Recovery of visual field function in the optic neuritis treatment trial

PURPOSE: To assess the pattern of recovery of the visual field of patients with optic neuritis and to determine whether all affected portions of the v isual field recover similarly or certain portions of the visual field have greater recovery. METHODS: We reviewed the Humphrey Visual Field (Allergan-Humphrey Inc, San Leandro, California) data from the initial and 6-month examination for the involved and fellow eyes of patients enrolled in the Optic Neuritis Treatme nt Trial (ONTT), The average threshold for each patient was calculated for the entire rested field and for locations within concentric rings having a radius 3, 9, 15, 21, and 27 degrees from fixation. The absolute amount of i mprovement and percentage improvement in average threshold between entry an d the 6-month follow-up examination were determined for each patient. These measurements were compared within the concentric rings to assess patterns of recovery. RESULTS: Patients with localized defects recovered 86% +/- 20% of their ini tial defect in average threshold, whereas those having diffuse defects reco vered an average of 85% +/- 23%. The area about fixation had the greatest r elative recovery of threshold (87% +/- 21% at 3 degrees); the relative reco very decreased with increasing eccentricity from fixation (P < .01). CONCLUSIONS: Patients with optic neuritis have a marked return of visual fi eld function that does not appear to differ between patients with diffuse o r localized field defects. The reduced redundancy of axons in the periphery of the field compared with near fixation may be responsible for the greate r relative recovery of threshold near fixation. (C) 1999 by Elsevier Scienc e Inc. All rights reserved.