[2 cases of acute retrobulbar neuritis by thinner inhalation; detected methanol of high concentration in gas phase assay].

We encountered two cases of acute retrobulbar neuritis due to lacquer thinner vapor sniffing. Two men, aged 21 and 23, had been addicted to thinner sniffing for many years. After they became conscious of their symptoms of slight visual disturbance, they continued the sniffing for several days until they lost their vision. The diagnoses of acute retrobulbar neuritis were obtained from their signs and clinical examinations. They recovered to some extent with injection of steroids and vitamin B complex administration, but still had severe impairment of visual acuity. Lacquer thinner is a mixture of solvents, and toluene is usually the main component of the thinner solution. Therefore, in the addiction to thinner sniffing, symptoms and signs of thinner intoxication are considered mainly to be the results of toluene inhalation. However, in our analysis of the thinner gas with gas chromatography, it was revealed that the main component of the gas phase of the thinner was methanol, accounting for as much as 60,000 ppm of the gas. We consider that in the thinner vapor sniffing, they are inhalating mainly methanol, not toluene.