Detection of Glaucomatous Visual Field Loss Using the Humphrey Matrix Frequency Doubling Technology (FDT) Perimeter

Abstract

Abstract: : Purpose: To determine the clinical performance characteristics of the 24–2 threshold test procedure on the Humphrey Matrix, a device that evaluates contrast sensitivity for frequency doubling technology (FDT) stimuli, in the detection of glaucomatous visual field loss. Methods: 261 subjects (ages 18 to 87 years) with normal visual fields (Humphrey SITA Standard) and normal ocular examinations in both eyes, and 156 patients with glaucomatous visual field loss (Humphrey SITA Standard) were evaluated with the 24–2 threshold stimulus program of the Humphrey Matrix FDT device. All participants had Humphrey Field Analyzer (SITA Standard) 24–2 test performed prior to Humphrey Matrix evaluations. Glaucomatous visual fields were classified as mild (MD better than –6 dB) moderate (MD between –6 and –12 dB) and severe (MD worse than –12 dB) visual field loss, according to the Humphrey Field Analyzer results. Contrast sensitivity for the 24–2 threshold test procedure of the Humphrey Matrix was conducted using a ZEST (Zippy Estimation of Sequential Testing) procedure and a 0.5 cycle per degree sinusoidal grating undergoing 18 Hz counterphase flicker. Results: Using a criterion of Pattern Standard Deviation (PSD) and Glaucoma Hemifield Test (GHT) visual field indices within normal limits for the Humphrey Matrix, specificity was approximately 86%. Sensitivity was 100% for moderate and severe glaucomatous visual field loss, and approximately 76% for mild glaucomatous visual field deficits. The use of an analysis procedure incorporating clusters of points with statistically reduced contrast sensitivity for the Humphrey Matrix increased the sensitivity for detecting mild glaucomatous visual field loss to 87%. Conclusions: Preliminary analysis of the Humphrey Matrix FDT perimeter indicates that it exhibits good sensitivity and specificity for detection of moderate and advanced glaucomatous visual field loss, using the PSD and GHT indices. Sensitivity for mild glaucomatous visual field deficits can be improved by inclusion of a cluster criterion for locations with reduced sensitivity. Further evaluations should provide additional improvements to the clinical performance of the Humphrey Matrix.

Keywords: perimetry • visual fields • temporal vision