Understanding choices in bioptics will greatly enhance outcomes

HONG KONG — Carefully selected IOLs in conjunction with femtosecond-flap creation and wavefront-guided LASIK can assist surgeons in their quest to provide spectacle independence for patients, according to a surgeon speaking here. Michael C. Knorz, MD, explained his approach to bioptics using IntraLase (Advanced Medical Optics) and a variety of phakic and multifocal IOLs at the World Ophthalmology Congress.

Michael C. Knorz

"Phakic IOLs or diffractive multifocal IOLs can be combined with IntraLase flap creation and ... wavefront-driven ablations to achieve perfect vision," he said.

He said his approach consists of offering an IOL and subsequent refractive surgery to correct residual refractive error as a package so patients know what to expect.

Yet he cautioned that "the multifocal and phakic IOLs work only if a patient is ametropic" because the goal is for the patient to achieve spectacle independence.

Dr. Knorz said he has two main approaches to bioptics. The first is to perform customized LASIK with the Visx Star S4 excimer laser (AMO) about 3 months after IOL implantation if there is unexpected refractive error.

"This is if there is [pre-existing] corneal astigmatism less than 2 D because I feel I can manage the astigmatism with my incision during the surgery," he said.

The second option is geared for patients with pre-existing astigmatism greater than 2 D. Dr. Knorz said he does not expect to be able to eliminate that level of astigmatism in the course of the IOL implantation and anticipates having to do another refractive procedure later.

In these cases, he creates an IntraLase flap before IOL implantation but does not lift it. He performs custom LASIK 3 to 4 months later.

He opts for custom LASIK because it "provides a perfect match of the measured and treated area and this gives you better astigmatism correction."

"If you have just 10° of error at the axis, that means 30% undercorrection. In these patients, it's very important that we align treatment and measurement areas, and this is only possible with custom LASIK," he said.

Custom LASIK compensates for cyclotorsion as well as changes in the pupil center position, he said.

One caveat Dr. Knorz offered is that wavefront-guided LASIK works with diffractive IOLs such as the Tecnis (AMO) or ReSTOR (Alcon) but not with a refractive IOL such as the ReZoom (AMO).