Comparison of temporal and spatiotemporal contrast-sensitivity tests in normal subjects and glaucoma patients

Contrast sensitivity (CS) is reduced in glaucoma diseases. This study compares the value of different CS measurements in glaucoma diagnosis. The study population consisted of age-matched groups of 31 normal subjects (age, 36-59 years; median, 47 years; mean +/- SD, 47.4 +/- 7 years) and 59 glaucoma patients with optic disk damage and visual field defects (age, 36-63 years; median, 53 years; mean +/- SD, 52.3 +/- 7 years). Three types of CS determination were carried out in all subjects: (1) temporal CS of a sinusoidally flickering light (37 Hz) in a ganzfeld bowl, (2) spatiotemporal CS (alternating pattern: 2.5 Hz, 1 cycle/degree; screen size, 5.3 degrees x 4.3 degrees) in a temporal upper retinal area (13.8 degrees horizontal, 4.2 degrees vertical), and (3) spatial CS of a static pattern (three spatial frequencies: 0.6, 3.0, and 12 cycles/degree; screen size, 5.3 degrees x 4.3 degrees) with central fixation. In glaucoma patients the results of CS tests with flickering stimuli were highly significantly correlated with the perimetric mean sensitivity (MS; Octopus G1 program: temporal CS, r = 0.67, P < 0.001; spatiotemporal CS, r = 0.8, P < 0.001). For spatial CS the frequency of 3.0 cycles/degree showed the strongest correlation with MS (r = 0.64, P < 0.001). Only the peripherally localized, spatiotemporal CS showed a strong correlation with optic disk damage (r = 0.59, P < 0.001). On the other hand, the full-field flicker test achieved the best separation between normal subjects and glaucoma patients (specificity, 90%; sensitivity, 71%). These results indicate that tests for temporal resolution are more sensitive to glaucoma defects than are tests for spatial resolution.