Retinal Vein Occlusion
Retinal vein occlusion is the second most common retinal vascular disease after diabetic retinopathy, classified as central (CRVO) or branch (BRVO), presenting with sudden painless visual loss and managed with anti-VEGF for macular oedema.
Key Facts
Retinal vein occlusion (RVO) is the second most common retinal vascular disorder after diabetic retinopathy Two types: CRVO (central retinal vein occlusion) and BRVO (branch retinal vein occlusion; more common, better prognosis) BRVO: occurs at AV crossing points (arteriole compresses venule); superotemporal most common CRVO: "stormy sunset" fundus — extensive haemorrhages in all quadrants, dilated tortuous veins, disc oedema, cotton wool spots Risk factors: hypertension (most important), age >50, glaucoma, diabetes, hyperlipidaemia, hyperviscosity Macular oedema is the main cause of visual loss; treated with anti-VEGF (ranibizumab, aflibercept) — NICE TA283/TA409 Ischaemic CRVO: >10 disc areas of non-perfusion on FFA; high risk of rubeosis and neovascular glaucoma → PRP Screen for cardiovascular risk factors in all patients with RVO: BP, HbA1c, lipids, FBC (polycythaemia)
Overview
Key Facts
RVO is a common cause of sudden painless visual loss in older adults. Cardiovascular risk factor management is essential alongside ophthalmic treatment.
Epidemiology
- Prevalence: 1-2% of adults >40
- BRVO is 4× more common than CRVO
- Mean age: BRVO 60-70; CRVO 65-75
- Second eye involvement: 5-15% over 5 years
Aetiology
- Hypertension: most important risk factor (present in >60%)
- Glaucoma: independent risk factor for CRVO
- Diabetes, hyperlipidaemia, smoking
- Hyperviscosity: polycythaemia, myeloma, Waldenström's
- Thrombophilia: consider in young patients (<50) with RVO (antiphospholipid, factor V Leiden)
- OCP: risk factor in young women
Pathophysiology
- BRVO: arteriosclerotic arteriole compresses venule at AV crossing (shared adventitia) → thrombosis → venous obstruction → haemorrhage and oedema in affected sector
- CRVO: thrombosis at lamina cribrosa (where CRV exits eye) → obstruction of all retinal venous drainage → widespread haemorrhages, oedema, ischaemia
- Macular oedema: increased capillary permeability → fluid accumulation → visual loss (most common cause)
- Ischaemia → VEGF production → neovascularisation (disc, retina, iris) → vitreous haemorrhage, neovascular glaucoma
Clinical Presentation
BRVO
- Sudden painless visual loss (or blurring) — often sector-specific
- Flame haemorrhages in one sector (along vein distribution)
- Cotton wool spots, dilated tortuous veins in affected sector
- Macular oedema (if superotemporal branch — most common — affects macula)
CRVO
- Sudden painless visual loss (more severe than BRVO)
- "Stormy sunset" fundus: extensive haemorrhages in ALL quadrants
- Dilated, tortuous veins throughout
- Disc oedema
- Cotton wool spots
- Macular oedema
CRVO Subtypes
- Non-ischaemic (75%): moderate visual loss, good prognosis, fewer haemorrhages
- Ischaemic (25%): severe visual loss (VA <6/60), extensive haemorrhages, RAPD, high risk of neovascularisation
Red Flags
- Rubeosis iridis (new iris vessels) → neovascular glaucoma imminent → urgent PRP
- VA <6/60 with RAPD → ischaemic CRVO
- Young patient (<50) with RVO → investigate for thrombophilia
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Diabetic retinopathy | Bilateral, microaneurysms, known diabetes | HbA1c, fundoscopy |
| Hypertensive retinopathy | Bilateral, AV nipping, silver wiring | BP, fundoscopy |
| Papilloedema | Bilateral disc swelling, no haemorrhage (unless severe) | MRI brain, LP |
| Ocular ischaemic syndrome | Carotid stenosis, dilated veins, mid-peripheral dot haemorrhages | Carotid duplex |
| Leukaemic retinopathy | White-centred haemorrhages (Roth spots) | FBC |
Diagnosis / Investigation
Bedside
- Visual acuity
- RAPD (ischaemic CRVO)
- Dilated fundoscopy
- IOP (glaucoma screening)
- Blood pressure
Bloods
- Cardiovascular screen: BP, HbA1c, lipid profile
- FBC (polycythaemia, leukaemia)
- ESR, plasma viscosity
- U&Es, TFTs
- Thrombophilia screen if <50: antiphospholipid antibodies, lupus anticoagulant, factor V Leiden, protein C/S, antithrombin III
- Serum protein electrophoresis (hyperviscosity)
Imaging
- OCT: macular oedema assessment (central macular thickness)
- Fundus fluorescein angiography (FFA): identifies ischaemia, non-perfusion areas, neovascularisation
- OCT angiography: non-invasive assessment of perfusion
Special Tests
- Gonioscopy: for neovascular glaucoma screening
- Visual field testing: BRVO sector defect
Management
Non-pharmacological
- Cardiovascular risk factor management: BP control, smoking cessation, diabetes management, lipid control
- Serial monitoring: OCT, IOP, gonioscopy for neovascularisation
Pharmacological
- Macular oedema (centre-involving):
- Anti-VEGF intravitreal injections: aflibercept 2mg or ranibizumab 0.5mg (NICE TA283 for CRVO; TA409 for BRVO)
- Loading: monthly × 3, then PRN or treat and extend
- Intravitreal dexamethasone implant (Ozurdex): alternative for RVO-related macular oedema; lasts ~4 months; risk of IOP rise and cataract
- No role for anticoagulation or antiplatelet therapy in RVO treatment
Surgical/Interventional
- Pan-retinal photocoagulation (PRP): for neovascularisation (NVI, NVD, NVE) — prevents neovascular glaucoma
- Sector laser: for BRVO with non-perfusion and neovascularisation
- Anti-VEGF intravitreal injection: for neovascular glaucoma
- Vitrectomy: for non-clearing vitreous haemorrhage
Referral Criteria
- All RVO: ophthalmology referral (within 1-2 weeks)
- Ischaemic CRVO or rubeosis: urgent ophthalmology
- Cardiovascular risk factors: GP management with monitoring
Prognosis
- BRVO: good prognosis; 60% improve spontaneously; anti-VEGF for macular oedema achieves mean 10-15 letter improvement
- Non-ischaemic CRVO: moderate prognosis; 33% convert to ischaemic over time
- Ischaemic CRVO: poor visual prognosis; 60% risk of neovascular glaucoma within 3 months ("100-day glaucoma")
- Anti-VEGF significantly improves visual outcomes for macular oedema in both BRVO and CRVO
- Cardiovascular risk: patients with RVO have increased risk of stroke, MI, and cardiovascular death
Other Relevant Information
CRVO: Non-Ischaemic vs Ischaemic
| Feature | Non-Ischaemic | Ischaemic |
|---|---|---|
| Frequency | 75% | 25% |
| Visual acuity | Moderate loss | Severe loss (<6/60) |
| RAPD | Absent | Present |
| Haemorrhages | Moderate | Extensive |
| Non-perfusion (FFA) | <10 disc areas | >10 disc areas |
| Neovascularisation risk | Low | High (60% NVG) |
| Prognosis | Better | Worse |