Features of the choriocapillaris on four different optical coherence tomography angiography devices.

PURPOSE: To investigate the features of the choriocapillaris using four different optical coherence tomography angiography (OCTA) devices.
METHODS: OCTA images of the choriocapillaris from consecutive healthy subjects were obtained with four different OCTA devices (Zeiss PLEX Elite, Topcon DRI OCT-1 Atlantis, Zeiss AngioPlex, and Heidelberg Spectralis OCTA). The 3 × 3 mm OCTA images were processed with ImageJ. The mean vascular density and mean flow void area of the choriocapillaris were compared among devices. Flow voids were analyzed with two different imaging adjustment methods, auto-local threshold with the Phansalkar method and a method using a device-specific threshold value.
RESULTS: The mean vascular density of the choriocapillaris differed among the four devices (all P < 0.001). The mean flow void area as measured with the auto-local threshold method also differed among devices (P < 0.001) and was not correlated among devices (all P > 0.05). Results for mean flow void area measured with a device-specific threshold value using the Plex-Elite and DRI OCT-1 Atlantis were correlated (ß = 2.271, P < 0.001), but there were no correlations among other devices (P > 0.05). For the Plex-Elite and DRI OCT-1 Atlantis, the mean flow void area was positively correlated between the two image adjustment methods (all P < 0.05).
CONCLUSIONS: Vascular densities and flow void areas of the choriocapillaris varied according to the device used and the image adjustment method. The characteristics of different devices and the image adjustment method should be considered for analysis of the choriocapillaris.