In central retinal artery occlusion (CRAO), the fundus typically shows a 'cherry-red spot' at the fovea because:
- A The fovea has the highest density of blood vessels and is therefore more congested
- B The ganglion cell layer is thickest at the fovea causing maximum oedema around it
- C The foveal avascular zone receives choroidal supply, and the thin fovea lacks inner retinal oedema obscuring the choroidal red reflex ✓
- D Xanthophyll pigment at the fovea concentrates the red appearance
Correct answer: C. The foveal avascular zone receives choroidal supply, and the thin fovea lacks inner retinal oedema obscuring the choroidal red reflex
Explanation
In CRAO, ischaemia of the inner retinal layers (which are supplied by central retinal artery branches) causes oedema and opacification of the entire posterior pole. The fovea itself lacks inner retinal layers (the ganglion cell and inner nuclear layers are absent at the foveal pit), so it does not undergo ischaemic oedema. The underlying choroid (fed by posterior ciliary arteries) remains perfused and is seen through the thin fovea as a red-orange spot contrasting with the surrounding oedematous white retina.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.