BACKGROUND: Cataract accounts for 50% of blindness globally and remains the leading cause of visual impairment in all regions of the world, despite improvements in surgical outcomes (WHO 2005). This number is expected to rise due to an aging population and increase in life expectancy. Although cataracts are not preventable, their surgical treatment is one of the most cost-effective interventions in healthcare. OBJECTIVES: To compare the effects of different surgical interventions for age-related cataract. SEARCH STRATEGY: We searched CENTRAL, MEDLINE, EMBASE up to July 2006, NRR Issue 3 2005, the reference lists of identified trials and we contacted investigators and experts in the field for details of published and unpublished trials. SELECTION CRITERIA: We included randomised controlled trials (RCTS). DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and discrepancies were resolved by discussion. Where appropriate, risk ratios, odds ratios and weighted mean differences were summarised after assessing heterogeneity between the studies. MAIN RESULTS: We identified 17 trials that randomised a total of 9627 people. Phacoemulsification gave a better visual outcome than extracapsular surgery but similar average cost per procedure in Europe but not in poorer countries. Extracapsular surgery with posterior chamber lens implant and ICCE with or without an anterior chamber intraocular lens (IOL) implant gave acceptable visual outcomes but extracapsular surgery had less complications. Manual small incision surgery provides better visual outcome than ECCE but slightly inferior unaided visual acuity compared to phacoemulsification. AUTHORS' CONCLUSIONS: This review provides evidence from seven RCTs that phacoemulsification gives a better outcome than ECCE with sutures. We also found evidence that ECCE with a posterior chamber lens implant provides better visual outcome than ICCE with aphakic glasses. The long term effect of posterior capsular opacification (PCO) needs to be assessed in larger populations. The data also suggests that ICCE with an anterior chamber lens implant is an effective alternative to ICCE with aphakic glasses, with similar safety. Phacoemulsification provides the best visual outcomes but will only be accessible to the poorer countries if the cost of phacoemulsification and foldable IOLs decrease. Manual small incision cataract surgery provides early visual rehabilitation and comparable visual outcome to PHACO. It has better visual outcomes than ECCE and can be used in any clinic that is currently carrying out ECCE with IOL. Further research from developing regions are needed to compare the cost and longer term outcomes of these procedures e.g. PCO and corneal endothelial cell damage.