Sustainability of Pain Relief After Corneal Collagen Cross-Linking in Eyes With Bullous Keratopathy.

PURPOSE: This study aimed to examine the efficiency and sustainability of pain relief produced by corneal collagen cross-linking (CXL) in eyes with bullous keratopathy (BK) and to explore the histopathological changes in the stroma by using in vivo confocal microscopy.

DESIGN: Prospective observational case series.

METHODS: Fourteen eyes of 14 consecutive BK patients were treated with CXL with dehydration of the corneal stroma and followed up for 1 year after treatment. The best-corrected visual acuity (BCVA), intraocular pressure, and central corneal thickness (CCT) were examined before the treatments and up to 1 year after. The intensity and frequency of pain were graded on a scale from 0 (minimum) to 10 (maximum). At 1 year after CXL, the corneal stroma was observed using confocal microscopy at depths of 100 and 200 μm.

RESULTS: The BCVA and CCT did not change significantly. The mean pain intensity and frequency scores were 5.6 and 4.6, respectively, before treatment. The intensity score significantly decreased at 1 week and onward, and the frequency score significantly decreased over 6 months after treatment. The confocal microscopy images showed that keratocytes and nerve fibers were rare and sparsely distributed in the stroma 1 year after CXL.

CONCLUSIONS: The CXL efficiently relieved pain due to BK for 1 year after treatment. The in vivo confocal microscopy observations and unchanged CCT demonstrated that the persistence of pain relief was due to the inadequate regeneration of nerve fibers in the corneal stroma.