Baseline features of idiopathic optic neuritis as determined by a multicenter treatment trial in Japan. Optic Neuritis Treatment Trial Multicenter Cooperative Research Group (ONMRG).

BACKGROUND

An optic neuritis treatment trial was conducted at 30 clinical centers in Japan using the same protocol. Patient participation was based on: age range of 14-55 years; acute symptoms indicative of unilateral optic neuritis of unknown or demyelinating origin; visual symptoms of 14-day duration or less; relative afferent pupillary defect in affected eye; and normal or swollen optic disc of affected eye.

CASES

Initially, 102 patients qualified for participation; baseline data were obtained for analysis from 70 of these patients. Demographic characteristics 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 of periventricular plaques were noted to be lower, and the incidence of disc swelling higher, in the Japanese patients, suggesting racial differences in the characteristics of the disease. Such differences may possibly be related to the lower incidence of multiple sclerosis in Japanese patients. The results of visual function tests were virtually the same in both studies. The nonaffected eyes of more than half the patients showed abnormal mean deviation in Humphrey field analysis, as also noted in the US study.

CONCLUSIONS

The baseline clinical features of optic neuritis in the Japanese patients have been defined. Some racial differences in the characteristics of the disease may exist.