A 70-year-old man wakes up with painless sudden loss of vision in one eye. Fundus examination shows disc oedema, splinter haemorrhages at the disc, and a pale swollen optic disc. Visual field shows an altitudinal defect. The MOST likely diagnosis is:

• A Central retinal artery occlusion
• B Non-arteritic anterior ischaemic optic neuropathy (NA-AION) ✓
• C Arteritic anterior ischaemic optic neuropathy (A-AION, giant cell arteritis)
• D Papillitis from demyelinating disease

Explanation

Non-arteritic AION is the most common acute optic neuropathy in patients over 50, caused by ischaemia of the short posterior ciliary arteries. The classic presentation is painless sudden visual loss on waking (nocturnal hypotension is implicated), disc oedema with splinter haemorrhages, and altitudinal field defect (typically inferior). CRAO shows a cherry-red spot with pale retina. A-AION (GCA) presents similarly but with scalp tenderness, jaw claudication, and dramatically elevated ESR/CRP. Papillitis causes a central scotoma and is painful.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.