Ocular Response Analyzer : étude de fiabilité et de corrélation sur des yeux normaux

doi:10.1016/S0181-5512(07)79273-2

Journal Français d'Ophtalmologie

Volume 30, Issue 10, December 2007, Pages 978-984

https://doi.org/10.1016/S0181-5512(07)79273-2 Get rights and content

Introduction

Étudier la fiabilité des paramètres de l’ORA (CH, CRF, IOPcc et IOPg) et leur corrélation aux données biométriques de l’Orbscan^® (Orbtek, Bausch et Lomb, Salt lake City, Utah, États-Unis).

Matériel et méthodes

L’Ocular Response Analyzer (ORA de Reichert, Depew, New York, États-Unis) donne la rigidité de la cornée (CH), son coefficient viscoélastique (CRF) ainsi qu’une pression intra-oculaire corrigé (IOPcc). Les paramètres de l’ORA ont été étudiés sur une population de 100 yeux normaux, puis corrélés aux données biométriques de la cornée mesurées à l’aide de l’Orbscan^®.

Résultats

Une bonne corrélation et une faible différence des mesures entre les yeux droit et gauche ont confirmé la fiabilité des mesures (r_S = 0,84, p < 0,001 et 8,52 %). La répartition des paramètres de l’ORA est considérée comme gaussienne, et avec une moyenne de 10,25 ± 1,6 mmHg (6,5 à 14,4) pour l’hystérésis et de 10,25 ± 1,85 mmHg (4,9 à 14,2) pour le coefficient de rigidité. De plus, ils sont très corrélés à la pachymétrie. La PIO corrigée n’est pas corrélée à la pachymétrie, mais n’est pas significativement différente de la PIO de Goldmann. Il existe une faible corrélation entre les facteurs biomécaniques (CH, CRF) et le diamètre cornéen et la puissance du cylindre.

Conclusion

Les valeurs normales et la répartition des facteurs biomécaniques sont équivalentes à ce qu’on retrouve dans la littérature et sont corrélées aux données biométriques de la cornée (pachymétrie, diamètre cornéen). La nouvelle mesure de PIO corrigée est indépendante de la pachymétrie, mais n’est pas significativement différente de la PIO tonométrique à air donc son intérêt reste à démontrer.

Introduction

To evaluate the accuracy of ocular response analyzer (ORA) parameters (corneal hysteresis (CH), corneal resistance factor (CRF), and ocular tension (IOPcc and IOPg)) and the correlation with corneal biometry measured with the Orbscan^® topographer.

Material and methods

The Ocular Response Analyzer is a new instrument that measures ocular rigidity/elasticity (CH and CRF) and intraocular pressure (IOPcc), which is assumed to be independent of corneal pachymetry. We compared the results of the ORA in 100 eyes with normal slit lamp examination, except ametropia, with the results from corneal measurements obtained with the Orbscan^®.

Results

A high correlation and a low difference between the right and left eyes show the accuracy of measurements (r_S=0.84, p<0.001 and 8.52%). The mean CH and CRF were 10.25 ± 1.6 mmHg (range, 6.5-14.4) and 10.25 ± 1.85 mmHg (range, 4.9-14.2), respectively with a Gaussian distribution in normal eyes. The relationship between CH and CRF was significant with corneal pachymetry but not with IOPcc (corneal corrected). CH and CRF were related, although to a lesser extent, with corneal diameter and astigmatism power, but not to keratometry, sex, age, or spherical equivalent.

Conclusion

The mean and the distribution of biomechanical factors are similar to the values found in the literature but the relationship to pachymetry seems to be stronger (pachymetry and corneal diameter) than what has been reported in previous publications. The new IOP corrected for the cornea is independent of pachymetry but is not significantly different from Goldmann IOP or IOP measured with a standard noncontact tonometer.

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Cited by (33)

Dependence of corneal hysteresis on non-central corneal thickness in healthy subjects
2023, Journal Francais d'Ophtalmologie
To evaluate the dependence of corneal hysteresis (CH) on non-central corneal thickness.
Cross-sectional study of 1561 eyes of 1561 healthy volunteers with IOP less than 21 mmHg, open angles on gonioscopy and no prior eye surgeries or local or systemic diseases. Pentacam-Scheimpflug technology was employed to segment the cornea into 6 circular zones centered on the apex (zones 1–6) and to determine the mean corneal thickness of these areas. CH was measured with ORA. Univariate and multivariate linear regression models adjusted for age and sex were created to model the dependence of CH on corneal thickness in zones 1 to 6.
In the univariate linear regression models, we found that CH was dependent on mean corneal thickness of zone 1 (B = 0,004; R² = 0.95%; P < 0.001), zone 2 (B = 0,004; R² = 0.57%; P = 0.002), zone 4 (B = 0,005; R² = 1.50%; P < 0.001) and zone 6 (B = 0,003; R² = 0.92%; P < 0.001). Similar results were obtained in the multivariate model (R² = 3.46%; P < 0.001).
This study suggests a significant dependence of CH on non-central corneal thickness. The model of corneal thickness segmentation into circular zones centered on the corneal apex is able to explain 3.47% of the variation in CH measurements.
Évaluer la dépendance de l’hystérèse cornéene (CH) de l’épaisseur cornéenne non centrale.
Étude transversale sur 1561 yeux de 1561 volontaires sains avec une PIO inférieure à 21 mmHg, angle iridocornéen ouvert et sans antécédent de chirurgie oculaire ni de pathologie locale ou systémique. La technologie Pentacam-Scheimpflug a été utilisée afin de segmenter la cornée en 6 zones circulaires centrées sur l’apex (zone 1–6) et pour déterminer l’épaisseur cornéenne moyenne de ces zones. Le CH a été mesurée avec l’ORA. Des modèles de régression linéaire simple et multiple, ajustés en fonction du sexe et de l’âge, ont été utilisés pour modéliser la relation entre le CH et les épaisseurs des zones 1 à 6.
Dans les modèles de régression linéaire simple, nous avons constaté que le CH dépendait de l’épaisseur cornéenne moyenne dans la zone 1 (B = 0,004 ; R² = 0,95 % ; p < 0,001), zone 2 (B = 0,004; R² = 0,57 % ; p = 0,002), zone 4 (B = 0,005 ; R² = 1,50 % ; p < 0,001) et zone 6 (B = 0,003 ; R² = 0,92 % ; p < 0,001). Des résultats similaires ont été obtenus dans le modèle de régression linéaire multiple (R² = 3,47 % ; p < 0,001).
Cette étude suggère une dépendance significative du CH de l’épaisseur cornéenne non centrale. Le modèle de segmentation de l’épaisseur cornéenne en zones circulaires centrées sur l’apex est capable d’expliquer les 3,47 % de la variation des mesures du CH.
Ex-vivo experimental validation of biomechanically-corrected intraocular pressure measurements on human eyes using the CorVis ST
2018, Experimental Eye Research
Citation Excerpt :
This operating principle of the GAT, makes the device susceptible to the natural variations in corneal stiffness, caused by variations in tissue thickness and biomechanics from average levels, and introduces inaccuracies in IOP measurements (Ehlers et al., 1975; Herndon et al., 1997). Based on these findings, several attempts were made to create IOP estimates that corrected for biomechanics including, most notably, the Dynamic Contour Tonometer (DCT, Swiss Microtechnology AG, Port, Switzerland) (Kanngiesser et al., 2005), the Ocular Response Analyzer (ORA Reichert Ophthalmic Instruments, Depew, NY) (Montard et al., 2007) with its Corneal Compensated IOP (IOPcc) estimates, and more recently the CorVis ST (Hong et al., 2013) (OCULUS Optikgeräte GmbH; Wetzlar, Germany) through its biomechanically-corrected IOP (bIOP) measurements (Joda et al., 2016; Vinciguerra et al., 2016). The effectiveness of these estimates has been assessed in clinical studies, primarily through evidence of reduced association between IOP measurements and the cornea's stiffness parameters, such as central corneal thickness (CCT) and age (Doyle and Lachkar, 2005; Kniestedt et al., 2005a).
The purpose of this study was to assess the validity of the Corvis ST (Oculus; Wetzlar, Germany) biomechanical correction algorithm (bIOP) in determining intraocular pressure (IOP) using experiments on ex-vivo human eyes. Five ex-vivo human ocular globes (age 69 ± 3 years) were obtained and tested within 3–5 days post mortem. Using a custom-built inflation rig, the internal pressure of the eyes was controlled mechanically and measured using the CorVis ST (CVS-IOP). The CVS-IOP measurements were then corrected to produce bIOP, which was developed for being less affected by variations in corneal biomechanical parameters, including tissue thickness and material properties. True IOP (IOPt) was defined as the pressure inside of the globe as monitored using a fixed pressure transducer. Statistical analyses were performed to assess the accuracy of both CVS-IOP and bIOP, and their correlation with corneal thickness. While no significant differences were found between bIOP and IOP_t (0.3 ± 1.6 mmHg, P = 0.989) using ANOVA and Bonferroni Post-Hoc test, the differences between CVS-IOP and IOPt were significant (7.5 ± 3.2 mmHg, P < 0.001). Similarly, bIOP exhibited no significant correlation with central corneal thickness (p = 0.756), whereas CVS-IOP was significantly correlated with the thickness (p < 0.001). The bIOP correction has been successful in providing close estimates of true IOP in ex-vivo tests conducted on human donor eye globes, and in reducing association with the cornea's thickness.
Assessment of anterior segment anatomy by OCT after non penetrating deep sclerectomy
2012, Journal Francais d'Ophtalmologie
Grâce aux progrès récents de l’imagerie, l’anatomie du segment antérieur peut être évaluée précisément et de manière non invasive. L’objectif de cette étude était d’évaluer les modifications postopératoires précoces induites par la sclérectomie profonde non perforante (SPNP) sur la profondeur de la chambre antérieure, l’angle iridocornéen et la pachymétrie.
Vingt yeux de 20 patients présentant un glaucome chronique à angle ouvert (GCAO) et opérés de SPNP ont été analysés dans cette étude. Tous les patients ont bénéficié d’un examen ophtalmologique incluant une analyse non invasive de l’architecture du segment antérieur. L’OCT-Visante^® a été utilisé pour évaluer l’ouverture de l’angle à l’éperon scléral (SSA), la distance d’ouverture de l’angle à 500 μm (AOD 500) et la surface de séparation iridotrabéculaire à 500 μm (TISA 500) dans les secteurs nasal et temporal. La profondeur de la chambre antérieure et la pachymétrie ont également été évaluées au centre de la cornée. Ces examens ont été réalisés à j –1, puis à j1, j7 et j30 après l’intervention chirurgicale.
En préopératoire, le SSA, l’AOD 500 et le TISA 500 étaient respectivement de 37,24 ± 12,67°, 0,42 ± 0,25 mm et 0,15 ± 0,1 mm² dans le secteur nasal, et de 39,62 ± 12,41°, 0,46 ± 0,25 mm et 0,16 ± 0,08 mm² dans le secteur temporal. La profondeur de la chambre antérieure était de 3,09 ± 0,54 mm, la pachymétrie centrale était de 530 ± 34,3 μm et la pression intraoculaire (PIO) était de 20,43 ± 7,25 mmHg. Après SPNP, hormis la PIO qui était significativement diminuée à j1 (5,57 ± 2,78 mmHg ; p < 0,0001), j7 (8,2 ± 3,12 mmHg ; p < 0,0001) et j30 (13,4 ± 3,47 mmHg ; p = 0,001), aucun des autres paramètres analysés n’était significativement modifié lors des différentes évaluations.
Aucune relation n’a été observée entre la PIO et l’architecture de la chambre antérieure après SPNP. La SPNP apparaît comme une technique permettant de diminuer significativement la PIO tout en conservant l’architecture de la chambre antérieure et en particulier l’ouverture de l’angle iridocornéen.
Thanks to recent progress in imaging techniques, the anatomy of the anterior segment can be measured accurately and noninvasively. The objective of this study was to assess early postoperative changes induced by non penetrating deep sclerectomy (NPDS) on anterior chamber depth, anterior chamber angle and central corneal thickness.
Twenty eyes of 20 patients with primary open-angle glaucoma (POAG) that underwent NPDS were studied. All patients underwent ophthalmologic examination including non invasive analysis of the anterior segment architecture. Visante^® OCT was used to determine anterior chamber depth, central corneal thickness, scleral spur angle (SSA), angle opening distance at 500 μm (AOD 500), and trabecular-iris space area at 500 μm (TISA 500) in the nasal and temporal quadrants. These evaluations were performed at 1 day preop, then day 1, day 7 and day 30 after surgery.
Preoperatively, SSA, AOD 500 and TISA 500 were 37.24 ± 12.67°, 0.42 ± 0.25 mm and 0.15 ± 0.1 mm², respectively, in the nasal quadrant, and 39.62 ± 12.41°, 0.46 ± 0.25 mm and 0.16 ± 0.08 mm², respectively, in the temporal quadrant. Mean anterior chamber depth, central corneal thickness and intraocular pressure (IOP) were 3.09 ± 0.54 mm, 530 ± 34.3 μm and 20.43 ± 7.25 mmHg respectively. After NPDS, aside from IOP being significantly decreased on day 1 (5.57 ± 2.78 mmHg, P < 0.0001), day 7 (8.2 ± 3.12 mmHg, P < 0.0001) and day 30 (13.4 ± 3.47 mmHg, P = 0.001), none of the other study parameters was significantly modified.
No relationship was found between IOP and anterior chamber architecture after NPDS. NPDS appears to significantly reduce IOP while maintaining the architecture of the anterior chamber, and in particular, the anterior chamber angle.
Comparison of Keeler Pulsair EasyEye tonometer and Ocular Response Analyzer for measuring intraocular pressure in healthy eyes
2012, Journal of Optometry
Citation Excerpt :
In our study, like Luce,10 we have observed that CH had low correlation with IOPg and IOPk and moderate with IOPcc. Our values of CRF and CCT are similar to those found in previous studies.15–17,24–27,34–37 Correlation between CRF and CH is strong like the results previously founded by Shah et al.,16,17 Montard et al.,27 or other authors.10,26,32
To evaluate the relationship between intraocular pressure (IOP) measurements obtained with Pulsair EasyEye (PEE) and Ocular Response Analyser (ORA) in healthy patients.
Sixty-five eyes from 65 patients underwent a full optometric examination, including central corneal thickness (CCT), and IOP measured with PEE and ORA. Differences between IOP measurements between both tonometers were analyzed. Pearson correlation coefficients between IOP values and ORA corneal biomechanics parameters were also obtained.
Statistically significant differences were found between IOP of PEE (IOPk) and Goldmann-corrected IOP of ORA (IOPg; p = 0.001). IOPk and corneal resistance-corrected IOP of ORA (IOPcc) were also found to differ significantly (p = 0.025). Mean differences between IOPg-IOPk, IOPcc-IOPk and IOPg-IOPcc were 0.71 ± 1.66, 0.70 ± 2.46 and 0.01 ± 1.54 mmHg (mean ± standard deviation), respectively.
Pearson correlation coefficients indicated that IOPk, IOPg, and IOPcc were significantly correlated among them (p < 0.001): r = 0.816 for IOPk-IOPg, r = 0.826 for IOPcc-IOPg and r = 0.587 IOPcc-IOPk. IOPk and IOPg were linearly associated with corneal resistance factor (CRF; r = 0.626 and r = 0.619, respectively) and with CCT (r = 0.531 and r = 0.579, respectively). IOPcc had a linear relationship with corneal hysteresis (CH) (r = −0.482) and similar results were found between CRF and CH (r = 0.841), CRF and CCT (r = 0.681) or between CH and CCT (r = 0.466).
Differences between mean values of IOP measured with PEE and ORA are statistically significant, with ORA tonometer taking higher IOP values than PEE in most of the cases. IOPk, IOPcc and IOPg have, al least, moderate positive linear correlations and ORA biomechanics parameters CRF, CH and CCT have a linear positive relation between them.
Evaluar la relación entre las mediciones de la presión intraocular (PIO) obtenidas mediante Pulsair EasyEye (PEE) y el Analizador de Respuesta Ocular (ORA) en pacientes sanos.
Sesenta y cinco ojos pertenecientes a 65 pacientes recibieron un examen optométrico completo, que incluía la medición del espesor corneal central (ECC) y la PIO, con PEE y ORA. Se analizaron las diferencias entre las mediciones de PIO realizadas con ambos tonómetros. También se calcularon los coeficientes de correlación de Pearson entre los valores de PIO y los parámetros biomecánicos corneales proporcionados por el ORA.
Se hallaron diferencias estadísticamente significativas entre la PIO medida con PEE (PIOk) y la PIO corregida de Goldman medida con ORA (PIOg; p = 0,001). La PIOk y la PIO corneal compensada medida con ORA (PIOcc) también fueron significativamente diferentes (p = 0,025). Las diferencias medias entre PIOg-PIOk, PIOcc-PIOk y PIOg-PIOcc fueron de 0,71 ± 1,66, 0,70 ± 2,46 y 0,01 ± 1,54 mmHg (desviación media ± estándar), respectivamente.
Los coeficientes de correlación de Pearson indicaron que los valores de PIOk, PIOg, PIOcc se hallaban significativamente correlacionados (p < 0,001): r = 0,816 para PIOk-PIOg, r = 0,826 para PIOcc-PIOg y r = 0,587 PIOcc-PIOk. Los valores de PIOk y PIOg se relacionaban linealmente con el factor de resistencia corneal (FRC; r = 0,626 y r = 0,619, respectivamente) y con el ECC (r = 0,531 y r = 0,579, respectivamente). La PIOcc también se relacionaba linealmente con la histéresis corneal (HC; r = −0,482), hallándose resultados similares entre la FRC y HC (r = 0,841), FRC y ECC (r = 0,681), o entre la HC y el ECC (r = 0,466).
Las diferencias entre los valores medios de la PIO, medidas con PEE y ORA son estadísticamente significativas, obteniendo el tonómetro ORA unos valores de PIO superiores a los obtenidos por PEE en la mayoría de los casos. Los valores de PIOk, PIOcc y PIOg presentan, como mínimo, unas correlaciones lineales positivas moderadas, y los parámetros biomecánicos medidos con ORA, como FRC, HC y ECC presentan una relación positiva lineal entre ellos.
Influence of corneal diameter on the accuracy of corneal tomography in patients with forme fruste keratoconus or thin corneas
2024, Clinical and Experimental Optometry
Introduction and Clinical Validation of an Updated Biomechanically Corrected Intraocular Pressure bIOP (v2)
2023, Current Eye Research

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Article originalOcular Response Analyzer : étude de fiabilité et de corrélation sur des yeux normauxOcular Response Analyzer: feasibility study and correlation with normal eyes

Introduction

Matériel et méthodes

Résultats

Conclusion

Introduction

Material and methods

Results

Conclusion

J Cataract Refract Surg

Am J Ophthalmol

Ophthalmology

Am J Ophthalmol

J Cataract Refract Surg

Cont Lens Anterior Eye

Anatomy of the human eye and adenexa

The specific architecture of the anterior stroma accounts for maintenance of corneal curvature

Br J Ophthalmol

Article original
Ocular Response Analyzer : étude de fiabilité et de corrélation sur des yeux normauxOcular Response Analyzer: feasibility study and correlation with normal eyes