A Spectral-domain Optical Coherence Tomography Study In Laser-induced Choroidal Neovascularization Model

Abstract

Purpose: : To use spectral domain optical coherence tomography (SD-OCT) for the evaluation of laser-induced choroidal neovascularization (CNV) model in mice.

Methods: : A 532 nm diode-laser (100,150 and 200 mW, 100 µm diameter, 0.1 sec duration) was used to induce retinal photocoagulation in the mouse fundus. SD-OCT imaging was obtained immediately after laser application, and at day 3, 5, 7, 14, 21 and 28. Fluorescein angiography (FA) and choroidal flatmounts (CFM) were performed at day 5, 7, 14 and 28. SD-OCT images were analyzed to evaluate morphologic findings, assess CNV size and retinal thickness, and measure the frequency of lesions resulting in fluid accumulation. SD-OCT images were compared to FA, CFM, and histologic sections with immunostaining.

Results: : Chorioretinal damage was evident by SD-OCT immediately after laser application as a hyperreflective lesion. CNV formation followed the injury response, and reached its maximum size at day 5. We observed a significant size reduction by day 7 (p<0.001). Quantification of CNV size with CFM showed the same time course. SD-OCT assessment of exudation signs, such as fluid accumulation and increase in retinal thickness, and FA assessment of leaky lesions revealed the same time course, with a peak at day 5 and a decrease by day 7. Histology and immunohistochemistry studies demonstrated inflammatory cells, Muller cells activation and endothelial cell proliferation.

Conclusions: : SD-OCT allows in-vivo characterization of laser-induced CNV model. Moreover, it provides morphologic information that correlates with histological findings.

Keywords: choroid: neovascularization • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)