Evaluation of Baseline-Related Suprathreshold Testing for Quick Determination of Visual Field Nonprogression

Abstract

To evaluate a commercially available means of baseline-related suprathreshold examination designed to detect visual field worsening. Patients for whom results of a baseline series of static-threshold visual field examinations were available underwent both a second static-threshold examination (full-threshold strategy; average time, 15 minutes) and a baseline-related suprathreshold examination ("fast-threshold" strategy; average time, 5 minutes). Most of the 1702 points examined were apparently unchanged from baseline, showing with either method only the degree of variation expected from the measurement inconsistency (short-term fluctuation). For points that did show a change, the changes shown by the two methods were correlated. Change in the field as a whole, represented by a cluster of locations showing deterioration, was evident more frequently with the standard testing strategy: 11 of 37 field examinations showed deterioration by both methods and an additional 11 examinations showed deterioration by the full-threshold method only. Each examination method identified pointwise changes not detected by the other, the combined effect of false-positive errors (imperfect specificity) and false-negative errors (imperfect sensitivity) with each of the two methods. The findings relating to clusters could represent a better sensitivity of the full-threshold method in detecting visual field deterioration, a better specificity of the suprathreshold method, or both.