Visual functions after optic nerve neuritis treated according to the optic neuritis treatment trial [ONTT]

ABSTRACT

The annual incidence of optic neuritis as estimated and population based studies is approximately 5 per 100000 per year. The aim of this work is to asses the effect of optic neuritis treatment according to [ONTT] by measures of visual acuity, color vision, and visual field. 24 patients diagnosed as acute optic neuritis were treatment according to [ONTT] by Intravenous methylprednisolone 250mg every 6 hours for 3 days, followed by an oral prednisone 1mg/kg/day for 11 days. The rate of visual recovery and long term visual outcome were both assisted by measures of visual acuity, color vision, and visual field at base line then at 6 and 12 months post treatment. Visual acuity recovery began rapidly within the first week in the treatment course but continued improvement for up to one month post treatment. Also, most patients [20 patients] recovered to 20/20 or near 20/20 acuity. As regards color vision 4 from 16 affected did not show any changes. The other 12 showed improvement after the treatment and stabilized till the end of follow up. As regards the visual field defect, it was only positive in 16 eyes [66.67%] in the form of cecocentral scotoma in 10 eyes [41.67%] and generalized depression in the peripheral field in 6 eyes [25%] the other 8 eyes [33.33%] showed no significant field changes. As regards the pain with extraocular muscle movement, it was positive specially with looking up in 20 [83.33%] patients, the other 4 [16.67%] was not presented with pain. All the 20 patients recovered from pain after 2 weeks of treatment. There was no recurrence of the inflammation within the one year follow up time after the first tapering of the steroid after the initial therapy. Treatment with intravenous methyl-prednisolone for 3 days followed by oral prednisone according to [ONTT] for 11 days then gradual tapering is of benefit for early recovery of vision and in reducing the time of recurrences in the early follow up time and restoring most of the visual functions like color discrimination and contrast sensitivity