Phakic IOLs: Ready for a Breakthrough?
Superior vision, newer designs could spur wider adoption.
By Jerry Helzner, Senior Editor
For years, the conventional wisdom in US ophthalmology has labeled phakic IOLs as a niche option, ideally suited for high myopes. Despite broad and longstanding adoption of phakic IOLs internationally, the annual Duffey-Leaming survey conducted for the American Society of Cataract and Refractive Surgery consistently confirms this line of thinking. Discuss the usefulness of phakic IOLs with refractive surgeons and the answer almost always comes back in words similar to these: “For younger moderate myopes, -8 D and below, LASIK is the first choice. It's really a no-brainer.”
And yet, there are some significant signs that phakic IOLs at last have the potential for wider US adoption. Consider:
■ Because of their experience in performing cataract surgery, almost all ophthalmologists are comfortable with implanting IOLs. The transition to implanting phakic lenses is not a difficult one, though attention to detail, ensuring patient safety, and experience with the procedure are key to successful results with these lenses.
“Any good cataract surgeon should have no problem in implanting phakic lenses,” says Elizabeth A. Davis, MD, FACS, of Minneapolis. “The procedure is a bit different but anyone adept at intraocular surgery can master it. The quality of vision from phakic lenses is excellent and the patients are usually thrilled. I've been using the Visian since 1999 and I really like the lens.”
■ The cost to the practice of implanting phakic lenses is minimal compared to purchasing an excimer laser and acquiring a femtosecond laser. In a cost-conscious environment, a young ophthalmologist in a solo or small practice could easily find that adding phakic IOLs to his or her array of patient choices could prove profitable without the initial investment needed to add a LASIK suite.
■ Surgeons who perform the highest volume of phakic IOL procedures are strong believers in the superior visual results achieved with this option. Stephen S. Lane, MD, of Associated Eye Care, Stillwater, Minn., says “the greatest wow factor I have experienced in ophthalmology has been from patients who have just been implanted with phakic lenses. They are seeing well right off the table and definitely within an hour. I believe visual results from phakic lenses are generally better than from LASIK.”
Anecdotally, ophthalmologists who perform a high volume of phakic procedures say that moderate myopes who require keen, crisp vision—pilots, photographers, race car drivers, professional golfers—have chosen phakic lenses over LASIK based on the quality of vision they can attain.
■ Surgeons with extensive experience in implanting phakic IOLs have been finding new ways to make the procedure safer, as long-term safety has always been a concern for surgeons thinking of offering the procedure. What's more, they have been conveying this knowledge to more recent adopters.
At least one recent paper recommends using ultrasonic biomicroscopy (UBM) to perform a sulcus-to-sulcus measurement for more accurate lens sizing. This can be in addition to a white-to-white measurement or as an alternative to a white-to-white measurement.
“Those of us who are more experienced with the procedure are getting the word out,” says Robert P. Rivera, MD, of Barnet Dulaney Perkins Eye Center in Phoenix. “The safer we can make the procedure, and the greater the confidence that the surgeon can feel in performing it, the more we will see wider adoption.”
■ Phakic IOLs can be explanted. Surgeons are certainly hoping they won't have to explant phakic IOLs from their patients, but removing the lenses is a viable option if problems arise or if the patient is simply unhappy.
■ Finally, the Duffey-Leaming survey annually indicates that many US ophthalmologists who are not currently implanting phakic IOLs are interested in doing so at some point in the future.
So what would it take to bring these fence-sitters into the phakic community? Better designs? Greater assurance of long-term safety? A large and respected eyecare company adding its name and marketing clout to drive wider phakic lens adoption?
If these are the essential issues holding back growth in phakic IOL implantations in this country, there is a strong chance that all of these hurdles may soon be overcome.
Current and Future
Currently, US surgeons have the choice of using two FDA-approved phakic IOLs: the foldable, collamer Staar Visian ICL posterior lens or the non-foldable Verisyse from Abbott Medical Optics, which requires a larger incision and that attaches to the anterior iris stroma. The learning curve for Verisyse implantation tends to be steeper than for the Visian, but many surgeons say that, depending on the individual patient, they use both lenses with confidence. A foldable version of the Verisyse called the Veriflex is under FDA review.
Recently, interest has been generated for Alcon's angle-supported AcrySof Cachet phakic lens, currently in the investigational stage with phase 3 clinical data yet to be released. Though no specific predictions can be made about the timing of the phase 3 data release or for an application for FDA approval, it appears possible that a 2012 filing with the FDA is feasible. The lens is already approved in Canada and in Europe, with 10-year data available to demonstrate its safety and efficacy.
The Visian ICL has proved to be a dependable phakic lens.
In this country, Dr. Lane has reported on the results of the four-year, 42-eye phase 2 US trial of the Cachet. Mean spherical myopia of the patients in this trial was -10.04 D.
He found that 95% of eyes were within 1 D of the desired refractive outcome and 81% were within 0.50 D, with more than 97% of eyes having UCVA of 20/40 or better and almost 60% having UCVA of 20/20 or better.
Post-surgical complications included one case of surgery-caused cataract, with one phakic IOL replaced due to incorrect power and two lenses removed for other reasons.
The Verisyse requires a large incision and has a steeper learning curve.
Evaluating the Cachet
Though the previous history of angle-supported lenses had been replete with instances of pupil ovalization, corneal decompensation and other negative side effects, surgeons who have implanted the Cachet say that Alcon has engineered an angle-supported lens that is safe, effective and easy to implant.
“With the history of angle-supported lenses, what we are first looking for is safety,” says Dr. Lane. “Alcon has done a great job in engineering a lens that eliminates the problems that plagued previous angle-supported designs.”
Dr. Lane notes that the Cachet is made of a flexible hydrophobic acrylic material rather than the rigid PMMA material used in previous angle-supported phakic IOLs.
“In terms of the specific design, the bridge off of the optic flexes and vaults over the iris and crystalline lens, so that there is no contact with the cornea,” notes Dr. Lane. “The haptics are also very flexible. They flex and act as shock absorbers in the angle. In contrast, a PMMA phakic lens would fit very tightly, which can easily lead to pupil ovalization due to synechiae formation.”
Dr. Lane says that in his own experience and in the phase 2 clinical trial, the Cachet has proved to be a very safe lens that should meet an enthusiastic reception when and if it's approved in the US.
“The Cachet is a totally different intraocular lens than any previous angle-supported lens. In addition, the Cachet will be the easiest phakic IOL for surgeons to implant,” asserts Dr. Lane. “It's a very straightforward procedure.”
Dr. Davis characterizes the design of the Cachet and its anterior positioning as “appealing.” She says that, if approved in the US, “the Alcon Cachet will expand the number of surgeons using phakic IOLs.
Alcon's Cachet has won praise but is not yet FDA-approved.
Toric Phakics: How Long the Wait
Surgeons such as Robert Rivera have been waiting for years for the FDA to approve the Visian Toric. They are still waiting. Dr. Rivera has a list of hundreds of patients who would be well-suited for this lens.
“With some patients who are candidates for phakic torics, you can use a spherical Visian and fix the astigmatism with PRK,” says Dr. Rivera. “However, if the patient has a thin cornea, they are probably better off waiting for the toric.”
Dr. Davis also uses the spherical Visian and PRK for her phakic lens patients with astigmatism.
“I'm okay with doing that,” she says. “The amount of tissue involved is minimal. We're not removing a lot of cornea.”
The current Cachet design is not suitable for use as a toric because the lens can rotate in the eye.
“If Alcon wants to offer a phakic toric, the company will have to do a redesign of the Cachet,” says Dr. Lane.
How Much Potential?
Dr. Rivera concedes that the current conventional thinking in ophthalmology presents some obstacles to wider adoption of phakic IOLs.
“They don't think of it as a first-line procedure; they put it in a tiny corner,” he says. “As surgeons become more acquainted with phakic IOLs and the visual results that can be achieved with them, I think that perception will change.” OM
| Q&A With Phakic IOL Advocate Robert Rivera, MD |
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| Robert P. Rivera, MD, of the Barnet Dulaney Perkins Eye Center in Arizona, is a strong advocate of phakic lenses and probably has implanted more Visian ICLs than any surgeon in the United States. (The Visian itself recently reached a milestone—200,000 lenses implanted worldwide.) Here, Dr. Rivera answers questions about his experience with phakic IOLs and the Visian specifically. Q. The usual perception of phakic IOLs is that they are a niche solution for high myopes. Do you see that perception changing in the future? A. That perception is most widely held by those surgeons who have not yet seen phakic IOLs mature within their practice. As surgeons do more and more phakic IOLs, and become more and more acquainted with both the excellent visual results chair-side and the stellar levels of satisfaction reported to them by their patients, the natural evolution is to begin to offer the procedure to a wider and wider range of patients, to where it becomes a “premium” option rather than an exclusionary niche procedure. Q. The doctors who have strong phakic IOL practices, such as yourself, seem to view phakic IOLs as the pinnacle of current vision correction—superior in many ways to eye-glasses, contact lenses and LASIK. Is it fair to make an analogy that phakic IOLs are like a high-performance sports car—more expensive and requiring a bit more attention but delivering the best possible vision to those patients who are candidates for this option? A. Phakic IOLs are a more expensive option for vision correction than excimer ablative procedures, that is sure. The way I describe this to our patients is to contrast the difference between a standard-definition television and one that is high def. When we decide to purchase a new television set, we are all very comfortable with standard-definition TV, since that is what we are most accustomed to. But when we have a chance to compare this to a high-definition TV, our jaw drops and the first word we utter is “wow!” We are quite happy to save up extra in order to purchase the HD option, knowing the view will be just that. In our experience, the Visian ICL provides that wow effect. At the same time, we educate all of our patients that LASIK is still an excellent choice for vision correction that will give them excellent vision. The ICL simply gives them “excellent-plus” vision that correlates well to high definition. Q. Have you seen Dr. Lane's study of the Alcon AcrySof Cachet phase 2 trial? What do you think of his findings? If Alcon gains approval for the Cachet, how do you see this impacting the phakic IOL marketplace? A. I've been following the international experience with the Cachet and am anxiously awaiting FDA approval, as it will provide yet another option for surgeons to consider. I believe this will make phakic IOL implantation an even more popular choice among refractive surgeons. I am already getting questions about the Cachet from patients who have heard about it and who may be potential candidates. I have studied all aspects of the Cachet, used it in the wet lab, and like the way Alcon has overcome the previous problems associated with angle-supported phakic lenses. If the Cachet is approved by the FDA, I would definitely offer it as another attractive option. Q. Have there been any improvements made to the basic Visian IOL in the last 18 months or so? A. Several international doctors have been working with Staar to add various design enhancements to the Visian ICL, which represents version 4. Since these would require further FDA review, however, I'm not aware of any of these design changes being implemented yet for domestic use. Q. Do you have any advice for ophthalmologists who would like to increase (or begin) their phakic IOL practice? A. My main advice to all surgeons would be to recognize that while phakic IOLs can deliver stunning visual results, the procedure has to be done correctly and there are no corners to be cut or shortcuts to be taken. These are young patients who lead active lifestyles and often place extreme demands upon their visual function. If you are going to add this to your practice, learn everything you can and consider spending time with a surgeon who already implants them. Making sure you know how to avoid complications, and to aggressively treat the rare ones that do occur, are key to building your successful phakic IOL practice. One other note is that in the US, phakic IOLs have not seen the wide level of acceptance that you will see in Europe, South America and Asia. Several international refractive practices have seen the penetration of phakic IOL procedures reach as much as 25% to 30% of their volume, while in the US the penetration is much, much lower. Internationally, phakic IOLs are not restricted to a “niche” procedure, and I believe as more US surgeons gain experience, familiarity and success with these IOLs, our refractive market will see more and more phakic IOL procedures become the norm and could very well mirror international statistics. |
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