Vol. 7, Issue 1, Part A (2025)

Background: Methanol poisoning is a medical emergency that can lead to metabolic acidosis, visual failure, and neurological impairment. While ocular toxicity is typically bilateral due to formate-induced dysfunction in the optic nerve and retina, unilateral central retinal artery occlusion from methanol is rare. This case highlights an unusual instance of unilateral occlusion following acute methanol ingestion and emphasises the need for early ophthalmic evaluation in suspected toxic alcohol cases.

Case Presentation: A 46-year-old man experienced sudden, painless vision loss in the right eye and blurred vision in the left eye after consuming locally brewed alcohol. He also had nausea, vomiting, and headache. Visual acuity was hand movement in the right eye and 6/24 in the left. Fundus examination revealed a pale, edematous retina with a cherry-red spot in the right eye and a normal left eye, along with a relative afferent pupillary defect. Laboratory studies confirmed methanol intoxication with severe metabolic acidosis (pH 7.09, HCO₃⁻ 9 mEq/L) and a serum methanol level of 35 mg/dL. MRI imaging showed partial loss of flow void with luminal narrowing of the visualised right internal carotid artery, suggesting thrombosis. The diagnosis of unilateral central retinal artery occlusion (CRAO) was made. Treatment included intravenous sodium bicarbonate, fomepizole, folinic acid, and urgent hemodialysis. Ophthalmic management involved ocular massage, carbogen inhalation, and acetazolamide. The patient's systemic condition improved, but there was no visual recovery in the right eye; the left eye improved to 6/12 at 2 weeks. Follow-up examination revealed optic disc pallor and retinal thinning in the right eye, indicating optic atrophy due to occlusion.

Conclusion: This case shows a rare instance of unilateral CRAO after methanol poisoning. Prompt detoxification and ophthalmic evaluation are essential to preserve vision and avoid bilateral blindness.