We conducted a prospective study of 293 elderly patients undergoing cataract surgery with intraocular lens implantation to determine the impact of the surgery on vision and on subjective and objective measures of patient function. Visual acuity in the surgical eye improved from a mean of 20/100 before surgery to 20/40 four months after surgery; improvement was maintained at one year. Positive changes occurred in some subjective measures of patient function, such as reported activities of daily living and patient report of vision-dependent activities, but these changes were modest. The most marked changes in patient function occurred in objective measures of function. Mental status had improved not quite significantly at four months but significantly at one year. Timed manual performance improved dramatically and significantly at four months and one year. Cataract surgery was associated with improved vision and improved objective function in most patients by four months after surgery, and these improvements were maintained at one year.