Assessment of Inter-Device Agreement in Quantifying Choriocapillaris Flow Deficits in Healthy Eyes

To compare the computation of the choriocapillaris flow deficit obtained from three different optical coherence tomography angiography devices in healthy subjects.

Twenty-six healthy subjects were included in this post hoc analysis of data from a prospective healthy subject optical coherence tomography angiography study. Fovea-centered 6 × 6 optical coherence tomography angiography volume scans were obtained by all three devices: Heidelberg Spectralis spectral domain optical coherence tomography angiography (Heidelberg, Germany) using a full spectrum probabilistic algorithm (512 × 512 pixels); Zeiss Cirrus 5000 AngioPlex (Zeiss Meditec, Dublin, CA) (spectral domain-optical coherence tomography angiography) using the optical microangiography algorithm (350 × 350 pixels); Zeiss PLEX Elite 9000 swept source optical coherence tomography angiography (Zeiss Meditec, Dublin, CA) using the optical microangiography algorithm (500 × 500 pixels). Choriocapillaris slabs were binarized using Image J (Bethesda, MD) and the choriocapillaris flow deficit % was measured applying a Phansalkar radius of ∼20 µm, adjusted for each device based on the size and resolution of the images.

Twenty-six healthy eyes of 26 subjects with no ocular or systemic disease were included in this analysis. The mean age of the subjects was 47.60 ± 13.00 (range, 26-69) years and 46.15% were females. The choriocapillaris flow deficit % measured by the devices varied significantly from each other (p < .01). The mean choriocapillaris flow deficit % measured by the Spectralis (Heidelberg, Germany) was the highest at 57.00% (±13.21%), followed by the Angioplex at 25.70% (±9.00%), and the Plex Elite at 7.62 (±3.06%). There was a significant positive correlation between choriocapillaris flow deficit % measured by swept source-optical coherence tomography angiography and spectral domain-optical coherence tomography angiography devices (Angioplex and PLEX Elite) using the optical microangiography algorithm (r = 0.78, p < .01). Of note, this correlation was better than the correlation between two spectral domain-optical coherence tomography angiography devices using different algorithms (Spectralis, Heidelberg, Germany, full spectrum probabilistic algorithm and Angioplex optical microangiography) (r = 0.389, p = .04).

The correlation between swept source and spectral domain optical coherence tomography angiography devices using the same optical coherence tomography angiography algorithm is better than between spectral domain-optical coherence tomography angiography devices using different algorithms.