Ethambutol toxic optic neuropathy

Ethambutol is a commonly used antituberculous medi cations. Ocular toxicity of ethambutol is well es� tablished. It needs to be detected early and medication stopped promptly to avoid irreversible damage. A 64�yearold lady was referred for gradual deterio ration of her vision of both eyes. Examination and investigations confirmed bilateral toxic optic neuropathy secondary to ethambutol. The drug was stopped with immediate effect. Three months later, her distance vision and colour vision improved significantly. The course and outcome of ethambutol induced toxic optic neuropathy is unpredictable. Optic nerve head remains normal on Fundoscopy until late in the disease. Improvement of vision after discontinuation of ethambutol occurs only in a minority of patients. This case highlights the importance of ocular screening to detect toxic neuropathies early to possibly prevent permanent visual disability.