The foveal avascular zone (FAZ) is the most sensitive region of the retina, which is connected by the macular capillary plexus. Its morphology can indirectly reflect the alterations of macular microcirculation. With strong repeatability and reliability, optical coherence tomography angiography (OCTA) can non-invasively visualize and quantify the FAZ region. The great value of OCTA makes it an important supplemental examination tool in ophthalmology and other professions. The area and perimeter of FAZ have been demonstrated to be an effective clinical diagnostic indicator in high myopia, diabetic retinopathy, glaucoma and other ocular diseases. In recent years, the geometry of FAZ has also proven to have clinical value. The parameters describing the geometry of FAZ, such as circularity index, acircularity index and axial ratio, provide a new perspective for ocular disease research. The comprehensive investigation of the morphological characteristics of the FAZ region is helpful to explore the pathological mechanism of the occurrence and development of ocular diseases, predict preclinical changes, accurate pathological stages of the disease, and provide a theoretical basis for monitoring the disease’s progression and assessing patients’ visual prognosis.