Corneal Nerve Fiber and Sensitivity Loss After Repeated Intravitreal Anti-VEGF Injections: An In Vivo Confocal Microscopy Study

Purpose: The purpose of this study was to investigate corneal sensation, subbasal nerve plexus (SBNP), and ocular surface symptoms in patients who underwent multiple intravitreal antivascular endothelial growth factor (anti-VEGF) injections for age-related macular degeneration (AMD) and diabetic macular edema (DME). Methods: Forty patients with previous anti-VEGF intravitreal injections (20 AMD and 20 DME) and 30 healthy controls were included in this study. In vivo corneal confocal microscopy (IVCM) of the SBNP, corneal sensitivity measurement with a Cochet-Bonnet esthesiometer, noninvasive tear break-up times, and ocular surface disease score index (OSDI) calculation were performed for each participant. Corneal nerve fiber density, corneal nerve branch density, total length of all nerve fibers, corneal total branch density, corneal nerve fiber area, corneal nerve fiber width, and corneal nerve fiber fractal dimension parameters were obtained by automatic digital analysis. Results: Corneal nerve fiber density, corneal nerve branch density, total length of all nerve fibers, and corneal nerve fiber fractal dimension in IVCM imaging and corneal sensitivity were significantly decreased in both AMD and DME groups compared with the control group. Corneal nerve fiber width and OSDI scores were significantly increased in AMD and DME groups compared with the control group. None of the IVCM parameters were significantly different between AMD and DME groups. Corneal sensitivity was decreased in patients with DME compared with patients with AMD. Tear break-up time was not different among the groups. Conclusions: Corneal SBNP parameters were affected, corneal sensitivity was decreased, and OSDI scores were increased in patients with multiple intravitreal anti-VEGF injections. IVCM parameters were not significantly different between AMD and DME groups.

Automated summary

This study investigated the corneal sensation, subbasal nerve plexus (SBNP), and ocular surface symptoms in patients who received multiple intravitreal anti-VEGF injections for AMD and DME. The results showed that the corneal nerve fiber density and corneal sensitivity were significantly decreased, while the OSDI scores were increased in these patients.