Central Retinal Vein Occlusion (CRVO)

Sudden painless monocular vision loss; less acute than CRAO (often days). Fundoscopy: 'blood and thunder' — extensive flame haemorrhages in all 4 quadrants, dilated tortuous veins, cotton wool spots, optic disc swelling. Classification: • Non-ischaemic (~75%) — better prognosis; gradual visual change; some macular oedema. • Ischaemic (~25%) — sudden severe vision loss + RAPD; risk of neovascularisation + neovascular glaucoma (rubeosis iridis). Risk: HTN, diabetes, glaucoma, hypercoagulable, hyperviscosity (myeloma, polycythaemia), OCP, smoking. Workup: • Bloods: FBC + ESR, U&E, glucose / HbA1c, lipids, coag screen, antiphospholipid, electrophoresis (if elderly), ANA. • BP measurement. • Glaucoma — IOP; gonioscopy. • Carotid Doppler if young / atypical. • OCT macula (oedema). • Fluorescein angiography (FFA) — distinguish ischaemic vs non-ischaemic.