Intrasession repeatability and intersession reproducibility of peripapillary OCTA vessel parameters in non-glaucomatous and glaucomatous eyes

Abstract

Objective: To compare intrasession repeatability versus intersession reproducibility of the peripapillary vessel parameters using optical microangiography-based optical coherence tomography angiography (OCTA) in non-glaucomatous and glaucomatous eyes.

Methods: In an observational, longitudinal study, peripapillary OCTA scans were collected to evaluate intrasession repeatability and intersession reproducibility using within-eye coefficient of variation (CV_W) and intraclass correlation coefficient (ICC). Images were quantified using a custom research-oriented quantification software calculating vessel area density (VAD) and flux and a commercially developed, clinic-oriented quantification software (Cirrus 11.0, Carl Zeiss Meditec) calculating perfusion density (PD) and flux index (FI). Effect of signal strength on the reliability of OCTA parameters was also evaluated.

Results: Among 120 non-glaucomatous eyes, intrasession CV_W were 4.2% for VAD, 5.3% for flux, 1.5% for PD and 2.0% for FI. The intersession CV_W were 6.5% for VAD, 8.0% for flux, 2.0% for PD and 3.2% for FI. The intrasession ICC ranged from 0.928 to 0.945, and intersession ICC ranged from 0.811 to 0.866. From 118 glaucomatous eyes, intrasession CV_W was 9.0% for VAD, 10.3% for flux, 1.7% for PD and 2.3% for FI. The intersession CV_W was 12.1% for VAD, 14.2% for flux, 2.3% for PD and 3.5% for FI. The intrasession ICC ranged from 0.904 to 0.972, and intersession ICC ranged from 0.855 to 0.955. Signal strength was significantly positively associated with OCTA vessel parameters (p<0.0001) for both groups.

Conclusion: Peripapillary OCTA vessel parameters had greater intrasession repeatability compared to intersession reproducibility in both non-glaucomatous and glaucomatous eyes. The built-in commercially developed quantification software demonstrated greater agreement than the custom research-oriented quantification software.

Keywords: Glaucoma; Imaging; Optic Nerve.