Comparison of size modulation and conventional standard automated perimetry with the 24-2 test protocol in glaucoma patients

This prospective randomized study compared test results of size modulation standard automated perimetry (SM-SAP) performed with the Octopus 600 and conventional SAP (C-SAP) performed with the Humphrey Field Analyzer (HFA) in glaucoma patients. Eighty-eight eyes of 88 glaucoma patients underwent SM-SAP and C-SAP tests with the Octopus 600 24-2 Dynamic and HFA 24-2 SITA-Standard, respectively. Fovea threshold, mean defect and square loss variance of SM-SAP were significantly correlated with the corresponding C-SAP indices (P < 0.001). The false-positive rate was slightly lower and false-negative rate slightly higher, with SM-SAP than C-SAP (P = 0.002). Point-wise threshold values obtained with SM-SAP were moderately to strongly correlated with those obtained with C-SAP (P < 0.001). The correlation coefficients of the central zone were significantly lower than those of the middle to peripheral zone (P = 0.031). The size and depth of the visual field (VF) defect were smaller (P = 0.039) and greater (P = 0.043), respectively, on SM-SAP than on C-SAP. Although small differences were observed in VF sensitivity in the central zone, the defect size and depth and the reliability indices between SM-SAP and C-SAP, global indices of the two testing modalities were well correlated.