Evaluation of Macular and Peripapillary Vessel Flow Density in Eyes with no known Pathology Using Optical Coherence Tomography Angiography.

Abstract

Purpose : Vessel flow density (VFD) around the fovea and optic disc using OCT angiography (OCTA) has not been reported in literature. In this prospective study, OCTA of eyes with no known pathology (controls) were analyzed to document normal VFD in the macular and peripapillary regions.

Methods : Optovue RTVue XR 100 AVANTI was used to capture OCTA images of 24 eyes. 3x3mm grid centered on the fovea was chosen to scan the parafoveal region. 4.5x4.5mm grid centered on the optic disc was used to scan the peripapillary region. ReVue software (Version: 2015.1.0.71) was used to measure the VFD in the regions of interest (ROI). In the macular ROI, VFD was measured in 5 sectors within the inner 2 circles of ETDRS grid (Figure 1A), and was correlated to the macular thickness values in the same areas. At the optic disc, VFD was reported in 6 sectors based on the Garway-Heath map centered on the optic disc (Figure 1B). The area and morphology of foveal avascular zone (FAZ) was assessed (Figure 1C & 1D). Mean and standard deviations in VFDs, and areas of FAZ in the macular and optic disc scans were reported.

Results : 24 eyes (12 subjects) (mean age: 30 years) were analyzed. Mean VFD in the macular sectors was 43.5 (±4.5) and 45.8 (±5.0)% in superficial and deep retinal plexus, respectively. Table 1 provides mean VFD, and its correlation with mean retinal thicknesses in the macular and peripapillary sectors. The mean area of FAZ was 0.33mm² (±0.15) and 0.47mm² (±0.15) in superficial and deep plexus, respectively. The FAZ was less well defined in the deep plexus compared to the superficial plexus. The area of FAZ was negatively correlated with central 1mm thickness and foveal VFD (r = -0.7 and -0.9, respectively).

Conclusions : OCTA may be used to measure VFD in superficial and deep retinal plexuses in the macular and peripapillary region. VFD in the foveal region strongly correlates with central retinal thickness. Data from the index study may be used to assess retinal vascular diseases.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

1A: Macular sectors for VFD analysis: A: Fovea; B: Superior; C: Nasal; D: Inferior; E: Temporal. 1B: Peripapillary sectors for VFD analysis: A: Temporal; B: Superior Temporal; C: Superior Nasal; D: Nasal; E: Inferior Nasal; F: Inferior Temporal. 1C: FAZ in Superficial Plexus. 1D: FAZ in Deep Plexus.

 

VFD and its correlation with mean retinal thicknesses in the macular and peripapillary sectors.