RETINAL VEIN OCCLUSION

1. Dr KN POORNESH WGH 03.11.2004 RETINAL VEIN OCCLUSION

2. CLASSIFICATION BRVO CRVO Major BRVO Non-ischemic Minor Macular BRVO Ischemic Peripheral BRVO Papillophlebitis Hemiretinal Vein occlusion

3. PATHOGENESIS Arteriosclerosis  Compression of the vein  Venous endothelial cell loss Thrombus formation Venous Occlusion

4. PATHOGENESIS 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

5. RISK FACTORS(in order of importance) • Advancing age: 50% cases over 65 yrs. • Systemic: HT, Hyperlipidemia, Diabetes, Smoking, Obesity. • Raised IOP: risk of CRVO • Inflammatory: Behcet’s, Sarcoid,AIDS, SLE, Toxoplasma. • Hyperviscosity: Polycythemia, MM, Waldenstrom macroglobulinemia.

6. RISK FACTORS 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

7. Major BRVO

8. COURSE of BRVO 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.

12. Prognosis and Complications of BRVO 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 3. Neovascularisation, NV (within 3 yrs) 10%- NVD, 20-30%- NVE 4. Recurrent VH, TRD.

16. Management of BRVO(BVOS) Wait for haemorrhage to clear (3 months). FFA : • Macular edema and VA 6/12 or worse after 3 months –grid laser & follow-up after 2-3 months. • Macular ischemia—no treatment. • 5 DD or > area of CNP– 4 monthly follow- up for 12-24 months. • Neovascularisation– scatter laser

18. CRVOIschemic Non-ischemic

19. CRVOIschemic Non-ischemic

23. Non-ischemic CRVO(Course and Follow-up) 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.

24. Ischemic CRVO:Management (CVOS) 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.

25. Hemiretinal vein occlusion • Less common than BRVO and CRVO • Occlusion of superior or inferior branch of the CRV. • Features of BRVO, involving the superior or inferior hemisphere • Prognosis depends on severity of macular edema and ischemia.

26. PAPILLOPHLEBITIS(Optic disc vasculitis) • Healthy individuals, < 50 years • Optic disc swelling with secondary venous congestion rather than venous thrombosis. • APD absent, retinal haemorrhages confined to posterior fundus. • Prognosis: 80% -- 6/12 or better 20% visual loss -- macular edema

27. Management:Recent advances • Recent onset of non-ischemic CRVO– high intensity laser to create chorioretinal shunt. • AV sheathotomy for treatment of CME due to BRVO. • Ischemic CRVO:- PP Vitrectomy + Intraocular gas + Radial neurotomy

28. Management: Recent advances • Intravitreal tPA • Transvitreal vein cannulation • Section of posterior scleral ring • Drug therapy -- Troxerutin -- Petroxyfylline -- Hemodilution • Intravitreal Triamcinolone

29. Thank You