Purpose: To quantify automated visual field defects seen at entry in the Optic Neuritis Treatment Trial (ONTT) to determine whether particular areas of the field are preferentially affected and to determine the extent of visual field involvement in patients having "localized" field defects.
Methods: Review of Humphrey 30-2 Visual Field (Allergan-Humphrey, Inc, San Leandro, CA) data from the involved and fellow eyes of 440 patients who were enrolled in the ONTT. Field defects were evaluated by comparing the involved eye to the fellow eye.
Results: Patients with diffuse visual field defects had a relatively equal diminution of visual threshold throughout the tested 30-2 field. Patients with localized central and cecocentral scotomas had their greatest depression of threshold centrally; however, even those patients with mild defects (mean defect, <6 dB) had diminution of visual threshold throughout the entire tested 30-degree field. Patients with moderate (mean defect, 6 to 20 dB) and severe (mean defect, >20 dB) central and cecocentral defects had even greater peripheral depression. Patients with altitudinal or quadrant defects had involvement of the "unaffected" field that also varied with the mean defect. The overall average depression of visual threshold for all patients averaged 36%+/-4% and was relatively uniform throughout the tested field.
Conclusions: Optic neuritis affects the entire central 30-2 field, even in patients who appear to have localized depression of visual threshold. Optic neuritis does not appear to have a predilection for any particular area of the visual field.