Imaging Laser-Induced Choroidal Neovascularization in the Rodent Retina Using Optical Coherence Tomography Angiography

PURPOSE. The purpose of this study was to evaluate the performance of optical coherence tomography angiography (OCTA) in visualizing laser-induced choroidal neovascularization (CNV) in the rodent retina. METHODS. Choroidal neovascularization was induced via laser photocoagulation in 2 male Brown Norway rats and 2 male C57BL/6 mice. For qualitative comparison, the animals were imaged in vivo with OCTA, indocyanine green angiography (ICGA), and fluorescein angiography (FA), and ex vivo with immunofluorescence confocal microscopy, 14 days post laser photocoagulation without anti-vascular endothelial growth factor (anti-VEGF) intervention. For longitudinal quantitative analysis, CNV was induced in 6 additional male C57BL/6 mice. Three mice intravitreally received an anti-VEGF agent and the remaining 3 mice phosphate buffered saline (PBS) vehicle 7 days post laser photocoagulation. These animals were imaged using OCTA 6, 14, and 21 days post laser photocoagulation. The area and volume of the laser-induced CNV lesions were measured longitudinally. RESULTS. In both mice and rats, OCTA qualitatively showed high correlation with FA, ICGA, and immunofluorescence imaging. Unlike FA and ICGA, which does not show the microvasculature due to dye leakage, OCTA visualized the CNV microvasculature with resolution and contrast comparable to immunofluorescence images. Longitudinal imaging enabled normalization of the CNV area and volume, reducing inherent variation in the CNV size. By using only 3 mice in each group, statistically significant differences (P < 0.01) in the CNV area and volume could be demonstrated. CONCLUSIONS. Optical coherence tomography angiography enables noninvasive visualization of the laser-induced CNV microvasculature in the rodent retina with high resolution and tissue-lumen contrast, providing quantifiable in vivo measurements for longitudinal analysis.