Cupping of the optic disk after methanol poisoning

Purpose To assess the frequency and significance of optic disk cupping after methanol poisoning. Methods We retrospectively reviewed the medical records of 50 consecutive patients with methanol poisoning, including visual acuity, pupillary reaction, and optic disk features such as the presence and degree of cupping. All patients were examined in the chronic phase after optic nerve damage. Results Optic disk cupping ≥0.8 c/d was present in at least one eye of 22 of these 50 patients (43/100 eyes). Severity of cupping was statistically symmetric in the two eyes, and increasing severity of cupping was correlated with worse visual acuity (p=0.007) and increasing visual field loss. Degree of cupping was significantly correlated with increasing patient age but not with putaminal necrosis. Conclusions Optic disk cupping after methanol poisoning may be more common than previously recognised. Cupping in this setting may reflect toxicity of methanol metabolites to axons and glial cells in the prelaminar, laminar and retrolaminar regions, and seems to be important as a marker for worse optic nerve damage.