Retinal Vein Occlusion: BRVO and CRVO Made Practical
Last updated: November 2026
Retinal vein occlusion (RVO) is the second commonest retinal vascular disease after diabetic retinopathy. Two questions decide management: is there macular oedema, and is the occlusion ischaemic? Everything else, from laser to neovascular glaucoma follow-up, flows from these.
Types
| Type | Site | Key features |
|---|---|---|
| BRVO | An arteriovenous crossing, usually superotemporal | Sectoral flame haemorrhages, cotton wool spots and oedema in one quadrant; vision depends on macular involvement |
| Hemi-retinal (hemi-central) RVO | Upper or lower half | Behaves like a large BRVO |
| CRVO | At or behind the lamina cribrosa | Haemorrhages in all four quadrants ("blood and thunder"), dilated tortuous veins, disc swelling |
Ischaemic or non-ischaemic CRVO?
| Feature | Non-ischaemic | Ischaemic |
|---|---|---|
| Vision | Often better than 6/60 | Usually 6/60 or worse |
| RAPD | Absent or mild | Marked |
| Haemorrhages and cotton wool spots | Fewer | Extensive |
| FFA capillary non-perfusion | Less than 10 disc areas | 10 disc areas or more (CVOS) |
| ERG | b-wave normal | Reduced b:a ratio |
| Risk of neovascular glaucoma | Low, but about a third convert to ischaemic | High: classically the "100-day glaucoma" |
Systemic and ocular work-up
- Blood pressure (the commonest association), blood sugar and HbA1c, lipids, full blood count and ESR.
- IOP and gonioscopy in both eyes: glaucoma and ocular hypertension are risk factors.
- In younger patients (under 50) or bilateral cases: clotting screen, homocysteine, antiphospholipid antibodies, myeloma screen and hyperviscosity tests, guided by history.
- Treat the risk factors with the physician; anticoagulants are not routinely indicated for RVO itself.
Treatment
| Problem | Treatment |
|---|---|
| Macular oedema (BRVO or CRVO) | Intravitreal anti-VEGF first line (BRAVO and CRUISE: ranibizumab; LEAVO: aflibercept and bevacizumab options). Dexamethasone implant for poor responders, pseudophakic eyes or those unable to attend monthly. Grid laser (BVOS) is now second line for BRVO. |
| Retinal or disc neovascularisation | Sectoral PRP for BRVO (BVOS: treat when new vessels appear, not prophylactically). |
| Iris or angle neovascularisation in CRVO | Urgent PRP plus anti-VEGF; treat raised IOP. CVOS: prophylactic PRP did not prevent NVI, so monitor closely and treat at the first sign. |
| Neovascular glaucoma | Anti-VEGF, PRP, IOP-lowering drugs, and tube surgery or cyclodestruction when needed. |
Follow-up
Ischaemic CRVO: monthly for the first 6 months with undilated gonioscopy for NVA. Non-ischaemic: watch for conversion. Always examine the fellow eye.
Where residents slip
- Missing gonioscopy in CRVO: new vessels in the angle can appear before iris new vessels.
- Giving prophylactic PRP to every ischaemic CRVO: CVOS supports close monitoring and treating at the first sign of NVI.
- Forgetting the fellow eye's IOP.
- Not checking blood pressure the same day.
Test yourself: flip cards
Related: Landmark Trials in Ophthalmology: High-Yield Summary, Diabetic Retinopathy: Classification and Management for Residents, Intravitreal Injection Protocol: Asepsis, Technique and Complications.
Key sources
- Central Vein Occlusion Study Group. Evaluation of grid pattern photocoagulation for macular edema in CRVO (CVOS M report). Ophthalmology. 1995;102:1425-1433
- Branch Vein Occlusion Study Group. Argon laser photocoagulation for macular edema in BRVO. Am J Ophthalmol. 1984;98:271-282
- Royal College of Ophthalmologists. Clinical guidelines: retinal vein occlusion (2022 update)
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