Comparing the Full-Threshold and Swedish Interactive Thresholding Algorithms for Short-Wavelength Automated Perimetry

Abstract

Purpose. To compare the Swedish interactive thresholding algorithm (SITA) with the full-threshold (FT) strategy for short-wavelength automated perimetry (SWAP). methods. One eye of 286 patients with glaucomatous optic neuropathy (GON) and 289 age-matched participants without GON from the Diagnostic Innovations in Glaucoma Study (DIGS) and the African Descent and Glaucoma Evaluation Study (ADAGES) were classified with optic disc stereophotographs taken within 6 months of visual field testing, conducted within a 3-month period. Six parameters were derived per test, including pattern standard deviation (PSD) and the number of pattern deviation plot (PDP) points triggered at P < 0.05). Sensitivity and specificity using the STATPAC PSD at 95% (P < 5%) and 99.5% (P < 0.05%) was similar between algorithms. Severity correlated significantly between algorithms (P < 0.001), although there was bias for SWAP-SITA to suggest more severe loss. SWAP-SITA required significantly less test time than did SWAP-FT (P < 0.001). Mean differences in PSD, PDP <1%, and MD between algorithms were not clinically significant. conclusions. Both algorithms performed similarly when equated for specificity. The reduced test duration makes SWAP-SITA the better choice. Testing with both algorithms within a short period is recommended for confirmation of results when switching from FT to SITA.