Effects of Bifocal versus Trifocal Diffractive Intraocular Lens Implantation on Visual Quality after Cataract Surgery

Abstract

Purpose: To compare the effects of bifocal versus trifocal diffractive intraocular lens (IOL) implantation on visual quality after phacoemulsification in patients with cataracts.

Methods: Eighty-eight eyes from 63 patients were analyzed. Trifocal (AT LISA tri 839MP), bifocal (AcrySof IQ ReSTOR) and bifocal (Tecnis MF ZLB00) IOLs were implanted into 53, 18, and 17 eyes, respectively. Uncorrected distance, intermediate and near visual acuity, refractive errors, contrast sensitivity, and patient satisfaction were measured at 1 week and 1 month after surgery. Refractive error was converted to a spherical equivalent and compared to predicted refraction calculated by IOL calculation formulas.

Results: Uncorrected distance, intermediate, and near visual acuity did not differ significantly between groups. One month after surgery, the mean refractive errors were -0.07 diopters (D) in the AT LISA tri 839MP group, +0.18 D in the AcrySof IQ ReSTOR group, and +0.31 D in the Tecnis MF ZLB00 group (p < 0.001). The predictive accuracy of IOL calculation formulas did not differ between groups. Contrast sensitivity, satisfaction, and spectacle independence in the trifocal group were comparable with those of the two bifocal groups.

Conclusions: Trifocal IOL and two different types of bifocal IOL implantation were all effective for improving visual quality, although refractive error in patients with trifocal IOL shows myopic tendencies.

Keywords: Multifocal intraocular lenses; Presbyopia; Refractive errors.

Fig. 1. Percentages of eyes with logarithm of the minimal angle of resolution uncorrected visual acuities better than 0, 0.1, and 0.3 (Snellen equivalent: 20 / 20, 20 / 25, and 20 / 40) with different multifocal intraocular lenses at (A) 1 week and (B) 1 month after surgery. UDVA = uncorrected distant visual acuity; UIVA = uncorrected intermediate visual acuity at an 80-cm distance; UNVA = uncorrected near visual acuity at a 40-cm distance.

Fig. 2. Postoperative mean spherical equivalent at (A) 1 week and (B) 1 month after surgery. The AT LISA tri 839MP group showed myopic tendencies compared to the AcrySof IQ ReSTOR and Tecnis MF ZLB00 groups. A p-value was determined using Mann-Whitney U-tests. IOL = intraocular lens.

Fig. 3. Predictive accuracy of five intraocular lens (IOL) calculation formulas in different multifocal IOL groups. (A) Comparison of mean numerical error (MNE). MNE was the actual postoperative spherical equivalent minus predicted spherical equivalent. (B) Comparison of mean absolute error (MAE). MAE was the average absolute value of MNE.

Fig. 4. Contrast sensitivity (CS) at five spatial frequencies in patients implanted with different multifocal intraocular lenses (IOLs) at 1 month postoperatively. The results for the AT LISA tri 839MP group were comparable to those of the two bifocal IOL groups. The bar represents standard deviation. A p-value was determined using Kruskal-Wallis tests.

Fig. 5. Patient-reported satisfaction and spectacle independence after implantations of different multifocal intraocular lenses (IOLs). Satisfaction was scored from 0 to 4 points (4 = completely satisfied, 3= very satisfied, 2 = moderate, 1 = poor, 0 = unsatisfied). Necessity of wearing glasses was scored from 0 to 4 points (4 = never, 3 = occasionally, 2 = sometimes, 1 = often, 0 = always). The bar represents standard deviation.