With blended visio, two different multifocals perform better thanone type, surgeon says

June 1, 2006

San Francisco-Blended vision with diffractive and refractivemultifocal IOLs offers better visual results in all lightingconditions than bilateral diffractive multifocal technology,explained Henry L. Milne, MD, at the American Society of Cataractand Refractive Surgery annual meeting.

Dr. Milne, a refractive surgeon in Columbia, SC, undertook a study of 52 patients to determine any advantage in terms of vision and patient satisfaction for those receiving the two different lenses compared with those who received the diffractive technology only. Twenty-nine patients received the apodized diffractive IOL (AcrySof ReSTOR, Alcon Laboratories) in one eye and the refractive multifocal IOL (ReZoom, Advanced Medical Optics) in the other. Twenty-three patients received the diffractive technology in each eye.

In the blended vision group, 27 of 29 patients (94%) were completely functional without glasses compared with only 15 of 23 patients (65%) in the diffractive technology group.

The reason that patient satisfaction is so high in the blended vision group is that one lens is performing better than the other in different lighting situations, Dr. Milne said.

"The AcrySof ReSTOR IOL is a very good near lens in bright light and in low light becomes a better distance lens, theoretically," Dr. Milne explained. "The ReZoom multifocal lens is a good intermediate vision lens. It does better up close in lower light and does better at a distance in bright light. So what is one lens' strength is another one's weakness, basically."

The diffractive lens uses +4.0 D of additional power in the lenticular plane for near, which translates into +3.2 D at the spectacle plane. The result is good near vision with materials held close but poorer-quality intermediate vision, which is needed for computer screen use.

On the other hand, the ReZoom multifocal lens has a +3.5-D add at the lenticular plane for near, achieving +2 to +2.25 D at the spectacle plane. This offers better intermediate vision, Dr. Milne explained.