A 24-year-old man hit his right forehead against a car dashboard in a motor vehicle accident. Visual acuity is counting fingers, there is a marked right relative afferent pupillary defect, but the optic disc and retina appear completely normal on dilated fundus examination. CT shows a fracture near the optic canal. The most likely diagnosis is:

• A Central retinal artery occlusion
• B Indirect traumatic optic neuropathy ✓
• C Commotio retinae involving the macula
• D Optic nerve avulsion

Explanation

Indirect traumatic optic neuropathy classically presents with profound visual loss and a relative afferent pupillary defect with a completely normal fundus in the acute phase; optic atrophy appears only after four to six weeks. It follows blunt head trauma with force transmission to the optic canal. Central retinal artery occlusion shows retinal whitening and a cherry-red spot, commotio shows retinal opacification, and avulsion shows a depressed excavated disc.

Reference: Kanski's Clinical Ophthalmology, 9th ed.

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Written and medically reviewed by the StethoPrep medical team.