Interaction Between Glaucoma and Central Retinal Vein Occlusion in a Cohort Study

<b>Objectives</b>: To study the associations of central retinal vein occlusion (CRVO) with glaucoma and cataract before and after the onset of CRVO. <b>Methods</b>: This study included 439 fundus photographically verified CRVO cases and a 5:1 set of 2195 registry-based age- and sex-matched control subjects without a record of CRVO. The study assessed rates of cataract and glaucoma before and after CRVO based on diagnoses, procedures, and prescriptions and analyzed their association with CRVO. Odds ratio (OR) and incidence rate ratio (IRR) estimates for 10 years prior to a subject's first CRVO and incident comorbidity after CRVO were compared. <b>Results</b>: The median age at the time of presentation of 439 eligible patients with CRVO was 71 years (interquartile range 11 years). In the 10 years leading up to the incidence of CRVO, the ORs for glaucoma and cataract were 6.01 (95% confidence interval (CI95) 4.05 to 8.94) and 2.13 (CI95 1.45 to 3.12), respectively. During a mean follow-up of 5.7 years after CRVO, the incidence rate ratios for glaucoma and cataract were 16.7 (CI95 9.32-30.1) and 1.99 (CI95 1.39-2.84), respectively. <b>Conclusions</b>: Glaucoma and cataract occurred at elevated rates compared with the background population, both before and after the clinical presentation of CRVO. The results fit a disease model where retinal perfusion is compromised by chronic venous congestion, leading to glaucomatous retinal degeneration. Chronic venous congestion may subsequently convert to clinically manifest CRVO when retinal capillaries have been sufficiently weakened to produce hemorrhage, edema and vision loss.