Elsevier

Ophthalmology

Volume 106, Issue 9, 1 September 1999, Pages 1684-1691
Ophthalmology

Comparing predictability between eyes after bilateral laser in situ keratomileusis: A theoretical analysis of simultaneous versus sequential procedures

https://doi.org/10.1016/S0161-6420(99)90390-1Get rights and content

Abstract

Objective

To compare the predictability of laser in situ keratomileusis (LASIK) between eyes of individuals to determine whether the refractive result of the first eye is useful in improving fellow eye outcomes.

Design

Single-center case series.

Participants

One surgeon and 196 eyes of 98 patients.

Intervention

All patients received sequential bilateral LASIK. The mean time between procedures was 11.6 days. Attempted corrections ranged from 2.30 to 12.00 diopters (D).

Main outcome measures

Predictability (achieved minus attempted correction), postoperative manifest refraction, and theoretical postoperative manifest refraction, using a proposed attempted correction on the second eye based on first eye results, were analyzed.

Results

At 1 week, 1 month, and 3 months, predictability of the first operated eye was correlated with predictability of the fellow eye (1 week: mean 1st = 0.33 D, mean 2nd = 0.33 D, Pearson coefficient = 0.46, P < 0.0005; 1 month: mean 1st = 0.028 D, mean 2nd = −0.020 D, Pearson coefficient = 0.43, P < 0.0005; 3 months: mean 1st = −0.22 D, mean 2nd = −0.12 D, Pearson coefficient = 0.52, P < 0.0005). At the 3-month follow-up of the second eye, comparing the actual distance from emmetropia with that calculated using a theoretical proposed attempted correction based on the first eye refraction, distance from emmetropia was closer in the theoretical correction group. This finding was stronger in patients with preoperative myopia less than 5.5 D (P = 0.03). For this group, 93% of patients in the proposed attempted correction group would fall within 1.0 D of emmetropia compared to 80% found in the actual outcomes.

Conclusions

The refractive predictability between the two eyes of an individual after LASIK is correlated. Theoretically, therefore, one may be able to achieve correction closer to emmetropia in the second eye by applying the refractive predictability results from the first operated eye. In this study, using a theoretical proposed attempted correction in the second eye based on the first eye outcome, we have shown that better outcomes in the second eye are possible, particularly in low myopes. Thus, it may be advantageous to perform bilateral LASIK sequentially rather than simultaneously, using predictability outcomes from the first operated eye in planning fellow eye treatment. Moreover, waiting approximately 1 week was found to be potentially as effective as waiting longer periods of time between treatments. Further studies are necessary to better assess the actual clinical significance of these findings.

Section snippets

Study design

Ninety-eight patients received sequential bilateral LASIK treatments with subsequent follow-up. The average time between the two eye treatments was 11.6 days. Attempted corrections ranged from 2.30 to 12.00 diopters (D). Patients were followed at 1 week, 1 month, and 3 months after surgery. LASIK procedures were performed by one surgeon (P.S.H.) in a single clinical center.

Patient selection

All patients entered in the study were 21 years of age or older. Patients were excluded if they had spectacle-corrected

Preoperative characteristics

A total of 196 eyes of 98 patients entered the study cohort. The mean age was 38 years (range, 21–58 years). Forty-seven patients (48%) were men and 51 patients (52%) were women. Preoperative manifest spherical equivalent refraction ranged from −2.25 to −16.88 D with a mean of −6.99 D and standard deviation (SD) of 3.13 D. There was no difference in the degree of myopia when comparing the preoperative manifest spherical equivalent refraction of the right and left eyes in each patient; the mean

Discussion

Recently, controversies concerning the timing of bilateral LASIK have evoked much debate. Many argue that the benefit/risk ratio favors same-day surgery. Simultaneous procedures are more convenient and avoid anisometropia between eye treatments. A recent study has also found that the risks of simultaneous surgery were not significantly different from sequential surgery.18 Others disagree, citing the potential for bilateral visual loss or simply bilateral patient dissatisfaction, increased

Acknowledgements

The authors thank Marian Rose Catherine Passannante, PhD, and Amiran M. Sheffet, PhD, of the Department of Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School, for their assistance in the statistical analysis.

References (24)

Cited by (17)

  • Correlation of visual and refractive outcomes between eyes after same-session bilateral laser in situ keratomileusis surgery

    2003, American Journal of Ophthalmology
    Citation Excerpt :

    Previous studies on patients undergoing PRK have suggested a correlation of outcomes between the two eyes.12 Chiang and Hersh11 studied correlation of outcomes between eyes undergoing sequential LASIK surgery (mean time between eyes, 11.6 days). The results of their study were very similar to those of the present study: A highly significant correlation was found in refractive outcomes between the two eyes.

  • Simultaneous bilateral LASIK [3] (multiple letters)

    2000, Journal of Cataract and Refractive Surgery
View all citing articles on Scopus

Supported in part by an unrestricted grant to the Department of Ophthalmology from Research to Prevent Blindness, Inc., New York, New York.

View full text