Relationship between vascular densities of choriocapillaris and the whole choroid using OCTA

Purpose To study the vascular density (VD) of choriocapillaris and the whole choroid using optical coherence tomography-angiography (OCTA). Methods Cross-sectional study enrolling healthy individuals between 18 and 35 years old and with an axial length (AL) lower than 26 mm, who were examined with swept-source OCTA Triton DRI (Topcon). Color pictures of both VD were obtained from a fovea-centered 6 x 6 mm macular exam, which were divided into 900 squares and codified into numbers. Results A total of 50 patients (100 eyes) with a mean age of 27.29 +/- 3.90 years and a mean AL of 23.67 +/- 0.74 mm were analyzed. The highest choroidal VD was found in juxtapapillary macula, being followed by the most temporal macula and fovea. The lowest was found in superior and inferior perifoveal areas. The highest VD in choriocapillaris was in the fovea. VD in this layer was uniform, with a decrease from temporal toward nasal. Both VD differed and but correlated, especially in the fovea and in inferior-temporal macula. Conclusion VD of choriocapillaris and the whole choroid are not similar. The former is maximal in the fovea, and the latter is maximal in the juxtapapillary macula. In general lines, choroidal VD is higher than that of choriocapillaris. Both VD are directly correlated.