Optical quality differences between three multifocal intraocular lenses: bifocal low add, bifocal moderate add, and trifocal.

PURPOSE: To compare the in vitro optical quality at different focal points of two new bifocal intraocular lenses (IOLs) and one new trifocal IOL.

METHODS: The AcrySof ReSTOR SV25T0 (+2.5 diopter [D] add) and the AcrySof ReSTOR SN6AD1 (+3.0 D add) with two main foci (Alcon Laboratories, Fort Worth, TX) and the AT LISA tri 839MP with three main foci (Carl Zeiss Meditec, Dublin, CA) were evaluated. The optical quality of the IOLs was measured with the PMTF optical bench (LAMBDA-X, Nivelles, Belgium). The optical quality of the IOLs was quantified by the modulation transfer function (MTF) at five different focal points (0.0, -1.5, -2.0, -2.5, and -3.0 D) and for 3.0- and 4.5-mm apertures. The through-focus MTF of the IOLs was also recorded.

RESULTS: For the 0.0 D focal point, the AcrySof ReSTOR (+2.5 D add) obtained the highest MTF values for all apertures. For the -2.5 D focal point, the AcrySof ReSTOR (+3.0 D add) showed the highest MTF values for 3.0 mm. For the -3.0 D focal point at 3.0- and 4.5-mm aperture, the best values were obtained with the AcrySof ReSTOR (+3.0 D add) and the AT LISA, respectively. For the -1.5 D focal point, the trifocal IOL provided better values. For the -2.0 D focal point, all IOLs provided comparable results. The through-focus MTF curves showed three and two peaks for the trifocal and bifocal IOLs, respectively.

CONCLUSIONS: The trifocal IOL provides a better optical quality at the -1.5 D focal point. However, the optical quality of the trifocal IOL significantly decreases compared to the bifocal IOLs at far distance and -2.5 D focal points.