Comparison of two fast strategies, SITA Fast and TOP, for the assessment of visual fields in glaucoma patients.

Abstract

To compare two fast threshold strategies of visual field assessment; SITA Fast (HSF) and Tendency Orientated Perimetry (TOP), in detecting visual field loss in patients with glaucoma. Seventy-six glaucoma, ocular hypertensive and normal patients had HSF and TOP performed in random order. Quantitative comparisons for the global visual field indices - mean deviation and defect (MD) for HSF and TOP, and pattern standard deviation (PSD) for HSF and loss variance (LV) for TOP - were made using correlation coefficients. Humphrey global parameters were converted to Octopus equivalents, and method comparison analysis was used to determine agreement between the two strategies. Test duration times were compared using t-test. Sensitivity and specificity for these two algorithms were determined according to predetermined criteria. High correlation coefficient values were obtained for MD measurements between HSF and TOP ( r=-0.89, P<0.0005) and for PSD (HSF) and LV (TOP) ( r=0.88, P<0.0005). Following conversion of HSF values to Octopus equivalents the TOP strategy estimated MD to be greater and LV to be less than HSF values, the difference increasing as the magnitude of the defect increased. The mean test duration time was 4.04 (0.87) min for HSF and 2.38 (0.34) min for TOP ( P<0.0005). Sensitivity of diagnostic criteria ranged from 86.4% to 89.2% for HSF and from 84.7% to 85.2% for TOP. Specificity ranged from 80.0% to 93.8% for HSF and from 76.5% to 86.7% for TOP. There was a high correlation between the HSF and TOP strategies for measurements of global indices. However, the TOP strategy tended to underestimate focal visual field loss compared with SITA Fast. The TOP strategy was faster than SITA Fast. The sensitivity and specificity of the two algorithms were similar. This study establishes the ability of these fast strategies to successfully assess visual fields in glaucoma patients with perimetric experience.