Measurement of Vessel Density Using Optical Coherence Tomography-angiography in Normal Subjects: Difference by Analysis Area

ABSTRACT

PURPOSE: To evaluate the vessel density of macula according to analysis area in health subjects using optical coherence tomography angiography (OCTA). METHODS: We retrospectively analyzed 30 eyes of 20 healthy people who underwent OCTA. We measured vessel density (VD) according to analysis area and foveal avascular zone (FAZ) size of superficial capillary plexus (SCP) and deep capillary plexus (DCP). The analysis areas were classified as 3 × 3 mm scan area (Box), Box area excluding FAZ (Box-FAZ), fovea centered 3 mm circle area (Circle), Circle area excluding FAZ (Circle-FAZ) and area between fovea centered 1 mm circle and 3 mm circle (Ring). RESULTS: The SCP VDs were Box 34.00 ± 3.97, Box-FAZ 35.37 ± 4.09, Circle 31.70 ± 4.56, Circle-FAZ 33.34 ± 4.72, and Ring 35.22 ± 5.09. The DCP VDs were Box 30.04 ± 3.51, Circle 29.49 ± 3.57, Box-FAZ 31.59 ± 3.65, Circle-FAZ 31.46 ± 3.72, and Ring 32.60 ± 4.00. There was a significant difference according to analysis area from both SCP and DCP (p < 0.001 and p < 0.001, respectively). Comparison of the vessel density between SCP and DCP in the same analysis area were different in all areas (p < 0.001, p = 0.001, p < 0.001, p = 0.005, p = 0.001, respectively). CONCLUSIONS: This study shows different results according to analysis area when measuring VD using OCTA. Therefore, when comparing studies related to VD, it is necessary to pay attention to the analysis area in the interpretation of the results.