Inter-relationship between retinal and choroidal vasculatures using optical coherence tomography angiography in normal eyes

Purpose: To quantify vascular and structural macular variables in healthy eyes and to investigate correlations between these variables and age using optical coherence tomography angiography. Materials and methods: A total of 261 eyes of 261 subjects with normal fundus were included. Central macular thickness, ganglion cell layer to inner plexiform layer thickness, outer retina layer thickness, subfoveal choroidal thickness, and choroidal vascularity index were measured using optical coherence tomography. Foveal avascular zone area, vascular density, and flow void area were measured using optical coherence tomography angiography. Results: Vascular density in the superficial capillary plexus was correlated with central macular thickness, ganglion cell layer to inner plexiform layer thickness, and outer retina layer thickness (P < 0.001, P = 0.004, and P < 0.001, respectively). Vascular density in the deep capillary plexus was correlated with central macular thickness and outer retina layer thickness (P = 0.003 and P = 0.001, respectively). Vascular density of choriocapillaris was correlated with vascular density of superficial capillary plexus and deep capillary plexus (P < 0.001 and P = 0.001, respectively). Conclusion: Vascular density of choriocapillaris varies with retinal vascular density rather than the structure of choroid using optical coherence tomography angiography. In contrast, retinal vascular density changes as the retinal structure. Our results provide more information about the relationship between retina and choroid.