ESCRS - FP08.06 - Whole-Eye And Whole-Cornea Higher Order Aberrations Have No Role On The Discrepancy Between Refractive And Corneal Astigmatism Axis

Whole-Eye And Whole-Cornea Higher Order Aberrations Have No Role On The Discrepancy Between Refractive And Corneal Astigmatism Axis

Published 2024 - 42nd Congress of the ESCRS

Reference: FP08.06 | Type: Free paper | DOI: 10.82333/tt9w-kk63

Authors: Kepa Balparda* 1 , Mariana Escobar-Giraldo 2 , Luisa Trujillo-Cabrera 2 , Yeliana Valencia-Gómez 3 , Alejandra Nicholls-Molina 2 , Tatiana Herrera-Chalarca 4

1Private Practice,Medellín,Colombia;Brain and Waves,Medellín,Colombia, 2Universidad Pontificia Bolivariana,Medellín,Colombia, 3Pontificia Universidad Javeriana,Cali,Colombia, 4Mammoth Research,Medellín,Colombia;Brain and Waves,Medellín,Colombia;Universidad CES,Medellín,Colombia

Purpose

Accurate astigmatism correction is crucial in refractive surgery. Incorrect treatment of cylinder axis can yield suboptimal results. Unfortunately, refractive astigmatism axis often mismatches corneal cylinder axis, complicating laser vision correction decisions. The ongoing debate revolves around whether modifying the axis based on corneal parameters or relying on subjective data. The factors causing this mismatch remain unclear. Some propose Higher-Order Aberrations (HOAs), particularly coma, as contributors. This study aims to determine whether corneal or ocular HOAs correlate with astigmatism axis differences in healthy refractive surgery candidates, utilizing a multivariate linear regression model with two construction methods.

Setting

High-volume solo refractive surgery clinic in Medellín, Colombia

Methods

This retrospective study examines the impact of whole-corneal and whole-eye LOAs and HOAs on the discrepancy between manifest refractive astigmatism axis and whole-corneal cylinder axis in 360 eyes of refractive surgery candidates in Medellín, Colombia. Utilizing Pentacam® AXL Wave, the evaluation includes corneal measurements and whole-eye aberrometry. Data analysis employs two multiple linear regression models. Statistical analysis is conducted using JASP, adhering to ethical guidelines and obtaining approval from the Ethical Committee of the Clínica de Oftalmología Sandiego. No conflicts of interest exist, and the study complies with the Declaration of Helsinki and Colombian law.

Results

Analyzing 360 eyes, 46.6% left eyes, mean age 29.1 ± 5.8 years, female preponderance 63.9% (n = 230). Manifest sphere –3.09 ± 2.36 D, mean cylinder –1.45 ± 1.37 D, axis 120.0 ± 67.0 degrees. Mean axis difference refractive to keratometric astigmatism was 14.4 ± 14.5 degrees. Small (58.3%), medium (33.6%), large (8.1%) axis differences observed. One-way ANOVA showed higher discrepancy linked to lower refractive/corneal cylinder and general LOAs. No significant difference in corneal/whole-eye HOAs in higher discrepancy cases. Upon multivariate model building, no single higher order aberration (either corneal or ocular) significantly loaded into any model, therefore suggesting that HOAs have no role in the axis mismatch.

Conclusions

The discrepancy between the manifest refractive and corneal astigmatism axis is primarily attributed to lower-order aberrations, particularly corneal cylinder. There is no evidence to suggest that any higher-order aberration in the cornea or the eye contributes to even a small part of this discrepancy. Therefore, higher-order aberrations should not be taken into consideration when planning laser vision correction treatment for otherwise normal subjects