Sensitivity and specificity of the Humphrey Matrix to detect homonymous hemianopias

To compare the sensitivity and specificity of the Humphrey Matrix frequency-doubling perimeter (Carl Zeiss Meditec, Inc., Dublin, CA) to that of standard automated perimetry (SAP) in detecting homonymous hemianopic visual field defects.

Thirty-three patients with homonymous hemianopias and 50 normal subjects were tested with SAP with the Humphrey Visual Field Analyzer (SITA standard program 24-2) and Humphrey Matrix frequency-doubling perimetry, program 24-2 (Matrix) on the same day. Patients with hemianopias had lesions of the retrochiasmal visual system that were documented by magnetic resonance imaging or by computed tomography. To be classified as a hemianopic visual field defect, the abnormal test location had to be homonymous, respect the vertical meridian, and have no additional scattered abnormal points that obscured the hemianopic pattern. The sensitivity and specificity of SAP and Matrix in detecting hemianopic defects were calculated. The chi(2) test was used to test for differences between groups.

The sensitivity for hemianopic defects by total deviation probability plots was 75% for SAP and 59% for Matrix (not statistically significant, P = 0.29). The sensitivity of hemianopic defects by pattern deviation probability plots was 88% for SAP and 69% for Matrix (not statistically significant, P = 0.13). The specificity of total deviation probability plots was 84% for SAP and 86% for Matrix. The specificity of the pattern deviation probability plots was 68% for SAP and 74% for Matrix.

Although there was no statistically significant difference between the Matrix and SAP in the detection of hemianopias, the sensitivity of SAP was higher, probably because of the obscuration of defects by scattered abnormal test locations with the Matrix.