Abstract
Purpose :
Retina hypoxia is a condition that the retina lacks oxygenation due to ischemic vascular change. If the retina is in ischemic condition for a prolonged period of time, it can lead to pathologic neovascularization in the retina. To explore the pathophysiology of the ischemic retinal disease, we induced oxygen-induced retinopathy (OIR) in the rat eye, and monitored retinal microvasculature using optical coherence tomography angiography (OCTA).
Methods :
Two groups of Sprague Dawley rat were prepared. The mother and pups in the OIR group were incubated in 80% oxygen chamber from one day after birth and returned to room at 12 days-old (P12), whereas the control group was remained in the room condition. A lab-built swept source OCTA system with 230 kHz A-line rate at 1050 nm was used for this study. The pups were imaged every 3 days from P15 to P24. Immunofluorescence imaging was also performed in the same eyes to compare with OCTA.
Results :
The neovascular tufts sprouting above the retinal surface are observed on the intensity images in the OIR rat (Figure 1. A1~A2). The tufts can be segmented from the retina and overlaid in magenta (Figure 1. A3). The vascular development in different capillary plexus is visualized by segmenting the inner plexiform layer. The deep capillary plexus in the OIR is suppressed (Figure 1. B4) while the control groups shows distinct capillary networks (Figure 1. B1~2). The blue areas in en face vascular projection images correspond to local regions where the intensity signal is below certain threshold level due to shadowing caused by hyaloid vessels in the vitreous.
Conclusions :
We observed the vascular change in the OIR rat using OCTA. In addition to neovascular tufts, quantitative analysis of retinal thickness and vascular development in different capillary plexus will be discussed.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.