ESCRS - FP18.08 - Refractive Error Derived From The Corneal Epithelium And Its Relationship With The Epithelial Profile In Normal And Keratoconic Eyes

Refractive Error Derived From The Corneal Epithelium And Its Relationship With The Epithelial Profile In Normal And Keratoconic Eyes

Published 2026 - 44th Congress of the ESCRS

Reference: FP18.08 | Type: Free paper | DOI: 10.82333/rgy9-x921

Authors: Dr Maria A. Henriquez* 1 , Dr Paola Padilla-Torrico 1 , Mrs Ruby Morales 2 , Mr Rolando Rojas 1 , Mr Jose Chauca 3 , Dr Luis Izquierdo Jr 4

1Research Department,Oftalmosalud Instituted of Eye,Lima,Peru, 2ROCOL - Schwind Latin,Bogota,Colombia, 3Research Department,Oftalmosalud Instituted of Eye,Lima,Peru;Department of Statistics, Demography, Humanities and Social Sciences,Universidad Peruana Cayetano Heredia,Lima,Peru, 4Research Department,Oftalmosalud Instituted of Eye,Lima,Peru;San Fernando School of Medicine,Universidad Nacional Mayor de San Marcos,Lima,Peru

Purpose

To determine the magnitude of refractive error attributed to the corneal epithelium and its relationship with epithelial thickness (ET) in normal and keratoconus (KC) eyes.

Setting

Research Department at Oftalmosalud, Instituto de Ojos, Lima, Peru.

Methods

This prospective, consecutive case series included patients evaluated between January 2023 and January 2025. Spherical and cylindrical components were derived from epithelial refraction at 0 mm and 12.5 mm corneal diameters using anterior segment OCT (MS-39, CSO). Objective refraction (ObjRx), subjective refraction (SubRx), and ET profiles were evaluated and compared between normal and KC eyes

Results

In normal (n=32) and KC (n=61) eyes, the epithelial-derived spherical equivalent was 0.1±0.33 D and 0.55±0.59 D, respectively (p=0.02). The mean ET difference (Max-Min) was 10.3±5.15 μm in normal eyes and 17.6±6.27 μm in KC eyes (p<0.001). A positive correlation was observed between epithelial variability and the spherical component of epithelial refraction in KC eyes (r=0.34, p=0.007), but not in normal eyes (r=-0.02, p=0.90). A significantly higher epithelial-derived spherical component from the ObjRx and SubRx was observed in KC eyes (32% of SubRx, 24% of ObjRx) compared to normal eyes (20% of SubRx, 16% of ObjRx).

Conclusions

A higher refractive error from epithelial refraction is observed in KC eyes compared with normal eyes. There is an association between the magnitude of refractive error derived from the corneal epithelium and the epithelial thickness profile; this could have implications for surface-based refractive laser surgery.