Toric IOLs yield minimal residual refractive cylinder

Key Points

Dr. Ernest, associate clinical professor, Kresge Eye Institute, Wayne State University, Detroit, and a private practitioner in Jackson, MI, based his comments on a study of 119 patients who returned to the clinic 1 year after implantation of the toric IOL. Eighty-four patients had received a model SA60T3 lens, 14 had received a model SA60T4 lens, and 21 had received a model SA60T5 lens.

At the time of implantation, the following patients had been deemed suitable candidates for the toric IOL: patients with astigmatism undergoing cataract and refractive surgery, patients with astigmatism undergoing refractive lens exchange, patients with significant astigmatism undergoing monovision correction, patients with astigmatic and presbyopia or hyperopia considering LASIK, and patients with no refractive astigmatism but with corneal astigmatism that offsets the natural lens.

The patients who returned for this study underwent refraction using an autorefractor. Cylinder results from the refraction were averaged by lens toricity (T3, T4, or T5) to arrive at a mean residual refractive cylinder by lens model.

Mean residual refractive cylinder for patients who received the SA60T3 lens was 0.38 D. Patients who had received the SA60T4 lens had a mean residual refractive cylinder of 0.52 D; patients who had received the SA60T5 model had a mean of 0.57 D.

Dr. Ernest said that the manufacturer's toric calculator ( http://www.acrysoftoriccalculator.com/ ) is a valuable tool. "The calculator allows you to predict anticipated residual astigmatism based on incision location and induced astigmatism from the surgeon's incision."

The accurate results achieved in this study depend on proper lens model calculations and surgical techniques, he said.

"As far as putting the lens in position, it's important to mark the three- and nine-o'clock positions and remove all viscoelastic," Dr. Ernest said. "In addition, I use a two-handed technique to center the lens. You also want to make sure the lens is stable and that you have no shallowing of the anterior chamber."

Dr. Ernest concluded that he uses the toric IOL as a functional lens, not a premium lens.