Carotid artery stenosis (CAS) is a consequence of systemic atherosclerotic disease affecting the aging populations of the Western world. CAS is frequently associated with cognitive impairment. However, the mechanisms contributing to the development of vascular cognitive impairment (VCI) associated with CAS are multifaceted and not fully understood. In addition to embolization and decreased blood flow due to the atherosclerotic lesion in the carotid artery, microcirculatory dysfunction in the cerebral circulation also plays a critical role in CAS-related VCI. To better understand the microvascular contributions to cognitive decline associated with CAS and evaluate microvascular protective effects of therapeutic interventions, it is essential to examine the structural and functional changes of the microvessels in the central nervous system (CNS). However, there are some limitations of in vivo brain vascular imaging modalities. The retinal microvasculature provides a unique opportunity to study pathogenesis of cerebral small vessel disease and VCI, because the cerebral circulation and the retinal circulation share similar anatomy, physiology and embryology. Similar microvascular pathologies may manifest in the brain and the retina, thus ocular examination can be used as a noninvasive screening tool to investigate pathological changes in the CNS associated with CAS. In this review, ocular signs of CAS and the retinal manifestations of CAS-associated microvascular dysfunction are discussed. The advantages and limitation of methods that are capable of imaging the ocular circulation (including funduscopy, fluorescein angiography, Doppler sonography, optical coherence tomography [OCT] and optical coherence tomography angiography [OCTA]) are discussed. The potential use of dynamic retinal vessel analysis (DVA), which allows for direct visualization of neurovascular coupling responses in the CNS, for understanding microvascular contributions to cognitive decline in CAS patients is also considered.

颈动脉狭窄（CAS）是影响西方世界人口老龄化的系统性动脉粥样硬化性疾病的结果。CAS 通常与认知障碍有关。然而，与 CAS 相关的血管性认知障碍 (VCI) 的发生机制是多方面的，且尚未完全了解。除了颈动脉粥样硬化病变导致的栓塞和血流减少外，脑循环中的微循环功能障碍也在 CAS 相关的 VCI 中发挥着关键作用。为了更好地了解微血管对 CAS 相关认知能力下降的影响并评估治疗干预的微血管保护作用，有必要检查中枢神经系统 (CNS) 中微血管的结构和功能变化。然而，体内脑血管成像方式存在一些局限性。视网膜微血管系统为研究脑小血管疾病和 VCI 的发病机制提供了独特的机会，因为脑循环和视网膜循环具有相似的解剖学、生理学和胚胎学。类似的微血管病变可能出现在大脑和视网膜中，因此眼部检查可以作为一种无创筛查工具来研究与 CAS 相关的 CNS 病理变化。本综述讨论了 CAS 的眼部体征以及 CAS 相关微血管功能障碍的视网膜表现。讨论了能够对眼循环进行成像的方法（包括眼底镜检查、荧光素血管造影、多普勒超声检查、光学相干断层扫描[OCT]和光学相干断层扫描血管造影[OCTA]）的优点和局限性。还考虑了动态视网膜血管分析 (DVA) 的潜在用途，该分析可以直接可视化中枢神经系统中的神经血管耦合反应，以了解微血管对 CAS 患者认知能力下降的影响。