Comparison of the Storz bifocal zonal and the 3M diffractive multifocal intraocular lenses

Visual acuity and contrast sensitivity after cataract surgery were evaluated in best-case eyes that received a Storz bifocal zonal intraocular lens (IOL) or a 3M diffractive multifocal IOL. A group of eyes with a monofocal IOL was used as a control. Postoperatively, all eyes had a best corrected visual acuity of 20/40 or better. At near, wearing the best distance correction, 86.0% of the Storz group and 94.5% of the 3M group had a visual acuity of 20/40 or better. Both the Storz and 3M groups had a significantly greater loss in visual acuity in dim light at the lowest contrast levels than the monofocal group. Under bright light, the Storz group's contrast sensitivity was not significantly different from that of the monofocal groups; however, the 3M group's contrast sensitivity decreased at all levels of contrast. The Storz lens performed slightly but significantly better than the 3M lens in bright light (96% and 25% Regan levels), perhaps because of the difference in IOL optics or small differences in the incidence of posterior capsule opacification, for which this study was not controlled. In the Storz and 3M groups, distance visual acuity was better than distance visual acuity using a minus addition, which makes the patient use the near portion of the optic.