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 including 75 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 distance-corrected 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.

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.