Cerebral small vessel disease (CSVD) is a series of clinical, imaging, and pathological syndromes resulting from various etiologies affecting small arteries (microarteries, capillaries, microvenules, and small veins in the brain). The diagnosis of CSVD is based on imaging presentations, but the high cost and bleeding risk of cranial imaging methods make the diagnosis of rare CSVD more difficult. Retinal vessels are the only vasculature visible in vivo and share anatomical and embryological features with small brain vessels. Retinal vascular abnormalities have been shown to exist in rare CSVD such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral amyloid angiopathy (CAA) and moyamoya disease (MMD). Retinal vascular examination may provide new ideas for the study of rare CSVD.