What are the key clinical features to differentiate between central retinal artery occlusion (CRAO) and branch retinal artery occlusion (BRAO)?

The key clinical features used to differentiate between central retinal artery occlusion (CRAO) and branch retinal artery occlusion (BRAO) primarily relate to the extent of vision loss and the specific fundoscopic findings (Hayreh, 2005).

• Central Retinal Artery Occlusion (CRAO) typically presents with sudden, profound, and painless monocular vision loss affecting the entire visual field of the eye (Hayreh, 2005). Fundoscopic examination often reveals a characteristic 'cherry-red spot' at the macula due to the preserved choroidal circulation, surrounded by a pale, oedematous retina in the posterior pole (Hayreh, 2005). An afferent pupillary defect (APD) is also commonly observed (Hayreh, 2005).
• In contrast, Branch Retinal Artery Occlusion (BRAO) results in sudden, painless monocular vision loss that is confined to a specific sector of the visual field, corresponding to the area supplied by the occluded branch artery (Hayreh, 2005). Fundoscopic findings in BRAO are localized to the affected retinal sector, showing retinal oedema (pallor) and sometimes a visible embolus within the occluded branch artery (Hayreh, 2005). The visual field defect is therefore sectoral, unlike the widespread loss seen in CRAO (Hayreh, 2005).