Association of glaucoma with risk of retinal vein occlusion: A meta-analysis

To summarize epidemiological evidences on the association between glaucoma and the risk of retinal vein occlusion (RVO). Relevant studies were identified by searching in PubMed, EMBASE and Cochrane until February 2018. Fifteen eligible observational studies were aggregated in this analysis. All results were analysed and pooled using random effects models with 95% confidence intervals (CI). In all studies, the odds ratio (OR) of glaucoma as a risk factor for RVO was 4.01 (95% CI: 3.28-4.91). In RVO subtype-differentiated subgroup analyses (six studies), the pooled OR showed that glaucoma was associated with central retinal vein occlusion (CRVO) (OR: 6.21; 95% CI: 4.64-8.31), branch retinal vein occlusion (BRVO) (OR: 2.38; 95% CI: 1.77-3.19) and hemiretinal vein occlusion (HRVO) (OR: 4.60; 95% CI: 2.26-9.35). In glaucoma-classified subgroup analyses (five studies), primary open-angle glaucoma (POAG) (OR: 5.03; 95% CI: 3.97-6.37) and chronic open-angle glaucoma (COAG) (OR: 2.36; 95% CI: 1.39-4.02) were significant risk factors for RVO development. There was a plausible relationship between primary angle closure glaucoma (PACG) and RVO risk (OR: 1.85; 95% CI: 0.41-8.35); to be precise, the OR was 5.3 in PACG and CRVO risk (95% CI: 1.04-26.95; p = 0.045), while the OR was 0.65 in PACG and BRVO risk (95% CI: 0.07-6.27; p = 0.707). To sum up, this meta-analysis shows that glaucoma is associated with the risk of RVO. Glaucoma should be kept in mind when investigating patients with RVO in the clinic.