Trial aims to provide scientific basis for evaluating 'mixing, matching' of presbyopia-correcting IOLs

July 15, 2007

When a prospective, randomized study was undertaken to investigate the outcomes of "mixing and matching" different multifocal IOLs in fellow eyes, results showed differences between the lenses in intermediate and near vision, and one-third of patients sought IOL exchange.

Key Points

San Diego-Prospective, randomized controlled trials are needed to determine the risks and benefits of "mixing and matching" presbyopia-correcting IOLs, said Richard J. Mackool, MD, here at the annual meeting of the American Society of Cataract and Refractive Surgery.

At 3 months after the second eye surgery, no differences were observed between the implants regarding BCDV outcomes. The refractive lens, however, provided better intermediate vision overall, whereas the diffractive implant was associated with better near vision. Five patients underwent IOL exchange, and all requested to have the refractive lens replaced with a diffractive IOL.

"This is the first randomized, prospective study comparing outcomes with these two ... IOLs," said Dr. Mackool, who also is an assistant clinical professor of ophthalmology at New York Medical College. "Further rigorous studies are needed, however, to determine the appropriateness of combining IOLs with different-power near adds and to answer questions such as whether patients with poor intermediate vision after [diffractive lens] implantation in their first eye should receive the [refractive lens] in the second eye or whether patients with poor near vision after first eye surgery with the [refractive lens] might be better off with a [diffractive lens] in the second eye."

Patients ranged in age from 37 to 82 years with a mean of 65 years. The second eye surgery was performed 2 to 4 weeks after the first eye procedure. Preoperatively, patients were told they could undergo IOL exchange in either eye to receive the alternate multifocal IOL or a monofocal IOL at 2 months or later after the second eye surgery.

In the objective testing of vision outcomes, intermediate visual acuity was measured at 50, 60, and 70 cm, and near acuity testing was performed at the patient's preferred distance. Subjective preference was assessed with a questionnaire asking which eye was preferred for distance vision, intermediate vision, and near vision with best distance correction.

One patient in the study was lost to follow-up, but 3-month outcome data were available for the remaining 14 patients.

"We might presume the patient lost to follow-up was happy, because patients come back when they are not," Dr. Mackool commented.

Results of objective testing of BCDV favored the diffractive-lens eye in six patients and the refractive-lens eye in four patients and showed no difference between the two IOLs in four patients. When asked about eye preference for distance vision, a slight majority (57%) had no preference, whereas the other six were equally divided between the two IOLs.

In intermediate vision testing, no difference was seen between eyes in five patients, whereas vision was better in the refractive-lens eye in seven patients and in the diffractive-lens eye in two patients. Subjectively, six patients expressed no preference for either eye, whereas six preferred the refractive-lens eye and only two preferred their intermediate vision with the diffractive-lens eye.

For near vision, only one patient showed no difference in objective testing, whereas 12 of the remaining 13 had better near vision with the diffractive-lens eye. Subjectively, all patients expressed a preference for one eye or the other, but 13 preferred the diffractive-lens eye and only one was happier with near vision with the refractive-lens eye.

All five patients who underwent IOL exchange did so after an extensive consultation.