Comparative analysis of the visual performance after cataract surgery with implantation of a bifocal or trifocal diffractive IOL.

PURPOSE To evaluate and compare the visual, refractive, contrast sensitivity, and aberrometric outcomes with a diffractive bifocal and trifocal intraocular lens (IOL) of the same material and haptic design. METHODS Sixty eyes of 30 patients undergoing bilateral cataract surgery were enrolled and randomly assigned to one of two groups: the bifocal group, including 30 eyes implanted with the bifocal diffractive IOL AT LISA 801 (Carl Zeiss Meditec, Jena, Germany), and the trifocal group, including eyes implanted with the trifocal diffractive IOL AT LISA tri 839 MP (Carl Zeiss Meditec). Analysis of visual and refractive outcomes, contrast sensitivity, ocular aberrations (OPD-Scan III; Nidek, Inc., Gagamori, Japan), and defocus curve were performed during a 3-month follow-up period. RESULTS No statistically significant differences between groups were found in 3-month postoperative uncorrected and corrected distance visual acuity (P ≥ .21). However, uncorrected, corrected, and distance-corrected near and intermediate visual acuities were significantly better in the trifocal group (P < .01). No significant differences between groups were found in postoperative spherical equivalent (P = .22). In the binocular defocus curve, the visual acuity was significantly better for defocus of -0.50 to -1.50 diopters in the trifocal group (P ≤ .04) and -3.50 to -4.00 diopters in the bifocal group (P ≤ .03). No statistically significant differences were found between groups in most of the postoperative corneal, internal, and ocular aberrations (P ≤ .31), and in contrast sensitivity for most frequencies analyzed (P ≤ .15). CONCLUSIONS Trifocal diffractive IOLs provide significantly better intermediate vision over bifocal IOLs, with equivalent postoperative levels of visual and ocular optical quality.