Variability of high-pass resolution perimetry in normals and patients with idiopathic intracranial hypertension.

High-pass resolution perimetry, or the "ring test," is a recently developed type of acuity perimetry. To determine its test-retest variability, we studied 10 normals and 10 patients with idiopathic intracranial hypertension (IIH) by testing both eyes four separate times. There was no increase in variability from the center out to 21 degrees of visual field eccentricity. However, there was a significant increase from 22 degrees to 29 degrees in both normals and IIH patients. Unlike light sensitivity threshold automated perimetry, with an increase in threshold level there was no significant increase in variability in either normals or patients. This may be because of the test's method, which thresholds by target size rather than intensity. As expected, there was a large intersubject variability in the patients, with the visual fields being significantly disturbed by analysis of total field, quadrants, concentric rings, and anatomic nerve fiber bundle regions. Surprisingly, there was no significant difference in the total within subject variability of normals and patients. Because with the ring test there is no increase in variability with an increase in threshold, this method of perimetry may have great utility for following patients with disturbed visual fields. The ring test appears to have advantages that promote low test-retest variability.