Comparison of central and peripheral visual field properties in the optic neuritis treatment trial

To compare the results of peripheral kinetic visual field testing and central static perimetry for patients enrolled in the Optic Neuritis Treatment Trial to determine (1) whether loss and recovery of visual field sensitivity in the far periphery was different from that observed in the central visual field and (2) whether the far peripheral visual field provided additional useful information that was not available in the central visual field results.

Both affected and fellow eyes of 448 patients with optic neuritis in the Optic Neuritis Treatment Trial were evaluated according to the trial protocol during the patients' first 3 years in the study. Central static visual field tests were performed with program 30-2 on the Humphrey Field Analyzer, and peripheral kinetic testing consisted of plotting the I3e and II4e isopters on the Goldmann perimeter. Both test procedures were conducted according to the trial protocols, and quality control assessments and clinical evaluations were performed on all the visual fields.

For both affected and fellow eyes at all 11 visits, there was a greater number of abnormal visual fields in the central static perimetry results than in the peripheral kinetic data. Only 2.9% of affected eyes had an abnormal peripheral visual field with a normal Humphrey mean deviation during year 1. At baseline, 97.1% of affected eyes had an abnormal Humphrey mean deviation on central static testing, whereas only 69.9% had abnormal peripheral kinetic visual fields. Approximately 80% of the I3e and II4e isopters for affected eyes that were abnormal at baseline were within normal limits at 30 days, but it took until week 19 for even 70% of the Humphrey mean deviations to return to normal. In addition, the II4e isopters (more peripheral than the I3e isopters) that were abnormal at baseline showed a somewhat greater percentage of improvement from baseline through day 30 than the abnormal I3e isopters. Although this difference is statistically significant, it is probably not clinically significant. For visits after week 19, approximately 25% to 30% of affected eyes had an abnormal Humphrey mean deviation, whereas only 10% to 15% of peripheral kinetic fields were abnormal.

For the affected eye in optic neuritis, the central visual field shows greater abnormalities than the far peripheral visual field. When the results obtained through Humphrey automated central static visual fields and Goldmann peripheral kinetic isopters are compared, the far periphery appears to recover more rapidly and more completely than the central field, at least in more severe cases of optic neuritis. In most cases, recovery in optic neuritis can probably be monitored effectively with automated perimetry of the central visual field alone. However, in cases of severe loss of the central visual field, a peripheral kinetic visual field obtained with a Goldmann perimeter may provide additional information about the patient's vision in the far periphery.