Abstract
Purpose :
Structure-function correlation in glaucoma is generally found to be moderate at best. One potential reason for this is that the most common structural and functional tests do not necessarily sample the same areas in the retina. In this preliminary study, we compared the correlations of OCT angiography (OCTA) to two commercial visual field (VF) tests patterns: a standard pattern (24-2) and one that added 10 new test points in the central 10° field (24-2C) that were found in literature to be highly sensitive to glaucoma.
Methods :
Retrospective VF and OCTA data were analyzed from an ongoing VF study including 19 eyes of 19 patients in both healthy and glaucoma groups, using CIRRUS™ 5000 HD-OCT (ZEISS, Dublin, CA)1 and HFA3 (ZEISS, Dublin, CA)1. The last qualified 24-2C SITA Faster (SFR24C) test and Angio 6x6 mm OCTA macular scan were used. 24-2 SITA Faster (SFR) VFs were extracted from SFR24C. Spearman’s correlations were calculated between structure-function pairs: a) structure – Full, Inner Ring, and Outer Ring Mean metrics for both perfusion and vessel densities; and b) function – Mean Total Deviation (MTD) of the central 10° test locations for SFR (12 locations) and SFR24C (22 locations).
Results :
Mean age was 56.5 (standard deviation, SD: 7.7; range: 44.3 to 73.1) years for healthy eyes and 73.4 (SD: 9.5; range 60.6 to 97.9) years for glaucoma eyes. Mean SFR MD was 0.64 (SD: 0.97; range: -1.58 to 2.17) dB and -6.49 (SD: 6.44; range: -24.40 to 1.52) dB in healthy and glaucoma eyes, respectively.
Moderate correlations (p < 0.001) were observed between both SFR and SFR24C and OCTA for Full and especially Outer Ring Mean metrics (range 0.628-0.685), respectively (see Table 1). Only low correlations were observed when comparing Inner Ring densities. Correlation using SFR24C were slightly higher than those using SFR, likely due to the perifoveal locations of the 10 new test points.
Conclusions :
The added central test points in the 24-2C pattern moderately increased the correlation to the perifoveal microvascular density. Increasing the overlap between areas tested in structural and functional tests may be a way to increase the strength of the relationship that merits further investigation.
References
[1] Callan et al. IOVS 2020; 61(7): Abstract 3876
Table 1. Correlations (p-values) between OCTA and VF Central Mean Total Deviation
This is a 2021 Imaging in the Eye Conference abstract.