Abstract:Diabetic retinopathy(DR), the most common microvascular complication of diabetes, has become a leading cause of visual impairment and blindness across all age groups. The early diagnosis and severity assessment of DR rely on the precise evaluation of retinal microvascular alterations. The periarterial capillary-free zone(paCFZ), a physiological avascular region surrounding retinal arteries, has recently been recognized as an important biomarker reflecting the status of retinal microcirculation. Advances in optical coherence tomography angiography(OCTA)have enabled noninvasive, high-resolution quantification of the paCFZ, offering a novel approach for the early detection and stratification of DR. This review systematically summarizes the definition and developmental mechanism of the paCFZ, as well as its morphological characteristics across different stages of DR, with a particular focus on the advantages of OCTA in visualizing and quantifying the paCFZ. We further discuss the differential manifestations of the paCFZ in nonproliferative DR and proliferative DR, and its associations with retinal ischemia and oxygenation status. In addition, the potential clinical value of paCFZ in evaluating responses to anti-vascular endothelial growth factor(VEGF)therapy and predicting disease progression is summarized. Finally, the challenges in clinical translation and future research directions are addressed, aiming to provide theoretical support and new perspectives for early screening, risk stratification, and personalized management of DR.
