Cost-effectiveness of the AMOArray multifocal intraocular lens in cataract surgery

Study sample Power calculations to determine the sample size were performed (apparently in the preliminary phase of the study). These suggested that a sample of 99 patients in each group was required to detect a 0.4 difference in mean scores between the two groups with 80% power and at a 5% level of significance. All of the patients who underwent bilateral implantation of the multifocal IOL were eligible for the study. Of the 126 patients identified, 110 (87%) agreed to participate and were enrolled in the study. A comparison group of 142 patients, who were implanted bilaterally with a monofocal IOL at the same sites as the multifocal patients, met the study criteria and were invited to participate as a control group. Of these, 112 agreed to participate. Reasons for refusal were not stated.