Toric intraocular lenses: correcting astigmatism while controlling axis shift.

We evaluated the efficacy of toric intraocular lenses (IOLs) implanted in the eyes of 47 patients who had preoperative against-the -rule astigmatism. The lenses, which had a cylinder power of 2.00 diopters (D) (n = 26) or 3.00 D (n = 21), were implanted through a 5.7 mm incision after cataract extraction by phacoemulsification. Best corrected visual acuity three months postoperatively was 20/25 or better in 77% of eyes. The 3.00 D IOLs resulted in better correction than the 2.00 D IOLs when the axis shift of the lens was less than 30 degrees. A negative effect occurred in some eyes in which the lens axis rotated more than 30 degrees. The maximum acceptable axis shift seems to be less than 30 degrees.