Purpose: The purpose of this present study was to evaluate longitudinal visual field information for 448 patients over their first year of follow-up in the Optic Neuritis Treatment Trial.
Methods: We reviewed 6536 automated static visual fields performed on a visual field analyzer (Humphrey Visual Field Analyzer) at nine visits within the 1-year period for each of the patients.
Results: The median values of the mean deviations for affected eyes were as follows: -22.88 dB at baseline, -1.94 dB at 6 months, and -1.62 dB at 1 year. At 6 months, 51% of affected eye visual fields were normal, and at 1 year 55.9% were normal. Approximately two thirds (68.8%) of the fellow eyes were classified as abnormal at baseline, although the defects were generally slight. One third (33.2%) were abnormal at 6 months, and approximately one third were still abnormal at 1 year. More than 87% of those abnormal at 6 months and at 1 year had been abnormal at baseline. Binocular analysis revealed that 13.2% of patients showed a chiasmal or retrochiasmal type of field defect at least once during the year (5.1% bitemporal; 8.9% homonymous). Of the patients who showed a retrochiasmal visual field defect, 75.7% had an abnormal magnetic resonance imaging scan at baseline compared with 46% of the rest of the patients in the Optic Neuritis Treatment Trial (chi 2 = 10.73, df = 1, P < .002).
Conclusion: Over the first year of follow-up, the majority of patients with visual field defects from acute optic neuritis returned to normal, as measured by automated static perimetry. Many fields showed variation in the pattern and location of the sensitivity loss. Chiasmal and retrochiasmal defects occurred more commonly than previously reported.