Assessment of corneal endothelial morphology in retinal vein occlusion

To evaluate corneal endothelial morphology in patients with retinal vein occlusion (RVO) and to investigate the differential impact of ischemic versus non-ischemic status on endothelial cell integrity, while controlling for therapeutic interventions.

This prospective observational study enrolled 42 patients (84 eyes) with unilateral RVO. All participants were receiving intravitreal anti-VEGF therapy as part of their standard clinical care for retinal vein occlusion-related macular edema. Based on fundus fluorescein angiography findings, participants were stratified into ischemic (n = 21) and non-ischemic (n = 21) subgroups. Detailed endothelial assessment-including endothelial cell density (ECD), average cell area, coefficient of variation (CV), and hexagonality-was performed using non-contact specular microscopy. The fellow unaffected eyes served as internal controls to calculate intra-individual differences (delta analysis), thereby minimizing the impact of inter-subject variability. The study also assessed the potential confounding roles of intravitreal anti-VEGF injections and retinal laser photocoagulation.

Direct intergroup comparison of absolute endothelial values showed no significant differences between ischemic and non-ischemic eyes (p > 0.05). However, intra-individual analysis revealed significant subclinical endothelial compromise specific to the ischemic phenotype. Ischemic RVO eyes demonstrated a significant reduction in ECD (p = 0.010), decreased analyzable cell count (p = 0.010), and increased average cell area (p = 0.002) compared to their healthy fellow eyes. Conversely, non-ischemic RVO eyes exhibited preserved endothelial structure comparable to fellow eyes, with no significant morphometric alterations. Importantly, the frequency of anti-VEGF injections did not differ significantly between the groups (p = 0.130), suggesting that the observed endothelial changes were ischemia-driven rather than treatment-induced.

Corneal endothelial alterations in RVO are predominantly ischemia driven, whereas non-ischemic eyes maintain structural integrity. This study highlights the importance of anterior segment monitoring in ischemic RVO and support the role of ischemic burden in subclinical endothelial compromise.