Similarity of eyes in a cataractous population—How reliable is the biometry of the fellow eye for lens power calculation?

Langenbucher, Achim; Szentmáry, Nóra; Cayless, Alan; Röggla, Veronika; Leydolt, Christina; Wendelstein, Jascha; Hoffmann, Peter

doi:10.1371/journal.pone.0269709

Cited by 6 publications

(6 citation statements)

References 20 publications

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“…While it is known from clinical experience that the astigmatic axes of both eyes of an individual are quite often 'mirrored' we have not found a final statistical proof of this finding in the literature [25]. However, reversing the sign of the C45 vector component for left eyes means that in the multivariate linear regression models as shown in the Results section we have to use the prediction 'case sensitive' for left and right eyes [25]. Nevertheless, as the 2 nd intercept element and both off-diagonal elements in the (2x2) matrix (to be reversed for left eyes) are close to 0 the effect of not reversing the sign of the C45 components is in general expected to be low.…”

Section: Plos Onecontrasting

confidence: 66%

“…We should also keep in mind that after decomposition of the corneal power into power vector components we subsequently reversed the C45 vector component in sign for left eyes in order to consider all eyes as 'right eyes' [18]. While it is known from clinical experience that the astigmatic axes of both eyes of an individual are quite often 'mirrored' we have not found a final statistical proof of this finding in the literature [25]. However, reversing the sign of the C45 vector component for left eyes means that in the multivariate linear regression models as shown in the Results section we have to use the prediction 'case sensitive' for left and right eyes [25].…”

Section: Plos Onementioning

confidence: 96%

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Prediction of corneal power vectors after cataract surgery with toric lens implantation–A vector analysis

Langenbucher,

Szentmáry,

Cayless

et al. 2023

PLoS ONE

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Background Intraocular lenses are typically calculated based on a pseudophakic eye model, and for toric lenses (tIOL) a good estimate of corneal astigmatism after cataract surgery is required in addition to the equivalent corneal power. The purpose of this study was to investigate the differences between the preoperative IOLMaster (IOLM) and the preoperative and postoperative Casia2 (CASIA) tomographic measurements of corneal power in a cataractous population with tIOL implantation, and to predict total power (TP) from the IOLM and CASIA keratometric measurements. Methods The analysis was based on a dataset of 88 eyes of 88 patients from 1 clinical centre before and after tIOL implantation. All IOLM and CASIA keratometric and total corneal power measurements were converted to power vector components, and the differences between preoperative IOLM or CASIA and postoperative CASIA measurements were assessed. Feedforward neural network and multivariate linear regression prediction algorithms were implemented to predict the postoperative total corneal power (as a reference for tIOL calculation) from the preoperative IOLM and CASIA keratometric measurements. Results On average, the preoperative IOLM keratometric / total corneal power under- / overestimates the postoperative CASIA keratometric / real corneal power by 0.12 dpt / 0.21 dpt. The prediction of postoperative CASIA real power from preoperative IOLM or CASIA keratometry shows that postoperative total corneal power is systematically (0.18 dpt / 0.27 dpt) shifted towards astigmatism against the rule, which is not reflected by keratometry. The correlation of postoperative CASIA real power to the corresponding preoperative CASIA values is better than those as compared to the preoperative IOLM keratometry. However, there is a large variation from preoperative IOLM or CASIA keratometry to the postoperative CASIA real power of up to 1.1 dpt (95% confidence interval). Conclusion One of the challenges of tIOL calculation is the prediction of postoperative total corneal power from preoperative keratometry. Keratometric power restricted to a front surface measurement does not fully reflect the situation of corneal back surface astigmatism, which typically adds some extra against the rule astigmatism.

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Section: Plos Onecontrasting

confidence: 66%

Section: Plos Onementioning

confidence: 96%

Prediction of corneal power vectors after cataract surgery with toric lens implantation–A vector analysis

Langenbucher,

Szentmáry,

Cayless

et al. 2023

PLoS ONE

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“…The AL of the eye is the most crucial parameter in IOL calculation 10 . A 0.1 mm error in AL is equivalent to an error of about 0.27 D in the spectacle plane 11 .…”

Section: Discussionmentioning

confidence: 99%

Fellow Eye Data for IOL Calculation in Eyes Undergoing Combined Phacovitrectomy

Kohnen,

Kaiser,

Bucur

et al. 2024

Preprint

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Purpose To evaluate whether the intraocular lens (IOL) calculation of the fellow eye (FE) can be used in eyes undergoing combined phacovitrectomy.Methods In this retrospective, consecutive case series, we enrolled patients who underwent silicone oil (SO) removal combined with phacoemulsification and IOL implantation at the Department of Ophthalmology, Goethe University, Frankfurt, Germany. Preoperative examinations included biometry using the IOL Master 700 (Carl Zeiss Meditec AG, Jena, Germany). We used the IOL calculation of the FE (FE group) to calculate the prediction error compared with the IOL calculation using only the axial length of the FE (AL-FE group), as well as using the axial length (AL) of the operated eye (OE group) in addition to the measurable biometric parameters. For the IOL calculation, the Barrett Universal II formula was used. We compared the mean prediction error (MPE) as well as the mean (MAE) and median absolute prediction error (MedAE) with each other. In addition, the number of eyes with ± 0.50, ± 1.00, and ± 2.00 diopters (D) deviation from the target refraction was compared.Results In total, 79 eyes of 79 patients met our inclusion criteria. MedAE was lowest in the OE group (0.41 D), followed by FE group (1.00 D) and AL-FE group (1.02 D). Comparison between the AL-FE and FE groups showed no statistically significant difference (p = 0.712). Comparing eyes within ± 0.50 D of the target refraction, the OE group (50 eyes, 63.3%) performed best, followed by the AL-FE group (22 eyes, 27.8%) and the FE group (21 eyes, 26.6%).Conclusion Our results indicate no clinically relevant difference between using the IOL calculation of the fellow eye versus using only the axial length of the fellow eye in addition to the measurable parameters for the IOL calculation. A two-step procedure should always be strived for.

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“…29 Under the assumption that left and right eyes behave symmetrically, the power vector components in 45/135 degrees anterior and posterior surface power, keratometry, total keratometry/real power, refraction, and the tIOL were reversed in sign for all left eyes in our dataset to present the data in the same orientation as for right eyes. 30…”

Section: Data Preprocessingmentioning

confidence: 99%

Evaluation of statistical correction strategies for corneal back surface astigmatism with toric lenses: a vector analysis

Langenbucher,

Hoffmann,

Cayless

et al. 2024

J Cataract Refract Surg

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Purpose: To compare actual and formula predicted postoperative refractive astigmatism using measured posterior corneal power measurements and four different empiric posterior corneal astigmatism correction models. Setting: Tertiary Care Center. Design: Single-center retrospective consecutive case series. Methods: Using a dataset of 211 eyes before and after tIOL implantation (Hoya Vivinex), IOLMaster (IOLM) or Casia2 (CASIA) keratometric and front / back surface corneal power measurements were converted to power vector components C0 (0/90°) and C45 (45/135°). Differences between postoperative and Castrop formula predicted refraction at the corneal plane using the labelled parameters of the tIOL and the keratometric or front / back surface corneal powers were recorded as the effect of corneal back surface astigmatism (BSA). Results: Generally, the centroid of the difference shifted towards negative C0 values indicating that BSA adds some against the rule corneal astigmatism (ATR). From IOLM / CASIA keratometry, the average difference in C0 was 0.39 / 0.32 dpt. After correction with the Abulafia-Koch, Goggin, La Hood, and Castrop nomograms it was -0.18 / -0.24 dpt, 0.27 / 0.18 dpt, 0.13 / 0.08 dpt, and 0.17 / 0.10 dpt. Using corneal front / back surface data from IOLM / CASIA, the difference was 0.18 / 0.12 dpt. Conclusions: The Abulafia-Koch method over-corrected the ATR, while the Goggin, La Hood, and Castrop models slightly under-corrected ATR, and using measurements from the Casia2 tomographer seemed to produce slightly less prediction error than IOLMaster 700.

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Similarity of eyes in a cataractous population—How reliable is the biometry of the fellow eye for lens power calculation?

Cited by 6 publications

References 20 publications

Prediction of corneal power vectors after cataract surgery with toric lens implantation–A vector analysis

Prediction of corneal power vectors after cataract surgery with toric lens implantation–A vector analysis

Fellow Eye Data for IOL Calculation in Eyes Undergoing Combined Phacovitrectomy

Evaluation of statistical correction strategies for corneal back surface astigmatism with toric lenses: a vector analysis

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