Measurement of Normative Foveal Avascular Zone Parameters in Healthy Adults Using Optical Coherence Tomography Angiography

The purpose of this study was to quantify the geometric dimension of the foveal avascular zone (FAZ) area and its index measurement of morphology as a circle (acircularity index) in healthy participants according to age and sex, using optical coherence tomography angiography (OCTA). This is a cross-sectional descriptive study conducted at LV Prasad Eye Institute, India. Written informed consent was obtained from all participants before the study. Deep range imaging-optical coherence tomography (DRI-OCT; Topcon) was performed on right eyes of all participants in this study. The OCTA scans were analyzed and processed; FAZ dimensions and the acircularity index were calculated for both superficial retinal capillary plexus (SCP) and deep retinal capillary plexus (DCP). A total of 88 normal right eyes from 88 participants were included (48 males, 40 females; mean 42 ± 13 years of age). Mean FAZ area for SCP and DCP was 3.37 ± 1.28 mm2 and 2.31 ± 1.12 mm2, respectively. Mean acircularity index for SCP and DCP was 1.76 ± 1.58 and 1.60 ± 0.90, respectively. In the SCP, male sex was correlated with lower FAZ values; however, there was no correlation with age or refractive error. For the DCP, male sex and increasing age correlated with lower FAZ values, but there was no correlation with refractive error. Foveal avascular zone areas decreased 0.0225 mm2 per year in the DCP. The acircularity index of both the SCP and DCP was not correlated with sex, age, or refractive error. Male sex and increasing age were correlated with lower FAZ values in the DCP, while only male sex was correlated with lower FAZ values in the SCP. There was no correlation between sex, age, or refractive error with the acircularity index for both the SCP and DCP