The Effect of Transitioning from SITA Standard to SITA Faster on Visual Field Performance

Abstract

To determine the effect of transitioning from Swedish Interactive Thresholding Algorithm (SITA) Standard to SITA Faster on visual field (VF) performance in glaucomatous eyes with a broad spectrum of disease severity undergoing longitudinal VF testing in a real-world clinical setting. Retrospective, longitudinal study. A total of 421 patients (766 eyes) with manifest or suspect glaucoma followed at a single institution. Each included eye received the following sequence of VF examinations during routine clinical care: (1) SITA Standard, (2) SITA Standard, and (3) SITA Faster (mean time between tests= 13.9 months). Intra-eye comparisons were made between the first 2 VFs (Standard-Standard sequence) and the last 2 VFs (Standard-Faster sequence). The primary dependent variable was the difference in mean deviation (MD) between the second and first VF of the sequence (ΔMD, calculated as MDVF2 - MDVF1). The primary independent variable was the VF sequence (Standard-Standard or Standard-Faster). Linear mixed-effects models were used to study the effect of testing sequence on ΔMD, adjusting for confounders including time between VFs and change in false-positive (FP) errors. Results were stratified to understand the effect of glaucoma severity on the relationship between testing sequence and ΔMD. The difference in ΔMD between Standard-Standard and Standard-Faster sequence by mild, moderate, and advanced disease severity. In eyes with mild or suspect glaucoma, there was no significant difference in ΔMD between Standard-Faster and Standard-Standard sequences (-0.23 decibels [dB]; 95% confidence interval [CI],-0.60 to 0.15 dB). However, the Standard-Faster sequence was associated with a 0.87 dB (95% CI, 0.18-1.57 dB) improvement in ΔMD compared with the Standard-Standard sequence in eyes with moderate glaucoma and a 1.49 dB (95% CI, 0.79-2.19 dB) improvement in ΔMD in eyes with advanced glaucoma. Converting to SITA Faster in eyes that were previously followed with SITA Standard led to similar VF performance in mild glaucoma but resulted in higher MD values in moderate and advanced glaucoma. For patients with moderate or severe glaucoma, this may conceal disease progression when transitioning testing strategies.