spotlight on technology & technique
Great Accommodations
Finally -- an IOL that truly offers the promise of overcoming presbyopia.
By Christopher Kent, Senior Associate Editor

There's a certain irony in the fact that implanting a standard IOL can correct refractive error -- but it guarantees presbyopia! Since most people receiving an IOL are already presbyopic, this isn't a big setback, but offering these patients an IOL that allows accommodation has always been the ultimate goal. Now, thanks to the crystalens IOL from eyeonics inc (formerly C&C Vision), that dream is becoming a reality.

The crystalens is made of a proprietary silicone material, with a unique design that took 14 years to develop. It accommodates by vaulting forward when the ciliary body contracts (see illustrations, page 61), allowing patients to see up close, in the distance and everything in be-tween, seamlessly. Vision improves progressively after surgery and during the postoperative course.

The crystalens isn't new; it's already received the CE Mark in Europe, and nearly 7,000 have been implanted around the world. Now, FDA approval appears to be imminent.

Beating the Odds

When the idea for an accommodating IOL based on this principle was first introduced in 1998, surgeons were skeptical. eyeonics CEO J. Andy Corley recalls: "People said the design would never work. Then they said, 'It will quit working when you YAG it.' Then they said the optic was too small. But all of these things have proven not to be an issue."

In fact, the results from the clinical trials have been remarkable. Unenhanced bilateral data for 124 patients 1 year post-op found that 97.6% could see 20/30 or better at distance; 100% could see J2 or better at intermediate; and 93.5% could see J2 or better at near. When all patients' distance vision was maximized, the number who could see J2 or better at near was 97.3%.

During the clinical trials, Corley says there were no problems in terms of stability in the bag, and the occurrence of fibrosis was no different from that found with a standard IOL. He reports that in three instances the implanted lens locked in the forward position, but the lens itself was never the source of the problem. "One patient rubbed his eye aggressively post-op; in the other two cases the capsulorhexis was extremely large," he explains. "Two cases were resolved by putting the patient on atropine; in one case the lens was exchanged."

Feedback from the Field

John Doane, M.D., FACS, who practices with Discover Vision Centers in Kansas City, Mo., and is clinical assistant professor of ophthalmology at Kansas University Medical Center, says that before participating in the clinical trials he had some reservations. "First, a 4.5-mm optic seemed like an invitation to nighttime symptoms. However, this is the best-centering IOL I've ever placed in an eye. If there's any diffraction off the edge of the lens, it's not symptomatic to the patient. Objective contrast sensitivity findings and subjective findings from the patient show this is a non-issue.

"I also worried that patients might lose early gains over time. But our data found that patients only get better as the months go by. An ever-increasing number of patients not only see great at distance and intermediate but achieve J1 near visual acuity.

"Third, I was concerned about the effect of YAG capsulotomy. The vitreous fluid, if liquefied, might get around the lens and prevent optic movement. But capsulotomy patients tended to have generally improved distance and near vision, even compared to their vision before posterior capsule opacification.

"I was also concerned that older patients might not achieve the same results as younger patients. But we found no significant difference between 50-year-old patients and 85-year-old patients as far as functional uncorrected near vision. So all of my concerns as an investigator were unwarranted.

"Now we're able to implant an IOL that provides distance, intermediate and near vision in both eyes simultaneously -- with no complaints about unwanted nighttime effects whatsoever."

The crystalens vaults forward when the ciliary body contracts, letting the patient change focus smoothly over a broad range encompassing both near and distance.

Great Results, Happy Patients

Steven Dell, M.D., who practices in Austin, Texas, also participated in the clinical trials and was impressed with the results. "The intermediate vision with this lens is absolutely spectacular. 100% of patients were able to see J2 or better through their distance correction using both eyes. Also, we found no significant differences between the youngest and oldest patients in the trial, and the accommodative ranges achieved by patients with long eyes and short eyes were statistically identical."

Dr. Dell says it will be interesting to watch what happens as surgeons become more experienced with the new technology. "We've done a relatively small number of patients under very controlled circumstances and achieved excellent results. This lens clearly has the potential to change the way we think about cataracts and presbyopia completely. However, implanting this lens will cost more, and not all patients will be willing to pay the premium. Also, for some patients -- such as those with pre-existing retinal pathology -- this lens won't be indicated. And even though we didn't see complaints of glare in the FDA trial, I'd proceed with caution if a patient has very large pupils."

Dr. Dell's enthusiasm for the lens is clear. "I absolutely plan to implant this lens in my patients. The level of satisfaction in the trial was very high. Some patients who received the crystalens in one eye have refused to have any other type of implant in the other eye. They're still waiting for FDA approval so they can get the second lens."

Outlook: Excellent

Andy Corley sums up: "The clinical trial results have been superb; they're the result of 15 years of focused research. Cataract patients who can see at all distances seamlessly without glasses should create a lot of excitement for ophthalmology."