Abstract
Purpose :
Retinal vascular occlusive diseases, including artery and vein occlusions, are a major cause of vision loss. Producing retinal vascular occlusions in animals with slit-lamp-based techniques can be challenging and inconsistent. To facilitate the production of retinal vascular occlusions, we developed an integrated imaging and laser occlusion device, which can consistently and precisely produce vascular occlusions with real-time monitoring.
Methods :
We developed an integrated imaging and laser occlusion system with the capabilities of near-infrared optical coherence tomography (OCT), OCT angiography (OCTA), fluorescent scanning laser ophthalmoscopy (fSLO), and high-power laser for inducing the occlusion. After anesthesia induction, C57BL/6 mice were imaged with OCT and OCTA to collect baseline structure and angiogram data. Next, a photosensitive solution of Rose Bengal (RB) dye was injected into the lateral tail vein. Using fSLO, the RB dye was imaged within the retinal vasculature. To perform vascular occlusion, the field of view of the fSLO system was adjusted to encompass the width of the target vessel. Then, the laser power of the fSLO system was increased to ~20 mW to begin occluding the vessel. With the fSLO, we monitored, in real-time, the occlusion process, which took <10 seconds. For longitudinal monitoring, we acquired OCT and OCTA images immediately after and on days 1, 3, and 7 post-occlusion.
Results :
Fig. A shows a montage of 3 en face baseline depth-colored OCTA images. After tail vein injection of RB, we imaged the area in pink dashed box in Fig. A with fSLO, resulting in the image shown in Fig. B (a: arteries; v: veins). We targeted the vein branch (solid yellow circle in Fig. B) for occlusion, which was achieved in 8 seconds. We repeated OCTA imaging post-occlusion (Fig. C). The area indicated by the white dashed line delineates an area of capillary non-perfusion, resulting from the occlusion. The occluded vein also showed loss of OCTA signal near the occlusion site indicating diminished blood flow motion.
Conclusions :
We successfully built an integrated imaging device for the production and monitoring of retinal vascular occlusions in rodents. We refined the experimental protocol for performing vascular occlusions using real-time image guidance. This device and protocol could serve as a foundation for novel research on retinal vascular occlusion pathophysiology and treatment strategies.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.