Compressive Optic Neuropathy from Allergic Fungal Sinusitis.

Ophthalmic manifestations of allergic fungal sinusitis (AFS) are rare, but can occur in advanced disease. A 32-year-old man with advanced AFS presented with severe bilateral vision loss and restricted ocular motility. Magnetic resonance imaging and histological analysis confirmed active chronic AFS. Functional endoscopic sinus surgery was performed, with adjunctive steroid therapy. Although AFS is a reasonably well-recognised entity, severe disease causing bilateral visual deficits is rarely encountered. This can confound the diagnosis and appropriate treatment. Ophthalmologists should thus be aware of compressive optic neuropathy as a complication of advanced AFS to prompt early treatment and mitigate visual loss.