Imaging of Retinal Vascular Layers: Adaptive Optics Scanning Laser Ophthalmoscopy Versus Optical Coherence Tomography Angiography

Retinal vascular networks are observed as a layered structure residing in a nerve fiber layer and an inner nuclear layer of the retina. This study aimed to evaluate reflectance confocal adaptive optics scanning laser ophthalmoscopy (AO-SLO) for imaging of the layered retinal vascular networks.This study included 16 eyes of 16 healthy cases. On the fovea, 2.8- and 3.0 mm(2)-areas were imaged using a prototype AO-SLO and optical coherence tomography angiography (OCTA), respectively. AO-SLO images focused on the nerve fiber and photoreceptor layers were recorded in the area. Two different vessel images (capillary networks in the superficial layer and in all layers) were generated to examine if the deep capillary network could be distinguished. We compared AO-SLO with OCTA in imaging of the layered retinal vascular networks.Sufficient images of capillary networks for analysis could be generated when the motion contrast was enhanced with AO-SLO movies in seven cases (43.8%). The deep capillary network could be distinguished in the merged image. Vascular depiction performance in AO-SLO was significantly better than in OCTA at both 0.5- and 1.0-mm areas from the fovea (P < 0.05).Retinal vascular imaging using AO-SLO might be a useful adjunct to OCTA as a supportive method to evaluate the retina in healthy patients and patients with disease.In cases requiring accurate and detailed retinal vasculature observation, AO-SLO might be useful for evaluating retinal vascular lesions as a supportive imaging method of OCTA.