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 implantation. Near vision however still requires additional refractive power, usually in the form of reading glasses. Multiple optic (multifocal) intraocular lenses are available that are claimed to allow good vision at a range of distances. It is unclear whether this benefit outweighs the optical compromises inherent in multifocal intraocular lenses.


OBJECTIVE
The objective of this review is to assess the effects of multifocal intraocular lenses, including effects on visual acuity, subjective visual satisfaction, spectacle dependence, glare and contrast sensitivity, compared to standard monofocal lenses.


METHODS
We searched the Cochrane Controlled Trials Register - CENTRAL (which includes the Cochrane Eyes and Vision Group specialised register), MEDLINE and EMBASE. The reference lists of relevant articles were searched. Investigators of included studies and manufacturers of multifocal intraocular lenses were contacted for information about additional published and unpublished studies.


METHODS
All randomised controlled trials comparing a multifocal intraocular lens of any type with a monofocal intraocular lens as control were included. Both unilateral and bilateral implantation trials were included.


METHODS
Data were collected and trial quality assessed. Where possible, statistical summary measures were calculated, otherwise data were tabulated.


RESULTS
One ongoing and six completed trials were identified. There was significant variability between the trials in the outcomes reported. Unaided distance acuity was similar in multifocal and monofocal intraocular lenses (Peto odds ratio 1.27 (95% Confidence Interval (CI) 0.76 to 2.11)), with a small increase in the proportion of multifocal intraocular lens participants achieving less than 6/6 best corrected visual acuity (Peto odds ratio 1.64 (95% CI 1.10 to 2.42)). Unaided near vision tended to improve with the multifocal intraocular lenses. This resulted in decreased spectacle dependence with use of the multifocal intraocular lenses (Peto odds ratio 0.16 (95% CI 0.11 to 0.23)). Adverse effects included reduced contrast sensitivity and the subjective experience of haloes around lights.


CONCLUSIONS
Multifocal intraocular lenses are effective at improving near vision relative to monofocal intraocular lenses. Whether that improvement outweighs the adverse effects of multifocal intraocular lenses will vary between patients, with motivation to achieve spectacle independence likely to be the deciding factor.
Leyland
M
M
Moorfields Eye Hospital, City Road, London, UK, EC1V 2PD. martin@mleyland.fsnet.co.uk
Zinicola
E
E
D002387:Cataract Extraction; D006801:Humans; D007910:Lenses, Intraocular; D016032:Randomized Controlled Trials as Topic; D014792:Visual Acuity