Corneal and Endothelial Parameters Following Scleral Lens Wear in Post-Keratoplasty Eyes

PURPOSE: To investigate the changes in corneal endothelial morphology and central corneal thickness following short-term scleral lens wear in eyes that had undergone penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK), and to examine the association between baseline endothelial characteristics and the magnitude of scleral lens-induced corneal oedema. METHODS: Twelve eyes were fitted with non-fenestrated scleral lenses (oxygen permeability [Dk] 100; centre thickness ≈ 250 µm). Endothelial cell density (ECD), coefficient of variation in cell size (CoV), percentage of hexagonal cells (% Hex) and central corneal thickness (CCT) were measured before and immediately after 8 h of scleral lens wear using specular microscopy. RESULTS: Following lens wear, ECD (2041 ± 557 vs 1827 ± 481 cells/mm²) and % Hex (44.4 ± 12.0% vs 38.2 ± 10.0%) decreased, while CoV (37.3 ± 10.3% vs 42.4 ± 9.4%) and CCT (485.3 ± 47.1 vs 520.4 ± 51.3 µm, 7.2 ± 3.1% oedema) increased (all p ≤ 0.001). These short‑term specular microscopy-derived changes in ECD and endothelial morphology may be an imaging artefact associated with transient corneal swelling rather than true endothelial cell loss. The magnitude of corneal oedema was not associated with any baseline corneal endothelial parameters (p > 0.20) but correlated with graft age (r = 0.80). Corneal oedema was greater in PK than DALK eyes (11.38% vs 5.23%, p = 0.003), and PK grafts were older on average (7 vs 5 years). CONCLUSIONS: Short-term scleral lens wear induced significant corneal swelling in post-keratoplasty eyes but was not associated with baseline endothelial parameters.