RETINAL VASCULAR OCCLUSIONS

Retinal vein occlusion• Branch• Central• Hemi-retinal

Retinal artery occlusion• Branch• Cilio-retinal• Hemi-retinal• Central

Retinal vein occlusion - predisposing factors

1. Systemic

• Raised intraocular pressure2. Ocular

• Periphlebitis

• Increasing age• Hypertension• Diabetes• Abnormalities of coagulation

Patho-physiology of venous occlusion

Venous Occlusion

Stagnation

Increased extravascularpressure

Hypoxia

Oedema andhaemorrhage

Branch retinal vein occlusion ( BRVO )

• Venous tortuosity and dilatation• Flame-shaped and ‘dot-blot’ haemorrhages• Cotton-wool spots and retinal oedema

Prognosis - VA 6/12 or better after 6 months in 50%

Complications - chronic macular oedema and neovascularization

Signs of acute BRVO

FA of branch retinal vein occlusion

Early - blocked background fluorescence due to haemorrhage

Late - hyperfluorescence dueto diffuse oedema

Signs of old branch retinal vein occlusion

Vascular sheathing and collaterals Hard exudates

Management of chronic macular oedema• Most common cause of persistent poor VA• Wait 6-12 weeks and perform FA

Macular non-perfusion - no treatment Good macular perfusion and VA 6/18or worse after 3 months - consider laser photocoagulation

Management of neovascularization

• Perform laser photocoagulation to involved segment• Most frequently after 6-12 months

• Occurs in about 30-50% of eyes

Central retinal vein occlusion ( CRVO )

• Chronic macular oedema

• Variable cotton-wool spots

• Mild to moderate disc oedema

• May subsequently convert to ischaemic

• Guarded prognosis

• VA > CF• APD - mild• Mild venous tortuosity and dilatation• Mild to moderate retinal haemorrhages

Signs of non-ischaemic CRVO

FA of non-ischaemic central retinal vein occlusion

Good retinal capillary perfusion

Signs of ischaemic central retinal vein occlusion

• Variable cotton wool spots• Severe disc oedema

• Very poor prognosis

• Macular ischaemia

• Rubeosis irides in 50%

• VA < 6/60• APD - marked• Marked venous tortuosity and engorgement• Extensive retinal haemorrhages

FA of ischaemic central retinal vein occlusion

Extensive capillary non-perfusion

Management of ischaemic central retinal vein occlusion

• Check every month for 6 months• Look for rubeosis and angle new vessels

• Treat neovascularization by panretinal photocoagulation

Hemi-retinal Vein Occlusion• VA< reduction is variable• Signs of BRVO• Superior or inferior hemisphere

involve

FA Hemi-retinal Vein Occlusion

Management of CRVO• Radial Optic Neurotomy

• A-V sheathotomy

• Chorio-retinal anastomosis

• Laser

• Surgical

• IVTA

• Anti-VEGF

RETINAL ARTERY OCCLUSION

Causes of retinal artery occlusion

Embolism

Vaso-obliteration

Cholesterol emboli (Hollenhorst plaques)

• Multiple, bright, refractile crystals• Often located at arteriolar bifurcations• Frequently asymptomatic

Fibrinoplatelet emboli

• Multiple, dull grey particles• Occasionally fill entire lumen• May cause amaurosis fugax and occasionally permanent obstruction

Calcific emboli

• Usually single, white and close to disc• May cause permanent obstruction

Branch retinal artery occlusion ( BRAO )

• VA - variable

• APD - mild or absent

• Retina whitening

• Arteriolar narrowing

FA of branch retinal artery occlusion

Early masking Extreme delay of arterial phase

Late staining of arterial walls

Cilioretinal artery occlusion

• Present in about 30% of individuals

• In young individuals with a systemic vasculitis

• Guarded prognosis

Combined with CRVO

• Usually good prognosis

• Elderly patients with giant cell arteritis

• Very poor prognosis

IsolatedCombined with anterior ischaemic optic neuropathy

• Cilioretinal artery derived from posterior ciliary circulation

Central retinal artery occlusion ( CRAO )

• VA < 6/60

• ‘Cherry-red spot’ at macula

• Arteriolar and venular narrowing

• Very poor prognosis

• Sludging and segmentation of blood column (cattle-trucking)

• APD - marked

• Retinal whitening

FA of central retinal artery occlusion

Early filling of cilioretinal artery

Non-filling of other vessels Late staining of vessel walls

Treatment of central retinal artery occlusion

• Ocular massage• Sub-lingual Iso-sorbide di-nitrate• Lowering of IOP

• AC paracentesis• IV Streptokinase