Evaluation of the Efficacy of Melatonin in Visual Disturbed Methanol-intoxicated Patients: A Randomized Clinical Trial

Abstract

Background: This study evaluates the role of oral melatonin in improving vision in methanol toxicity since vision disorders are one of the side effects related to methanol toxicity and assumes the potential effects of melatonin in protecting neurons and optic nerves. Meanwhile, little attention has been paid by researchers to the effect of melatonin in these patients. Methods: A double-blind randomized controlled clinical trial study was conducted on 40 patients diagnosed with methanol toxicity who were referred to Khorshid Hospital of Isfahan City, Iran, from May 2022 to May 2023. These patients were randomly divided into two groups. In the first group (the intervention group), in addition to the usual treatment, the patients were prescribed orally 3 mg of melatonin every morning and 6 mg of melatonin every night for 10 days. In the second group (the control group), in addition to the usual treatment, a placebo was administered similar to the intervention group protocol. Then, the clinical and vision parameters of the patients were evaluated before, during, and after the intervention. Results: The mean pH, PCO2 and HCO3 increased significantly after the intervention compared to the pre-intervention in both groups (P<0.05); however, no significant difference was found between the two groups in any of the two follow-up times (P>0.05). The most common visual complication caused by methadone toxicity was blurred vision with 71.4% and 90% in the melatonin and non-melatonin groups, respectively. Visual complications improved significantly after the intervention compared to the pre-intervention; accordingly, the complete improvement of vision complications in the melatonin group (76.2%) was significantly more than the non-melatonin group (53.3%) (P=0.040). Conclusion: Melatonin improves blurred or snowfield vision in methanol poisoning. Therefore, the administration of melatonin plus routine treatment can be effective in improving vision disorders (blurred or snowfield vision) caused by methanol poisoning.