Branch retinal vein occlusion and optic nerve head topographic parameters: the Singapore Indian eye study

Aim To examine the association between branch retinal vein occlusion (BRVO) and quantitative optic disc topographic parameters. Methods The Singapore Indian Eye Study (SINDI) is a population-based study of 3400 Singapore Indians aged 40+years. BRVO was defined and graded from retinal photographs. Optic disc parameters were quantified using the Heidelberg Retinal Tomograph III (HRT III). Associations were evaluated for individual eyes; the generalised estimating equation was used to account for correlation between fellow eyes. Results 6173 eyes (comprising 19 BRVO) had gradable retinal photographs and HRT images. After controlling for age, gender, and systemic (hypertension, diabetes, myocardial infarction) and ocular factors (intraocular pressure, glaucoma, central corneal thickness, axial length, previous laser photocoagulation), BRVO was associated with larger optic disc area (OR highest vs lowest tertile, 4.70; 95% CI 1.00 to 22.01; p=0.036), larger cup area (OR highest vs lowest tertile, 4.80; 95% CI 1.03 to 22.35; p=0.029) and larger cup-disc area ratio (OR highest vs lowest tertile, 4.44; 95% CI 0.95 to 20.66; p=0.037). After excluding glaucoma eyes, BRVO remained significantly associated with these parameters (p=0.027, p=0.018, p=0.024, respectively). Conclusions Quantitative optic disc parameters (optic cup and disc area) are associated with BRVO, even in non-glaucomatous eyes. Optic nerve head morphology may play a role in BRVO pathogenesis.