To assess the effect of blepharoptosis on patients' visual function and health-related quality of life and to determine what measures are associated with postsurgical change in functional status. Prospective, observational case series. One hundred patients with unilateral or bilateral blepharoptosis. INTERVENTION/MAIN OUTCOME MEASURES: Preoperative and postoperative upper eyelid position (i.e., margin reflex distance [MRD]) and superior visual field (SVF) height, as well as subjective visual function and health-related quality-of-life functional status before and after ptosis surgery. There was a mean 30-point increase in functional index score after ptosis repair (P < 0.001). Lower (more ptotic) preoperative upper eyelid position and SVF (combined eye) were associated with greater change in functional index after surgery (r = -0.290, P = 0.007 and r = -0.39, P = 0.003, respectively). Preoperative visual field testing with manual lid elevation was not significantly correlated to the postoperative change in functional index (P > 0.100). The strongest correlation of postoperative functional index change was with the preoperative functional status (r = -0.79, P < 0.001). Patients' functional status is reduced by blepharoptosis, and surgical repair results in measurable increase in health-related quality of life. Patients' self-reported preoperative functional impairment is most strongly associated with the degree of postsurgical functional improvement.