Assessing the influence of stimulus size on defect detectability in the central visual field

Abstract

Purpose : To compare the diagnostic utility of Size III and V stimuli using the 10-2 visual field (VF) test pattern on a sample of participants with glaucoma.

Methods : VFs were acquired using a HFA3 Model 840 (ZEISS, Dublin, CA) perimeter over two visits for Size III 10-2 Full Threshold (FT) and Size V 10-2 FT strategies. 18 glaucomatous eyes were included in the study (Size III 10-2 MD: mean =-8.78 dB; standard deviation (SD) = 7.18 dB; range = -0.93 to -29.18 dB). The mean age of the study sample was 77.7 years (SD = 5.3; range = 63.2 – 87.6). Data from visit 2 were used for further analysis. Size V normative limits were interpolated from a previous study [1]. Topographic plots (Figure 1) were used to investigate the total number of flagged locations at the 5% level for both total deviation (TD) and pattern deviation (PD) across the central 10 degrees of the VF. We also investigated the correlation and agreement of the number of times each location was flagged as defective between Size III and V using scatter plots and Bland-Altman plots respectively (Figure 2).

Results : There was good agreement between Size III and V FT 10-2 test strategies with respect to the total number of flagged points at the 5% level at each location for both TD (mean difference = -0.25, SD = 1.52) and PD (mean difference = 0.16, SD = 1.50). Furthermore, there was a strong correlation observed between III and V for both TD (r² = 0.81) and PD (r² = 0.82).

Conclusions : The preliminary results from this study suggest that the diagnostic utility of Size V may be comparable to that of Size III when detecting glaucomatous VF defects within the central 10 degrees of the VF.

[1] Flanagan et al. IOVS 2016; 57(12).

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.

 

Figure 1: Topographic plots illustrating the total number of TD and PD flagged locations at the P<5% level across all 18 glaucomatous eyes for Goldmann Sizes III and V at each of the 68 locations in the 10-2 test pattern. The top row provides a visual illustration, where larger and darker circles indicate more flagged locations. The bottom row provides the corresponding numerical values.

 

Figure 2: Total number of flagged points across 18 glaucomatous visual fields at the 5% level at each location. Left column: Total Deviation; Right column: Pattern Deviation; Top row: Scatter plots illustrating correlation between 10-2 Size III and Size V; Bottom row: Bland-Altman plots illustrating agreement between 10-2 Size III and V.