The Eyes Have It: Unmasking Ethambutol Optic Neuropathy and Toxicity on MRI

Ethambutol is a commonly used antimycobacterial agent used in the treatment of tuberculosis (TB) and known for its potential to cause optic neuropathy. It typically presents as bilateral, painless visual loss and incidence can range between 0.5% and 18% depending on factors such as duration of treatment and dosage [1,2]. We report the case of a 35-year-old female presenting with bilateral optic neuritis suggestive of toxic optic neuropathy secondary to ethambutol with associated central nervous system (CNS) imaging abnormalities on the MRI. In clinical practice, ethambutol optic neuropathy (EON) is often under-recognised, but the condition is potentially reversible if detected early, making diagnosis crucial.