Retinal Artery Occlusion

Blockage of one of the retinal arteries

Aetiology

Classification

• Occlusion of the central retinal artery

• Results in diffuse retinal ischemia

• Occlusion of a branch retinal artery

• Causes sectoral retinal ischemia

• Involves the cilioretinal artery, if present

• May preserve some central vision depending on involvement

Etiology

• Cholesterol emboli (Hollenhorst plaques) from carotid arteries

• Calcific emboli from cardiac valves

• Platelet-fibrin emboli

• Atherosclerosis of the retinal artery

• Hypercoagulable states

• Giant cell arteritis (GCA) — critical to exclude in elderly patients

• Systemic hypotension

• Trauma

• Vasospasm

• Iatrogenic (e.g., intraocular procedures)

Central retinal artery occlusion

• Occlusion of the central retinal artery, with resultant infarction of the inner 2/3 of the retina (outer 1/3 is supplied by choroid) and vision loss

Clinical presentation

• Sudden, painless severe loss of vision

• RAPD (relative afferent pupil defect) - occurs because the input is not being sensed by the ischaemic retina when testing the direct light reflex but is being sensed by the normal retina during the consensual light reflex

Fundoscopy

• Arteries become narrow ('thread-like')

• Retina becomes pale, opaque and oedematous

• Cherry-red spot is seen at the fovea

Management

• Immediate referral to stroke clinic

Branch retinal artery occlusion

• Occurs when one of the branches of the central retinal artery becomes occluded, resulting in ischamic damage to the area the branch supplies

Clinical presentation

• Acute onset of painless, monocular visual impairment

• The severity of visual loss depends upon the area of retinal tissue affected by the vascular occlusion

Fundoscopy

• Absence of perfusion in the affected artery

Management

• Refer to stroke clinic

Amaurosis fugax

• Transient central retinal artery occlusion

Clinical presentation

• Transient painless visual loss

• 'Like a curtain coming down'

• Lasts ~5 mins with full recovery

Fundoscopy

• Usually no abnormal signs

Management

• Refer to stroke clinic