Diagnostic Efficacy of 24-2 and 24-2C SITA Faster Global Summary Indices

Abstract

Purpose : SITA Faster is a version of the SITA Fast thresholding visual field strategy optimized for speed and available for the 24-2 and 24-2C test patterns. In this clinical study, we explored the diagnostic efficacy of global summary indices derived from SITA Faster in a preliminary cohort of normal and glaucomatous eyes.

Methods : 24-2 SITA Standard (SS), 24-2 SITA Fast (SF), and 24-2C SITA Faster (SFR-C) visual fields (VFs) were acquired on an HFA3 perimeter (ZEISS, Dublin, CA) at each of two visits on one eye of a group of 25 normal and 25 glaucomatous subjects. 24-2 SITA Faster (SFR) VFs were extracted from SFR-C. The last qualified test for each VF was used for data analyses. The diagnostic performance for the VF global indices of Mean Deviation (MD) and Visual Field Index (VFI) was assessed using the area under the receiver operator characteristic curve (AROC) and sensitivity. Indices were calculated with 54 (24-2) and 64 (24-2C) points. SS and SF parameter AROCs were compared to those of SFR.

Results : Mean age was 55.2 (standard deviation, SD: 9.4; range: 27 to 69) years for normal subjects and 68.8 ± 9.1 (SD: 9.1; range 52 to 83) years for glaucoma patients (P<0.001). Mean MD_SFR was 0.75 (SD: 1.11; range: -2.76 to 2.28) dB and -2.83 (SD: 5.33; range: -21.77 to 1.61) dB in normal and glaucomatous eyes (P=0.002), respectively (see Table 1). The AROC of MD_SFR was 0.85. Compared to MD_SFR, the AROCs for MD_SS, MD_SF, and MD_SFR-C were 0.85 (P=0.970), 0.86 (P=0.754), and 0.85 (P=1.000), as shown in Table 2. The sensitivities at 95% specificity were 60.0% (MD_SS), 52.0% (MD_SF), 56.0% (MD_SFR), and 52.0% (MD_SFR-C), respectively. The AROC of VFI_SFR was 0.90. Compared to VFI_SFR, the AROCs for VFI_SS, VFI_SF, and VFI_SFR-C were 0.84 (P=0.224), 0.87 (P=0.468), and 0.87 (P=0.115), as shown in Table 2. The sensitivities at 95% specificity were 60.0% (VFI_SS), 56.0% (VFI_SF), 68.0% (VFI_SFR), and 56.0% (VFI_SFR-C), respectively.

Conclusions : The findings in this preliminary cohort suggest that the 24-2 and 24-2C SITA Faster global summary indices may have similar (non-inferior) diagnostic performance to those of SITA Standard and SITA Fast. In terms of global summary indices, SITA Faster may provide a reasonable clinical alternative to current clinical threshold strategies for the diagnosis of glaucoma.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

Table 1. Summary Indices (Mean ± SD)

 

Table 2. AROC with 95% Confidence Interval and Sensitivity at 95% Specificity