Case Report: Disulfiram-induced optic neuropathy

Background: Toxic optic neuropathy (TON) is characterized by bilateral, symmetric vision loss with damage to the papillomacular bundle, central or cecocentral scotomas, and impaired color vision. While TON has been well-documented with medications such as ethambutol and linezolid, disulfiram-induced optic neuropathy remains rare with limited case reports in the literature. Case presentation: We report two cases of disulfiram-induced TON in patients with alcohol use disorder. Case 1 involved a 52-year-old man who developed painless, progressive bilateral vision loss after 9 months of disulfiram therapy (250 mg daily). Initial visual acuity was 20/100 OD and 20/70 OS with severe dyschromatopsia (control plate only bilaterally on Ishihara testing) and central scotomas. Case 2 involved a 55-year-old man with 5 years of disulfiram use (250 mg daily) who presented with bilateral central vision loss, visual acuity of 20/50 OD and 20/40 OS, and marked color vision impairment. Both patients underwent extensive workup including neuroimaging, autoimmune panels, infectious serologies, nutritional markers, heavy metal screening, and genetic testing for hereditary optic neuropathies, all of which were unremarkable. Results: Following disulfiram discontinuation, both patients demonstrated significant visual recovery. In Case 1, visual acuity improved to 20/40 OD and 20/30 OS at 7 months with normalization of visual fields. In Case 2, visual acuity recovered to 20/20 bilaterally at 3 months with complete restoration of color vision (14/14 Ishihara plates). Both cases showed persistent temporal retinal nerve fiber layer thinning on optical coherence tomography despite functional recovery. Conclusion: These cases highlight disulfiram as an important cause of TON in patients with alcohol use disorder. The differential diagnosis in this population must include nutritional and hereditary optic neuropathies, as mitochondrial dysfunction likely represents a common final pathway. Early recognition and drug cessation can result in substantial visual recovery, although structural changes may persist. Clinicians should maintain awareness of this rare but reversible complication when prescribing disulfiram for alcohol dependence.