- Condition causing impaired blood flow to the retina
- Essentially vascular disease of the eye
- Ophthalmic emergency- although outcomes are generally poor
- Hypertension (up to 66%)
- Diabetes mellitus
- Valvular disease/PFO (cardiac embolus)
- Hypercholesterolaemia (carotid artery disease)
- Giant cell arteritis (inflammation)
- Acute, persistent, and usually profound painless visual loss. This may come on like ‘a curtain drop’ but more often than not is just sudden.
- Common signs of a CRAO are a relative afferent pupil defect.
- On fundoscopy, there is a pale retina (loss of arterial blood and build up of oedema), with thread-like retinal vessels.
- There may also be a classical ‘cherry red spot’ (this is actually choroidal vessels that are seen through the thin and now pale macula where the retina is thinnest).
- Giant cell arteritis should be excluded by investigating plasma viscosity and ESR.
- If the patient presents within 24 hours with CRAO, ocular massage may help (only to dislodge an embolus to cause a branch retinal artery inclusion instead).
- Carotid doppler should also be used to investigate carotid disease.
- Medication may be required to reduced the IOP which can build up due to oedema secondary to the blockage.
- CA inhibitors (azetazolomide), beta-blockers
- Outcome is often poor
This is a temporary retinal artery occlusion causing a temporary complete loss of vision. This is commonly due to an embolus that has been dislodged or inflammatory spasm that has resolved.
Branch Retinal Artery Occlusion
- As above but one branch of the retinal artery affected
- Typically presents with visual field loss (depending on the branch)