Is high-dose intravenous steroid effective on preserving vision in acute methanol poisoning?

I read with interest the study conducted by Sharma et al. recently published in Optometry and Vision Science. I think some points are worth noting about this study. First, the aim of the authors was to examine the effectiveness of ethanol and high-dose intravenous (IV) steroid on the preservation and restoration of visual acuity when fomipizole is not available in acute methanol poisoning. However, interestingly, they have not given both ethanol and IV prednisolone to all their patients. It seems that their aim was to evaluate the effect of administration of high-dose steroids on the methanol-induced visual disturbances (VD) that has previously been performed in four other studies. Second, although all of their patients had shown the presence of methanol in their blood, only two with additional neurological manifestations and metabolic acidosis underwent hemodialysis. As you know and despite what the authors claim, hemodialysis is being performed in methanol poisoning not only for the correction of systemic acidosis but also for the removal of the toxic anion formate and reducing formate toxicity by correction of metabolic acidosis. Therefore, in methanol poisoning, hemodialysis is absolutely indicated in any patient with any degree of VD accompanied by metabolic acidosis or a detectable methanol level as well as the antidotal therapy (ethanol or fomepizole), administration of folic or folinic acid, and sodium bicarbonate if indicated. Third, 50% of the patients had presented after 24 hours and the authors have attributed this to the lack of awareness about the potentially dangerous effects of the ingested alcohol. This is while the patients who present with methanol poisoning have usually ingested alcohol beverages containing methanol as an adulterant. Symptoms of methanol poisoning are therefore usually delayed for 12 to 24 hours and even longer due to concomitant ethanol postponing the metabolism of methanol. Fourth, VD had been improved in 81.25% of their patients using their treatment at the time of discharge and at 1-week follow-up. Two-eye vision deteriorated at 1 month while remaining unchanged in one. Therefore, they concluded that most patients had shown an improvement of vision using methylprednisolone. However, it has previously been shown that in methanol poisoning, even without treatment with fomepizole and high-dose IV prednisolone, patients’ VD is grouped into four categories: group I: patients whose blurred or snowfield vision completely recovers within up to a maximum of 2 weeks after discharge; group II, the patients who are blind at the time of discharge and partly recover within a maximum of 3 to 4 weeks; group III, the patients who are blind at the time of discharge and gain no improvement in their vision; and group IV, who are blind at the time of discharge, partly recover within few days to approximately 1 month and experience reduced vision and blindness after about a maximum of 9 months. Therefore, their patients might have gone through this course even without the administration of the steroids. It seems that a case-control study is warranted to evaluate the effect of high-dose steroid in methanol-induced VD. Hossein Sanaei-Zadeh, MD Department of Forensic Medicine and Toxicology Tehran University of Medical Sciences, Hazrat Rasoul Akram Hospital Tehran, Iran