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Central or branch retinal artery occlusion

Occlusion of the retinal artery may be caused by arteriosclerotic changes, embolus 
(from heart or carotid artery) or inflammation (rare)

History:

  • Sudden painless visual loss which may be complete (due to central retinal artery 

  • occlusion) or partial (due to branch retinal artery occlusion)
  • Patient usually have a history of hypertension or heart disease
Examination:
  • The visual acuity is reduced in central retinal artery occlusion but may be normal 

  • in branch retinal artery occlusion
  • Relative afferent pupillary defect is present in central retinal artery occlusion
  • The retinal arteries are narrow or collapsed. 
  • In central retinal artery occlusion, the fovea shows a cherry-red spot against the 

  • white infarcted retina. 
  • In branch retinal artery occlusion, the white infarcted retina corresponds to the 

  • occluded retina. 
  • Emboli may be seen in the arteries if the cause is emboli
Management:
  • Immediate referral if the visual loss is less than 6 hours as treatment may restore 

  • some or most of the function. 
  • Treatment involves the use of intravenous acetazolamide and globe massage to 

  • lower the intraocular pressure and hopefully re-establish the arterial flow.
  • Further management aim to uncover any underlying diseases such as hypertension, 

  • cardiac or carotid thrombus. An ESR is usually performed in the absence of obvious 
    embolus to exclude arteritic causes.
  • Long term low dose aspirin is advised to reduce the risk of occurrence.
Figure 1
Central retinal artery occlusion showing the typical "cherry-red" spots again 
the white infarcted retina. This appearance is not permanent and usually 
disappears after about three days when the flow of the retina artery 
is re-established but the retina does not regain its function.
.

Figure 2
Branch retinal artery occlusion in the infero-lateral retinal artery. The infarcted 
retina appears as white.
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Figure 3
Cholesterol emboli from the carotid artery. This is the most common 
cause of transient visual loss. If the occlusion is prolonged, the retina 
may become infarcted. Investigation should include carotid doppler 
and echocardiogram to search for the source of the emboli.

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