AVL: Retinal vein occlusion

Question 1

Types of retinal vein occlusion

Answer 1

Central retinal vein occlusion
Branch retinal vein occlusion

Question 2

Central retinal vein occlusion

Answer 2

Thrombus is proximal to the lamina cribosa* and obstructs central retinal vein, involving entire retina
- Non-ischemic CRVO vs Ischemia CRVO

(*where the central retinal vein leaves the eyeball)

Question 3

Non-ischemic CRVO vs Ischemia CRVO

Answer 3

Non-ischemic CRVO
- Mild-moderate visual loss
- NIL RAPD
- Fundoscopy does not reveal significant haemorrhage
- Resolves spontaneously

Ischemic CRVO
- Marked visual loss
- RAPD
- Significant haemorrhage
- Worse visual prognosis

Question 4

Branch retinal vein occlusion

Answer 4

Occlusion distal to lamina cribosa at an arteriovenous crossing* which results in a branch of retinal vein being occluded
- Blockage of a small portion of retina

(*where the vein shares a common adventitial sheath with a retinal artery)

Question 5

Risk factors of retinal vein occlusion

Answer 5

DM
HTN
HLD
Arteriosclerosis
Vessel wall inflammation: Sarcoidosis/ SLE
Raised IOP: Causing extrinsic pressure on vein
Hypercoagulability

Question 6

Clinical presentation of BRVO

Answer 6

Gradual onset, painless monocular visual loss
- Less complete loss of sight
- Less abrupt than CRAO

Question 7

Fundoscopy signs seen in CRVO

Answer 7

• Grossly tortuous and dilated retinal veins
• Unilateral disc edema; Blurring of disc margins -> Swollen optic disc
• Blood and Thunder Appearance: Diffuse flame and blot haemorrhages at all 4 quadrants of the retina
• Cotton wool spots
• Neovascularisation at optic disc, retina and iris

Question 8

Clinical presentation of BRVO

Answer 8

• Asymptomatic
• Symptomatic: Visual loss if macula involved or visual field defect

Question 9

Fundoscopy signs seen in BRVO

Answer 9

Occurs at arteriovenous junction where vein is compressed by atherosclerotic artery
- Fan-shaped distribution or scattered flame and blot hemorrhages in a segmental area
- Cotton wool spots
- Dilated and tortuous veins

Question 10

Which branch is most commonly affected in BRVO?

Answer 10

Superior temporal branch

Question 11

Investigations for retinal vein occlusion

Answer 11

Ocular:
Fluorescein angiography to prognosticate patient based on ischemic vs. non-ischemic CRVO and assess degree of neovascularization
OCT
HRT

Systemic:
Fasting glucose, Fasting lipids, BP, BMI

In young patient: add
protein C/S
lupus anticoagulant
AT3
serum homocysteine levels
VRDL

Question 12

Management of retinal vein occlusion

Answer 12

• Treat underlying predisposing metabolic factors + Co-manage with endocrinologist
• Retinal laser photocoagulation
• Intravitreal anti-VEGF agents

Question 13

Sight threatening complications of retinal vein occlusion

Answer 13

• Cystoid macular edema
• Neovascularization glaucoma
• Vitreous hemorrhage