Large-scale analysis of risk factors for developing retinal vein occlusion in the fellow eye

The main objective was to elucidate the associations for developing a fellow-eye retinal vein occlusion (RVO) after a patient experiences a first-time unilateral RVO event.

Large, multicenter, retrospective study using the global TriNetX database. We included patients newly diagnosed with unilateral RVO from 1 January 2015 to 1 January 2025. We estimated the incidence of fellow-eye RVO using Kaplan-Meier survival analysis, compared baseline demographic and medical characteristics between groups with and without progression to bilateral RVO and calculated hazard ratios with 95% confidence intervals for fellow-eye RVO based on various systemic and ocular comorbidities.

437 of 22,969 patients (1.90%) developed RVO in the fellow eye. Patients with fellow-eye RVO had higher rates of primary open-angle glaucoma (POAG; 22% vs. 17%, p = 0.006), dry age-related macular degeneration (AMD; 15% vs. 12%, p = 0.008) and anemia (39% vs. 31%, p = 0.0001). They also were more likely to self-identify as Black/African American (21% vs. 17%, p = 0.03) and less likely to be White (50% vs. 58%, p = 0.0008). No significant difference was identified between mean age, sex, or rates of traditional cardiovascular risk factors across these two groups. There was a 1.41- (95% CI 1.03-1.94), 1.46- (95% CI 1.02-2.10) and 1.84-fold (95% CI 1.38-2.47) increased hazard of developing bilateral sequential RVO with baseline POAG, dry AMD and anemia, respectively.

The presence of primary open-angle glaucoma, dry age-related macular degeneration and anemia is significantly associated with fellow-eye RVO and may help prognosticate the development of progressive disease in patients with unilateral RVO.