Abstract
Purpose :
To characterize retinal vascular density and reactivity in the human retina in the macula, temporal macula and peripapillary retina using optical coherence tomography angiography (OCTA).
Methods :
OCTA 3*3mm2 images were acquired from the macula (M), temporal macula (TM) and peripapillary retina (PP) in 8 healthy subjects. Images from the superficial, deep and choriocapillaris layers of the M and TM were extracted and the vessel skeleton densities (VSD) computed. In addition, the mean flow deficit sizes (MFDS) of the choriocapillaris and mean PP VSD was calculated. Choriocapillaris reactivity (CR) and retinal vascular reactivity (RVR) in each region and layer were assessed under three gas non-rebreathing conditions – room air (RA), 5%CO2 and 100%O2. RVR is the percent change in VSD between RA-CO2 and RA-O2. CR is computed in a similar manner with MFDS. ANOVA was used to compare the VSD measurements with significance at p=0.05.
Results :
Under RA conditions, the mean VSD of the superficial layer was significantly different across regions [M= 0.16, TM=0.13, RPV=0.15; F(1,7)=15.6,p=0.006] and a similar trend occurred in the deep layer [M =0.14, TM=0.12; F(1,7)=5.0,p=0.06, Fig1A]. RVR differed among regions of the superficial layer [M=8%, TM=15%, and PP=7%; F(2,7)=28.22,p<0.001, Fig 1B] and the deep layer [M=19%, TM =37%; F(1,7)=8.7,p=0.02, Fig 1B]. There was a significant heterogeneity in the layer specific vascular reactivities [superficial =12.8%, deep =28.2% and CR =2.8%;F(2,7)=58.03,p<0.001]. However, CR and MFDS did not differ between regions.
Conclusions :
There are significant differences in the regional retinal capillary density and vascular reactivity in the macula, temporal macula and peripapillary retina. These regional differences may help explain the spatial distribution of pathology in retinal vascular diseases. Similar regional difference are not present in the choriocapillaris.
This is a 2021 ARVO Annual Meeting abstract.