What is Retinal Vascular Occlusion?
Retinal vascular occlusion is a blockage of retinal arteries or veins that disrupts blood flow to retinal tissue. This includes central and branch occlusions of both arteries (CRAO, BRAO) and veins (CRVO, BRVO), each with different causes, symptoms, and prognoses.
Types of Retinal Vascular Occlusion
Central Retinal Artery Occlusion (CRAO)
Complete blockage of the central retinal artery causing severe, sudden vision loss. This is an ocular emergency with poor prognosis if not treated within hours.
Branch Retinal Artery Occlusion (BRAO)
Blockage of a branch artery affecting only part of the retina. Less severe than CRAO but still requires immediate attention.
Central Retinal Vein Occlusion (CRVO)
Blockage of the central retinal vein causing variable vision loss and macular edema. Treatable with anti-VEGF injections with variable outcomes.
Branch Retinal Vein Occlusion (BRVO)
Blockage of a branch retinal vein with more localized effects. Generally has the best prognosis among vascular occlusions.
Understanding the Disease
Risk Factors
Arterial Occlusions:
- • Age (typically 60s)
- • Male gender (more common)
- • Atherosclerotic factors
- • Carotid artery disease
Venous Occlusions:
- • Diabetes mellitus
- • Hypertension
- • Glaucoma
- • Hyperlipidemia
Symptoms by Type
CRAO (Central Retinal Artery Occlusion)
Severe sudden painless vision loss, often described as "curtain falling"
CRVO (Central Retinal Vein Occlusion)
Blurry or distorted vision, may be gradual or sudden onset
BRVO (Branch Retinal Vein Occlusion)
Sudden painless vision loss in part of visual field
Diagnostic Methods
Comprehensive Eye Examination
Detailed retinal evaluation
Fluorescein Angiography
Assess vascular flow and perfusion
OCT Imaging
Monitor macular edema
Systemic Workup
Evaluate cardiovascular risk factors
Treatment Options
CRAO (Central Retinal Artery Occlusion)
No proven treatment if symptoms persist >4-6 hours
Emergency measures may be attempted within hours of onset
CRVO & BRVO (Retinal Vein Occlusions)
Anti-VEGF intravitreal injections (primary treatment)
Monthly injections to reduce macular edema and improve vision
Supplementary Treatments
Steroid injections, laser photocoagulation, systemic management
Used in combination or when anti-VEGF is contraindicated
Emergency Treatment
CRAO requires immediate emergency treatment within hours. Other occlusions benefit from prompt evaluation and treatment initiation as soon as possible.
Prevention & Management
- • Control blood pressure and diabetes
- • Manage cholesterol levels
- • Regular cardiovascular monitoring
- • Smoking cessation
- • Regular eye examinations
- • Immediate evaluation of vision loss
Prognosis by Type
CRAO (Central Retinal Artery Occlusion)
Poor prognosis - Often results in severe permanent vision loss
CRVO (Central Retinal Vein Occlusion)
Variable outcomes - Depends on severity and response to treatment
BRVO (Branch Retinal Vein Occlusion)
Good prognosis - >60% of patients maintain 20/40 vision or better
Critical Emergency Warning
Central retinal artery occlusion is an ocular emergency! Like a stroke of the eye, immediate treatment within 4-6 hours is crucial. Any sudden, severe vision loss requires emergency evaluation. Early intervention may help preserve some vision in select cases.