Multifocal versus monofocal intraocular lenses after cataract extraction.

BACKGROUND Good unaided distance visual acuity is now a realistic expectation following cataract surgery and intraocular lens (IOL) implantation. Near vision however still requires additional refractive power usually in the form of reading glasses. Multiple optic (multifocal) IOLs are available which claim to allow good vision at a range of distances. It is unclear whether this benefit outweighs the optical compromises inherent in multifocal IOLs. OBJECTIVES The objective of this review was to assess the effects of multifocal IOLs, including effects on visual acuity, subjective visual satisfaction, spectacle dependence, glare and contrast sensitivity, compared to standard monofocal lenses. SEARCH STRATEGY We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which includes the Eyes and Vision Group Trials Register) on The Cochrane Library (2006, Issue 3), MEDLINE (1966 to July 2006), EMBASE (1980 to July 2006), NRR (2006, Issue 3) and PUBMED searched on 25 July 2006, limit: 90 days (entry date). We searched the reference lists of relevant articles and contacted investigators of included studies and manufacturers of multifocal intraocular lenses for information about additional published and unpublished studies. SELECTION CRITERIA All randomised controlled trials comparing a multifocal IOL of any type with a monofocal IOL as control were included. Both unilateral and bilateral implantation trials were included. DATA COLLECTION AND ANALYSIS Data were collected and trial quality was assessed. Where possible, statistical summary measures were calculated otherwise data were tabulated. MAIN RESULTS Ten trials were identified, and a further three are pending review. There was significant variability between the trials in which outcomes were reported. Unaided distance acuity was similar in multifocal and monofocal IOLs (standardised mean difference (SMD) 0.03, 95% Confidence Interval (CI) -0.13 to 0.19). There was no statistical difference between multifocal IOLs and monofocals with respect to the proportion of participants achieving 6/6 best corrected visual acuity (Peto odds ratio (OR) 1.05, 95% CI 0.67 to 1.63). Unaided near vision was improved with the multifocal IOLs. Total freedom from use of glasses was achieved more frequently with multifocal than monofocal IOLs (OR for spectacle dependence 0.17, 95% CI 0.12 to 0.24). Adverse effects included reduced contrast sensitivity and the subjective experience of haloes around lights. AUTHORS' CONCLUSIONS Multifocal IOLs are effective at improving near vision relative to monofocal IOLs. Whether that improvement outweighs the adverse effects of multifocal IOLs will vary between patients. Motivation to achieve spectacle independence is likely to be the deciding factor.