Abstract
Purpose :
Imaging of the choriocapillaris is challenging using any modality. Multiple en face optical coherence tomography (OCT) angiography image averaging enables visualization of the choriocapillaris. This study aimed to demonstrate the choriocapillaris structure in normal subjects by multiple en face image averaging using swept-source OCT and evaluate its association with gender, age, and axial length.
Methods :
All subjects underwent OCT angiography imaging of the macula covering 3×3 mm area using swept-source OCT (PLEX Elite 9000, Carl Zeiss Meditec). One eye per subject was imaged repeatedly to obtain 9 raster scan sets. Registration was performed using superficial capillary plexus images, which was applied to the deep capillary plexus and choriocapillaris images. The 9 registered en face images were averaged; vessel density and diameters of the choriocapillaris were measured using ImageJ software.
Results :
Thirty normal eyes of 30 healthy subjects (15 male, 15 female; mean age 50 ± 20 years) were included. In all eyes, the choriocapillaris showed a meshwork appearance after en face image averaging. The mean flow void area of the choriocapillaris was 1.275 ± 0.246 mm2 and correlated positively with age (P<0.001, r=0.742). The mean size of each flow void was 736.2 ± 305.8 mm2 and correlated positively with age (P<0.001, r=0.634). The mean number of flow voids was 1,863 ± 287 and correlated negatively with age (P=0.001, r=0.569). The vascular diameter index, which was calculated as vessel density divided by vessel length density, was 6.1 ± 0.4 and correlated negatively with age (P<0.001, r=0.739). There was no significant correlation between flow void area, size of each flow void, number of flow voids, vascular diameter index, and the axial length (P=0.603, 0.457, 0.446, and 0.545, respectively). There were no significant differences in these parameters between men and women (P=0.138, 0.125, 0.175, and 0.637, respectively).
Conclusions :
Multiple en face image averaging revealed the precise structure of the choriocapillaris in normal eyes. The flow area and diameter of the choriocapillaris reduced with aging, while the choriocapillaris structure showed no significant variations by axial length and gender.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.