Higgins 2011) and as outlined in Table 1.

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Table 1. Risk of bias assessment

Domain

Low risk of bias

Unclear risk of bias

High risk of bias

Sequence generation

Computer‐generated list, random table, other method of generating random list.

Not reported how list was generated. Trial may be described as "randomised" but with no further details.

Alternate allocation, date of birth, records (these RCTs were excluded).

Allocation concealment

Central centre (web/telephone access), sealed opaque envelopes.

Not reported how allocation administered. Trial may be described as "randomised" but with no further details.

Investigator involved in treatment allocation or treatment allocation clearly not masked.

Masking of participants and personnel

Clearly stated that participants and personnel (apart from surgeon) not aware of which lens received.

Described as "double blind" with no information on who was masked.

No information on masking. As lenses were different, we assumed that in the absence of reporting on this participants and personnel were not masked.

Masking of outcome assessors

Clearly stated that outcome assessors were masked.

Described as "double blind" with no information on who was masked.

No information on masking. As lenses were different, we assumed that in absence of reporting on this outcome assessors were not masked.

Incomplete outcome data

Missing data < 20% (i.e. > 80% follow‐up) and equal follow‐up in both groups and no obvious reason why loss to follow‐up should be related to outcome.

Follow‐up not reported or missing data > 20% (i.e. follow‐up < 80%) but follow‐up equal in both groups.

Follow‐up different in each group or related to outcome (or both).

Selective outcome reporting

All outcomes in protocol or trials registry entry (or both) are reported.

No access to protocol or trials registry entry.

Outcomes in protocol or trials registry entry (or both) selectively reported.

Other sources of bias

No other source of bias.

Trial stopped early due to poor recruitment.

Baseline imbalance but not clear that it is important.

Trial stopped early because of outcome.

Important baseline imbalance that might have an effect on the results.

RCT: randomised controlled trial.

Measures of treatment effect

Our measure of treatment effect was the risk ratio (RR) for dichotomous outcomes and mean difference (MD) or standardised mean difference (SMD) for continuous outcomes, with 95% confidence intervals (CI). The use of the MD was a protocol amendment ‐ see Differences between protocol and review. Where possible, we checked for skewness using the method outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Deeks 2011).

Unit of analysis issues

The intervention could be applied to one or both eyes. We have indicated for each trial whether unilateral or bilateral surgery was done.

For the unilateral trials, the outcome was measured on the operated eye. For the bilateral trials, the outcome could be measured and reported on both eyes, or for the person (i.e. binocular vision). Where available, we have chosen reported binocular vision for the analyses. Where data were reported for both eyes, and appropriate methods of adjustment were not included, we requested further data from the investigators.

For studies with multiple multifocal treatment groups, we combined data for the different groups using the Review Manager 5 calculator (RevMan 2014).

Dealing with missing data

The analyses in this review were available case analyses. This makes the assumption that data were missing at random. We recorded the amount of missing data and reasons for exclusions and attrition, where available and documented this in the 'Risk of bias' table for each study (Characteristics of included studies table, "incomplete outcome data").

Assessment of heterogeneity

We assessed heterogeneity by examining the forest plots to see whether the direction of effect was similar in all studies and whether the CIs for the individual study estimates overlapped. To assess the role of chance we used the Chi2 test, although this may have low power when there are few studies, or the studies are small. We also considered the I2 statistic (Higgins 2003). We took an I2 value of 50% or more to indicate substantial inconsistency in study results.

Assessment of reporting biases

We assessed publication bias when the meta‐analysis included 10 or more trials by plotting effect size against standard error.

Data synthesis

Where three or more studies contributed to the analyses, we pooled the data using a random‐effects model. If there were fewer than three studies, we used a fixed‐effect model. If there was substantial heterogeneity or inconsistency (see Assessment of heterogeneity), we did not report the pooled analyses unless all individual study estimates were in the same direction.

Subgroup analysis and investigation of heterogeneity

We considered two main sources of heterogeneity: type of lens (refractive or diffractive) and whether the surgery was unilateral or bilateral. We compared subgroups using the standard test for interaction implemented in Review Manager 5 (RevMan 2014).

Sensitivity analysis

We performed a sensitivity analysis excluding studies at high risk of bias in one or more domains. This was a protocol amendment (see Differences between protocol and review).

'Summary of findings' table

We prepared a 'Summary of findings' table presenting absolute and RRs with an assessment of the overall quality of the evidence using GRADE (GRADEpro 2014). We included the following outcomes in the table.

  • Unaided distance VA worse than 6/6.

  • Corrected distance VA worse than 6/6.

  • Unaided near VA worse than J3/J4.

  • Spectacle dependence.

  • Participant‐reported outcomes: quality of life or visual function.

  • Participant‐reported outcomes: glare.

  • Participant‐reported outcomes: halos.

Results

Description of studies

Results of the search

Original review

The initial electronic searches found 239 titles and abstracts. We obtained the full copies of possibly relevant papers according to the criteria specified (see Search methods for identification of studies). One trial did not include a monofocal control group and was excluded (Walkow 1997). We identified nine papers as meeting the inclusion criteria for this review. On contacting the authors, we identified three as descriptions of the same cohort of participants (Haaskjold 1998a). Interim data were available on 149 participants with five to six months' follow‐up (Allen 1996), and a subsequent paper reported corrected distance acuity and contrast sensitivity data only (with no numerical data for contrast sensitivity) on 221 participants (Haaskjold 1998b). An unpublished report from the lens manufacturer described limited data on 190 participants at one year (Pharmacia 1995). The study author was also able to supply additional unpublished results.

Search updates

Updated searches in May 2002 identified 32 reports of which two further studies were relevant (Kamlesh 2001; Leyland 2002). An updated in September 2005 found 218 reports of which two further studies were relevant (Nijkamp 2004; Sen 2004). One trial was excluded because it was not randomised (Richter‐Mueksch 2002).

An updated search done in March 2012 identified 432 new records. The Trials Search Co‐ordinator scanned the search results and removed 308 records which were not relevant to the scope of the review. We assessed the remaining 124 records for potential inclusion. We rejected a further 100 records and obtained the full text of 24 records for further assessment. We included six studies in the review (Cillino 2008; Harman 2008; Palmer 2008; Zhao 2010; Alio 2011a; Jusufovic 2011). We identified two studies that were ongoing in 2012 ‐ one of which has now been included in the review (Wilkins 2013, ISRCTN37400841) and one of which has now been excluded (NCT01088282). We excluded 16 studies (Xu 2007; Maxwell 2008; Ortiz 2008; Allen 2009; Cionni 2009; Hayashi 2009a; Hayashi 2009b; Hayashi 2009c; Hida 2009; Hayashi 2010; Huang 2010; Shah 2010; Alio 2011a; Alio 2011b; Ji 2011; Zhang 2011). See Characteristics of excluded studies table for reasons for exclusion.

To assess the three Chinese studies, we asked Taixiang Wu, who is a Cochrane author and heads the Chinese Clinical Trials Registry, to contact the study authors and ask if the studies were randomised (Xu 2007; Huang 2010; Ji 2011). Taixiang Wu confirmed that none of the three studies randomised participants to interventions.

We assessed three studies which had previously been awaiting assessment and excluded them from the review (Liang 2005; Rocha 2005; Souza 2006). See Characteristics of excluded studies table for details of reasons for exclusion.

Update searches ran in June 2016 yielded a further 981 records (Figure 1). After removing 119 duplicates, the Cochrane Information Specialist (CIS) screened the remaining 862 records and removed 670 references which were not relevant to the scope of the review. We screened the remaining 192 references and obtained seven full‐text reports for further assessment. We included five reports (Peng 2012; Rasp 2012; Ji 2013; Wilkins 2013; Labiris 2015), and excluded two (Alio 2015; Puell 2015). We checked the status of the ongoing studies published in the previous version of this review and have excluded one study (NCT01088282) and study ISRCTN37400841 has been completed and included (Wilkins 2013). We re‐assessed one study which was previously included and have now excluded the study (Alio 2011c).


Study flow diagram.

Study flow diagram.

Included studies

Details of the individual trials are summarised in Table 2; information on the individual trials are included in the Characteristics of included studies table.

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Table 2. Included studies

Study

Country

Multicentre?

Eyes operated

Number of people randomised

Number of people randomised (assuming same as number analysed when not reported)

Number of people included in the analysis

Number of eyes included in the analysis

For eye outcomes, reporting by eye or person?

Cillino 2008

Italy

No

Both

NR

62

62

124

Eye (no adjustment for within‐person correlation)

el Maghraby 1992

Saudi Arabia

No

1

77

77

61

61

Eye (unilateral surgery)

Haaskjold 1998a

Europe

Yes

1

NR

221

221

221

Eye (unilateral surgery)

Harman 2008

England

No

Both

60

60

43

86

Person

Javitt 2000

USA, Germany, Austria

Yes

Both

261

261

235

470

Person

Ji 2013

China

No

1 or both

NR

51

51

64

Eye (no adjustment for within‐person correlation)

Jusufovic 2011

Bosnia and Herzegovina

No

1

NR

100

100

100

Eye (unilateral surgery)

Kamlesh 2001

India

No

1

NR

40

40

40

Eye (unilateral surgery)

Labiris 2015

Greece

No

Both

75

75

75

150

Leyland 2002

England

No

Both

69

69

60

120

Person

Nijkamp 2004

Netherlands

No

Both

190

190

137

274

Unclear

Palmer 2008

Spain

No

Both

NR

114

114

228

Eye (no adjustment for within‐person correlation)

Peng 2012

China

No

Both

102

102

101

202

Eye (no adjustment for within‐person correlation)

Percival 1993

England

No

1

NR

50

50

50

Eye (unilateral surgery)

Rasp 2012

Austria

No

Both

NR

146

146

292

Eye (no adjustment for within‐person correlation)

Rossetti 1994

Italy

No

1

NR

80

80

80

Eye (unilateral surgery)

Sen 2004

Finland

No

1 or both

80

80

75

110

Eye (no adjustment for within‐person correlation)

Steinert 1992

USA

Yes

1

80

80

62

62

Eye (unilateral surgery)

Wilkins 2013

England

Yes

Both

211

211

187

374

Person

Zhao 2010

China

No

1

NR

161

161

161

Eye (unilateral surgery)

Total

2230

2061

3194

NR: not reported.

Design

There were four multicentre and 16 single‐centre studies.

Participants

The total number of people enrolled was 2230. Of these people, 2061 (3194 eyes) were followed up and were included in the analyses. The smallest study randomised 40 people (Kamlesh 2001) and the largest trial randomised 261 people (Javitt 2000). All studies recruited people with age‐related cataract with no other apparent ocular morbidity and without excess corneal astigmatism.

Table 3 shows the mean age and sex of people enrolled in these trials. The median mean age was 69 years and median percentage women was 57%.

Open in table viewer
Table 3. Age and sex of participants in included studies

Study

Mean age in years (range)

% female

Multifocal 1

Multifocal 2

Multifocal 3

Multifocal 4

Monofocal

Multifocal 1

Multifocal 2

Multifocal 3

Multifocal 4

Monofocal

Cillino 2008

57

65

60

68

56

47

63

47

el Maghraby 1992

57 (45 to 90)

56 (45 to 70)

59

Haaskjold 1998a

67 (max 88)

67 (max 90)

Harman 2008

73

71

50

60

Javitt 2000

74

75

51

61

Ji 2013

63 (52 to 71)

63 (55 to 75)

58

56

Jusufovic 2011

43 (20 to 57)

50 (26 to 64)

46

42

Kamlesh 2001

56

54

Labiris 2015

61

60

Leyland 2002

75

74

NA

76

53

60

44

Nijkamp 2004

72

72

67

64

Palmer 2008

73

72

74

75

61

69

67

53

Peng 2012

66

NA

NA

67

58

47

Percival 1993

77 (59 to 89)

78 (60 to 92)

58

58

Rasp 2012

76 (62 to 91)

74 (63 to 89)

79 (66 to 89)

75 (62 to 87)

76 (63 to 80)

Rossetti 1994

72 (55 to 84)

70 (50 to 90)

61

57

Sen 2004

69 (48 to 84)

72 (41 to 88)

74

63

Steinert 1992

72

71

55

78

Wilkins 2013

67

69

56

58

Zhao 2010

65 (34 to 80)

67 (51 to 92)

49

46

max: maximum; NA: not applicable.

Interventions

The studies considered different types of multifocal lenses including refractive (10 studies), diffractive (six studies), mixture of refractive and diffractive lenses (three studies) and one study used a multifocal lens with both refractive and diffractive properties (Table 4). Two studies compared the multifocal lens to monovision (Wilkins 2013; Labiris 2015).

Open in table viewer
Table 4. Lenses used in included studies

Study 

Multifocal lens model (manufacturer) type

Monofocal lens name (manufacturer)

Cillino 2008

Array SA40N

(AMO)

refractive

AR40

(AMO)

ReZoom

(AMO)

refractive

Tecnis ZM900

(AMO)

diffractive

el Maghraby 1992

815LE

(3M Vision Care)

diffractive

15LE

(3M Vision Care)

Haaskjold 1998a

808X

(Pharmacia Ophthalmics)

diffractive bifocal

808D

(Pharmacia Ophthalmics)

Harman 2008

Array SA40N

(AMO)

refractive

Clariflex

(AMO)

Javitt 2000

Array SA40N

(AMO)

refractive

PhacoFlex II SI40NB

(AMO)

Ji 2013

AcrySof ReSTOR

(Alcon Laboratories)

diffractive

AcrySof Natural

(Alcon Laboratories)

Jusufovic 2011

ReZoom NXG1

(AMO)

refractive

AcrySof MA60BM

(Alcon Laboratories)

Kamlesh 2001

Progress 3

(Laboratoires Domilens)

refractive

Flex 65

(Laboratoires Domilens)

Labiris 2015

Isert PY60MV (Hoya Surgical Optics)

SN60WF (Alcon Laboratories)

Leyland 2002

Array SA40NB

(Allergan)

refractive

PhacoFlex I SI40N

(Allergan)

TrueVista 68STUV

(Storz)

refractive

Nijkamp 2004

Array SA40N

(AMO)

refractive

PhacoFlex II SI40NB

(AMO)

Palmer 2008

Tecnis ZM900

(AMO)

diffractive

Tecnis Z9000

(AMO)

ReZoom

(AMO)

refractive

TwinSet

(Acri.Tec, GmbH)

diffractive

Peng 2012

AcrySof ReSTOR SN6AD1

(Alcon Laboratories)

diffractive

AcrySof IQ SN60WF

(Alcon Laboratories)

Percival 1993

MPC25

(AMO)

refractive

PC25

(AMO)

Rasp 2012

AcrySof ReSTOR SN6AD3

(Alcon Laboratories)

diffractive

Acri.Smart 48S (also known as CT Spheris 209M)

(Carl Zeiss)

AT LISA 366D

(Carl Zeiss)

diffractive

ReZoom (AMO)

refractive

Tecnis ZMA00

(AMO)

diffractive

Rossetti 1994

3M lens "with both refractive and diffractive optics"

Model not reported

Sen 2004

Array SA40N

(AMO)

refractive

PhacoFlex II SI40NB

(AMO)

Steinert 1992

Array MPC‐25NB

(AMO)

refractive

PC‐25NB

(AMO)

Wilkins 2013

Tecnis ZM900

(AMO)

diffractive

Akreos AO

(Bausch & Lomb)

Zhao 2010

AcrySof ReSTOR SA60D3

(Alcon Laboratories)

diffractive

AcrySof  SA60AT

(Alcon Laboratories)

AMO: Advanced Medical Optics.

The cataract surgery performed in 16 studies was small incision phacoemulsification. Three studies employed extracapsular cataract extraction and one study included both types of surgery. In 12 studies the cataract surgery was bilateral in all or some people (participants had the same type of lens inserted into both eyes).

In cataract surgery, the lens capsule must be breached to gain access to the crystalline lens. A continuous circular tear (capsulorhexis) is preferred to the older 'can‐opener' technique using multiple small tears or incisions because the incidence of postoperative IOL decentration is likely to be reduced. Decentration leads to induced astigmatism and a reduction in unaided VA. Most studies used capsulorhexis and four studies used envelope capsulotomy (el Maghraby 1992; Percival 1993; Rossetti 1994; Kamlesh 2001).

Outcomes

Distance VA was measured using either Snellen charts (10 studies), Early Treatment of Diabetic Retinopathy Study charts (ETDRS) (Rossetti 1994; Leyland 2002; Nijkamp 2004; Harman 2008; Peng 2012; Wilkins 2013; Labiris 2015) or Regan contrast acuity charts (Steinert 1992; Javitt 2000). One study did not specify the chart but reported logMAR VA (Rasp 2012).

Jaeger reading cards were most commonly used to measure near VA (seven studies); however, other studies used Sloan near acuity charts (Cillino 2008; Zhao 2010), the De Nederlander Reading chart (Nijkamp 2004), Bailey‐Love logMAR word reading acuity chart (Leyland 2002; Harman 2008); Rosenbaum near acuity card (Steinert 1992; Javitt 2000); Snellen chart (Percival 1993; Palmer 2008); and handheld ETDRS near‐reading chart (Rossetti 1994; Peng 2012; Wilkins 2013). Labiris 2015 did not state which chart was used but this was likely to be ETDRS.

There was variety in the way that studies reported distance and near acuity. Some trials reported cut‐points used in this review (worse than 6/6, worse than J3/J4), some reported acuity as a continuous variable and some reported both.

Contrast sensitivity was measured and reported in many ways. Six studies used the Pelli‐Robson chart (Rossetti 1994; Kamlesh 2001; Leyland 2002; Harman 2008; Wilkins 2013; Labiris 2015), four trials used the Vision Contrast Test System (VCTS) chart (Haaskjold 1998a; Sen 2004; Cillino 2008; Zhao 2010), two trials used the Regan Contrast Acuity chart (Steinert 1992; Percival 1993), one trial used the CGT‑1000 contrast sensitivity testing instrument (Ji 2013), and one trial used the Functional Acuity Contrast Test (FACT) chart in the OPTEC 6500 chart (Palmer 2008). Even trials using the same chart did not report the results in the same way ‐ the data were described variously as contrast sensitivity, VA at different contrast levels and difference between high contrast and lower contrast acuity ‐ and it was difficult to pool data for contrast sensitivity. Three studies assessed the extent of glare disability using the Brightness Acuity Tester (Steinert 1992; Leyland 2002; Harman 2008), and most studies elicited information from participants as to the extent of problems with glare or haloes (or both).

Some studies formally addressed visual functioning after surgery using validated instruments such as the VF‐7 (Sen 2004; Cillino 2008; Zhao 2010), VF‐14 (Nijkamp 2004; Labiris 2015), and TyPE questionnaire (Javitt 2000; Leyland 2002). Eleven studies reported participant‐reported satisfaction (Steinert 1992; Percival 1993; Rossetti 1994; Haaskjold 1998a; Kamlesh 2001; Sen 2004; Nijkamp 2004; Cillino 2008; Zhao 2010; Peng 2012; Wilkins 2013).

Follow‐up ranged from one month to 18 months.

Data collection and reporting

Near vision and subjective outcomes were poorly assessed and reported. Only five studies reported both unequivocal unaided and corrected logMAR near acuity measures (Javitt 2000; Leyland 2002; Harman 2008; Peng 2012; Rasp 2012). Palmer 2008 reported corrected near vision using Snellen that was converted to logMAR, and near vision with best distance correction. Only five studies used validated instruments for subjective outcomes (Javitt 2000; Leyland 2002; Nijkamp 2004; Sen 2004; Zhao 2010).

Financial support

Two studies had no external funding, eight studies did not give funding details and four studies received some funding from multifocal IOL manufacturers. Seven studies used other sources of funding, namely the Saudi Eye Foundation, Hillingdon Hospital Research and Development Fund, Shanghai Leading Academic Discipline Project, Eye Research Institute Maastricht, Education Department of Liaoning Province grants, a Finnish Government Special Grant and a Finnish Eye Foundation Grant and UK National Institute for Health Research Biomedical Research Centre in Ophthalmology at Moorfields Eye Hospital and UCL Institute of Ophthalmology funding.

Excluded studies

See Characteristics of excluded studies table.

Risk of bias in included studies

See Figure 2 and Figure 3.


'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.


'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.

'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.

We contacted the authors of included papers for further information on their studies. We received replies clarifying various methodological issues for three studies (el Maghraby 1992; Haaskjold 1998a; Javitt 2000).

Allocation

Eight studies described an adequate method for random sequence generation (el Maghraby 1992; Javitt 2000; Nijkamp 2004; Cillino 2008; Zhao 2010; Jusufovic 2011; Wilkins 2013; Labiris 2015). The other studies did not report any information on how the sequence was generated but were described as "randomised".

Seven studies provided a convincing description of allocation concealment (Leyland 2002; Nijkamp 2004; Harman 2008; Cillino 2008; Jusufovic 2011; Peng 2012; Wilkins 2013), and authors for two studies confirmed allocation concealment (el Maghraby 1992; Haaskjold 1998a). Two studies were at high risk of allocation bias because methods of concealment were not clearly reported and there were baseline imbalances (Kamlesh 2001; Palmer 2008).

Masking (performance bias and detection bias)

Four studies described masking of participants (Steinert 1992; Javitt 2000; Cillino 2008; Wilkins 2013). In Harman 2008, the IOL type was disclosed to participants at the three‐month visit. All outcomes for this study have therefore been reported for the three‐month visit prior to the IOL disclosure, except for spectacle dependence and symptoms of glare/haloes that were only reported at the 18‐month visit. Interestingly, following disclosure of multifocal IOL status, participants in this group showed an improvement in near vision and spectacle independence by the 18‐month visit.

Several studies mentioned masking but it was not clear how successful it had been. In Leyland 2002, participants were informed that the IOL type implanted would not be revealed to them until completion of the trial but a proportion of participants were reported to be unmasked; in Palmer 2008, participants were not told which lens they would receive but it was unclear whether any of them could have guessed; in Peng 2012, the study was described as a "prospective, randomised, comparative, and observer‐masked trial" but there was no information on masking in the study report; in Zhao 2010, participants and medical staff collecting data were masked but there was no information on the staff providing care.

The remaining studies did not mention masking and we have assumed therefore that it was not done. Labiris 2015 did not describe masking and on the clinical trials registry was described as 'open label'.

Three studies that were (possibly) not masked successfully to participants reported masking outcome assessors (Leyland 2002; Harman 2008; Zhao 2010). In general, studies that masked participants and personnel also masked outcome assessors, the exception being Wilkins 2013.

Incomplete outcome data

We judged attrition bias to be low risk in two studies where reasons and numbers of participants who exited the study after intervention and before outcomes were clearly reported and we thought unlikely to affect the outcome (Peng 2012; Wilkins 2013). Five studies were at high risk of attrition bias (Steinert 1992; el Maghraby 1992; Percival 1993; Nijkamp 2004; Sen 2004). This was either due to significant numbers of participants being lost to follow‐up without clear indication of which group they had been randomised to, or exclusion of participants after randomisation based on outcome such as high astigmatism. However, most studies did not clearly report follow‐up and it was difficult to make a judgement.

Selective reporting

The extent to which selective reporting had occurred for each individual study was unclear because in general we did not have access to study protocols. Of studies registered prospectively on a publicly available database, Labiris 2015 was deemed to have low reporting bias since all outcomes were reported; for Wilkins 2013, there were some differences between the trial registry entry and outcomes reported.

Effects of interventions

See: Summary of findings for the main comparison Multifocal compared to monofocal intraocular lenses after cataract extraction

The lenses used in each study are detailed in Table 4 and refractive aims are summarised in Table 5. Five studies compared two (el Maghraby 1992; Leyland 2002), three (Cillino 2008; Palmer 2008), or four (Rasp 2012) different multifocal IOLs with a monofocal control group. The multifocal IOL results within these studies were similar and therefore we have pooled them for this review. Two studies compared multifocal with monovision and are considered separately (Wilkins 2013; Labiris 2015).

Open in table viewer
Table 5. Refractive aims in included studies

Study ID

Refractive aim

Cillino 2008

Emmetropia

el Maghraby 1992

Emmetropia

Haaskjold 1998a

Not stated

Harman 2008

Emmetropia

Javitt 2000

Not stated

Ji 2013

Not stated

Jusufovic 2011

Not stated

Kamlesh 2001

Not stated

Labiris 2015

Multifocal: +3.00 D of near addition; monofocal (monovision): targeting ‐0.50 D in the dominant eye and ‐1.25 D in the non‐dominant eye.

Leyland 2002

Emmetropia

Nijkamp 2004

Within 1 D of emmetropia

Palmer 2008

Between emmetropia and ‐0.5 D for monofocal emmetropia for multifocal.

Peng 2012

Emmetropia

Percival 1993

Emmetropia (treatment)/myopic astigmatism (control)

Rasp 2012

Not stated

Rossetti 1994

< 2 D astigmatism

Sen 2004

Not stated

Steinert 1992

Not stated

Wilkins 2013

Multifocal: emmetropia Monofocal (monovision): Emmetropia in distance eye; myopia ‐1.0 D to ‐1.5 D in the near eye.

Zhao 2010

Not stated

D: dioptre.

Multifocal versus monofocal lenses

Primary outcomes
Distance visual acuity

Eight studies reported the number of participants who did not achieve an unaided VA of 6/6 (n = 682) (Analysis 1.1). These tended to be older studies (Steinert 1992; el Maghraby 1992; Percival 1993; Rossetti 1994; Haaskjold 1998a; Leyland 2002; Sen 2004; Jusufovic 2011). There was little evidence for any important difference between the two groups with a pooled risk ratio (RR) 0.96, 95% confidence interval (CI) 0.89 to 1.03). We judged this to be moderate‐certainty evidence, downgrading one level for risk of bias (summary of findings Table for the main comparison).

Six studies reported mean unaided logMAR VA (n = 848) (Analysis 1.2). There was substantial inconsistency (I2 = 74%) but in all studies the mean difference between groups was less than 0.1 logMAR.

Eight studies reported the number of participants that did not achieve a corrected VA of 6/6 (n = 692) (Analysis 1.3). Again these studies were older, all being conducted no later than 2004. There was inconsistency (i2=54%) possibly reflecting changes over time in lenses used. The individual study estimates ranged from RR 0.20 (95% CI 0.03 to 1.56) (Kamlesh 2001) in favour of multifocal lenses to 1.50 (0.63 to 3.59) (Percival 1993) in favour of monofocal lenses. We judged this to be very low‐certainty evidence, downgrading one level for risk of bias, one level for imprecision due to the wide CIs and one level for inconsistency. (summary of findings Table for the main comparison).

Six studies reported mean corrected logMAR VA (n = 848) (Analysis 1.4). There was no evidence for any major difference between groups with all studies reporting a mean difference of 0.1 logMAR or less but again with substantial inconsistency (I2 = 64%).

Intermediate visual acuity

One study reported intermediate VA (Analysis 1.5). Mean unaided logMAR VA was 0.17 (standard deviation (SD) 0.15) in the multifocal group (n = 100) and 0.27 (SD 0.15) in the monofocal group (n = 102). The MD was therefore small at ‐0.10 logMAR (95% CI ‐0.14 to ‐0.06). Mean corrected logMAR intermediate VA was similar at 0.16 (SD 0.11) in the multifocal group and 0.24 (SD 0.11) in the monofocal group, with a small difference between groups (MD ‐0.08 logMAR, 95% CI ‐0.11 to ‐0.05).

Near visual acuity

Eight studies reported unaided near VA of worse than J3/J4 or equivalent (n = 782) (Analysis 1.6). There was significant heterogeneity in the method used for near VA measurement which may affect the accuracy of pooled outcomes. People receiving a multifocal lens were less likely to have poor near vision (RR 0.20, 95% CI 0.07 to 0.58). We judged the evidence to be of low‐certainty. We downgraded one level for risk of bias and one level for inconsistency between studies (I2 = 93%). The RRs ranged from 0.02 (Jusufovic 2011) to 0.73 (Leyland 2002) in the individual studies (summary of findings Table for the main comparison).

Five studies reported mean unaided near VA (n = 829) (Analysis 1.7). There was substantial inconsistency between studies (I2 = 98%) but all studies favoured the multifocal group.

Four studies reported corrected near VA worse than J3/J4 or equivalent (n = 344) (Analysis 1.8). There were better outcomes in the multifocal group (RR 0.32, 95% CI 0.08 to 1.27, I2 = 18%).

Six studies reported mean corrected near VA (n = 1003) (Analysis 1.9). There was substantial inconsistency (I2=99%). Four studies reported similar VA in both groups with a mean difference of less than or equal to 0.1 logMAR (Harman 2008; Javitt 2000; Palmer 2008; Rasp 2012). One study documented slightly better corrected near VA in the monofocal group (Leyland 2002) and one study reported substantially better corrected near VA in the multifocal group (Rasp 2012).

Spectacle dependence

Ten studies (n = 1000) reported the outcome of spectacle dependence for distance or near vision (Analysis 1.11). Fewer participants in the multifocal group were spectacle dependent in the multifocal compared with the monofocal group (RR 0.63, 95% CI 0.55 to 0.73). There was substantial heterogeneity between studies (I2 = 67%) but all studies favoured multifocal IOLs. Since there were data from 10 studies for this outcome, we produced a funnel plot to evaluate publication bias as planned in our protocol. This showed evidence of publication bias with a skewed pattern (Figure 4). We downgraded the evidence for spectacle independence one level for risk of bias and one level for publication bias. We did not additionally downgrade for inconsistency (summary of findings Table for the main comparison).


Funnel plot of comparison: 1 Multifocal versus monofocal intraocular lenses, outcome: 1.10 Spectacle dependence (any).

Funnel plot of comparison: 1 Multifocal versus monofocal intraocular lenses, outcome: 1.10 Spectacle dependence (any).

Four studies reported spectacle dependence for distance vision (n = 618) which overall was reduced in the multifocal group (RR 0.71, 95% CI 0.46 to 1.09) (Analysis 1.11). However, there was some inconsistency between studies with two studies showing no overall difference and with the other two studies in favour of the multifocal group (I2 = 67%).

Six studies reported spectacle dependence for near vision (n = 772) (Analysis 1.11). Fewer participants in the multifocal group required spectacles for near vision (RR 0.53, 95% CI 0.40 to 0.71). Again there was wide variation between studies (I2 = 85%) but all had better outcomes in the multifocal group.

Secondary outcomes
Contrast sensitivity

Thirteen studies measured contrast sensitivity; however, they used several different methods (see 'Outcomes' of Included studies) and therefore combined analysis of results was difficult. We pooled and analysed data from four trials (n = 288) that used the Pelli‐Robson chart (Analysis 1.12). This indicated little evidence of any important difference in contrast sensitivity between groups (MD ‐0.09, 95% CI ‐0.26 to 0.08).

The remaining studies reported poorer contrast sensitivity outcomes in the multifocal group. One study reported a small difference in contrast sensitivity in participants with good VA (Haaskjold 1998a); three studies reported contrast sensitivity at a particular spatial frequency (Cillino 2008; Palmer 2008; Zhao 2010), and four studies reported overall poorer contrast sensitivity in the multifocal group (Steinert 1992; Percival 1993; Kamlesh 2001; Ji 2013).

Participant‐reported outcomes: visual function and quality of life

Four studies reported results of visual function questionnaires (n = 480) (Analysis 1.13). There was some evidence of more favourable outcomes in the multifocal group, however the size of the effect was small and uncertain due to wide CIs and there was inconsistency between studies such that a pooled result may not be meaningful. (I2 = 92%).

Only one study assessed vision‐related quality of life and found no difference between multifocal or monofocal IOL groups (Analysis 1.14).

Participant‐reported outcomes: satisfaction

Six studies reported satisfaction scores (n = 643). The difference between groups was uncertain due to inconsistency between studies (I2 = 88%) (Analysis 1.15).

Four studies reported the number of participants that reported having 'good' vision or being 'satisfied' with their overall vision (n = 388). There was no evidence of any important differences between groups (RR 0.99, 95% CI 0.92 to 1.06) (Analysis 1.16).

One study assessed participant satisfaction for near vision (n = 80) and found a greater number of participants reporting good outcomes in the multifocal IOL group (RR 1.42, 95% CI 1.13 to 1.78) (Analysis 1.16) (Rossetti 1994). The same study also assessed participant satisfaction for distance vision with a slightly greater level of satisfaction in the monofocal group (RR 0.89, 95% CI 0.72 to 1.10) (Analysis 1.16).

One study assessed visual satisfaction at 12 months using the TyPE questionnaire and found no difference between groups (Analysis 1.17) (Leyland 2002).

Participant‐reported outcomes: visual symptoms

Cataract symptom scores

Two studies with 257 participants reported cataract symptom scores (Analysis 1.18). Both studies used the Cataract Symptom Score (CSS) (Steinberg 1994). Nijkamp 2004 reported final value at 3 months, Sen 2004 reported change between surgery and 1 month.

The CSS requires participants to reported whether they are bothered by any of five symptoms: double or distorted vision; seeing glare, halo, or rings around light; blurry vision; colours looking different than they used to in a way that is disturbing; and worsening of vision within the past month. A score was given for each symptom: 0 = "no symptom or not bothered"; 1="a little bothered"; 2 = "somewhat bothered"; and 3 = "very bothered". A total score of 15 was possible ranging from 0 (no symptoms or not bothered by any of the symptoms) to 15 (very bothered by all five symptoms). On average people in the multifocal group had worse symptom scores (MD 1.01 score, 95% CI 0.39 to 1.64; I2 = 0%).

Glare

Seven studies (n = 544) assessed postoperative glare. More people in the multifocal group reported problems with glare: (RR 1.41, 95% CI 1.03 to 1.93) (Analysis 1.19). We judged this to be low‐certainty evidence downgrading one level for risk of bias and one level for imprecision as the lower CI was close to 1 (summary of findings Table for the main comparison).

Haloes

Seven studies (n = 662) questioned participants regarding postoperative haloes. More people in the multifocal group reported haloes (RR 3.58, 95% CI 1.99 to 6.46) (Analysis 1.20). We judged this to be moderate‐certainty evidence downgrading one level for risk of bias (summary of findings Table for the main comparison).

Dysphotopsia

One study reported postoperative dysphotopsia (n = 114). There were more people with dysphotopsia in the multifocal group compared with the monofocal group (RR 1.18, 95% CI 0.76 to 1.82) (Analysis 1.21).

Complications

Complications of surgery can be expected to be similar for multifocal and monofocal IOLs as the lenses are similar in all but the design of the optics and require no modifications to surgical technique. Ten studies reported perioperative and postoperative complications (el Maghraby 1992; Percival 1993; Javitt 2000; Leyland 2002; Sen 2004; Nijkamp 2004; Cillino 2008; Harman 2008; Zhao 2010; Peng 2012). The incidence of complications was low and similar in the multifocal and monofocal groups.

Subgroup analyses

We did two subgroup analyses: refractive lenses versus diffractive lenses (Table 6) and bilateral surgery versus unilateral surgery (Table 7).

Open in table viewer
Table 6. Subgroup analyses: refractive versus diffractive lenses

Outcome

Effect measure

Analysis model

Studies

Number of eyes

Effect estimate (95% CI)

I2

Test for interaction (P value)

Unaided distance VA worse than 6/6

RR

Random

8

682

0.96

(0.89,1.03)

13.62

0.22

Both refractive and diffractive optics

RR

Random

1

80

1.02

(0.89,1.17)

0.00

Refractive

RR

Random

5

392

0.91

(0.83,0.99)

0.00

Diffractive

RR

Random

2

210

1.06

(0.87,1.30)

26.32

Mean unaided distance VA (logMAR)

MD

Random

8

924

0.01

(‐0.02,0.05)

69.87

0.91

Refractive

MD

Random

5

414

0.01

(‐0.01,0.04)

0.00

Diffractive

MD

Random

3

510

0.02

(‐0.05,0.09)

89.72

Corrected distance VA worse than 6/6

RR

Random

8

692

1.02

(0.71,1.45)

53.97

0.24

Both refractive and diffractive optics

RR

Random

1

80

1.05

(0.65,1.68)

0.00

Refractive

RR

Random

5

332

0.84

(0.50,1.41)

46.89

Diffractive

RR

Random

2

280

1.44

(0.97,2.13)

0.00

Mean corrected distance VA (logMAR)

MD

Random

8

924

0.03

(0.02,0.05)

55.65

0.92

Refractive

MD

Random

5

414

0.04

(0.00,0.07)

68.47

Diffractive

MD

Random

3

510

0.03

(0.02,0.05)

31.97

Mean unaided intermediate VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ diffractive (1 trial)

Mean corrected intermediate VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ diffractive (1 trial)

Unaided near VA worse than J3/J4 or equivalent

RR

Random

8

782

0.20

(0.07,0.63)

93.38

0.88

Both refractive and diffractive optics

RR

Random

1

80

0.22

(0.09,0.52)

0.00

Refractive

RR

Random

4

442

0.21

(0.03,1.63)

95.35

Diffractive

RR

Random

3

260

0.16

(0.07,0.40)

62.77

Mean unaided near VA (logMAR)

MD

Random

6

881

‐0.20

(‐0.37,‐0.03)

98.28

0.13

Refractive

MD

Random

4

453

‐0.11

(‐0.19,‐0.03)

81.28

Diffractive

MD

Random

2

428

‐0.39

(‐0.74,‐0.03)

99.26

Corrected near VA worse than J3/J4 or equivalent

RR

Random

4

344

0.32

(0.08,1.27)

17.58

0.18

Both refractive and diffractive optics

RR

Random

1

80

0.55

(0.05,5.85)

0.00

Refractive

RR

Random

1

59

2.90

(0.12,68.50)

0.00

Diffractive

RR

Random

2

205

0.12

(0.02,0.61)

0.00

Mean corrected near VA (logMAR)

MD

Random

8

1079

‐0.05

(‐0.15,0.05)

98.11

0.29

Refractive

MD

Random

5

569

0.02

(‐0.02,0.06)

83.89

Diffractive

MD

Random

3

510

‐0.17

(‐0.52,0.18)

99.40

Contrast sensitivity

MD

Random

4

288

‐0.07

(‐0.15,0.00)

0.00

0.60

Both refractive and diffractive optics

MD

Random

1

80

‐0.03

(‐0.23,0.17)

0.00

Refractive

MD

Random

3

208

‐0.09

(‐0.20,0.02)

2.89

Diffractive

MD

Random

1

0

Participant‐reported outcomes: visual function questionnaires

MD

Random

5

495

4.43

(‐0.79,9.66)

90.66

0.02

Refractive

MD

Random

3

303

0.65

(‐4.60,5.89)

69.05

Diffractive

MD

Random

2

192

8.88

(4.81,12.95)

55.23

Participant‐reported outcomes: vision‐related quality‐of‐life questionnaires

No subgroup analysis because only 1 subgroup ‐ diffractive (1 trial)

Participant‐reported outcomes: satisfaction scores

SMD

Random

7

658

0.24

(‐0.20,0.68)

86.02

0.00

Refractive

SMD

Random

4

365

‐0.10

(‐0.32,0.11)

5.78

Diffractive

SMD

Random

3

293

0.83

(0.42,1.23)

57.33

Participant‐reported outcomes: "good" or "satisfied" with vision

RR

Random

4

388

0.99

(0.92,1.06)

0.00

0.64

Both refractive and diffractive optics

RR

Random

1

80

0.87

(0.67,1.14)

0.00

Refractive

RR

Random

2

159

1.00

(0.91,1.09)

0.00

Diffractive

RR

Random

1

149

0.99

(0.87,1.13)

0.00

Participant‐reported outcomes: cataract symptom scores

No subgroup analysis because only 1 subgroup ‐ refractive (2 trials)

Participant‐reported outcomes: glare

RR

Random

8

559

1.41

(1.03,1.93)

0.00

0.68

Both refractive and diffractive optics

RR

Random

1

80

0.97

(0.39,2.41)

0.00

Refractive

RR

Random

5

299

1.50

(1.05,2.14)

0.00

Diffractive

RR

Random

2

180

1.34

(0.50,3.62)

0.00

Participant‐reported outcomes: halos

RR

Random

8

677

3.58

(2.06,6.25)

19.65

1.00

Both refractive and diffractive optics

RR

Random

1

80

4.86

(2.05,11.56)

0.00

Refractive

RR

Random

4

256

4.65

(1.59,13.60)

0.00

Diffractive

RR

Random

3

341

4.53

(0.81,25.30)

54.02

Participant‐reported outcomes: dysphotopsia

RR

Random

2

138

1.13

(0.81,1.60)

0.00

0.54

Refractive

RR

Random

1

56

1.00

(0.59,1.70)

0.00

Diffractive

RR

Random

1

82

1.24

(0.79,1.94)

0.00

Spectacle dependence

RR

Random

11

1015

0.63

(0.54,0.73)

68.19

0.04

Both refractive and diffractive optics

RR

Random

1

80

0.57

(0.41,0.78)

0.00

Refractive

RR

Random

6

493

0.74

(0.67,0.80)

0.00

Diffractive

RR

Random

4

442

0.43

(0.26,0.71)

82.56

CI: confidence interval; MD: mean difference; RR: risk ratio; SMD: standardised mean difference; VA: visual acuity.

Open in table viewer
Table 7. Subgroup analyses: unilateral versus bilateral surgery

Outcome

Effect measure

Analysis model

Studies

Number of eyes

Effect estimate (95% CI)

I2

Test for interaction (P value)

Unaided distance VA worse than 6/6

RR

Random

8

682

0.96

(0.89,1.03)

13.62

0.75

Unilateral

RR

Random

6

502

0.98

(0.88,1.08)

33.14

Bilateral

RR

Random

1

60

0.85

(0.25,2.89)

0.00

Mixed unilateral/bilateral

RR

Random

1

120

0.92

(0.80,1.05)

100.00

Mean unaided distance VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ bilateral (6 trials)

Corrected distance VA worse than 6/6

RR

Random

8

692

1.02

(0.71,1.45)

53.97

0.00

Unilateral

RR

Random

6

512

1.24

(0.96,1.62)

0.00

Bilateral

RR

Random

1

60

0.73

(0.15,3.60)

0.00

Mixed unilateral/bilateral

RR

Random

1

120

0.61

(0.43,0.85)

0.00

Mean corrected distance VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ bilateral (6 trials)

Mean unaided intermediate VA (logMAR)

MD

Fixed

1

0

Mean corrected intermediate VA (logMAR)

MD

Fixed

1

0

Unaided near VA worse than J3/J4 or equivalent

RR

Random

8

782

0.20

(0.07,0.58)

92.77

0.89

Unilateral

RR

Random

5

426

0.20

(0.08,0.51)

73.56

Bilateral

RR

Random

2

292

0.27

(0.01,6.63)

97.36

Mixed unilateral/bilateral

RR

Random

1

64

0.15

(0.06,0.38)

0.00

Mean unaided near VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ bilateral (5 trials)

Corrected near VA worse than J3/J4 or equivalent

No subgroup analysis because only 1 subgroup ‐ unilateral (4 trials)

Mean corrected near VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ bilateral (6 trials)

Contrast sensitivity

MD

Random

4

288

‐0.09

(‐0.26,0.08)

0.00

0.37

Unilateral

MD

Random

1

80

‐0.03

(‐0.23,0.17)

0.00

Bilateral

MD

Random

2

88

‐0.10

(‐0.47,0.27)

0.00

Mixed unilateral/bilateral

MD

Random

1

120

‐0.40

(‐0.87,0.07)

0.00

Participant‐reported outcomes: visual function questionnaires

MD

Random

4

480

3.09

(‐2.77,8.96)

92.18

0.00

Unilateral

MD

Random

1

161

7.50

(5.95,9.05)

0.00

Bilateral

MD

Random

2

199

3.54

(‐5.90,12.97)

88.24

Mixed unilateral/bilateral

MD

Random

1

120

‐3.60

(‐10.19,2.99)

0.00

Participant‐reported outcomes: vision‐related quality‐of‐life questionnaires

MD

Fixed

1

0

Participant‐reported outcomes: satisfaction scores

SMD

Random

6

643

0.26

(‐0.21,0.73)

87.75

0.91

Unilateral

SMD

Random

2

223

0.24

(‐0.92,1.40)

93.35

Bilateral

SMD

Random

3

300

0.31

(‐0.55,1.18)

91.45

Mixed unilateral/bilateral

SMD

Random

1

120

0.12

(‐0.24,0.48)

0.00

Participant‐reported outcomes: "good" or "satisfied" with vision

RR

Random

1

0

Unilateral

RR

Random

3

269

0.96

(0.85,1.07)

0.00

Mixed unilateral/bilateral

RR

Random

1

119

1.00

(0.92,1.10)

0.00

Participant‐reported outcomes: cataract symptom scores

MD

Fixed

2

257

1.01

(0.39,1.64)

0.00

0.57

Bilateral

MD

Fixed

1

137

0.90

(0.16,1.64)

0.00

Mixed unilateral/bilateral

MD

Fixed

1

120

1.30

(0.12,2.48)

0.00

Participant‐reported outcomes: glare

RR

Random

7

544

1.41

(1.03,1.93)

0.00

0.33

Unilateral

RR

Random

4

319

1.31

(0.77,2.21)

0.00

Bilateral

RR

Random

2

105

2.05

(1.12,3.75)

0.00

Mixed unilateral/bilateral

RR

Random

1

120

1.14

(0.67,1.92)

0.00

Participant‐reported outcomes: halos

RR

Random

7

662

3.58

(1.99,6.46)

24.75

0.69

Unilateral

RR

Random

5

480

3.50

(1.70,7.19)

36.86

Bilateral

RR

Random

1

62

12.33 (0.79,193.20)

0.00

Mixed unilateral/bilateral

RR

Random

1

120

3.79

(0.80,18.03)

0.00

Participant‐reported outcomes: dysphotopsia

RR

Random

1

114

1.18

(0.76,1.82)

0.00

1.00

Spectacle dependence

RR

Random

10

1000

0.63

(0.55,0.73)

66.86

0.81

Unilateral

RR

Random

5

499

0.62

(0.51,0.75)

58.74

Bilateral

RR

Random

5

501

0.64

(0.51,0.80)

73.16

CI: confidence interval; RR: risk ratio; VA: visual acuity.

These analyses must be interpreted with caution due to the small numbers of studies in each group which means the test for interaction may have low power and the large number of outcomes which may lead to spurious findings.

Comparing diffractive and refractive lenses, there was some indication that the diffractive lenses performed better. Specifically diffractive lenses had better visual function questionnaire scores and better satisfaction scores, and lower spectacle dependence.

The comparison between bilateral and unilateral surgery was difficult to interpret. There were two outcomes that had a significant P value for interaction, corrected distance VA worse than 6/6 and visual function scores, but in both these cases there was only one trial in some of the subgroups so it is difficult to attribute the difference in effect solely to this characteristic.

Sensitivity analysis

We excluded studies at high risk of bias in one or more domain as planned in our protocol (Table 8). There were some differences in outcome but these were not consistent and, due to the relatively high proportion of trials at high risk of bias, it is difficult to interpret these comparisons due to increased imprecision.

Open in table viewer
Table 8. Sensitivity analysis: excluding studies at high risk of bias

Outcome

Effect measure

All trials

Excluding studies at high risk of bias in ≥ 1 domain

Number of studies

Number of eyes

Effect estimate (95% CI)

I2

Number of studies

Number of eyes

Effect estimate (95% CI)

I2

Unaided distance VA worse than 6/6

RR

8

682

0.96

(0.89,1.03)

13.62

1

60

0.85

(0.25,2.89)

0.00

Mean unaided distance VA (logMAR)

MD

6

848

0.01

(‐0.03,0.05)

74.32

2

262

‐0.01

(‐0.10,0.08)

81.23

Corrected distance VA worse than 6/6

RR

8

692

1.02

(0.71,1.45)

53.97

1

60

0.73

(0.15,3.60)

0.00

Mean corrected distance VA (logMAR)

MD

6

848

0.03

(0.01,0.06)

63.79

2

262

0.02

(0.00,0.04)

0.00

Mean unaided intermediate VA (logMAR)

Only 1 study reported this outcome

Mean corrected intermediate VA (logMAR)

Only 1 study reported this outcome

Unaided near VA worse than J3/J4 or equivalent

RR

8

782

0.20

(0.07,0.58)

92.77

2

292

0.29

(0.01,8.39)

97.57

Mean unaided near VA (logMAR)

MD

5

829

‐0.22

(‐0.42,‐0.03)

98.41

3

494

‐0.26

(‐0.58,0.06)

98.94

Corrected near VA worse than J3/J4 or equivalent

All trials were high risk of bias in ≥ 1 domain

Mean corrected near VA (logMAR)

MD

6

1003

‐0.07

(‐0.20,0.06)

98.59

3

554

‐0.16

(‐0.50,0.18)

99.38

Contrast sensitivity

MD

4

288

‐0.09

(‐0.26,0.08)

0.00

1

45

‐0.07

(‐0.16,0.02)

0.00

Participant‐reported outcomes: visual function questionnaires

MD

4

480

3.09

(‐2.77,8.96)

92.18

2

223

7.58

(6.08,9.08)

0.00

Participant‐reported outcomes: vision‐related quality‐of‐life questionnaires

Only 1 study reported this outcome

Participant‐reported outcomes: satisfaction scores

SMD

6

643

0.26

(‐0.21,0.73)

87.75

3

324

0.64

(0.00,1.28)

84.77

Participant‐reported outcomes: "good" or "satisfied" with vision

All trials were high risk of bias in ≥ 1 domain

Participant‐reported outcomes: cataract symptom scores

All trials were high risk of bias in ≥ 1 domain

Participant‐reported outcomes: glare

RR

7

544

1.41

(1.03,1.93)

0.00

1

62

2.23

(0.30,16.72)

0.00

Participant‐reported outcomes: halos

RR

7

662

3.58

(1.99,6.46)

24.75

2

223

3.27

(0.64,16.67)

45.56

Participant‐reported outcomes: dysphotopsia

Only 1 study reported this outcome

Spectacle dependence (any)

RR

10

1000

0.63

(0.55,0.73)

66.86

5

619

0.55

(0.41,0.75)

83.77

CI: confidence interval; MD: mean difference; RR: risk ratio; SMD: standardised mean difference; VA: visual acuity.

Multifocal lenses versus monovision

Two studies compared multifocal lenses with monovision (Wilkins 2013; Labiris 2015).

In Wilkins 2013, the investigators enrolled 212 people who received bilateral sequential cataract surgery either to receive bilateral Tecnis ZM900 diffractive multifocal lenses or Akreos AO monofocal lenses with the powers adjusted to target ‐1.25 D monovision. The participants were followed up to four months and 187 (88%) were seen at that point.

In Labiris 2015, the investigators enrolled 75 people who received bilateral cataract surgery either to receive bilateral Isert PY60MV refractive multifocal lenses or SN60WF monofocal lenses with the powers adjusted to target ‐1.25 D monovision. The participants were followed up to six months. Follow‐up was unclearly reported but the impression was given that all 75 participants were followed up.

There was no evidence for any important difference in distance VA between the two groups (MD 0.02 logMAR, 95% CI ‐0.02 to 0.06; n = 186; studies = 1) (Analysis 2.1) (Wilkins 2013). The outcome was similar in Labiris 2015, which reported decimal VA and showed similar distance VA in the two groups.

People receiving multifocal lenses had similar or very slightly worse unaided intermediate VA compared with people receiving monovision (MD 0.07 logMAR, 95% CI 0.04 to 0.10; n = 181; studies = 1) (Analysis 2.1).

People receiving multifocal lenses had similar unaided near VA compared with people receiving monovision (MD ‐0.04 logMAR, 95% CI ‐0.08 to ‐0.00; n = 186; studies = 1) (Analysis 2.1) This was supported by Labiris 2015 which reported decimal VA and showed no significant difference in near VA between the two groups.

People receiving multifocal lenses were less likely to be spectacle dependent compared with people with monovision (RR 0.40, 95% CI 0.30 to 0.53; n = 262; studies = 2; I2 = 0%) (Analysis 2.2). Only Labiris 2015 reported these separately according to near and distance vision, with people receiving multifocal lenses being less likely to be spectacle dependent for near vision. There was little evidence of any effect on spectacle dependence for distance vision (Analysis 2.2).

Contrast sensitivity was marginally better in the monovision group (MD ‐0.06, 95% CI ‐0.10 to ‐0.02) in Wilkins 2013, but there was little evidence for any difference in Labiris 2015 (I2 = 67%, data not pooled) (Analysis 2.3).

People receiving multifocal lenses were more likely to report glare compared to people receiving monovision (RR 1.41, 95% CI 1.14 to 1.73; n = 187; studies = 1) (Analysis 2.5). This was supported by data from Labiris 2015, which reported glare and "unwanted shadows" on a 4‐point Likert scale. There were higher mean scores in the multifocal group for both glare (MD 0.15, 95% CI ‐0.00 to 0.30; n = 75; studies = 1) and shadows (MD 0.36, 95% CI 0.07 to 0.65; n = 75; studies = 1).

Wilkins 2013 reported IOL exchange. Quote "In the first postoperative year, 6 patients (5.7%) in the multifocal group underwent IOL exchange (4 had a bilateral and 2 had a unilateral exchange). No patients in the monovision group underwent IOL exchange."

Discussion

Summary of main results

The results are summarised in summary of findings Table for the main comparison. Distance VA was similar in the multifocal and monofocal groups but people with multifocal lenses achieved better near vision overall and were less dependent on spectacles. Adverse subjective visual phenomena, particularly haloes, were common and troublesome in people receiving multifocal IOLs.

There was some evidence that contrast sensitivity may be lower in people receiving multifocal IOLs. The differences were smaller than would be expected given the division of light between distance and near focus, which may result from visual processing. Whether the reduction in contrast sensitivity induced by the IOL would be clinically significant would depend on the contrast presented by the visual target and the contrast sensitivity of the person's retina. There were no significant differences between IOLs with respect to objective glare.

Participant satisfaction was not consistently reported between the two lens types. There was some evidence that participants with multifocal lenses experienced improved visual functioning for tasks requiring near vision compared to participants with monofocal lenses.

There was less evidence available for the comparison between multifocal lenses and monovision. The data available suggested similar distance and better near VA in the multifocal and monovision groups. Multifocal lenses were associated with less spectacle dependence but also an increased chance of experiencing glare and haloes compared with monovision.

Overall completeness and applicability of evidence

Ten of the 20 included studies involved participants with surgery on both eyes and two studies had a mixture of both unilateral and bilateral surgery. Unilateral studies allow measurement of uniocular outcomes such as VA but are of limited use when attempting to measure the effect of the multifocal IOLs on quality of life, especially where the fellow eye has good vision. Of the studies that involved unilateral surgery only, Steinert 1992 and Rossetti 1994 reported fellow eye vision as good, Percival 1993 described the fellow eyes as cataractous and Jusufovic 2011 and Zhao 2010 commented that participants had no prior ocular surgery suggesting a phakic status in the other eye. The other studies involving unilateral surgery and the two studies that performed surgery on one or both eyes did not comment on the status of the fellow eye.

We presented results as a combined group of refractive and diffractive IOL studies. Combination of data was valid as both IOL types use the same principle of simultaneous vision once incident light has been split by either the refractive or diffractive optic. Holladay 1990 found very similar optical properties of all multifocal IOLs tested including the Array refractive IOLs and the 3M diffractive IOL used in some of the studies reviewed here (the Pharmacia diffractive IOL is of a similar design to the 3M IOL). We presented separated data, which are likely to become more useful as further studies are published.

Unaided near vision is critical to assessment of multifocal efficacy but was reported in a manner that made comparison between studies difficult. Only eight studies reported unaided near VA worse than J3/J4 or equivalent, and five studies reported mean LogMAR unaided near VA allowing pooled data analysis. Furthermore, only seven studies reported both unaided and corrected near acuity and Palmer 2008 reported corrected near acuity together with unaided near acuity but wearing a distance correction. Reading distances differed in the individual studies and it was unclear in most studies whether the reported print size read had been corrected for reading distance to allow a near acuity to be calculated. A further problem arose because Jaeger cards are not standardised between manufacturers so that J3 from one study cannot be assumed to equal J3 from another (Bailey 1978). Despite these caveats, it is likely that unaided near vision is improved by a multifocal IOL. It is important to remember, however, that monofocal IOL near acuity can be restored using reading glasses.

This review has highlighted the need for a core set of outcome measures in trials comparing multifocal and monofocal lenses. Ideally these outcomes should be based on validated measures, particularly for the more subjective outcome measures.

The optical and visual effects of these IOLs are now well‐known, particularly near vision. The search for alternative strategies to achieve spectacle independence, such as monovision and accommodating IOLs, should continue.

Quality of the evidence

We graded the certainty of the evidence as low to moderate for those outcomes for which we could estimate an effect (summary of findings Table for the main comparison). In general, we downgraded results for risk of bias because it was difficult to mask participants and outcome assessors in these trials and difficult to assess reporting bias. There was substantial methodological and statistical heterogeneity for some outcomes, in particular for the measurement of corrected distance VA and both unaided and corrected near VA, as well as participant‐reported spectacle dependence. There was also some evidence of publication bias with respect to the outcome of spectacle dependence.

Agreements and disagreements with other studies or reviews

One meta‐analysis of outcomes of multifocal IOLs that included both randomised controlled trials and studies of other design found slightly better uncorrected distance VA in the monofocal groups but better uncorrected near VA and greater spectacle independence in the multifocal group, the latter being similar to the results from our analysis (Cochener 2011). They also reported better near VA using diffractive (rather than refractive) multifocal IOLs, which is similar to the outcomes we found albeit with small numbers used for analysis. de Vries and colleagues conducted a review including both randomised controlled trials and case series (de Vries 2013). This was a narrative review summarising the outcomes of included studies but did not draw any definitive conclusions regarding outcomes that could be compared with results presented in this systematic Cochrane Review.

Study flow diagram.
Figures and Tables -
Figure 1

Study flow diagram.

'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
Figures and Tables -
Figure 2

'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.
Figures and Tables -
Figure 3

'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.

Funnel plot of comparison: 1 Multifocal versus monofocal intraocular lenses, outcome: 1.10 Spectacle dependence (any).
Figures and Tables -
Figure 4

Funnel plot of comparison: 1 Multifocal versus monofocal intraocular lenses, outcome: 1.10 Spectacle dependence (any).

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 1 Unaided distance visual acuity (VA) worse than 6/6.
Figures and Tables -
Analysis 1.1

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 1 Unaided distance visual acuity (VA) worse than 6/6.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 2 Mean unaided distance VA.
Figures and Tables -
Analysis 1.2

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 2 Mean unaided distance VA.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 3 Corrected distance VA worse than 6/6.
Figures and Tables -
Analysis 1.3

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 3 Corrected distance VA worse than 6/6.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 4 Mean corrected distance VA.
Figures and Tables -
Analysis 1.4

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 4 Mean corrected distance VA.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 5 Mean intermediate VA.
Figures and Tables -
Analysis 1.5

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 5 Mean intermediate VA.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 6 Unaided near VA worse than J3/J4 or equivalent.
Figures and Tables -
Analysis 1.6

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 6 Unaided near VA worse than J3/J4 or equivalent.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 7 Mean unaided near VA.
Figures and Tables -
Analysis 1.7

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 7 Mean unaided near VA.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 8 Corrected near VA worse than J3/J4 or equivalent.
Figures and Tables -
Analysis 1.8

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 8 Corrected near VA worse than J3/J4 or equivalent.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 9 Mean corrected near VA.
Figures and Tables -
Analysis 1.9

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 9 Mean corrected near VA.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 10 Spectacle dependence (any).
Figures and Tables -
Analysis 1.10

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 10 Spectacle dependence (any).

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 11 Spectacle dependence (distance or near).
Figures and Tables -
Analysis 1.11

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 11 Spectacle dependence (distance or near).

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 12 Contrast sensitivity.
Figures and Tables -
Analysis 1.12

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 12 Contrast sensitivity.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 13 Participant‐reported outcomes: visual function questionnaires.
Figures and Tables -
Analysis 1.13

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 13 Participant‐reported outcomes: visual function questionnaires.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 14 Participant‐reported outcomes: vision‐related quality‐of‐life questionnaires.
Figures and Tables -
Analysis 1.14

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 14 Participant‐reported outcomes: vision‐related quality‐of‐life questionnaires.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 15 Participant‐reported outcomes: satisfaction scores.
Figures and Tables -
Analysis 1.15

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 15 Participant‐reported outcomes: satisfaction scores.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 16 Participant‐reported outcomes: "good" or "satisfied" with vision.
Figures and Tables -
Analysis 1.16

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 16 Participant‐reported outcomes: "good" or "satisfied" with vision.

Study

Follow‐up

Outcome

Metric

Multifocal

Bifocal

Monofocal

Leyland 2002

12 months

TyPE questionnaire response: overall visual satisfaction (0‐10)

Median (range)

8 (1‐10)

8 (1‐10)

8 (4‐10)

Figures and Tables -
Analysis 1.17

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 17 Participant‐reported outcomes: other data on satisfaction.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 18 Participant‐reported outcomes: cataract symptom scores.
Figures and Tables -
Analysis 1.18

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 18 Participant‐reported outcomes: cataract symptom scores.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 19 Participant‐reported outcomes: glare.
Figures and Tables -
Analysis 1.19

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 19 Participant‐reported outcomes: glare.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 20 Participant‐reported outcomes: haloes.
Figures and Tables -
Analysis 1.20

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 20 Participant‐reported outcomes: haloes.

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 21 Participant‐reported outcomes: dysphotopsia.
Figures and Tables -
Analysis 1.21

Comparison 1 Multifocal versus monofocal intraocular lenses, Outcome 21 Participant‐reported outcomes: dysphotopsia.

Comparison 2 Multifocal versus monovision, Outcome 1 Visual acuity (VA).
Figures and Tables -
Analysis 2.1

Comparison 2 Multifocal versus monovision, Outcome 1 Visual acuity (VA).

Comparison 2 Multifocal versus monovision, Outcome 2 Spectacle dependence.
Figures and Tables -
Analysis 2.2

Comparison 2 Multifocal versus monovision, Outcome 2 Spectacle dependence.

Comparison 2 Multifocal versus monovision, Outcome 3 Contrast sensitivity.
Figures and Tables -
Analysis 2.3

Comparison 2 Multifocal versus monovision, Outcome 3 Contrast sensitivity.

Comparison 2 Multifocal versus monovision, Outcome 4 Participant‐reported outcomes: visual function.
Figures and Tables -
Analysis 2.4

Comparison 2 Multifocal versus monovision, Outcome 4 Participant‐reported outcomes: visual function.

Comparison 2 Multifocal versus monovision, Outcome 5 Participant‐reported outcomes: glare.
Figures and Tables -
Analysis 2.5

Comparison 2 Multifocal versus monovision, Outcome 5 Participant‐reported outcomes: glare.

Comparison 2 Multifocal versus monovision, Outcome 6 Participant‐reported outcomes: glare mean score.
Figures and Tables -
Analysis 2.6

Comparison 2 Multifocal versus monovision, Outcome 6 Participant‐reported outcomes: glare mean score.

Comparison 2 Multifocal versus monovision, Outcome 7 Participant‐reported outcomes: shadows mean score.
Figures and Tables -
Analysis 2.7

Comparison 2 Multifocal versus monovision, Outcome 7 Participant‐reported outcomes: shadows mean score.

Summary of findings for the main comparison. Multifocal compared to monofocal intraocular lenses after cataract extraction

Multifocal compared to monofocal intraocular lenses after cataract extraction

Patient or population: people with cataract
Settings: eye hospital
Intervention: multifocal intraocular lens
Comparison: monofocal intraocular lens

Outcomes

Illustrative comparative risks* (95% CI)

Relative effect
(95% CI)

No of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Assumed risk

Corresponding risk

Monofocal intraocular lens

Multifocal intraocular lens

Unaided distance visual acuity worse than 6/6

Follow‐up: 6 weeks to 18 months

800 per 1000

768 per 1000
(712 to 824)

RR 0.96

(0.89 to 1.03)

682
(8 studies)

⊕⊕⊕⊝
Moderate1

Corrected distance visual acuity worse than 6/6

Follow‐up: 6 weeks to 18 months

See comment

⊕⊝⊝⊝
Very low1,2, 3

Substantial inconsistency I2 = 54%. Individual study RR ranged from 0.2 (95% CI 0.03 to 1.56) to 1.50 (0.63 to 3.59).

Unaided near visual acuity worse than J3/J4
Follow‐up: 6 weeks to 18 months

570 per 1000

114 per 1000

(40 to 330)

RR 0.20

(0.07 to 0.58)

782
(8 studies)

⊕⊕⊝⊝
Low1,3

Substantial inconsistency I2 = 93% but all individual study results in direction favouring multifocal IOLs. Individual study RR ranged from 0.02 (0.00 to 0.31) to 0.73 (0.54 to 0.97)

Spectacle dependence

Follow‐up: 6 weeks to 18 months

880 per 1000

554 per 1000 (484 to 642)

RR 0.63

(0.55 to 0.73)

1000
(10 studies)

⊕⊕⊝⊝
Low1,4

Substantial inconsistency I2 = 67% but all individual study results favoured multifocal IOLs. Individual study RR ranged from 0.35 (0.21 to 0.57) to 0.79 (0.61 to 1.03)

Participant‐reported outcomes: quality of life or visual function

See comment

435

(4 studies)

⊕⊝⊝⊝

Very low1,2, 3

On average most people in both groups achieved high scores on VF‐7/VF‐14 questionnaires but inconsistent comparative results between the 2 groups.

Participant‐reported outcomes: glare

Follow‐up: 6 weeks to 18 months

180 per 1000

254 per 1000
(185 to 347)

RR 1.41

(1.03 to 1.93)

544

(7 studies)

⊕⊕⊝⊝
Low1,2

Participant‐reported outcomes: haloes

Follow‐up: 6 weeks to 18 months

80 per 1000

286 per 1000 (159 to 517)

RR 3.58

(1.99 to 6.46)

662

(7 studies)

⊕⊕⊕⊝
Moderate1

*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: confidence interval; IOL: intraocular lens; RR: risk ratio.

GRADE Working Group grades of evidence
High certainty: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate certainty: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low certainty: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low certainty: We are very uncertain about the estimate.

1 Downgraded for risk of bias (‐1): masking of participants and outcome assessors difficult in these trials; reporting bias unclear.

2 Downgraded for imprecision (‐1): wide confidence intervals.

3 Downgraded for inconsistency (‐1): I2 > 50%.

4 Downgraded for publication bias (‐1): asymmetric funnel plot.

Figures and Tables -
Summary of findings for the main comparison. Multifocal compared to monofocal intraocular lenses after cataract extraction
Table 1. Risk of bias assessment

Domain

Low risk of bias

Unclear risk of bias

High risk of bias

Sequence generation

Computer‐generated list, random table, other method of generating random list.

Not reported how list was generated. Trial may be described as "randomised" but with no further details.

Alternate allocation, date of birth, records (these RCTs were excluded).

Allocation concealment

Central centre (web/telephone access), sealed opaque envelopes.

Not reported how allocation administered. Trial may be described as "randomised" but with no further details.

Investigator involved in treatment allocation or treatment allocation clearly not masked.

Masking of participants and personnel

Clearly stated that participants and personnel (apart from surgeon) not aware of which lens received.

Described as "double blind" with no information on who was masked.

No information on masking. As lenses were different, we assumed that in the absence of reporting on this participants and personnel were not masked.

Masking of outcome assessors

Clearly stated that outcome assessors were masked.

Described as "double blind" with no information on who was masked.

No information on masking. As lenses were different, we assumed that in absence of reporting on this outcome assessors were not masked.

Incomplete outcome data

Missing data < 20% (i.e. > 80% follow‐up) and equal follow‐up in both groups and no obvious reason why loss to follow‐up should be related to outcome.

Follow‐up not reported or missing data > 20% (i.e. follow‐up < 80%) but follow‐up equal in both groups.

Follow‐up different in each group or related to outcome (or both).

Selective outcome reporting

All outcomes in protocol or trials registry entry (or both) are reported.

No access to protocol or trials registry entry.

Outcomes in protocol or trials registry entry (or both) selectively reported.

Other sources of bias

No other source of bias.

Trial stopped early due to poor recruitment.

Baseline imbalance but not clear that it is important.

Trial stopped early because of outcome.

Important baseline imbalance that might have an effect on the results.

RCT: randomised controlled trial.

Figures and Tables -
Table 1. Risk of bias assessment
Table 2. Included studies

Study

Country

Multicentre?

Eyes operated

Number of people randomised

Number of people randomised (assuming same as number analysed when not reported)

Number of people included in the analysis

Number of eyes included in the analysis

For eye outcomes, reporting by eye or person?

Cillino 2008

Italy

No

Both

NR

62

62

124

Eye (no adjustment for within‐person correlation)

el Maghraby 1992

Saudi Arabia

No

1

77

77

61

61

Eye (unilateral surgery)

Haaskjold 1998a

Europe

Yes

1

NR

221

221

221

Eye (unilateral surgery)

Harman 2008

England

No

Both

60

60

43

86

Person

Javitt 2000

USA, Germany, Austria

Yes

Both

261

261

235

470

Person

Ji 2013

China

No

1 or both

NR

51

51

64

Eye (no adjustment for within‐person correlation)

Jusufovic 2011

Bosnia and Herzegovina

No

1

NR

100

100

100

Eye (unilateral surgery)

Kamlesh 2001

India

No

1

NR

40

40

40

Eye (unilateral surgery)

Labiris 2015

Greece

No

Both

75

75

75

150

Leyland 2002

England

No

Both

69

69

60

120

Person

Nijkamp 2004

Netherlands

No

Both

190

190

137

274

Unclear

Palmer 2008

Spain

No

Both

NR

114

114

228

Eye (no adjustment for within‐person correlation)

Peng 2012

China

No

Both

102

102

101

202

Eye (no adjustment for within‐person correlation)

Percival 1993

England

No

1

NR

50

50

50

Eye (unilateral surgery)

Rasp 2012

Austria

No

Both

NR

146

146

292

Eye (no adjustment for within‐person correlation)

Rossetti 1994

Italy

No

1

NR

80

80

80

Eye (unilateral surgery)

Sen 2004

Finland

No

1 or both

80

80

75

110

Eye (no adjustment for within‐person correlation)

Steinert 1992

USA

Yes

1

80

80

62

62

Eye (unilateral surgery)

Wilkins 2013

England

Yes

Both

211

211

187

374

Person

Zhao 2010

China

No

1

NR

161

161

161

Eye (unilateral surgery)

Total

2230

2061

3194

NR: not reported.

Figures and Tables -
Table 2. Included studies
Table 3. Age and sex of participants in included studies

Study

Mean age in years (range)

% female

Multifocal 1

Multifocal 2

Multifocal 3

Multifocal 4

Monofocal

Multifocal 1

Multifocal 2

Multifocal 3

Multifocal 4

Monofocal

Cillino 2008

57

65

60

68

56

47

63

47

el Maghraby 1992

57 (45 to 90)

56 (45 to 70)

59

Haaskjold 1998a

67 (max 88)

67 (max 90)

Harman 2008

73

71

50

60

Javitt 2000

74

75

51

61

Ji 2013

63 (52 to 71)

63 (55 to 75)

58

56

Jusufovic 2011

43 (20 to 57)

50 (26 to 64)

46

42

Kamlesh 2001

56

54

Labiris 2015

61

60

Leyland 2002

75

74

NA

76

53

60

44

Nijkamp 2004

72

72

67

64

Palmer 2008

73

72

74

75

61

69

67

53

Peng 2012

66

NA

NA

67

58

47

Percival 1993

77 (59 to 89)

78 (60 to 92)

58

58

Rasp 2012

76 (62 to 91)

74 (63 to 89)

79 (66 to 89)

75 (62 to 87)

76 (63 to 80)

Rossetti 1994

72 (55 to 84)

70 (50 to 90)

61

57

Sen 2004

69 (48 to 84)

72 (41 to 88)

74

63

Steinert 1992

72

71

55

78

Wilkins 2013

67

69

56

58

Zhao 2010

65 (34 to 80)

67 (51 to 92)

49

46

max: maximum; NA: not applicable.

Figures and Tables -
Table 3. Age and sex of participants in included studies
Table 4. Lenses used in included studies

Study 

Multifocal lens model (manufacturer) type

Monofocal lens name (manufacturer)

Cillino 2008

Array SA40N

(AMO)

refractive

AR40

(AMO)

ReZoom

(AMO)

refractive

Tecnis ZM900

(AMO)

diffractive

el Maghraby 1992

815LE

(3M Vision Care)

diffractive

15LE

(3M Vision Care)

Haaskjold 1998a

808X

(Pharmacia Ophthalmics)

diffractive bifocal

808D

(Pharmacia Ophthalmics)

Harman 2008

Array SA40N

(AMO)

refractive

Clariflex

(AMO)

Javitt 2000

Array SA40N

(AMO)

refractive

PhacoFlex II SI40NB

(AMO)

Ji 2013

AcrySof ReSTOR

(Alcon Laboratories)

diffractive

AcrySof Natural

(Alcon Laboratories)

Jusufovic 2011

ReZoom NXG1

(AMO)

refractive

AcrySof MA60BM

(Alcon Laboratories)

Kamlesh 2001

Progress 3

(Laboratoires Domilens)

refractive

Flex 65

(Laboratoires Domilens)

Labiris 2015

Isert PY60MV (Hoya Surgical Optics)

SN60WF (Alcon Laboratories)

Leyland 2002

Array SA40NB

(Allergan)

refractive

PhacoFlex I SI40N

(Allergan)

TrueVista 68STUV

(Storz)

refractive

Nijkamp 2004

Array SA40N

(AMO)

refractive

PhacoFlex II SI40NB

(AMO)

Palmer 2008

Tecnis ZM900

(AMO)

diffractive

Tecnis Z9000

(AMO)

ReZoom

(AMO)

refractive

TwinSet

(Acri.Tec, GmbH)

diffractive

Peng 2012

AcrySof ReSTOR SN6AD1

(Alcon Laboratories)

diffractive

AcrySof IQ SN60WF

(Alcon Laboratories)

Percival 1993

MPC25

(AMO)

refractive

PC25

(AMO)

Rasp 2012

AcrySof ReSTOR SN6AD3

(Alcon Laboratories)

diffractive

Acri.Smart 48S (also known as CT Spheris 209M)

(Carl Zeiss)

AT LISA 366D

(Carl Zeiss)

diffractive

ReZoom (AMO)

refractive

Tecnis ZMA00

(AMO)

diffractive

Rossetti 1994

3M lens "with both refractive and diffractive optics"

Model not reported

Sen 2004

Array SA40N

(AMO)

refractive

PhacoFlex II SI40NB

(AMO)

Steinert 1992

Array MPC‐25NB

(AMO)

refractive

PC‐25NB

(AMO)

Wilkins 2013

Tecnis ZM900

(AMO)

diffractive

Akreos AO

(Bausch & Lomb)

Zhao 2010

AcrySof ReSTOR SA60D3

(Alcon Laboratories)

diffractive

AcrySof  SA60AT

(Alcon Laboratories)

AMO: Advanced Medical Optics.

Figures and Tables -
Table 4. Lenses used in included studies
Table 5. Refractive aims in included studies

Study ID

Refractive aim

Cillino 2008

Emmetropia

el Maghraby 1992

Emmetropia

Haaskjold 1998a

Not stated

Harman 2008

Emmetropia

Javitt 2000

Not stated

Ji 2013

Not stated

Jusufovic 2011

Not stated

Kamlesh 2001

Not stated

Labiris 2015

Multifocal: +3.00 D of near addition; monofocal (monovision): targeting ‐0.50 D in the dominant eye and ‐1.25 D in the non‐dominant eye.

Leyland 2002

Emmetropia

Nijkamp 2004

Within 1 D of emmetropia

Palmer 2008

Between emmetropia and ‐0.5 D for monofocal emmetropia for multifocal.

Peng 2012

Emmetropia

Percival 1993

Emmetropia (treatment)/myopic astigmatism (control)

Rasp 2012

Not stated

Rossetti 1994

< 2 D astigmatism

Sen 2004

Not stated

Steinert 1992

Not stated

Wilkins 2013

Multifocal: emmetropia Monofocal (monovision): Emmetropia in distance eye; myopia ‐1.0 D to ‐1.5 D in the near eye.

Zhao 2010

Not stated

D: dioptre.

Figures and Tables -
Table 5. Refractive aims in included studies
Table 6. Subgroup analyses: refractive versus diffractive lenses

Outcome

Effect measure

Analysis model

Studies

Number of eyes

Effect estimate (95% CI)

I2

Test for interaction (P value)

Unaided distance VA worse than 6/6

RR

Random

8

682

0.96

(0.89,1.03)

13.62

0.22

Both refractive and diffractive optics

RR

Random

1

80

1.02

(0.89,1.17)

0.00

Refractive

RR

Random

5

392

0.91

(0.83,0.99)

0.00

Diffractive

RR

Random

2

210

1.06

(0.87,1.30)

26.32

Mean unaided distance VA (logMAR)

MD

Random

8

924

0.01

(‐0.02,0.05)

69.87

0.91

Refractive

MD

Random

5

414

0.01

(‐0.01,0.04)

0.00

Diffractive

MD

Random

3

510

0.02

(‐0.05,0.09)

89.72

Corrected distance VA worse than 6/6

RR

Random

8

692

1.02

(0.71,1.45)

53.97

0.24

Both refractive and diffractive optics

RR

Random

1

80

1.05

(0.65,1.68)

0.00

Refractive

RR

Random

5

332

0.84

(0.50,1.41)

46.89

Diffractive

RR

Random

2

280

1.44

(0.97,2.13)

0.00

Mean corrected distance VA (logMAR)

MD

Random

8

924

0.03

(0.02,0.05)

55.65

0.92

Refractive

MD

Random

5

414

0.04

(0.00,0.07)

68.47

Diffractive

MD

Random

3

510

0.03

(0.02,0.05)

31.97

Mean unaided intermediate VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ diffractive (1 trial)

Mean corrected intermediate VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ diffractive (1 trial)

Unaided near VA worse than J3/J4 or equivalent

RR

Random

8

782

0.20

(0.07,0.63)

93.38

0.88

Both refractive and diffractive optics

RR

Random

1

80

0.22

(0.09,0.52)

0.00

Refractive

RR

Random

4

442

0.21

(0.03,1.63)

95.35

Diffractive

RR

Random

3

260

0.16

(0.07,0.40)

62.77

Mean unaided near VA (logMAR)

MD

Random

6

881

‐0.20

(‐0.37,‐0.03)

98.28

0.13

Refractive

MD

Random

4

453

‐0.11

(‐0.19,‐0.03)

81.28

Diffractive

MD

Random

2

428

‐0.39

(‐0.74,‐0.03)

99.26

Corrected near VA worse than J3/J4 or equivalent

RR

Random

4

344

0.32

(0.08,1.27)

17.58

0.18

Both refractive and diffractive optics

RR

Random

1

80

0.55

(0.05,5.85)

0.00

Refractive

RR

Random

1

59

2.90

(0.12,68.50)

0.00

Diffractive

RR

Random

2

205

0.12

(0.02,0.61)

0.00

Mean corrected near VA (logMAR)

MD

Random

8

1079

‐0.05

(‐0.15,0.05)

98.11

0.29

Refractive

MD

Random

5

569

0.02

(‐0.02,0.06)

83.89

Diffractive

MD

Random

3

510

‐0.17

(‐0.52,0.18)

99.40

Contrast sensitivity

MD

Random

4

288

‐0.07

(‐0.15,0.00)

0.00

0.60

Both refractive and diffractive optics

MD

Random

1

80

‐0.03

(‐0.23,0.17)

0.00

Refractive

MD

Random

3

208

‐0.09

(‐0.20,0.02)

2.89

Diffractive

MD

Random

1

0

Participant‐reported outcomes: visual function questionnaires

MD

Random

5

495

4.43

(‐0.79,9.66)

90.66

0.02

Refractive

MD

Random

3

303

0.65

(‐4.60,5.89)

69.05

Diffractive

MD

Random

2

192

8.88

(4.81,12.95)

55.23

Participant‐reported outcomes: vision‐related quality‐of‐life questionnaires

No subgroup analysis because only 1 subgroup ‐ diffractive (1 trial)

Participant‐reported outcomes: satisfaction scores

SMD

Random

7

658

0.24

(‐0.20,0.68)

86.02

0.00

Refractive

SMD

Random

4

365

‐0.10

(‐0.32,0.11)

5.78

Diffractive

SMD

Random

3

293

0.83

(0.42,1.23)

57.33

Participant‐reported outcomes: "good" or "satisfied" with vision

RR

Random

4

388

0.99

(0.92,1.06)

0.00

0.64

Both refractive and diffractive optics

RR

Random

1

80

0.87

(0.67,1.14)

0.00

Refractive

RR

Random

2

159

1.00

(0.91,1.09)

0.00

Diffractive

RR

Random

1

149

0.99

(0.87,1.13)

0.00

Participant‐reported outcomes: cataract symptom scores

No subgroup analysis because only 1 subgroup ‐ refractive (2 trials)

Participant‐reported outcomes: glare

RR

Random

8

559

1.41

(1.03,1.93)

0.00

0.68

Both refractive and diffractive optics

RR

Random

1

80

0.97

(0.39,2.41)

0.00

Refractive

RR

Random

5

299

1.50

(1.05,2.14)

0.00

Diffractive

RR

Random

2

180

1.34

(0.50,3.62)

0.00

Participant‐reported outcomes: halos

RR

Random

8

677

3.58

(2.06,6.25)

19.65

1.00

Both refractive and diffractive optics

RR

Random

1

80

4.86

(2.05,11.56)

0.00

Refractive

RR

Random

4

256

4.65

(1.59,13.60)

0.00

Diffractive

RR

Random

3

341

4.53

(0.81,25.30)

54.02

Participant‐reported outcomes: dysphotopsia

RR

Random

2

138

1.13

(0.81,1.60)

0.00

0.54

Refractive

RR

Random

1

56

1.00

(0.59,1.70)

0.00

Diffractive

RR

Random

1

82

1.24

(0.79,1.94)

0.00

Spectacle dependence

RR

Random

11

1015

0.63

(0.54,0.73)

68.19

0.04

Both refractive and diffractive optics

RR

Random

1

80

0.57

(0.41,0.78)

0.00

Refractive

RR

Random

6

493

0.74

(0.67,0.80)

0.00

Diffractive

RR

Random

4

442

0.43

(0.26,0.71)

82.56

CI: confidence interval; MD: mean difference; RR: risk ratio; SMD: standardised mean difference; VA: visual acuity.

Figures and Tables -
Table 6. Subgroup analyses: refractive versus diffractive lenses
Table 7. Subgroup analyses: unilateral versus bilateral surgery

Outcome

Effect measure

Analysis model

Studies

Number of eyes

Effect estimate (95% CI)

I2

Test for interaction (P value)

Unaided distance VA worse than 6/6

RR

Random

8

682

0.96

(0.89,1.03)

13.62

0.75

Unilateral

RR

Random

6

502

0.98

(0.88,1.08)

33.14

Bilateral

RR

Random

1

60

0.85

(0.25,2.89)

0.00

Mixed unilateral/bilateral

RR

Random

1

120

0.92

(0.80,1.05)

100.00

Mean unaided distance VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ bilateral (6 trials)

Corrected distance VA worse than 6/6

RR

Random

8

692

1.02

(0.71,1.45)

53.97

0.00

Unilateral

RR

Random

6

512

1.24

(0.96,1.62)

0.00

Bilateral

RR

Random

1

60

0.73

(0.15,3.60)

0.00

Mixed unilateral/bilateral

RR

Random

1

120

0.61

(0.43,0.85)

0.00

Mean corrected distance VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ bilateral (6 trials)

Mean unaided intermediate VA (logMAR)

MD

Fixed

1

0

Mean corrected intermediate VA (logMAR)

MD

Fixed

1

0

Unaided near VA worse than J3/J4 or equivalent

RR

Random

8

782

0.20

(0.07,0.58)

92.77

0.89

Unilateral

RR

Random

5

426

0.20

(0.08,0.51)

73.56

Bilateral

RR

Random

2

292

0.27

(0.01,6.63)

97.36

Mixed unilateral/bilateral

RR

Random

1

64

0.15

(0.06,0.38)

0.00

Mean unaided near VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ bilateral (5 trials)

Corrected near VA worse than J3/J4 or equivalent

No subgroup analysis because only 1 subgroup ‐ unilateral (4 trials)

Mean corrected near VA (logMAR)

No subgroup analysis because only 1 subgroup ‐ bilateral (6 trials)

Contrast sensitivity

MD

Random

4

288

‐0.09

(‐0.26,0.08)

0.00

0.37

Unilateral

MD

Random

1

80

‐0.03

(‐0.23,0.17)

0.00

Bilateral

MD

Random

2

88

‐0.10

(‐0.47,0.27)

0.00

Mixed unilateral/bilateral

MD

Random

1

120

‐0.40

(‐0.87,0.07)

0.00

Participant‐reported outcomes: visual function questionnaires

MD

Random

4

480

3.09

(‐2.77,8.96)

92.18

0.00

Unilateral

MD

Random

1

161

7.50

(5.95,9.05)

0.00

Bilateral

MD

Random

2

199

3.54

(‐5.90,12.97)

88.24

Mixed unilateral/bilateral

MD

Random

1

120

‐3.60

(‐10.19,2.99)

0.00

Participant‐reported outcomes: vision‐related quality‐of‐life questionnaires

MD

Fixed

1

0

Participant‐reported outcomes: satisfaction scores

SMD

Random

6

643

0.26

(‐0.21,0.73)

87.75

0.91

Unilateral

SMD

Random

2

223

0.24

(‐0.92,1.40)

93.35

Bilateral

SMD

Random

3

300

0.31

(‐0.55,1.18)

91.45

Mixed unilateral/bilateral

SMD

Random

1

120

0.12

(‐0.24,0.48)

0.00

Participant‐reported outcomes: "good" or "satisfied" with vision

RR

Random

1

0

Unilateral

RR

Random

3

269

0.96

(0.85,1.07)

0.00

Mixed unilateral/bilateral

RR

Random

1

119

1.00

(0.92,1.10)

0.00

Participant‐reported outcomes: cataract symptom scores

MD

Fixed

2

257

1.01

(0.39,1.64)

0.00

0.57

Bilateral

MD

Fixed

1

137

0.90

(0.16,1.64)

0.00

Mixed unilateral/bilateral

MD

Fixed

1

120

1.30

(0.12,2.48)

0.00

Participant‐reported outcomes: glare

RR

Random

7

544

1.41

(1.03,1.93)

0.00

0.33

Unilateral

RR

Random

4

319

1.31

(0.77,2.21)

0.00

Bilateral

RR

Random

2

105

2.05

(1.12,3.75)

0.00

Mixed unilateral/bilateral

RR

Random

1

120

1.14

(0.67,1.92)

0.00

Participant‐reported outcomes: halos

RR

Random

7

662

3.58

(1.99,6.46)

24.75

0.69

Unilateral

RR

Random

5

480

3.50

(1.70,7.19)

36.86

Bilateral

RR

Random

1

62

12.33 (0.79,193.20)

0.00

Mixed unilateral/bilateral

RR

Random

1

120

3.79

(0.80,18.03)

0.00

Participant‐reported outcomes: dysphotopsia

RR

Random

1

114

1.18

(0.76,1.82)

0.00

1.00

Spectacle dependence

RR

Random

10

1000

0.63

(0.55,0.73)

66.86

0.81

Unilateral

RR

Random

5

499

0.62

(0.51,0.75)

58.74

Bilateral

RR

Random

5

501

0.64

(0.51,0.80)

73.16

CI: confidence interval; RR: risk ratio; VA: visual acuity.

Figures and Tables -
Table 7. Subgroup analyses: unilateral versus bilateral surgery
Table 8. Sensitivity analysis: excluding studies at high risk of bias

Outcome

Effect measure

All trials

Excluding studies at high risk of bias in ≥ 1 domain

Number of studies

Number of eyes

Effect estimate (95% CI)

I2

Number of studies

Number of eyes

Effect estimate (95% CI)

I2

Unaided distance VA worse than 6/6

RR

8

682

0.96

(0.89,1.03)

13.62

1

60

0.85

(0.25,2.89)

0.00

Mean unaided distance VA (logMAR)

MD

6

848

0.01

(‐0.03,0.05)

74.32

2

262

‐0.01

(‐0.10,0.08)

81.23

Corrected distance VA worse than 6/6

RR

8

692

1.02

(0.71,1.45)

53.97

1

60

0.73

(0.15,3.60)

0.00

Mean corrected distance VA (logMAR)

MD

6

848

0.03

(0.01,0.06)

63.79

2

262

0.02

(0.00,0.04)

0.00

Mean unaided intermediate VA (logMAR)

Only 1 study reported this outcome

Mean corrected intermediate VA (logMAR)

Only 1 study reported this outcome

Unaided near VA worse than J3/J4 or equivalent

RR

8

782

0.20

(0.07,0.58)

92.77

2

292

0.29

(0.01,8.39)

97.57

Mean unaided near VA (logMAR)

MD

5

829

‐0.22

(‐0.42,‐0.03)

98.41

3

494

‐0.26

(‐0.58,0.06)

98.94

Corrected near VA worse than J3/J4 or equivalent

All trials were high risk of bias in ≥ 1 domain

Mean corrected near VA (logMAR)

MD

6

1003

‐0.07

(‐0.20,0.06)

98.59

3

554

‐0.16

(‐0.50,0.18)

99.38

Contrast sensitivity

MD

4

288

‐0.09

(‐0.26,0.08)

0.00

1

45

‐0.07

(‐0.16,0.02)

0.00

Participant‐reported outcomes: visual function questionnaires

MD

4

480

3.09

(‐2.77,8.96)

92.18

2

223

7.58

(6.08,9.08)

0.00

Participant‐reported outcomes: vision‐related quality‐of‐life questionnaires

Only 1 study reported this outcome

Participant‐reported outcomes: satisfaction scores

SMD

6

643

0.26

(‐0.21,0.73)

87.75

3

324

0.64

(0.00,1.28)

84.77

Participant‐reported outcomes: "good" or "satisfied" with vision

All trials were high risk of bias in ≥ 1 domain

Participant‐reported outcomes: cataract symptom scores

All trials were high risk of bias in ≥ 1 domain

Participant‐reported outcomes: glare

RR

7

544

1.41

(1.03,1.93)

0.00

1

62

2.23

(0.30,16.72)

0.00

Participant‐reported outcomes: halos

RR

7

662

3.58

(1.99,6.46)

24.75

2

223

3.27

(0.64,16.67)

45.56

Participant‐reported outcomes: dysphotopsia

Only 1 study reported this outcome

Spectacle dependence (any)

RR

10

1000

0.63

(0.55,0.73)

66.86

5

619

0.55

(0.41,0.75)

83.77

CI: confidence interval; MD: mean difference; RR: risk ratio; SMD: standardised mean difference; VA: visual acuity.

Figures and Tables -
Table 8. Sensitivity analysis: excluding studies at high risk of bias
Comparison 1. Multifocal versus monofocal intraocular lenses

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Unaided distance visual acuity (VA) worse than 6/6 Show forest plot

8

682

Risk Ratio (M‐H, Random, 95% CI)

0.96 [0.89, 1.03]

2 Mean unaided distance VA Show forest plot

6

Mean Difference (IV, Random, 95% CI)

Totals not selected

3 Corrected distance VA worse than 6/6 Show forest plot

8

Risk Ratio (M‐H, Random, 95% CI)

Totals not selected

4 Mean corrected distance VA Show forest plot

6

Mean Difference (IV, Random, 95% CI)

Totals not selected

5 Mean intermediate VA Show forest plot

1

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

5.1 Unaided

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

5.2 Corrected

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

6 Unaided near VA worse than J3/J4 or equivalent Show forest plot

8

782

Risk Ratio (M‐H, Random, 95% CI)

0.20 [0.07, 0.58]

7 Mean unaided near VA Show forest plot

5

Mean Difference (IV, Random, 95% CI)

Totals not selected

8 Corrected near VA worse than J3/J4 or equivalent Show forest plot

4

344

Risk Ratio (M‐H, Random, 95% CI)

0.32 [0.08, 1.27]

9 Mean corrected near VA Show forest plot

6

Mean Difference (IV, Random, 95% CI)

Totals not selected

10 Spectacle dependence (any) Show forest plot

10

1000

Risk Ratio (M‐H, Random, 95% CI)

0.63 [0.55, 0.73]

11 Spectacle dependence (distance or near) Show forest plot

6

Risk Ratio (M‐H, Random, 95% CI)

Subtotals only

11.1 Distance

4

618

Risk Ratio (M‐H, Random, 95% CI)

0.71 [0.46, 1.09]

11.2 Near

6

772

Risk Ratio (M‐H, Random, 95% CI)

0.53 [0.40, 0.71]

12 Contrast sensitivity Show forest plot

4

288

Mean Difference (IV, Random, 95% CI)

‐0.09 [‐0.26, 0.08]

13 Participant‐reported outcomes: visual function questionnaires Show forest plot

4

Mean Difference (IV, Random, 95% CI)

Totals not selected

14 Participant‐reported outcomes: vision‐related quality‐of‐life questionnaires Show forest plot

1

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

15 Participant‐reported outcomes: satisfaction scores Show forest plot

6

Std. Mean Difference (IV, Random, 95% CI)

Totals not selected

16 Participant‐reported outcomes: "good" or "satisfied" with vision Show forest plot

4

Risk Ratio (M‐H, Random, 95% CI)

Subtotals only

16.1 Overall

4

344

Risk Ratio (M‐H, Random, 95% CI)

0.97 [0.86, 1.08]

16.2 Near vision

1

80

Risk Ratio (M‐H, Random, 95% CI)

1.42 [1.13, 1.78]

16.3 Distance vision

1

80

Risk Ratio (M‐H, Random, 95% CI)

0.89 [0.72, 1.10]

17 Participant‐reported outcomes: other data on satisfaction Show forest plot

Other data

No numeric data

18 Participant‐reported outcomes: cataract symptom scores Show forest plot

2

257

Mean Difference (IV, Fixed, 95% CI)

1.01 [0.39, 1.64]

19 Participant‐reported outcomes: glare Show forest plot

7

544

Risk Ratio (M‐H, Random, 95% CI)

1.41 [1.03, 1.93]

20 Participant‐reported outcomes: haloes Show forest plot

7

662

Risk Ratio (M‐H, Random, 95% CI)

3.58 [1.99, 6.46]

21 Participant‐reported outcomes: dysphotopsia Show forest plot

1

Risk Ratio (M‐H, Fixed, 95% CI)

Totals not selected

Figures and Tables -
Comparison 1. Multifocal versus monofocal intraocular lenses
Comparison 2. Multifocal versus monovision

Outcome or subgroup title

No. of studies

No. of participants

Statistical method

Effect size

1 Visual acuity (VA) Show forest plot

1

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

1.1 Mean unaided distance VA

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

1.2 Mean unaided intermediate VA

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

1.3 Mean unaided near VA

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

2 Spectacle dependence Show forest plot

2

Risk Ratio (IV, Fixed, 95% CI)

Subtotals only

2.1 Overall

2

262

Risk Ratio (IV, Fixed, 95% CI)

0.40 [0.30, 0.53]

2.2 Near vision

1

75

Risk Ratio (IV, Fixed, 95% CI)

0.40 [0.22, 0.70]

2.3 Distance vision

1

75

Risk Ratio (IV, Fixed, 95% CI)

1.54 [0.27, 8.70]

3 Contrast sensitivity Show forest plot

2

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

4 Participant‐reported outcomes: visual function Show forest plot

1

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

4.1 Overall VF‐14 score

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

4.2 Near vision VF‐14 score

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

4.3 Distance vision VF‐14 score

1

Mean Difference (IV, Fixed, 95% CI)

0.0 [0.0, 0.0]

5 Participant‐reported outcomes: glare Show forest plot

1

Risk Ratio (IV, Fixed, 95% CI)

Totals not selected

6 Participant‐reported outcomes: glare mean score Show forest plot

1

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

7 Participant‐reported outcomes: shadows mean score Show forest plot

1

Mean Difference (IV, Fixed, 95% CI)

Totals not selected

Figures and Tables -
Comparison 2. Multifocal versus monovision