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

Objectives: To study the associations of central retinal vein occlusion (CRVO) with glaucoma and cataract before and after the onset of CRVO. Methods: This study of 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 examined rates of cataract and glaucoma before and after CRVO based on diagnoses, procedures, and prescriptions and compared odds ratio (OR) and incidence rate ratio (IRR) estimates for 10 years prior to a subject’s first CRVO and incident comorbidity after CRVO. Results: The median age at the time of presentation of 439 eligible patients with CRVO was 71 years (interquartile range 11 years). In 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. Conclusions: Glaucoma and cataract occurred at elevated rates compared to the background population both before and after the clinical presentation with CRVO. The results fit a model where glaucoma, cataract, and CRVO share a common underlying cause in the form of venous hypertension that converts to classic CRVO when capillary wall integrity has been sufficiently weakened by conditions such as diabetes, cardiovascular disease, and aging to begin leaking, thereby producing retinal haemorrhage and oedema.