Effect of Posterior Corneal Surgically Induced Astigmatism on Toric Intraocular Lens Power Calculations

Stephen Stewart,1– 3 Tun Kuan Yeo,3 Salissou Moutari,4 Richard N McNeely,1 Jonathan E Moore1 1Cathedral Eye Clinic, Belfast, UK; 2Centre for Public Health, Queen’s University Belfast, Belfast, UK; 3National Health Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore; 4School of Mathemat...

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Main Authors: Stewart S, Yeo TK, Moutari S, McNeely RN, Moore JE
Format: Article
Language:English
Published: Dove Medical Press 2025-01-01
Series:Clinical Ophthalmology
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Online Access:https://www.dovepress.com/effect-of-posterior-corneal-surgically-induced-astigmatism-on-toric-in-peer-reviewed-fulltext-article-OPTH
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author Stewart S
Yeo TK
Moutari S
McNeely RN
Moore JE
author_facet Stewart S
Yeo TK
Moutari S
McNeely RN
Moore JE
author_sort Stewart S
collection DOAJ
description Stephen Stewart,1– 3 Tun Kuan Yeo,3 Salissou Moutari,4 Richard N McNeely,1 Jonathan E Moore1 1Cathedral Eye Clinic, Belfast, UK; 2Centre for Public Health, Queen’s University Belfast, Belfast, UK; 3National Health Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore; 4School of Mathematics and Physics, Queen’s University Belfast, Belfast, UKCorrespondence: Stephen Stewart, Cathedral Eye Clinic, 89-91 Academy Street, Belfast, BT1 2LS, UK, Email stephen.stewart@doctors.org.ukBackground: To determine whether accounting for posterior corneal surgically induced astigmatism (SIA) would improve toric intraocular lens power calculation prediction error.Methods: A total of 189 eyes of 148 patients undergoing routine cataract surgery were included in the study. Standard and posterior keratometry were measured pre- and postoperatively. Centroid SIA with standard keratometry and posterior keratometry were calculated separately. Prediction errors for postoperative refractive astigmatism at 4 weeks postoperatively were compared for Barrett Toric with predicted posterior corneal astigmatism (PPCA); Barrett Toric with preoperative measured posterior corneal astigmatism (MPCA); Barrett Toric with postoperative MPCA, which accounts for posterior corneal SIA.Results: There was a significant increase in PCA magnitude postoperatively (p < 0.001), although a change of > 0.3D occurred in only 3% of eyes. There was a postoperative rotation in the steep meridian of > 10° in 32% of eyes. The Barrett Toric formula with PPCA yielded a significantly smaller refractive astigmatism prediction error compared to when a postoperative MPCA value was used (p < 0.01). Postoperative MPCA had a lower proportion of eyes within 0.50, 0.75 and 1.00D of predicted refractive astigmatism than PPCA or preoperative MPCA, although this was not statistically significant.Conclusion: This study demonstrated postoperative changes in posterior corneal astigmatism magnitude and the orientation of the steep meridian. However, accounting for posterior keratometric SIA in the Barrett Toric formula does not improve refractive astigmatism prediction accuracy.Keywords: cataract, posterior corneal astigmatism, Toric IOL power calculations
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spelling doaj-art-49e4f83deaf149bb8c6366cf04aaaf1c2025-01-07T16:42:39ZengDove Medical PressClinical Ophthalmology1177-54832025-01-01Volume 19354399009Effect of Posterior Corneal Surgically Induced Astigmatism on Toric Intraocular Lens Power CalculationsStewart SYeo TKMoutari SMcNeely RNMoore JEStephen Stewart,1– 3 Tun Kuan Yeo,3 Salissou Moutari,4 Richard N McNeely,1 Jonathan E Moore1 1Cathedral Eye Clinic, Belfast, UK; 2Centre for Public Health, Queen’s University Belfast, Belfast, UK; 3National Health Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore; 4School of Mathematics and Physics, Queen’s University Belfast, Belfast, UKCorrespondence: Stephen Stewart, Cathedral Eye Clinic, 89-91 Academy Street, Belfast, BT1 2LS, UK, Email stephen.stewart@doctors.org.ukBackground: To determine whether accounting for posterior corneal surgically induced astigmatism (SIA) would improve toric intraocular lens power calculation prediction error.Methods: A total of 189 eyes of 148 patients undergoing routine cataract surgery were included in the study. Standard and posterior keratometry were measured pre- and postoperatively. Centroid SIA with standard keratometry and posterior keratometry were calculated separately. Prediction errors for postoperative refractive astigmatism at 4 weeks postoperatively were compared for Barrett Toric with predicted posterior corneal astigmatism (PPCA); Barrett Toric with preoperative measured posterior corneal astigmatism (MPCA); Barrett Toric with postoperative MPCA, which accounts for posterior corneal SIA.Results: There was a significant increase in PCA magnitude postoperatively (p < 0.001), although a change of > 0.3D occurred in only 3% of eyes. There was a postoperative rotation in the steep meridian of > 10° in 32% of eyes. The Barrett Toric formula with PPCA yielded a significantly smaller refractive astigmatism prediction error compared to when a postoperative MPCA value was used (p < 0.01). Postoperative MPCA had a lower proportion of eyes within 0.50, 0.75 and 1.00D of predicted refractive astigmatism than PPCA or preoperative MPCA, although this was not statistically significant.Conclusion: This study demonstrated postoperative changes in posterior corneal astigmatism magnitude and the orientation of the steep meridian. However, accounting for posterior keratometric SIA in the Barrett Toric formula does not improve refractive astigmatism prediction accuracy.Keywords: cataract, posterior corneal astigmatism, Toric IOL power calculationshttps://www.dovepress.com/effect-of-posterior-corneal-surgically-induced-astigmatism-on-toric-in-peer-reviewed-fulltext-article-OPTHcataractposterior corneal astigmatismtoric iol power calculations
spellingShingle Stewart S
Yeo TK
Moutari S
McNeely RN
Moore JE
Effect of Posterior Corneal Surgically Induced Astigmatism on Toric Intraocular Lens Power Calculations
Clinical Ophthalmology
cataract
posterior corneal astigmatism
toric iol power calculations
title Effect of Posterior Corneal Surgically Induced Astigmatism on Toric Intraocular Lens Power Calculations
title_full Effect of Posterior Corneal Surgically Induced Astigmatism on Toric Intraocular Lens Power Calculations
title_fullStr Effect of Posterior Corneal Surgically Induced Astigmatism on Toric Intraocular Lens Power Calculations
title_full_unstemmed Effect of Posterior Corneal Surgically Induced Astigmatism on Toric Intraocular Lens Power Calculations
title_short Effect of Posterior Corneal Surgically Induced Astigmatism on Toric Intraocular Lens Power Calculations
title_sort effect of posterior corneal surgically induced astigmatism on toric intraocular lens power calculations
topic cataract
posterior corneal astigmatism
toric iol power calculations
url https://www.dovepress.com/effect-of-posterior-corneal-surgically-induced-astigmatism-on-toric-in-peer-reviewed-fulltext-article-OPTH
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