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New refractive IOLs may help shape future of refractive surgery
Surgeons explore the uncertainties of new technologies, while the refractive industry braces for change.
Regulatory status: where they stand |
Among the phakic IOLs, the Artisan, ICL and PRL are the farthest along in the U.S. regulatory approval pipeline. The CIBA Vision Vivarte and the Vision Membrane IOL have not yet begun clinical trials here. The Artisan, which has been used in Europe for more than a decade, is an anterior chamber PMMA IOL that attaches to the midperipheral iris. It is indicated to correct myopia, hyperopia and astigmatism. Sources said the device has performed well in FDA trials, and approval for marketing is expected possibly by next year. Surgeons who have worked with the Artisan give it high marks for the quality of vision it affords patients and for the fact that it can be centered with precision. Yet some caution the lens is tricky to implant, because it requires some ambidexterity on the part of the surgeon. “The Artisan lens takes a bit more surgical manipulation because you have to have two instruments in the eye at once. It also requires a slightly larger incision, but I think it has an advantage in that you can center it where you want it,” Dr. Durrie said. STAAR Surgical’s ICL has also performed well in U.S. clinical trials. While this lens appeared to be associated with a relatively high incidence of cataract development in patients in earlier experience outside the United States, this finding has not been duplicated here. “With the ICL, there was a concern over cataract formation, but as they’ve changed the vault of the lens the incidence has gone down,” Dr. Davis said. CIBA Vision’s PRL could be a third phakic IOL to enter the U.S. market. The device has entered phase 3 U.S. clinical trials for myopia and is in phase 2 for hyperopia. Like the ICL, the PRL is foldable can go through a small incision. But also like the ICL, the PRL is a posterior implant, and this is a source of concern for some surgeons. “In my opinion, phakic lenses are only acceptable if they are placed in the anterior chamber. With posterior chamber phakic IOLs, there is too great a risk of cataract formation,” Dr. Maloney said. Finally, the concept of Calhoun’s Light Adjustable Lens has many in the industry excited at the prospect of an IOL whose power can be adjusted by light application once implanted in the eye. “The LAL is a wonderful concept, but still a concept. It’s a reflection at this stage of our shift in emphasis away from the cornea, and that’s where I think the future is,” Dr. Maloney said. |
A new generation of IOLs is poised to transform the way refractive surgery is performed in the United States.
With advances in lens design, and with potential regulatory approvals in the future for a selection of phakic, accommodative and light adjustable implants, refractive IOLs are seemingly shaping up to be the industry’s next big boom.
But while everyone seems to have an opinion on the matter, nobody really knows what the new face of refractive surgery will look like once the dust settles.
“You have to look at the data — both the good and the bad news — and then see how the market is going to accept (these devices),” said Daniel S. Durrie, MD.
“There will be other types of intraocular adjustable concepts that nobody has even thought of yet,” Dr. Durrie added.
For now, the future of lens-based refractive surgery turns on the Food and Drug Administration approvals of more than a half dozen devices, most of which are already in use outside the United States.
The devices are in various states of U.S. clinical investigation, from early human implantation to completed phase 3 trials.
Among these implants are a number of phakic IOLs: Artisan (Ophtec), ICL (STAAR Surgical), PRL (CIBA Vision), Vivarte (CIBA Vision) and Vision Membrane (Vision Membrane Technologies).
Another IOL, the CrystaLens (C&C Vision) holds the promise of accommodation with excellent visual quality.
And the Light Adjustable Lens (Calhoun Vision) is generating attention as the first lens that can be adjusted by light after implantation in the eye to achieve higher refractive precision.
In addition to these lenses, two pseudophakic IOLs that are already FDA-approved and on the market, the Array (AMO) multifocal and the Tecnis (Pharmacia) IOL, have drawn particular interest for use in refractive lensectomy.
Looking ahead
William F. Maloney, MD, predicts that implants will eventually become the primary refractive surgical tool to correct moderate and large refractive errors and that cornea-based procedures will be viewed more as fine-tuning mechanisms. Both corneal and lens-based procedures will have a role to play, he said.
“There is no question that lens-based refractive surgery is an idea whose time has come,” Dr. Maloney said.
Dr. Maloney’s news column for Ocular Surgery News, Lens-Based Refractive Surgery, debuts in this issue.
Others, like Dr. Durrie, believe that cornea-based surgery will not be so easily replaced, with laser technology growing increasingly sophisticated.
“(Implants) will be an important part of the treatment regime for patients who are really looking for major refractive correction. But that is really only about 5% of the population of refractive patients,” Dr. Durrie said.
Elizabeth A. Davis, MD, FACS, said surgeons should not view the future of refractive surgery as an all-or-nothing situation. She said there is room in the market for all the latest technology, and that physicians will need to become more broadly trained and flexible in their approaches.
“I don’t envision one dominant technology. Refractive surgeons will have to be schooled in multiple technologies and be able to tailor treatments to the individual patient,” she said.
Phakic vs. pseudophakic
Lens-based refractive surgery presents a number of alternatives to laser-based techniques. One of the choices facing the surgeon is whether a phakic or a pseudophakic lens is preferable. There are risks and benefits to each.
On the one hand, removing a healthy lens may represent an increased risk of complications such as retinal detachment and posterior capsular opacification. On the other, phakic IOLs carry their own risks of complications, such as induced cataract and glaucoma.
On the plus side for lensectomy, replacing a healthy lens enables older patients to avoid cataract surgery later in life. And for phakic IOL implantation, avoiding removal of the crystalline lens makes for a less invasive procedure.
“The risks associated with refractive lensectomy are skill-dependent for the most part. It is becoming increasingly clear that complications can be reduced to a level that is readily acceptable when there is the combination of state-of-the-art technology and surgical skill,” Dr. Maloney said.
For Dr. Durrie, phakic IOLs are preferable for many refractive patients who are not good candidates for laser. He does, however, acknowledge that refractive lensectomy may be in order for older patients with early signs of a cataract.
“I am not a fan of clear lens extraction. But if somebody is 55 and interested in refractive surgery, and they have a 2+ nuclear sclerosis, why have them go through two surgeries?” Dr. Durrie said.
Still, Dr. Durrie calls for conservatism when it comes to advising patients on the best course of treatment.
“If a patient comes in with a 1+ nuclear sclerosis, I usually tell them to take a year and see if the cataract grows. If they come back in a year and the cataract hasn’t grown, then they could be a great candidate for (laser surgery),” he said.
Dr. Davis agreed that age is an important factor to consider.
“If the patient is young, you might want to maintain their accommodative status, so a phakic IOL would be ideal. But for an older patient, aside from not having accommodation anymore, they may have a bit of a cataract forming anyway, so it’s more reasonable to consider clear lens extraction with them,” Dr. Davis said.
One possibility for refractive lensectomy in presbyopic patients is attempting to restore accommodation with a multifocal IOL such as the Array. And for patients in whom contrast sensitivity may be an issue, Pharmacia’s Tecnis has been shown to significantly improve contrast sensitivity in older patients. Both of these devices have been well-received by refractive lensectomy patients, surgeons said.
Refractive results with cataracts
One of the mistakes surgeons make is assuming that all cataract patients are looking for optimal refractive results from their cataract surgery, according to Dr. Maloney.
“For practitioners to initially get involved in lens-based refractive surgery, they should consider bifurcating the population of cataract patients into those who want refractive results and those who do not,” he said.
By making this distinction, the surgeon knows whether or not to focus on correcting refractive error, and the patient has appropriate expectations of the surgery’s outcome. This approach will also eliminate unreasonable expectations when patients do not choose vision correction with their cataract surgery.
“If a cataract patient declares that the refractive result is of primary importance to them, then they become a refractive patient in every sense of the word, and we use whatever refractive tools are available,” Dr. Maloney said.
This approach, in turn, will enable cataract surgeons to exercise their lens-based refractive surgery skills on patients who would undergo the surgery anyway, so there is less pressure, he said.
Regulatory Status of Refractive IOLs |
C&C Vision Calhoun Vision CIBA Vision Ophtec STAAR Surgical Vision Membrane Technologies |
To wait or not to wait
By turning their attention back to themselves and their own skills, surgeons are less likely to “sit back and wait” for the next innovation, Dr. Maloney said.
“Some surgeons tend to think that something better is coming and it will reduce the need for them to do the hard work necessary to be successful at this,” he said. “But this is the challenge I would make to my colleagues: focus on doing whatever is necessary to develop a strong confidence in your surgical skills that will never come from a new technology.”
The new devices that are on the way present interesting options and challenges, but technological advances mean nothing without surgical skill, Dr. Maloney said.
“The point is that the idea that refractive surgery is easy is beginning to fade, and in order to satisfy the reasonable expectations of our patients we have to accept that you can never separate a surgeon from his or her skill,” he said.
For Dr. Davis, the decision of whether to wait for forthcoming technology should depend on the patient.
“If you think the current technology might be less than satisfactory or a higher potential than average to worsen things, it’s appropriate to tell that patient to wait or to do nothing,” she said.
For Your Information:
- Daniel S. Durrie, MD, can be reached at Durrie Vision, 5520 College Blvd., Suite 200, Overland Park, KS 66211; (913) 491-3737; fax: (913) 491-9650; e-mail: ddurrie@hunkeler.com. Dr. Durrie is a paid consultant for Alcon, Bausch & Lomb, Calhoun Vision and Ophtec.
- William F. Maloney, MD, can be reached at 2023 West Vista Way, Suite A, Vista, CA 92083; (760) 941-1400; fax: (760) 941-9643; e-mail: williammaloney2000@yahoo.com. Dr. Maloney has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- Elizabeth A. Davis, MD, FACS, can be reached at Minnesota Eye Consultants, 710 E. 24th St., Minneapolis, MN 55404: (952) 885-2467; fax: (952) 885-9942; e-mail: eadavis@mneye.com. Dr. Davis is a paid consultant for Advanced Medical Optics.