Accommodating IOL delivers excellent near vision

West Hills, CA-A near-vision accommodating IOL (crystalens, eyeonics) provides significantly better near vision compared with a conventional IOL (AcrySof, Alcon Laboratories). The ability to measure the difference in the results with the two lenses allows surgeons to counsel patients in their choice of implants based on their visual needs in the real world, according to Jonathan M. Davidorf, MD.

That was the rationale for this study, which compared the efficacy in providing near vision using an accommodating IOL and a conventional IOL. "From the standpoint of a patient, the purpose was to determine what a surgeon can offer a patient in terms of an appreciable difference in vision compared with a conventional IOL," said Dr. Davidorf, who is in private practice in West Hills, CA.

The demographics of the two groups of patients were similar with the exception that more patients received the accommodating lens. Only eyes with 20/25 or better postoperative best-corrected visual acuity were analyzed. All eyes had a minimum of 1 month follow-up.

Accommodative amplitude

The investigators measured the accommodative amplitude, which Dr. Davidorf described as difficult to do. "We measured the manifest refraction and determined the smallest line of vision that the patient could see. We then showed the patient the line that was 2 lines above the smallest line the patient could see until the patient could not read any characters in that line," he said.

The investigators measured the best distance-corrected near vision by determining the manifest refraction monocularly. The patients could move the near vision card (the Jaeger card) to any distance to determine the smallest line of vision in which they could read most of the letters.

"The accommodative amplitudes that we measured were statistically greater in the [accommodating lens] group. There was no change between the measurement done at 1 month and those done at 3 to 6 months after implantation," Dr. Davidorf reported.

The more important measurement, he underscored, is the best distance-corrected visual acuity. "The patients who had the [accommodating lens] implanted saw a great deal better on the near vision card compared with the patients with the conventional IOL implanted," he said. One eye of one patient saw J12, so not every patient was able to read the card from a short distance with the [accommodating lens]. However, the mean measurements were much better in the patients with the [accommodating lens].

"The best distance-corrected near vision is the most meaningful statistic when evaluating this group of patients. There is a rather significant difference between the ability to see small letters on the near vision chart when it is viewed through the manifest refraction in eyes with the [accommodating lens] implanted compared with the conventional IOL," Dr. Davidorf said.

In clinical practice, the difference between the lenses is even greater, he said. "In the real world, patients look through both eyes. In this study, we often left one eye with residual myopia, so the observed mean best-distance corrected near vision of J3.7 in the patients with the [accommodating lens] implanted becomes a lot smaller," he said.

The advice he can now give patients is that if they have a conventional lens implanted and have perfect distance vision, their near vision will be about J6 to J12; the patients with the [accommodating lens] implanted will be able to see between J2 and J5. "I can state this based on good data. If the increase in the near vision with the [accommodating lens] is worth it to patients, they can choose that lens, and if that increase in vision is not worth it to them they can choose the conventional IOL. This makes it a great deal easier for us to gauge our expectations as surgeons and to counsel our patients," he concluded.