OBJECTIVE The aim of this study was to examine whether differences exist after cataract surgery is performed in patients over and under 90 years of age. METHODS Retrospective, nonrandomized study. METHODS Cataract surgery was performed in 21 patients (31 eyes) who were older than 90 years of age and in 45 patients (70 eyes) who were younger than 90 years of age. METHODS The medical records of all patients who underwent cataract surgery between January 2005 and September 2010 at Dokkyo Medical University Koshigaya Hospital were reviewed. Factors evaluated included systemic disease, changes in systemic condition, surgical time, preoperative and postoperative visual acuity, corneal endothelial cell density, and intraoperative complications. RESULTS The group of patients older than 90 years of age experienced greater occurrences of systemic disease (p < 0.05; χ(2) test) and intraoperative changes in systemic conditions (p < 0.001; χ(2) test). These patients also had significantly lower preoperative visual acuity (p < 0.001; Student t test). No differences were noted between the 2 age groups in surgical time, postoperative visual acuity, preoperative corneal endothelial cell density, or intraoperative complications. CONCLUSIONS Poorer cataract surgery outcome results were noted in patients older than 90 years due to systemic disease and intraoperative changes in systemic condition. Factors that need to be taken into consideration prior to performing cataract surgery in older patients include age, systemic disease, and the likelihood of intraoperative changes in systemic condition.