Time course study of optical coherence tomography angiography in patients with methanol induced optic neuropathy.

INTRODUCTION: In countries where alcoholic beverages are legally prohibited, methanol toxicity usually occurs due to ingesting homemade alcoholic drinks. The initial ophthalmologic symptoms of methanol toxicity typically appear 6-48 h after ingestion, and the severity of symptoms varies widely from mild and painless decreased vision to no-light perception vision. METHODS: This prospective study examines 20 patients with acute methanol poisoning within 10 days of use. Patients underwent ocular examinations, BCVA (Best Corrected Visual Acuity) recording, and OCTA (Optical Coherence Tomography Angiography) of the macula and optic disc. BCVA measurement and imaging were repeated one month and three months after intoxication. RESULTS: There was a statistically significant reduction in superficial parafoveal vascular density (P-value = 0.026), inner retinal thickness (P-value = 0.022), RNFL (Retinal Nerve Fiber Layer) thickness (P-value = 0.031), and an increase in cup to disc ratio (P-value < 0.001), and central visual acuity (P-value = 0.002) in this time course. However, there was no statistically significant difference in FAZ (Foveal Avascular Zone) area (P-value = 0.309), FAZ perimeter (P-value = 0.504), FD-300 (Foveal density, vascular density within a 300 µm wide region of the FAZ) (P-value = 0.541), superficial vascular density (P-value = 0.187), deep foveal vascular density (P-value = 0.889), deep parafoveal vascular density (P-value = 0.830), choroidal flow area (P-value = 0.464), total retinal thickness (P-value = 0.597), outer retinal thickness (P-value = 0.067), optic disc whole image vascular density (P-value = 0.146), vascular density inside the disc (P-value = 0.864), or peripapillary vascular density (P-value = 0.680) at different times. CONCLUSION: Over time, methanol poisoning can cause changes in retinal layers thickness, vasculature, and optic nerve head. The most important changes include cupping of the optic nerve head, reduction in RNFL thickness, and inner retinal thickness.

Severe Optic Disc Cupping Following the Methanol Toxicity in a 20-Year-old Man: A Case Report.

In April 2018, a 20-year-old man with a history of methanol intoxication from an alcoholic drink two years ago, when he was 18 years old, was referred to Nikookari Eye Hospital in Tabriz, Iran. He was admitted to emergency service and underwent eight hours of hemodialysis at the time of poisoning. His past medical history was negative, and he did not take any medication after discharge. The patient had a driving license and never experienced any visual problems before. At presentation, his visual acuity was 160/200 in both eyes with the main complaint of visual field deterioration. Other neurologic exams and brain magnetic resonance imaging (MRI) were reported normal by a neurologist. Optic disc cupping was near total in both eyes with a very narrow remaining rim. Optic disc cupping was very similar to glaucomatous cupping. Intraocular pressure was checked several times via Goldmann tonometry and was 13 mmHg. There was no history of refractive surgery leading to thin cornea. Based on this case, methanol poisoning can mimic glaucomatous optic disc cupping. This is the first case report of methanol toxicity-related optic disc cupping from Iran.