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Brian Soetikno, Lisa Beckmann, Xian Zhang, Hyun Jung Ryu, Amani Fawzi, Hao F. Zhang; Longitudinal characterization of branched retinal vein occlusions created by imaging-guided photocoagulation. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5820. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Branched retinal vein occlusions (BRVO) are the most common retinal vascular occlusive disease. Traditionally, producing a BRVO model in rodents has relied on a slit-lamp based technique. Recently, our lab developed a BRVO model using an image-guided laser photocoagulation approach. In this study, we sought to characterize this model by longitudinally monitoring subjects with multiple imaging modalities, including OCT, OCT angiography (OCTA), and fundus photography. We compared changes in the retinal and capillary structures over time.
After anesthesia induction, C57BL/6 mice (25-30g) were imaged with OCT and OCTA to obtain structure and angiogram data. Rose Bengal (RB) dye was then delivered via tail vein injection. Using a fluorescent scanning laser ophthalmoscope (SLO), the RB dye was imaged in the vasculature. The field of view was reduced to encompass the targeted vessel, and the laser power was increased to 15 mW. This enabled the real-time observation of the occlusion formation. With a Phoenix Micron III fundus camera, fundus photos were also acquired post-occlusion. The BRVO model was then monitored with a combination of OCT and OCTA for days 1, 4, 7, 11, and 14 after the occlusion. The retinal thickness was measured in the region of the occlusion as well 180 degrees away from the occlusion.
Figs. A and B show the pre-occlusion OCTA and SLO for a vein branch (yellow arrow). Figs. C and D show the OCTA and SLO, respectively, after the occlusion. An area of retinal non-perfusion can be clearly observed as well as areas of dye leakage (yellow arrows). As expected, before the occlusion, the retinal thickness at the occlusion site was not significantly different than away from the site (229 +/- 6 um vs. 233 +/- 21 um; p > 0.05). On day 1, a significant increase in total retinal thickness was observed in the region of the occlusion (381 +/- 33 um vs. 247 +/- 11 um; p < 0.05). Retinal thickness increase was mainly due to retinal edema. By day 7 retinal thickness normalized (251 +/- 19 um vs. 225 +/- 9 um; p>0.05).
We successfully created a BRVO model using an image-guided laser photocoagulation approach. Using a combination of OCT, OCTA, and fundus photography, we characterized the longitudinal outcome of the model. Our study serves as a foundation for future studies of the BRVO model, which may inform the pathophysiology of the disease in humans.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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