Vector analysis of corneal astigmatism in cataractous eyes based on IOLMaster 700 biometry.

<h4>Purpose</h4>The purpose of this study was to investigate the effect of the corneal back surface by comparing the keratometric astigmatism (K, derived from the corneal front surface) of a modern optical biometer against astigmatism of Total Keratometry (TK, derived from both corneal s...

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Main Authors: Achim Langenbucher, Jascha Wendelstein, Alan Cayless, Peter Hoffmann, Nóra Szentmáry
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2024-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0300576&type=printable
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author Achim Langenbucher
Jascha Wendelstein
Alan Cayless
Peter Hoffmann
Nóra Szentmáry
author_facet Achim Langenbucher
Jascha Wendelstein
Alan Cayless
Peter Hoffmann
Nóra Szentmáry
author_sort Achim Langenbucher
collection DOAJ
description <h4>Purpose</h4>The purpose of this study was to investigate the effect of the corneal back surface by comparing the keratometric astigmatism (K, derived from the corneal front surface) of a modern optical biometer against astigmatism of Total Keratometry (TK, derived from both corneal surfaces) in a large population with cataractous eyes. The results were then used to define linear prediction models to map K to TK.<h4>Methods</h4>From a large dataset containing bilateral biometric measurements (IOLMaster 700) in 9736 patients prior to cataract surgery, the total corneal astigmatism was decomposed into vectors for K, corneal back surface (BS), and TK. A multivariate prediction model (MV), simplified model with separation of vector components (SM) and a constant model (CM) were defined to map K to TK vector components.<h4>Results</h4>The K centroid (X/Y) showed some astigmatism with-the-rule (0.1981/-0.0211 dioptre (dpt)) whereas the TK centroid was located around zero (-0.0071/-0.0381 dpt against-the-rule) and the BS centroid showed systematic astigmatism against-the-rule (-0.2367/-0.0145 dpt). The respective TK-K centroid was located at -0.2052/-0.0302 dpt. The MV model showed the same performance (i.e. mean absolute residuum) as the SM did (0.1098 and 0.1099 dpt respectively) while the CM performed only slightly worse (0.1121 dpt mean absolute residuum).<h4>Conclusion</h4>In cases where tomographic data are unavailable statistical models could be used to consider the overall contribution of the back surface to the total corneal astigmatism. Since the performance of the CM is sufficiently close to that of MV and SM we recommend using the CM which can be directly considered e.g. as surgically induced astigmatism.
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spelling doaj.art-dc6295d4dece4f2ca87b9e9cdfab332e2024-04-23T05:31:33ZengPublic Library of Science (PLoS)PLoS ONE1932-62032024-01-01194e030057610.1371/journal.pone.0300576Vector analysis of corneal astigmatism in cataractous eyes based on IOLMaster 700 biometry.Achim LangenbucherJascha WendelsteinAlan CaylessPeter HoffmannNóra Szentmáry<h4>Purpose</h4>The purpose of this study was to investigate the effect of the corneal back surface by comparing the keratometric astigmatism (K, derived from the corneal front surface) of a modern optical biometer against astigmatism of Total Keratometry (TK, derived from both corneal surfaces) in a large population with cataractous eyes. The results were then used to define linear prediction models to map K to TK.<h4>Methods</h4>From a large dataset containing bilateral biometric measurements (IOLMaster 700) in 9736 patients prior to cataract surgery, the total corneal astigmatism was decomposed into vectors for K, corneal back surface (BS), and TK. A multivariate prediction model (MV), simplified model with separation of vector components (SM) and a constant model (CM) were defined to map K to TK vector components.<h4>Results</h4>The K centroid (X/Y) showed some astigmatism with-the-rule (0.1981/-0.0211 dioptre (dpt)) whereas the TK centroid was located around zero (-0.0071/-0.0381 dpt against-the-rule) and the BS centroid showed systematic astigmatism against-the-rule (-0.2367/-0.0145 dpt). The respective TK-K centroid was located at -0.2052/-0.0302 dpt. The MV model showed the same performance (i.e. mean absolute residuum) as the SM did (0.1098 and 0.1099 dpt respectively) while the CM performed only slightly worse (0.1121 dpt mean absolute residuum).<h4>Conclusion</h4>In cases where tomographic data are unavailable statistical models could be used to consider the overall contribution of the back surface to the total corneal astigmatism. Since the performance of the CM is sufficiently close to that of MV and SM we recommend using the CM which can be directly considered e.g. as surgically induced astigmatism.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0300576&type=printable
spellingShingle Achim Langenbucher
Jascha Wendelstein
Alan Cayless
Peter Hoffmann
Nóra Szentmáry
Vector analysis of corneal astigmatism in cataractous eyes based on IOLMaster 700 biometry.
PLoS ONE
title Vector analysis of corneal astigmatism in cataractous eyes based on IOLMaster 700 biometry.
title_full Vector analysis of corneal astigmatism in cataractous eyes based on IOLMaster 700 biometry.
title_fullStr Vector analysis of corneal astigmatism in cataractous eyes based on IOLMaster 700 biometry.
title_full_unstemmed Vector analysis of corneal astigmatism in cataractous eyes based on IOLMaster 700 biometry.
title_short Vector analysis of corneal astigmatism in cataractous eyes based on IOLMaster 700 biometry.
title_sort vector analysis of corneal astigmatism in cataractous eyes based on iolmaster 700 biometry
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0300576&type=printable
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