Synthesis of the Literature on Visual Acuity and Complications Following Cataract Extraction With Intraocular Lens Implantation

OBJECTIVE: To better define the effectiveness and risks of modern cataract surgery. DESIGN: Meta-analysis (formal systematic identification, selection, review, and synthesis) of published literature. PATIENTS: Patients described in 90 studies published between 1979 and 1991 that addressed visual acuity (n = 17,390 eyes) or complications (n = 68,316 eyes) following standard extracapsular cataract extraction with posterior chamber intraocular lens implantation, phaco-emulsification with posterior chamber intraocular lens implantation, or intracapsular cataract extraction with flexible anterior chamber intraocular lens implantation. MAIN OUTCOME MEASURES: The proportion of eyes with postoperative Snellen visual acuity of 20/40 or better and the proportion of eyes with each of 18 complications. RESULTS: The pooled percentage of eyes (weighted by sample size) with postoperative visual acuity of 20/40 or better was 95.5% (95% confidence interval CI, 95.1% to 95.9%) among eyes without preexisting ocular comorbidity and 89.7% (95% CI, 89.3% to 90.2%) for all eyes. The pooled percentage of eyes experiencing complications (weighted by sample size and, when pertinent, by quality score of the individual studies but not adjusted for variation in duration of follow-up) ranged from 0.13% for endophthalmitis to 19.7% for posterior capsule opacification. Pooled proportions of eyes with other complications were as follows: bullous keratopathy, 0.3%; intraocular lens malposition/dislocation, 1.1%; clinically apparent cystoid macular edema, 1.5%; and retinal detachment, 0.7%. Pooled results for postoperative Snellen visual acuity and most complications were similar for surgery performed via phacoemulsification vs standard extracapsular cataract extraction, although comparisons of the outcomes between these procedures should be interpreted with caution. CONCLUSIONS: The published literature indicates that modern cataract surgery yields excellent visual acuity and, although not free of complications, is a very safe procedure regardless of the extraction technique used.