Hartman, Holly

ABSTRACT Purpose Substantial endothelial cell loss (∼80%) occurs after keratoplasty. Corneal rigid and scleral lenses are frequently prescribed to manage irregular astigmatism and high refractive error, but lens wear may contribute to hypoxic stress. The relationship between various lens wear and corneal stress after penetrating keratoplasty remains unclear. This study characterizes cell density distribution in post‐keratoplasty corneas and evaluates its influence on swelling during lens wear. Methods Participants ≥5 years post‐surgery, with or without habitual lens wear, were enrolled. Specular microscopy measured endothelial cell density in central, superior, inferior, superotemporal, and superonasal corneal quadrants (@3 mm). Baseline corneal thickness maps (>2 h after waking without lens wear) were acquired using Scheimpflug imaging (Pentacam). Wearers applied habitual lenses and all participants returned 6–8 h later for imaging. Nonparametric tests assessed cell density variation by quadrant and lens designs. Linear mixed models evaluated associations between endothelial parameters and corneal swelling while accounting for within‐subject correlation, repeated measures, lens type, location, and interactions. Results Twenty‐five participants (31 eyes) from three centers were included; 90% had keratoconus preoperatively. Four wore large‐diameter scleral lenses (13%), nine wore small‐diameter scleral lenses (29%), 12 wore corneal rigid lenses (39%), and six did not wear lenses (19%). Cell density across quadrants averaged 780 ± 240 cells/mm 2 . Central thickness decreased slightly in non‐lens‐wearing eyes (−0.3%) but increased in lens‐wearing eyes (1.9% ± 3.1%). Central cell density showed a weak negative correlation with swelling ( r = −0.39, p = 0.03). Compared with non‐lens wearers, corneal rigid ( p = 0.02) and large diameter scleral lenses ( p = 0.05) generated greater swelling; smaller diameter scleral lenses did not. Conclusions Although all eyes fitted with various lens designs were clear, lower central cell density correlated with increased swelling during lens wear, except when smaller diameter scleral lenses were worn. Clinically, however, cell density does not seem to be a robust predictor of corneal swelling induced by lens wear post‐keratoplasty.