Development and evaluation of a contrast sensitivity perimetry test for patients with glaucoma

PURPOSE. To design a contrast sensitivity perimetry (CSP) protocol that decreases variability in glaucomatous defects while maintaining good sensitivity to glaucomatous loss. METHODS. Twenty patients with glaucoma and 20 control subjects were tested with a CSP protocol implemented on a monitor-based testing station. In the protocol 26 locations were tested over the central visual field with Gabor patches with a peak spatial frequency of 0.4 cyc/deg and a two-dimensional spatial Gaussian envelope, with most of the energy concentrated within a 4° circular region. Threshold was estimated by a staircase method. Patients and 10 age-similar control subjects were also tested on conventional automated perimetry (CAP), with the 24-2 pattern with the SITA Standard testing strategy. The neuroretinal rim area of the patients was measured with a retinal tomograph (Retina Tomograph II [HRT]; Heidelberg Engineering, Heidelberg, Germany). A Bland-Altman analysis of agreement was used to assess test-retest variability, compare depth of defect shown by the two perimetric tests, and investigate the relations between contrast sensitivity and neuroretinal rim area. RESULTS. Variability showed less dependence on defect depth for CSP than for CAP (z = 9.3, P < 0.001). Defect depth was similar for CAP and CSP when averaged by quadrant (r = 0.26, P > 0.13). The relation between defect depth and rim area was more consistent with CSP than with CAP (z = 9, P < 0.001). CONCLUSIONS. The implementation of CSP was successful in reducing test-retest variability in glaucomatous defects. CSP was in general agreement with CAP in terms of depth of defect and was in better agreement than CAP with HRT-determined rim area.