Abstract
Purpose :
Optical coherence tomography angiography（OCT-A）is a recently released, noninvasive and dye-less imaging technique for evaluating the vessels by capturing the dynamic motion of the erythrocytes. There are, however, some variabilities between machines due to differences in features of instrument and scanning algorithms. We, therefore, measured Vessel Density (VD) and area of the foveal avascular zone (FAZ) in healthy adults using two kinds OCT-A and compared the valuations.
Methods :
The study was a retrospective chart review of healthy volunteers who had undergone OCT-A. We used Optovue RTVue XR Avanti® (Optovue, Fremont CA, USA) and Zeiss Cirrus HD-OCT 5000 AngioPlex® (Carl Zeiss Meditec, Dublin CA, USA). A 3×3-mm area, centered at the fovea, was scanned for all the study eyes. The automated segmentation allowed separate analysis of the superficial capillary plexus (SCP), the deep capillary plexus (DCP), and choriocapillaris. On the obtained images, VD and FAZ were measured using the built-in software with Optovue and Angio Exerciser (Ver1.2.1) tool with Zeiss.
Results :
A total of 48 eyes of 24 subjects (45.8% male) were analyzed. The mean age was 33±10.4. The FAZ areas were 0.291 ± 0.091mm2 with Optovue and 0.258 ± 0.084mm2 with Zeiss. The VD were 50.5 ± 4.7% vs 39.7 ± 0.7% at SCP level and 57.0 ± 2.8% vs 35.1 ± 3.7% at DCP level, with Optovue and Zeiss, respectively. At the level of the choriocapillaris, the VD were 65.0 ± 1.9% with Optovue and 42.7 ± 1.3% with Zeiss. FAZ areas with Optovue was significantly correlated with those with Zeiss (p<0.0001), but VDs with Optovue were not correlated with those with Zeiss.
Conclusions :
Measurements of FAZ were reliable between instruments, whereas significant variability exists in VD.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.