Serum methanol levels in subjects with or without optic nerve head disease

We evaluated serum methanol levels in subjects with or without optic nerve head disease. Serum methanol levels were determined using gas chromatography in 71 patients with optic nerve head disease and in 127 subjects without optic nerve head disease. Their ages ranged from 17 to 89 years. Serum methanol levels in 127 subjects without optic nerve head disease ranged from 0.12 to 3.86 microg/ml (mean +/- standard deviation, 1.72 +/- 0.86 microg/ml). In the subjects without optic nerve head disease, the differences in the levels between those with cataract versus retinal detachment, men versus women, and between each age-group (50-80 years) were not significant. The methanol levels in patients with optic neuritis (n = 2), Wolfram syndrome (n = 1), Leber hereditary optic neuropathy at the late stage (n = 2), retinitis pigmentosa (n = 23), and primary open-angle glaucoma (n = 16) were less than 3.86 microg/ml. Methanol levels in 1 patient with Leber hereditary optic neuropathy at the acute stage was 5.28 microg/ml. Of 10 patients with primary angle-closure glaucoma, 1 had a slightly elevated level and 9 had levels less than 3.86 microg/ml. Of 17 patients with normal tension glaucoma, 5 had methanol levels higher than 3.86 microg/ml, and 12 patients had levels less than 3.86 microg/ml. The present study shows that serum methanol levels in subjects without optic nerve head disease ranged from 0.12 to 3.86 microg/ml and were much lower than the levels that produce acute ocular symptoms of methanol intoxication. It is possible that high serum methanol levels may play a part in the acute stage of Leber hereditary optic neuropathy and normal tension glaucoma in certain patients. It is unlikely that increased serum methanol levels participate in primary angle-closure glaucoma.