Effectiveness of multifocal and monofocal intraocular lenses for cataract surgery and lens replacement: a systematic review and meta-analysis

Multifocal intraocular lenses (IOLs) offer the possibility of spectacle-free vision following cataract surgery compared to standard IOLs. Existing systematic reviews have generally concluded that multifocal IOLs result in better uncorrected near vision and greater spectacle independence, but more unwanted visual phenomena such as glare and halos, compared to monofocal IOLs. However, the certainty of evidence has been low for most outcomes, and pooled analyses have grouped together technologically obsolete lenses with newer lenses, potentially obscuring differences in performance across different lens types.We performed a systematic review searching for RCTs of a multifocal IOL to a standard IOL or monovision that reported spectacle independence, visual acuity, or quality of life. Databases were searched from 1/1/2006-4/30/2017. Existing reviews were used to identify older studies. Title/abstract screening and data extraction were done in duplicate. Where possible, random effects meta-analysis was performed to synthesize results. In addition to comparing multifocal IOLs as a group to monofocal IOLs, we also compared newer diffractive lenses to obsolete or refractive lenses.Twenty-five eligible studies were identified. There was no difference in pooled estimates of corrected or uncorrected distance vision between multifocal and standard IOLs. Compared to monofocal IOLs, multifocal IOLs had statistically significantly better pooled results for the outcome of near vision (10 studies, 1025 patients, mean difference in logMAR of -0.26 (95% CI -0.37, -0.15)); spectacle dependence (12 studies, 1237 patients, relative risk of 0.27 (95% CI 0.20, 0.38)) and borderline significantly better quality of vision (6 studies, 596 patients, standardized mean difference of -0.54, (95% CI -1.12, 0.04)). Compared to monofocal IOLs, multifocal IOLs had statistically significantly worse pooled results for the outcomes of glare (9 studies, 847 patients, risk ratio of 1.36 (95% CI 1.15, 1.61) and halos (7 studies, 754 patients, risk ratio of 3.14 (95% CI 1.63, 6.08). Newer multifocal lenses had statistically significantly better outcomes than older diffractive lenses or refractive lenses, when compared to monofocal IOLs, in near vision, quality of vision, and risk of halos.Multifocal IOLs compared to standard IOLs or monovision result in better uncorrected near vision and a higher proportion of patients who achieve spectacle independence, but greater risk of unwanted visual phenomena. Newer diffractive lenses may be better than refractive lenses in near vision and quality of vision outcomes, with less risk of halos than older diffractive lenses and refractive lenses. (PROSPERO registration CRD42017069949).