The efficacy of erythropoietin in methanol induced optic neuropathy: a systematic review

Methanol toxicity outbreaks have been a recurring problem around the world, and the recent pandemic has contributed to an increase in their incidence. The resulting toxic optic neuropathy may lead to complete permanent blindness. Erythropoietin (EPO) has demonstrated potential neuroprotective and neuroregenerative capabilities, which may improve the outcomes of patients with methanol-induced optic neuropathy (MTON). This work aimed to understand the efficacy and practical applications of EPO in cases of MTON. We included all original studies if they had patients with MTON, treated with EPO, and reported the outcomes of interest for clinical questions, including the end visual outcome. MEDLINE, Embase, Cochrane Library, and Web of Science databases were searched with no date restriction to obtain records. We included 9 articles in our review, with a total of 192 patients, all of whom had been diagnosed with MTON. Erythropoietin treatment started 2 to 29 days after the onset of visual symptoms. Most studies reported an improvement in visual acuity compared to baseline. However, compared to the standard corticosteroid treatment alone, the results of EPO were conflicting. No adverse events were reported. The result of adding EPO to corticosteroid treatment in the management of MTON had variable improvements in visual acuity. EPO has potential beneficial effects if used early on in the acute phase of exposure to methanol. The role of repeating or maintaining therapy for a longer duration to enhance the protective effects or prevent relapses remains unknown. Future clinical trials to investigate these options.