AIMS: To describe the impact of cataract surgery in terms of visual function (functioning in everyday life with respect to vision dependent activities) and health related quality of life. METHODS: An observational, longitudinal study of patients undergoing cataract surgery was carried out at three district general hospitals in outer London districts of North Thames Region with follow up at 4 and 12 months postoperatively for a clinical assessment and a standardised administered interview. Patients were admitted for surgery to the first eye for age-related cataract between 1 May 1993 and 31 August 1994. Visual functioning was assessed by the VF-14, health related quality of life was assessed by the sickness impact profile (SIP), and vision related quality of life was assessed by VR-SIP (a modification of the generic SIP). RESULTS: Significant gains in all the outcome measures were demonstrated at 4 months postoperatively. No significant change (gain or loss) was observed between 4 and 12 months after surgery to the first eye. Postoperatively, the mean visual function (VF-14) scores, and health related (SIP) and vision related (VR-SIP) quality of life scores, indicated less reported trouble with vision dependent activities and better perceived quality of life, respectively. The average gains in visual function and quality of life (health and vision related) were apparent in groups with good visual outcome and poor visual outcome. Significant additional gains were seen at 1 year in patients who had second eye surgery in the interval between the postoperative assessments. CONCLUSIONS: Gains in visual functioning and quality of life (health and vision related) have been demonstrated following cataract surgery. These gains were sustained at 1 year after surgery to the first eye, with additional gains being conferred if second eye surgery had been performed. Assessment of the outcomes of cataract surgery by clinical indicators alone may underestimate the overall benefits of surgery, particularly in patients with poor visual outcome.