Scleral Lens-Induced Corneal Edema after Penetrating Keratoplasty

SIGNIFICANCE: Modern highly oxygen-permeable nonfenestrated scleral lenses induce approximately 1 to 2% corneal edema after short periods of lens wear in healthy individuals. This study investigated the magnitude and regional variation in scleral lens-induced central corneal edema after penetrating keratoplasty. PURPOSE: The purpose of this study was to examine the magnitude and regional variation in corneal edema after a short period of scleral lens wear in post-penetrating keratoplasty eyes and a control group of eyes with healthy corneas. METHODS: Nine post-penetrating keratoplasty eyes (nine participants; mean age, 32 years) were fitted with highly oxygen-permeable nonfenestrated scleral lenses (Dk 100 x 10(-11) cm(3) O-2 (cm)/[(s) (cm(2)) (mmHg)]). Central corneal thickness was measured using Scheimpflug imaging before lens insertion and immediately after lens removal (mean wearing time, 6.2 hours). Corneal edema was quantified across the central 6 mm and compared with data obtained from a historical control group of healthy eyes using a similar experimental paradigm. RESULTS: Post-penetrating keratoplasty eyes exhibited significant corneal edema after lens wear (2.99% [95% confidence interval, 1.13 to 4.85%]) averaged across the central 6 mm (P = .006) and regional variations in edema (P < .001) (greater swelling toward the graft-host junction inferiorly). Compared with healthy eyes, postpenetrating keratoplasty eyes displayed a greater magnitude of corneal edema (by similar to 3x) and greater variability in the corneal response (by similar to 2.5x). CONCLUSIONS: Scleral lens-induced central corneal edema is greater in post-penetrating keratoplasty eyes and varies regionally compared with healthy corneas after short-term wear. Lens design and fitting factors contributing to hypoxic and mechanical corneal stress should be carefully considered for all post-penetrating keratoplasty scleral lens fits to minimize potential graft rejection or failure in the longer-term.