Time course study of optical coherence tomography angiography in patients with methanol toxicity

Abstract

Methanol is a clear, colorless, and flammable liquid which is metabolized in the body to formaldehyde by alcohol dehydrogenase, following which formaldehyde is rapidly converted to formic acid, a metabolite that causes the majority of the toxicity associated with Methanol. Ingestion of as little as 10 mL can result in complete and permanent visual loss from bilateral optic neuropathy, and 30 mL can be fatal, although the fatal dose is typically 100–125 mL. Toxicity usually occurs from accidental ingestion with homemade alcoholic drinks in countries that alcoholic beverages are legally prohibited.The initial ophthalmologic symptoms of methanol toxicity typically appear 6–48 ho post-ingestion and severity of symptoms vary widely from mild and painless decreases in vision to no-light perception vision. Due to the lack of a previous similar study, the aim of this study was to evaluate the course of OCTA changes in patients at intervals of 10 days, one month and three months after methanol poisoning. Materials and Methods: This study was an analytical study of patients with acute methanol poisoning (within 10 days of use) whom referred to the Tabriz Nikoukari Ophthalmology Center, underwent ocular clinical examination such as BCVA, OCT and OCT angiography of the macula and optic nerve, and these imaging were repeated at intervals of one month and three months after intoxication. And all patients with a history of ocular disease and low quality of their OCT images excluded from the study. Then, all findings were statistically analyzed over a period of three months. Results: In this study, 20 patients with methanol poisoning after receiving the necessary treatments Were examined at intervals of one to three months. As a result of statistical studies, the following data were determined: FAZarea (p = 0.309), FAZperimeter (p = 0.504), FD (P = 0.541), Superficial foveal vascular density (P = 0.187), deep foveal vascular density (P = 0.889), Superficial parafoveal vascular density (P = 0.026), deep parafoveal vascular density (p = 0.830), choroidal flow area (p = 0.460), total retinal thickness (p = 0.597), inner retinal thickness (P = 0.022) Outer retinal thickness (p = 0.067), Vascular density-whole image (p = 0.146), Vascular density-inside disc (p = 0.864), Vascular density-peripapillary (P = 0.680), Cup to disc ratio With (p = 0.000), RNFL with (p = 0.031), Vision with (P = 0.002)