Follow-up of Methanol-related Visual Defects in a Cohort Study: Initial Severity Predicts Long-term Outcome.

Objective: Methanol poisoning can occur either intentionally through the consumption of methanol-containing products or accidentally through ingestion, resulting in visual impairment. We assessed the long-term visual sequelae in patients with methanol poisoning. Methods: This prospective cohort study was conducted at referral centers, Khorshid and Alzahra University Hospitals, affiliated with Isfahan University of Medical Sciences, Isfahan, Iran. The study included patients hospitalized for methanol poisoning from June 22, 2018, to June 21, 2020, with follow-up extended until June 2021. Toxico-clinical and ophthalmologic examination data were collected from patients upon hospital admission, discharge, and during follow-up. Findings: Thirty-nine patients were assessed in this study. The majority of them (94.9%) were male, with an average age of 34 years. Patients who presented with reduced visual acuity (VA) upon admission subsequently showed abnormalities (in acuity and visual fields) during follow-up ( Conclusion: Patients who demonstrated VA deficits upon admission are more likely to experience long-term VA and visual field defects, as well as optic disc atrophy. Patients who solely complained of blurred vision, with or without photophobia, during admission were less likely to develop long-term visual defects.