Effect of Customized Corneal Crosslinking on Patients With Pellucid Marginal Degeneration

To evaluate the effect of customized corneal crosslinking on pellucid marginal degeneration (PMD).

Twenty-eight eyes with PMD were included. Fifteen eyes were treated with customized corneal crosslinking at Helsinki University Eye Hospital. Three treatment zones with different ultraviolet energy levels were planned according to corneal tomography, focusing on the inferior part of the cornea. The control group consisted of 13 conventionally crosslinked eyes. Visual acuity, refraction, and corneal tomography were obtained preoperatively and at 1 month, 6 months, and 1 year after treatment.

Corneal tomography showed stability and visual acuity improvement after customized crosslinking in all but 1 patient with a 1-year follow-up. Mean change in logMAR visual acuity was -0.15 ( P = 0.02). However, the improvement in Kmax was not significant (-0.11D, P = 0.8). In the control group, the mean visual acuity did not change (-0.04, P = 0.44), although there were significant changes in keratometry (Kmax -0.81 D, P = 0.02 and Kavg -0.57 D, P = 0.007).

Customized corneal crosslinking can be safely used in patients with PMD. No clear advantages over standard crosslinking were observed in this study.