# Higher‐Order Aberrations, Corneal Density, and Visual Acuity After Excimer Laser Phototherapeutic Keratectomy (PTK) for Epithelial Basement Membrane Dystrophy

## TL;DR

This study shows that excimer laser PTK improves vision in patients with epithelial basement membrane dystrophy by reducing corneal irregularities and haze.

## Contribution

The study provides new evidence on the long-term effectiveness of PTK in EBMD, including objective measures like higher-order aberrations and corneal density.

## Key findings

- PTK improved best corrected visual acuity by 0.17 logMAR in EBMD patients without visual limitations.
- Higher-order aberrations and corneal density significantly decreased after PTK treatment.
- A correlation was found between visual acuity and parameters like HOA, corneal density, and K max.

## Abstract

To evaluate visual acuity outcome after excimer laser phototherapeutic keratectomy (PTK) for epithelial basement membrane dystrophy (EBMD) and to provide new insights into higher‐order aberrations (HOAs) and corneal density changes.

In this single‐center cohort, 92 eyes from 80 individuals underwent PTK for EBMD, with follow‐up durations reaching up to 7.5 years (mean 332 ± 526.5 days).

Mean BCVA in EBMD improved by 0.17 ± 0.17 logMAR (p < 0.001) for patients without visual acuity limitations and by 0.14 ± 0.31 (p = 0.004) logMAR if patients had additional visual acuity limitations. Refraction remained stable after PTK. HOA reduced by 0.16 ± 0.23 μm (p < 0.001), corneal density by 6.73 ± 11.83 gray scale units (p < 0.001), and K
max by 1.02 dpt (±2.73) (p = 0.006) after PTK. A correlation before and after PTK between HOA (p = 0.014 and 0.002), corneal density (p < 0.002), and K
max (p = 0.010) with BCVA was observed. Light haze occurred in 10% of the cases. Re‐PTK was necessary for 1 patient (1.1%).

PTK significantly enhances visual acuity in patients with EBMD, independently of additional visual acuity limitations. The significant reduction of HOA, corneal density, and K
max as well as the correlation of these parameters with visual acuity prove an effective therapy on an objective level.