Comparison of 24-2 Faster, Fast, and Standard Programs of Swedish Interactive Threshold Algorithm of Humphrey Field Analyzer for Perimetry in Patients With Manifest and Suspect Glaucoma

Abstract

Précis: Swedish Interactive Threshold Algorithm (SITA) Faster (SFR) saves considerable test time but needs further amendments for considering it to be an accurate test that can replace SITA Fast (SF) or SITA Standard (SS). Purpose: To compare visual field results obtained using SFR, SF, and SS programs in patients with manifest and suspect glaucoma. Materials and Methods: In this cross-sectional observational study involving manifest patients with glaucoma and glaucoma suspects, perimetric outcomes of SFR, SF, and SS were compared. Outcomes included test time, mean deviation, pattern standard deviation (PSD), Visual Field Index (VFI), foveal threshold, number of points depressed at P<5%, P<2%, P<1%, and P<0.5% on PSD probability plot, individual threshold test points, glaucoma hemifield test, and grade of field defect. Results: Seventy eyes of 70 patients were included in this study. SFR test times averaged 36.1% shorter than SF and 60.7% shorter than SS (P<0.001). Mean deviation values were lower with SFR compared with both SF and SS (Δ=1.5, P<0.001). Mean PSD and VFI showed no significant differences between the algorithms. The mean foveal threshold was higher for SFR compared with SF (Δ=1.6, P<0.001) and SS (Δ=2.1, P<0.001). The number of points depressed at P<0.5% was lesser in SFR than in both SF and SS (P=0.002). Bland-Altman plots showed that considerable variability existed between the algorithms. Conclusion: SFR provides benefits in test time and shows similar VFI compared with SF and SS. However, the detection of early cases with SFR is questionable and few modifications are needed in the future to improve its accuracy. SF and SS gave almost similar results. The algorithms cannot be used interchangeably for the same patient on different test sessions.

Differences in visual field loss pattern when transitioning from SITA standard to SITA faster

“…The ERF is used in VF testing to determine at which point the algorithm can stop testing a location before completing the full staircase and all reversals. Other studies have suggested that the ERF differences could be an explanation for higher MD values in SITA Faster compared to SITA Standard, particularly in the foveal thresholds 12 . The observation that foveal threshold values were higher in SITA Faster exams than SITA Standard exams complements our findings that AT 7 (central scotoma) was more strongly associated with transition to AT 1 (normal) in the Standard-Faster sequence compared to the Standard-Standard sequence.…”

The Frontloading Fields Study: The Impact of False Positives and Seeding Point Errors on Visual Field Reliability When Using SITA-Faster

“…Although historical methods of perimetric testing have not been conducive to obtaining this many results in routine clinical practice due to the long test duration, recent algorithmic changes leading to faster testing protocols, such as SITA-Faster, have provided an opportunity to meet these recommendations. 5 – 7 The frontloading approach, doing more than one visual field test per clinical visit, has been proposed as a practical method for capturing sufficient clinical data to facilitate more confident clinical diagnosis and patient management. 8 , 9 …”

Viability of Performing Multiple 24-2 Visual Field Examinations at the Same Clinical Visit: The Frontloading Fields Study (FFS)

“…More recently, SITA-Faster reduces the test duration by over half compared to SITA-Standard, whilst largely preserving similar perimetric results in terms of output mean deviation, pattern standard deviation, and pattern deviation map defects. [7][8][9][10] Therefore, it may be feasible to use SITA-Faster in lieu of SITA-Standard to obtain two times the test results in the same time frame, which would potentially be additive to the clinical decision making process. Performing quick tests at the same clinical visit could also overcome inter-session learning or practice effects and could potentially reduce the occasions of service.…”