RIGOR OF RESEARCH METHODS IN STUDIES OF THE EFFECTIVENESS AND SAFETY OF CATARACT-EXTRACTION WITH INTRAOCULAR-LENS IMPLANTATION

Objective: To assess the rigor of research methods reported in studies of the safety or effectiveness of contemporary cataract surgery. Desi gn: Formal systematic identification of pertinent studies and critical appraisal of each study's research methods. Subjects: From 6113 uniqu e, potentially relevant citations that we identified, 90 original stud ies published between 1979 and 1991 that addressed visual acuity or co mplications following standard extracapsular cataract extraction with posterior chamber intraocular lens implantation, phacoemulsification w ith posterior chamber intraocular lens implantation, or intracapsular cataract extraction with flexible anterior chamber intraocular lens im plantation. Main Outcome Measures: Strength of study design, performan ce, and reporting in 11 methodologic areas assessed with a standardize d abstraction form by two reviewers masked to authors, their instituti ons, and the journal of publication. Results of reviews were tallied t o produce an overall quality score (measure of rigor in research metho ds) for each study. Results: The mean (+/-SD) quality score was 43.1+/ -20.1 out of a maximum possible score of 100. Studies received interme diate scores on description of baseline ocular disease and low scores on descriptions of other characteristics of enrolled patients, standar dization of outcome assessment and follow-up duration, and handling of patient attrition. Eighty-three studies (92%) lacked a comparison gro up. The rigor of research methods in studies varied by the journal of publication, did not improve over time, and was no greater for studies with larger vs smaller sample sizes. Conclusions: The rigor of resear ch methods in studies of cataract surgery can be improved if more atte ntion is paid to fundamental principles of study design, data analysis , and reporting.