Diseased retinal multivascular network phantom for the evaluation of optical coherence tomography angiography

The healthiness of the retinal vascular network plays an essential role in maintaining healthy vision. Numerous efforts have been devoted to developing accessible high-resolution retinal vascular network mapping instruments for ocular disease diagnosis and systematic disorder screening. Although optical coherence tomography (OCT) is the current standard-of-care high-resolution noninvasive retinal imaging technique, it only provides 3D structural retinal images. To enable the noninvasive visualization and assessment of the retinal vascular network, OCT angiography (OCTA) was invented to analyze differences within repeatedly scanned cross-sectional areas to form volumetric retina blood flow maps. With these unprecedented advantages, OCTA has been quickly employed by ophthalmic clinics. Nevertheless, the inconsistencies in current imaging protocols, data analysis metrics, and clinical practices result in difficulties in OCTA function evaluation during product registration, periodic calibration, and inspection. A retinal vascular phantom could facilitate the OCTA product performance evaluation to promote the standardization of OCTA instruments. In this work, we designed and fabricated a retinal multivascular phantom with an eleven-layer structure and a diseased multivascular network with microaneurysms and vein occlusions to evaluate OCTA instrument performance. To mimic the blood flow in the retina, an intralipid solution was injected into the vascular network phantom with an infusion pump. OCT and OCTA images of the retina phantom were obtained with a commercial OCTA system. Critical retinal vascular network parameters of the phantom were also examined to validate its quantitative evaluation function. Results prove that the diseased multivascular network retinal phantom could provide an assessment of the OCTA function.