Evaluating short-term corneal endothelial alterations post-intravitreal Anti-VEGF injections in treatment naïve eyes.

Background and objective: The cornea is the outermost transparent layer of the eye. Various anatomical and physiological factors, such as a healthy functioning monolayer of corneal endothelial cells, play an essential role in maintaining corneal transparency. Conditions or events that cause endothelial loss beyond the threshold result in loss of corneal transparency. The present study aimed to evaluate the short-term effects of intravitreal anti-VEGF injections on the corneal endothelium using non-contact specular microscopy in patients undergoing anti-VEGF injections for various retinal diseases.

Materials and methods: This prospective cohort study included 47 eyes of 47 treatment-naïve patients who received intravitreal anti-VEGF injections for various retinal diseases. Using a non-contact specular microscope, pre-injection parameters, including ECD, cell count, CV, and hexagonality, were compared with those on post-injection days 1, 1st week, 1st month, and 3rd month. A statistically significant result was defined as a "p" value of less than 0.05 using the appropriate test of significance.

Results: Early morphological changes in endothelial cells were indicated by a significant increase in the mean value of the coefficient of variation of the area of endothelial cells in the first week (p < 0.001) and the first month (p < 0.027) of the post-injection period. However, at the follow-up examination 30 days later, no noticeable change in the patient's ECD, cell count, or hexagonal shape could be detected under the specular microscope.

Discussion: This prospective cohort study evaluated the effects of intravitreal anti-VEGF injections on corneal endothelial morphology in 47 treatment-naïve, non-diabetic patients with various retinal conditions. While endothelial cell count, density, and hexagonality remained stable, a transient increase in polymegathism was observed at both day 7- and one-month post-injection. No differences were found between phakic and pseudophakic eyes or between different anti-VEGF agents (Aflibercept vs. Ranibizumab).

Conclusion: Intravitreal anti-VEGF injections were found to induce morphological alterations in corneal endothelial cells during the first week and first month following injection, as evidenced by an increase in the coefficient of variation. However, these endothelial changes are subtle and do not typically translate into clinical concerns.