BACKGROUND: The effect of ptosis on visual quality is a crucial consideration in the oculoplastic surgeon's practice that cannot be ignored before performing corrective surgery. The aim of this review is to summarize the manifestations and mechanisms of visual quality impairment in ptosis. MAIN TEXT: A literature search was conducted in multiple databases to identify studies reporting changes in various visual quality parameters and mechanisms that affect visual quality loss in ptotic eyes. The studies included both retrospective and cross-sectional designs. This paper comprehensively describes the changes in a variety of subjective and objective visual quality parameters such as visual acuity, contrast sensitivity, visual field, refraction, higher-order aberrations, and OQAS parameters in the ptotic eye, and provides a detailed in-depth analysis of the specific mechanisms by which the eyelids, eyelashes, and ocular position interfere with visual quality. CONCLUSIONS: The manifestations of the impact of ptosis on visual quality are diverse and influenced by multiple mechanisms. A comprehensive and objective assessment of the manifestations and specific mechanisms of visual quality impairment in patients with ptosis will provide an important reference for treatment selection and prognosis of visual function.