# Epithelial Thickness Changes After Descemet Membrane Endothelial Keratoplasty (DMEK): An Observational Study

## TL;DR

This study finds that DMEK surgery restores central corneal thickness but increases the difference in thickness between the bottom and top of the cornea compared to healthy eyes.

## Contribution

The study provides new insights into epithelial thickness changes after DMEK surgery, focusing on inferior–superior differences and their independence from age.

## Key findings

- Post-DMEK eyes had significantly lower central corneal thickness than controls.
- The inferior–superior epithelial thickness difference was greater in post-DMEK eyes compared to controls.
- Age had no significant effect on epithelial thickness distribution after DMEK.

## Abstract

Aims: The aim of this study is to characterise corneal epithelial thickness profiles after Descemet membrane endothelial keratoplasty (DMEK) and compare it with healthy controls, focusing on inferior–superior (I–S) epithelial thickness differences and their relationship with age. Methods: This single-centre observational study included 36 post-DMEK eyes with at least 6 months’ follow-up and 36 healthy control eyes. High-resolution spectral-domain anterior segment OCT maps were analysed for central epithelial thickness (CET, defined as the mean epithelial thickness within the central 2 mm zone [E2.0]) and peripheral sectors to derive inferior (E–I) and superior (E–S) values (between 2 and 7 mm), with the I–S difference computed at a 3 mm radius; group comparisons used t-tests and correlations used Pearson’s r (α = 0.05). Central corneal thickness (CCT) was also compared between groups. Results: Post-DMEK eyes had significantly lower mean CCT than controls (525.7 ± 98.4 μm vs. 544.71 ± 27.8 μm, p = 0.04). Central epithelial thickness did not differ between groups (post-DMEK 53.7 ± 5.5 μm vs. controls 52.7 ± 3.3 μm, p = 0.62), but the I–S epithelial difference was greater after DMEK (5.9 ± 4.3 μm) than controls (3.0 ± 2.2 μm, p < 0.01), indicating a more pronounced inferior thickening pattern. Age showed no significant relationship with epithelial thickness in controls, and only very weak or non-significant correlations with central thickness and I–S difference in post-DMEK eyes, indicating no clinically meaningful age effect postoperatively. Conclusions: DMEK restores central epithelial thickness to values comparable to normal eyes, while accentuating the physiologic inferior–superior epithelial gradient, consistent with localised postoperative epithelial remodelling rather than global epithelial thickening or thinning. Corneal stromal remodelling may result in lower CCT post-DMEK versus controls, and age does not meaningfully influence epithelial distribution after surgery.