In vitro optical performance of nonrotational symmetric and refractive-diffractive aspheric multifocal intraocular lenses: impact of tilt and decentration.

PURPOSE

To evaluate the optical quality of Acrysof Restor SN6AD1 refractive-diffractive +3.00 D and Lentis Mplus LS-312 nonrotational symmetric +3.00 D aspheric multifocal intraocular lenses (IOLs) and analyze the effect of tilt and decentration.

SETTING

University of Valencia, Valencia, and University of Murcia, Murcia, Spain.

DESIGN

Experimental study.

METHODS

An artificial model eye was used to measure wavefront aberrations of both IOL models. The modulation transfer function (MTF) and point-spread function (PSF) were calculated for a 5.0 mm pupil and under 5 situations: centered, 0.2 mm and 0.4 mm decentered, and 2 degrees and 4 degrees tilted.

RESULTS

The refractive-diffractive IOL had the highest MTF values at all spatial frequencies. Similarly, the PSF was worse for the refractive-diffractive IOL. The MTFs for the refractive-diffractive IOL decreased when the IOL was decentered or tilted, being more robust for tilting than decentration. The MTFs for the nonrotational symmetric IOL were similar under all testing conditions. Cutoff frequencies for the refractive-diffractive IOL were stable over the range of tilting studied and comparable with the cutoff when the IOL was centered (approximately 50 cycles per degree [cpd]). When the IOL was decentered, the cutoff frequency decreased by approximately 40 cpd. The nonrotational symmetric IOL cutoff frequencies for misalignment and tilt were low (approximately 30 cpd) and similar under all conditions.

CONCLUSIONS

The refractive-diffractive IOL provided better optical quality than the nonrotational symmetric IOL. Tilt and decentration had a significant impact on optical quality with both IOLs, being more severe with the nonrotational symmetric IOL.