Abstract
Purpose :
Hyaloid, retinal, and choroidal vascular systems are main sources of blood supply in a developing eye. We performed longitudinal three-dimensional (3D) vasculature imaging of normal and oxygen-induced retinopathy (OIR) rat retinas to simultaneously assess the hyaloid vessel regression and retinal/choroidal vascular development using optical coherence tomography angiography (OCTA).
Methods :
Hyaloid, retinal, and choroidal vasculatures of control and OIR groups of Sprague Dawley (SD) rats were imaged using a lab-built swept source OCTA system with 230 kHz A-line rate at 1050 nm. In each group, three eyes were imaged every 3 days from 15 days after birth (P15) to P24. Imaging of hyaloid and retinal/choroidal vasculatures were sequentially performed by adjusting the focus and imaging range of the OCT system. In addition, in vivo fluorescein angiography (FA) imaging was performed immediately after OCTA imaging at P24.
Results :
Three-dimensional morphology of a posterior eye was observed at P18 as shown in Figure 1.A. Figure 1.B and C show an en face projection of the hyaloid vasculature and a cross-sectional angiogram at the location indicated by the blue dashed line in Figure 1.B. Figure 1.D shows the hyaloid vessel regression over time. The diameter and density of the hyaloid vessels are larger in the OIR group. Figure 1.E shows quantitative regression rate of hyaloid vessel volume measured by OCTA.
The hyaloid vasculature from an OIR eye at P24 is observed with OCTA and FA as shown in Figure 2.A and B. Figure 2.C and D visualize retinal and choroidal vasculature in the same eye. A wide avascular region is observed in the superior and temporal retina where the hyaloid vasculature persists the most in the corresponding direction. Figure 2.E and F elucidate that the hyaloid regression has a spatially negative correlation (r=-0.7755) with the retinal vessel density whereas there is no correlation with the choroidal vessel density.
Conclusions :
Hyaloid vessel regression and its spatial correlation with retinal and choroidal vasculature developments were quantitatively analyzed through longitudinal OCTA imaging, for the first time to our knowledge. By concurrently and longitudinally imaging the three vasculatures of normal and OIR rat retinas, the hyaloid vessel regression in OIR was observed to be preferentially delayed to supply the avascular retina.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.