Dr KN POORNESH WGH 03.11.2004. RETINAL VEIN OCCLUSION. CLASSIFICATION. BRVO CRVO Major BRVO Non-ischemic Minor Macular BRVO Ischemic Peripheral BRVO Papillophlebitis Hemiretinal Vein occlusion . PATHOGENESIS.
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03.11.2004RETINAL VEIN OCCLUSION
Major BRVO Non-ischemic
Minor Macular BRVO Ischemic
Peripheral BRVO Papillophlebitis
Hemiretinal Vein occlusion
Compression of the vein
Venous endothelial cell loss
Venous occlusion elevation of venous
& capillary pressure
Stagnation of blood flow
Increased tissue pressure Hypoxia of the retina
Damage to capillary endothelial cells &
extravasation of blood constituents
6. Acquired thrombophilic: Hyperhomocystinemia, Antiphospholipid antibody syndrome.
7. Inherited thrombophilic: increased levels of clotting factors 7 & 11, deficiency of antithrombin 3, protein C &S, resistance to activated protein C.
Other Risk factors:
•Hypermetropia (BRVO), Congenital anomaly of Central retinal vein (CRVO), Optic disc drusen,
• Drugs (OC, Diuretics), Migraine (rare).
• Retrobulbar external compression: Dysthyroid eye disease, Orbital tumor
6 to 12 months to resolve
• Venous sheathing
• Collateral venous channels
• Microaneurysms, Hard exudates, Cholesterol crystal deposition.
• Macula: RPE changes or
ER gliosis, chronic CME.
Depends on • Site & Size of occluded vein • Integrity of perifoveal capillary network
50% : Recover VA of 6/12 or better.
Complications: 1. Chronic macular edema
2. Macular ischemia
NV (within 3 yrs)
10%- NVD, 20-30%- NVE
4. Recurrent VH, TRD.
Wait for haemorrhage to clear (3 months).
Residual signs: Disc collaterals, epiretinal gliosis, pigmentary changes at macula.
Conversion to ischemic CRVO occurs in 15% of cases within 4 months and 34% within 3 years.
Follow-up: should be for 3 years.
Prognosis: depends on initial VA, near normal VA in 50%, Chronic CMO- unresponsive to laser (CVOS).
8-10% risk of BRVO or CRVO in the fellow eye.
Follow-up: monthly for 6 months
IOP, undilated gonioscopy & SLE
Angle NV is the best clinical predictor of NVG.
Treatment: PRP in eyes with angle or iris NV. Monthly follow-up until stabilisation or regression.
20% visual loss -- macular edema