What is the significance of a 'cherry-red spot' on fundus?

• A. Macular degeneration.
• B. Central retinal artery occlusion.
• C. Retinal detachment.
• D. Glaucoma.

Answer: (B)

A cherry-red spot on the fundus points to central retinal artery occlusion. When the central retinal artery is blocked, the inner retinal layers become pale due to acute ischemia, so the surrounding retina looks white and opaque. The fovea appears as a bright red spot because it is thin and its color comes from the underlying choroidal circulation, which is still perfused. This creates the distinctive cherry-red appearance. Clinically, it presents as sudden, painless monocular vision loss and is an ophthalmic emergency requiring urgent evaluation to restore retinal blood flow. The usual culprits are emboli or thrombi from the carotid arteries or heart in patients with vascular risk factors. Other conditions like macular degeneration, retinal detachment, or glaucoma produce different fundus findings, so the cherry-red spot helps differentiate an arterial occlusion from those entities.