Baseline features of idiopathic optic neuritis as determined by a multicenter treatment trial in Japan

Background: An optic neuritis treatment trial was conducted at 30 clinical centers in Japan using the same protocol. Patient participation was based o n: age range of 14-55 years; acute symptoms indicative of unilateral optic neuritis of unknown or demyelinating origin; visual symptoms of 14-day dura tion or less; relative afferent pupillary defect in affected eye; and norma l or swollen optic disc of affected eye. Cases: Initially, 102 patients qualified for participation; baseline data w ere obtained for analysis from 70 of these patients. Demographic characteri stics of Japanese patients with optic neuritis were clarified and compared with those in a US study. Observations: The incidence of ocular or periocular pain and the presence o f periventricular plaques were noted to be lower? and the incidence of disc swelling higher, in the Japanese patients, suggesting racial differences i n the characteristics of the disease. Such differences may possibly be rela ted to the lower incidence of multiple sclerosis in Japanese patients. The results of visual function tests were virtually the same in both studies. T he nonaffected eyes of more than half the patients showed abnormal mean dev iation in Humphrey field analysis, as also noted in the US study. Conclusions: The baseline clinical features of optic neuritis in the Japane se patients have been defined. Some racial differences in the characteristi cs of the disease may exist. (C) 1999 Japanese Ophthalmological Society.