Acrylic lens is step closer to customized cataract surgery

Rogers, AR-The recent approval of the Tecnis IOL (AMO) on an acrylic platform gives cataract surgeons another option in an expanding menu of choices, said Randy Cole, MD, FACS, who is medical director and founder of Boozman-Hof Eye Surgery and Laser Center, Rogers, AR.

The Tecnis IOLs, both acrylic and silicone, also represent a step toward more customized cataract surgery, because they can reduce spherical aberration and improve functional vision, Dr. Cole said.

Dr. Cole also noted that there is some concern about using silicone lenses with certain patients, such as those with chronic iritis or diabetic patients who may need vitrectomy or silicone oil in the future. "You have this material available for them as well," he added.

Aspheric lens option

"The only real difference between this lens and the Sensar is that now you have a modified anterior prolate surface that gives negative asphericity to compensate for the positive corneal asphericity that is present in the general population," Dr. Cole said. "This is another aspheric lens; we had it in silicone, and we now have it in acrylic. It's another aspheric lens option to offer for patients who may need even better vision in low-contrast situations than the general population."

There should be no learning curve for surgeons and assistants who are familiar with other acrylic lenses, he added, but mentioned that proper centration (within 0.8 mm) is important to reap the benefits of the aspheric Tecnis IOLs.

He has implanted the new acrylic lens in selected patients, choosing those in whom an improvement in subtle higher-order aberrations would be apparent because their optical system is otherwise healthy. Results have been good, and a reduction in positive spherical aberrations has been confirmed with VISX/AMO WaveScan measurements. Patient satisfaction is also high, he reported.

The Tecnis acrylic is also a harbinger of developments in cataract surgery, Dr. Cole said. "It's getting to be a more complex menu now in terms of what lenses are available and what the individual needs of the patient are," he continued. "I think this particular lens is another step in the evolution of this trend toward lenticular refractive surgery."

He explained that surgeons can correct for astigmatism by performing astigmatic keratotomy or limbal relaxing incisions and that they can follow two different directions with lenses, depending on the patient. With the Tecnis IOLs, they can correct for corneal asphericity or spherical aberrations in the cornea, which should improve lower-order aberrations and reduce, or at least not increase, higher-order aberrations.

In this respect, cataract surgery is beginning to resemble refractive LASIK procedures in which surgeons use custom ablation to set individual treatment targets for each patient.