Retinal Artery/Vein Occlusion

Question 1

Retinal Artery Occlusion - clinical features

Answer 1

Dramatic vision loss - within seconds of occlusion
- visual acuity reduced to counting fingers or worse
Painless

Question 2

Retinal Artery Occlusion - pathophysiology

Answer 2

A form of stroke
Occlusion; causes
- often thromboembolic (e.g. carotid artery atherosclerosis in the elderly)
- embolus from AF
- thrombus formation
- fat embolus 
- amniotic fluid embolus

Question 3

Retinal Artery Occlusion - examination

Answer 3

Relative Afferent Pupillary Defect (RAPD)
- may precede retinal changes by an hour
Fundoscopy
- white retina
- cherry red spot on macula
Exclude temporal arteritis

Question 4

Retinal Artery Occlusion - risk factors

Answer 4

Signs of atherosclerosis (e.g. carotid artery bruit and increased blood pressure)
AF
Heart valve disease
Diabetes 
Smoking 
Hyperlipidaemia

Question 5

Retinal Artery Occlusion - emergency management

Answer 5

(Within 100 mins of onset)
Try and increase retinal blood flow by reducing intraocular pressure
- ocular massage
- surgical removal of aqueous from the anterior chamber
- intraocular hypotensive treatment
Chances of recovering vision are poor

Question 6

Retinal Artery Occlusion - best management

Answer 6

Prevention

Primary prevention of CVS risk factors to prevent further event on remaining eye

Question 7

Retinal Vein Occlusion - epidemiology

Answer 7

Retinal vein occlusion is much more common than retinal artery occlusion
Incidence increases with age
2nd most common cause of blindness from retinal vascular disease (diabetic retinopathy being first)

Question 8

Retinal Vein Occlusion - causes/associations

Answer 8

Arteriosclerosis 
Hypertension
Diabetes Mellitus 
Polycythaemia 
Glaucoma (all types)

Question 9

Retinal Vein Occlusion - presentation

Answer 9

Central retinal vein occlusion

• vision loss (acuity reduced to finger counting)
• less sudden than retinal artery occlusion (although may seem sudden to the patient)

Question 10

Retinal Vein Occlusion - pathology

Answer 10

Development of ischaemia and macular oedema causes the vision loss

Question 11

Retinal Vein Occlusion - classification

Answer 11

According to the anatomical location of the occlusion along the central retinal vein
Central retinal vein occlusion
- occurs at the level of the optic nerve
- presents as sudden onset, painless, blurred vision in one eye
- is never asymptomatic
Branch retinal vein occlusion
- can be asymptomatic if the macula is not affected
- most have visual deficits corresponding to the area of occlusion

Question 12

Retinal Vein Occlusion - forms of central retinal vein occlusion

Answer 12

Ischaemic
- cotton wool spots, swollen optic nerve, macular oedema and the risk of neovascularisation
Non-ischaemic
- more common
- have better acuity and prognosis
- 30% convert to ischaemic form (so require follow-up)

Question 13

Retinal Vein Occlusion - investigations

Answer 13

Fundus fluorescein angiogram
- degree of ischaemia
Panretinal photocoagulation
- to prevent or treat neovascularisation
- even if macular oedema resolves anatomically, visual prognosis is poor

Question 14

Retinal Vein Occlusion - secondary complications

Answer 14

Retinal neovascularisation (new vessels have a high risk of haemorrhaging)
Chronic macular oedema
These can both threaten sight; so management is focused on ameliorating these conditions

Question 15

Retinal Vein Occlusion - management

Answer 15

Refer the ophthalmology (they do the following)
No secondary complications (sight intact)
- monitor carefully
Visual loss
- intravitreal anti-VEGF therapy 
- dexamethasone
- intravitreal triamcinolone acetonide 
Retinal neovascularisation 
- photocoagulation

Question 16

Retinal Vein Occlusion - prevention of rubeotic glaucoma

Answer 16

This is indicated by the development of a painful eye 
Bevacizumab and ranibizumab 
- can treat macular oedema 
Lasers
Intravitreal dexamethasone implants