Bilateral Sequential Non-arteritic Anterior Ischaemic Optic Neuropathy (NA-AION) Presumed Secondary to 5-Fluorouracil (5-FU): A Case Report and Literature Review.

Bilateral successive anterior ischaemic optic neuropathy (AION) episodes are uncommon occurrences with a short list of differential diagnoses. We present the case of a 75-year-old male who developed bilateral consecutive non-arteritic AION after commencing 5-fluorouracil (5-FU) chemotherapy. The case report describes a temporal sequence of events with a halt in the progression of signs and symptoms upon cessation of treatment with this agent. Our patient demonstrated preexisting cardiovascular risk factors that were medically well controlled, as evidenced by laboratory results and blood pressure measurements. We reaffirm the current evidence that postulates an association between 5-FU use and arterial vasospasm in blood vessels predisposed to narrowing resulting in prolonged ischaemia to the optic nerve head.