An Updated Review on the Most Common Agents Causing Toxic Optic Neuropathies

Background: Toxic optic neuropathies (TONs) often present with a gradual and bilateral decrease in visual acuity, scotomas and optic disc pallor. Obtaining an accurate history is the critical first step in determining the etiology of TONs. Methods: This updated review contains a thorough analysis of the current PubMed-indexed literature on the most common agents responsible for TONs, including methanol, ethambutol, amiodarone, linezolid, tumor necrosis factor alpha inhibitors and phosphodiesterase 5 inhibitors. Results: The reviewed articles are mainly case reports presenting new and controversial aspects of the above agents. New treatment strategies, such as erythropoietin for methanol optic neuropathy, are being proposed for TONs, a condition that was previously regarded as untreatable. Conclusion: TONs could cause significant disability due to visual impairment. In case of early diagnosis and drug withdrawal, most TONs are treatable. Patients need to be appropriately counseled, and prescribing physicians should be especially made aware of TON-inducing medications.