Performance of a modified 24-2 test pattern using SITA Faster

Abstract

Purpose : Increasing the number of test points in a 24-2 visual field (VF) may increase the chance of detecting early field loss. However, adding an additional 10-2 test for glaucoma suspects may identify some eyes with central field defects that were missed on 24-2 testing, but will increase test time substantially. Here, we explored the performance of a modified 24-2 pattern (24-2C) with 10 added central points along with the SITA Faster testing strategy in a preliminary cohort of glaucomatous eyes.

Methods : Ten test locations common to the 10-2 pattern, correlating to physiological central field defect patterns [deMoraes et al. Ophth. 2014; 121(3)], were added to the 24-2 pattern (Fig 1). Both 24-2C SITA Faster and 10-2 SITA Fast VFs were acquired on 60 eyes of 60 glaucoma patients at each of two visits using HFA3 Model 860 (ZEISS, Dublin, CA). 24-2 SITA Faster test times and VFs were extracted from the 24-2C VFs. Summary statistics and significance testing (paired equivalence t-tests, α = 0.05) were calculated for cumulative sums of various levels of Total Deviation (TD) and Pattern Deviation (PD) defects, using limits of equivalence of ±1 defect.

Results : Mean ± SD Mean Deviation (MD) values for 24-2, 24-2C, and 10-2 VFs were -9.0±7.8, -8.9±7.9, and -7.6±7.4 dB, respectively. Mean ± SD test times for 24-2, 24-2C, and 10-2 VFs were 3.0±0.8, 3.5±0.9, and 4.2±1.1 minutes, respectively. Cumulative number of defects in the newly added 24-2C points were all statistically equivalent to the number of defects in the same 10-2 test locations (Table 1). Mean TDs of the new 24-2C points were highly correlated with mean TDs of all 10-2 points (Pearson’s r = 0.96). Paired 24-2C and 10-2 pooled thresholds were highly correlated (r = 0.91) and comparable to the intra-strategy correlation between 10-2 pooled thresholds from both visits (r = 0.90).

Conclusions : The 24-2C pattern adds ten new paracentral test locations that provide additional information about the central visual field that detects defects comparable to the analogous test locations in a 10-2 SITA Fast field, while preserving the results of a 24-2 field. 24-2C SITA Faster may provide a clinical alternative to the current 24-2 based clinical visual fields in cases where users would like to perform additional testing in the very central visual field.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Figure 1. Test Locations for 24-2C (Right Eye).

 

Table 1. Summary of Mean (SD) Values for Defect Flagging of the Ten Added Locations