Retinal Vein Occlusion (CRVO & BRVO - Eye Stroke)
Blockage of the central retinal vein or its branch tributaries, causing widespread retinal hemorrhages, severe macular edema, and sudden visual loss.
Article Table of Contents
1. Comprehensive Overview
Retinal Vein Occlusion (RVO) is the second most common retinal vascular disease after diabetic retinopathy, representing an acute venous thrombosis of the retinal circulation.
Classification & Pathogenesis: 1. Central Retinal Vein Occlusion (CRVO): Thrombus formation in the central retinal vein at or posterior to the lamina cribrosa. Outflow obstruction causes massive capillary hypertension, widespread intraretinal hemorrhages in all 4 quadrants ('Blood and Thunder' fundus), dilated tortuous veins, and optic disc edema. - Non-Ischemic CRVO (80%): Milder, better visual prognosis. - Ischemic CRVO (20%): >10 disc areas of non-perfusion on fluorescein angiography, profound visual drop, relative afferent pupillary defect (RAPD), and extreme risk of neovascular glaucoma ('100-Day Glaucoma'). 2. Branch Retinal Vein Occlusion (BRVO): Compression and thrombosis of a branch retinal vein at an arteriovenous crossing (AV crossing) where a rigid arteriolosclerotic artery compresses the shared adventitial sheath of the underlying thin-walled vein.
Complications: Cystoid Macular Edema (CME), retinal ischemia, vitreous hemorrhage, and neovascularization of the iris/angle (NVI/NVA).
2. Symptoms & Warning Signs
If you observe any of the following symptoms repeatedly, an eye exam is strongly recommended:
- Sudden, painless, unilateral visual reduction, classically discovered upon waking in the morning
- Severe central visual blur, dimness, or graying of vision
- Sectoral or altitudinal visual field defect corresponding to the occluded quadrant in BRVO
- Metamorphopsia caused by cystoid macular edema
- Absence of external redness or ocular pain at onset
3. Causes & Risk Factors
- 1Systemic arterial hypertension and advanced arteriolosclerosis (most significant risk factor)
- 2Advancing age (>90% occur in patients over 50 years old)
- 3Diabetes mellitus, hyperlipidemia, and metabolic syndrome
- 4Primary open-angle glaucoma and elevated IOP compressing the central vein at the cribriform plate
- 5Hypercoagulable and thrombophilic states (Antiphospholipid syndrome, Factor V Leiden, Hyperhomocysteinemia, Polycythemia)
- 6Cigarette smoking and obstructive sleep apnea
4. Treatments & Medical Management
5. Prevention & Daily Eye Care Advice
- Strict long-term blood pressure control and avoiding hypertensive crises
- Routine annual screening of intraocular pressure and optic nerve head
- Maintaining adequate systemic hydration to prevent hemoconcentration
- Complete smoking cessation and regular cardiovascular aerobic exercise
6. When to Seek Emergency Eye Care
Visit an immediate eye emergency center if you experience any of the following critical indicators:
- ⚠Sudden, painless unilateral drop in vision or graying out of the visual field
- ⚠Central visual blur or sudden reading difficulty upon awakening
- ⚠Onset of deep ocular pain and redness weeks/months after an RVO (warning sign of secondary neovascular glaucoma)
7. Frequently Asked Questions
Q:What is '100-Day Glaucoma' after a retinal vein stroke?
It is acute neovascular glaucoma resulting from severe retinal ischemia following ischemic CRVO, typically presenting ~100 days post-occlusion. Pathological new vessels block the trabecular angle, causing painful IOP spikes (>60 mmHg). It is preventable via timely prophylactic PRP laser and Anti-VEGF therapy.