Simultaneous optical coherence tomography angiography and fluorescein angiography in rodents with normal retina and laser-induced choroidal neovascularization.

Fluorescein angiography (FA) is the current clinical imaging standard for vascular related retinal diseases such as macular degeneration and diabetic retinopathy. However, FA is considered invasive and can provide only two-dimensional imaging. In comparison, optical coherence tomography angiography (OCTA) is noninvasive and can generate three-dimensional imaging; investigations of OCTA already demonstrated great promise in retinal vascular imaging. Yet, to further develop and apply OCTA, strengths and weaknesses between OCTA and FA need to be thoroughly compared. To avoid complications in image registration, an ideal comparison requires co-registered and simultaneous imaging by both FA and OCTA. In this Letter, we developed a system with integrated laser-scanning ophthalmoscope FA (SLO-FA) and OCTA, and conducted simultaneous dual-modality retinal vascular imaging in rodents. In imaging healthy rodent eyes, OCTA can resolve retinal capillaries better than SLO-FA does, particularly deep capillaries. In imaging rodent eyes with laser-induced choroidal neovascularization (CNV), OCTA can identify CNV that eludes SLO-FA detection.