Postoperative visual performance with a bifocal and trifocal diffractive intraocular lens during a 1-year follow-up

AIM：To evaluate and compare the clinical outcomes with a diffractive bifocal and trifocal intraocular lens（IOL）during a 12-month follow-up.METHODS：Prospective comparative study including75 eyes of 38 patients（44-70y）undergoing uneventful cataract surgery.Each patient was randomly assigned to one type of IOL,bifocal（35 eyes）or trifocal（40 eyes）.Visual,refractive,and contrast sensitivity changes were evaluated in a 12-month follow-up.The binocular defocus curve was also measured at 12mo postoperatively.RESULTS：No statistically significant differences between groups were found in postoperative uncorrected and corrected distance visual acuities（P≥0.276）.Postoperative corrected near visual acuity（33 cm）was significantly better in the trifocal group during all follow-up（P≤0.004）as well as 6-month uncorrected near（P=0.008）and distancecorrected near visual acuities（P=0.016）（33/40 cm）.Significantly better uncorrected intermediate and distance corrected-intermediate visual acuity were found during all follow-up in the trifocal group（P〈0.001）,which was consistent with differences among groups in binocular defocus curve.Differences among groups in contrast sensitivity were minimal,being only significant at 6 months for some low to medium spatial frequencies（P≤0.006）.CONCLUSION：Bifocal and trifocal diffractive IOLs are able to provide an effective visual restoration which is maintained during a 12-month follow-up,with a clear benefit of the trifocal IOL for the intermediate vision.