The Refractive Lens Exchange Debate
Patient demand for refractive lens exchange is on the rise, but physicians are divided over which patients are right for the procedure and whether the risks are worth taking.
It’s an increasingly common scenario: A middle-aged woman with minimal refractive error visits her ophthalmologist. She’s annoyed by the fact that she needs reading glasses and she’s determined to get rid of them. She’s been surfing the Web, reading about accommodative and pseudoaccommodative IOLs, and arrives armed with articles. She hates wearing glasses. She cannot (or will not) tolerate monovision contact lenses. She has no sign of cataracts, but she is “desperate to do something,” and she wants to talk about refractive lens exchange procedures.
What do you tell such a person when she visits your office? For James J. Salz, MD, the answer is obvious: No way. “Regardless of the extent of the patient consent she signed, there is not a chance I could defend in court performing intraocular surgery simply to get rid of a $10 pair of reading glasses.” It is a view he shares with the Ophthalmic Mutual Insurance Company, which has, in the past several years, published guidelines to help surgeons navigate the somewhat murky legal and ethical waters of this increasingly popular refractive procedure.¹ (See “Legal Considerations” below.)
Other ophthalmologists take a different view, seeing these procedures, especially as they improve and evolve, as safe and powerful tools that can preclude cataract surgery. Whatever approach you take in your practice, it’s important to accurately assess the risks—clinical and legal—inherent in these procedures before proceeding with surgery.
From a clinical perspective, refractive lens exchange—also referred to as clear lens exchange or, more recently, refractive lensectomy—is a viable alternative for patients with refractive errors who are not candidates for LASIK. For many years, only two modalities existed for refractive lens exchange: monofocal or the multifocal Array lens (AMO). However, with the recent FDA approval of the accommodative intraocular Crystalens (Eyeonics), the multifocal Restor (Alcon) and the ReZoom (AMO)—which is an acrylic multifocal lens that is expected to replace the Array—the consumer market for the refractive lensectomy procedure has the potential to expand significantly.
Views Vary on Candidates
D. Michael Colvard, MD, was a clinical investigator in early FDA trials of the Crystalens, and he saw favorable results with it. Yet despite the success of the Crystalens in cataract patients, Dr. Colvard described himself as “conservative” when it comes to recommending and performing clear lens extraction. “There are only certain groups of candidates for the procedure,” he said.
Hyperopes. “While there can be exceptions to every rule, in general, I believe that clear lens extraction—which means an operation where patients have absolutely no cataract—should be reserved for contact lens intolerant hyperopes over the age of 40 who have hyperopia greater than +3 diopters,” said Dr. Colvard.
Another group is older hyperopes who show any evidence of cataracts. These individuals, even if the level of hyperopia is moderate, are candidates for lens surgery rather than LASIK because aging hyperopes tend to experience problems with the tear film and reduction in visual quality with laser surgery.
Myopes. Because of the risk of retinal detachment, noted Dr. Colvard, high myopes “must be viewed differently.” Clear lens extraction is not necessarily an optimal procedure for these patients, he added. They may be better served with the Verisyse IOL (Ophtec/AMO), which features an iris fixation method that enables the lens to attach to the periphery of the iris, allowing the patient’s original lens to remain intact.
“On the other hand, if the high myope has early cataract changes, the Verisyse lens may not be appropriate,” he continued. “Indeed, in these patients, I would not recommend any procedure until there was enough cataract to warrant surgery from a functional viewpoint.”
Suitable for many patients. According to I. Howard Fine, MD, refractive lens exchange “is no different from any other refractive procedure” and represents a key component in the surgeon’s armamentarium. To support his views, he noted that in 1970 cataract surgery was performed only if the patient was 20/70 or worse in the better eye. “Now the guideline is a cataract sufficient to interfere with the activities of daily living. And the reason that parameter changed—and I was part of two groups that worked on the Academy’s Preferred Practice Pattern—is that cataract surgery has become safe and effective.”
He said cataract surgery advancements that involve lower energy with phacoemulsification, smaller incisions and greater accuracy have led cataract surgery to evolve into refractive surgery. And he offers refractive lens exchange to a wide range of patients, especially those with a refractive error of a substantial nature and who are approaching presbyopia. “While we know high myopes are at higher risk of retinal detachment, with new technology these patients also can be candidates—and this population is very enthusiastic and [represents] some of our most grateful patients.
“LASIK surgery has its limitations,” added Dr. Fine. “Even the most sophisticated shaping to remove spherical aberrations will degrade as the patient ages. On the other hand, intraocular optics do not change with age. We were early in the field with refractive lens exchange, and our experience with the Array multifocal lens was excellent. A huge percentage of our patients were spectacle independent.”
Not ready for prime time. As a general ophthalmologist who specializes in glaucoma and cataracts, Carl V. Migliazzo, MD, speaks for many surgeons who are aware of the procedure but are not ready to endorse it. While refractive surgeons in Kansas City are starting to offer refractive lensectomy, Dr. Migliazzo continues to have concerns.
“As a cataract surgeon, I have always been acutely aware of the downsides of cataract surgery . . . always wary of the potential complications and loss of vision from the surgical procedure,” Dr. Migliazzo pointed out. While he conceded that the Crystalens has answered concerns with accommodative amplitude in younger individuals when the lens is removed, the other potential drawbacks still must be taken into consideration.
These drawbacks include posterior capsular opacification and retinal detachment. “The risk of retinal detachment in high myopes undergoing cataract surgery is well known, at 1 percent to 3 percent,” said Dr. Migliazzo. “Yet if someone has an operable cataract, we will still do the surgery.
“And it is important to note that this is a risk shared with clear lens exchange,” he added. “There are clear risks and benefits to this procedure. The risk of loss of vision including retinal detachment is very real and can happen.”
Ron P. Gallemore, MD, PhD, added that myopic patients need close monitoring, whether or not they undergo surgery.
Patient communication is key. “Physicians need to speak to their patients about the risk of vision loss with cataract surgery,” Dr. Gallemore said. “This also holds true for clear lens extraction. While the procedure may increase the risk of retinal detachment, the true incidence is not yet known, with reports ranging from 1 to 10 percent. Many of the patients included in clear lens extraction studies were extremely high myopes, and whether or not the clear lens extraction actually caused the retinal detachment in a given patient is unclear.”
Dr. Gallemore also stressed the importance of educating patients on the symptoms of retinal detachment such as floaters, flashes and loss of peripheral vision. “Some refractive surgeons have incorporated this information into their informed consent documents,” he noted.
Risk reduction technique. In a very select subgroup of well-informed patients with appropriate indications, Dr. Gallemore said refractive lens exchange is a “reasonable procedure to consider.” Elderly patients with early cataract and other patients with debilitating high myopia or hyperopia not amenable to other procedures may benefit the most. Some of these patients, however, also carry the greatest risk for complications. The risk of retinal detachment may be decreased by minimizing pressure changes in the eye through smaller incisions, and implanting the new lens in the bag at the time of surgery. This will help reduce the displacement of vitreous and may reduce the incidence of retinal detachment.
Retinal detachment risk reassessed. For Jonathan M. Davidorf, MD, the risk of retinal detachment in clear lens extraction is a concern, but not a deterrent. “Clear lens extraction is a distinct part of our refractive surgery practice, comprising 10 percent of the procedures we perform,” he said. “We do have parameters. I tend not to offer this procedure to those under age 45 unless they are high hyperopes. Interestingly, while phakic IOLs are not necessarily a good option for high hyperopes because the anterior segment is already crowded, making it difficult to fit in a lens, for high myopes, it may be an excellent alternative.”
Although high myopes have a higher rate of retinal detachment, Dr. Davidorf believes it may be lower than has been reported. “There are different studies quoting different risks of retinal detachment in patients who have undergone clear lens exchange in myopic eyes and the incidence is up to 8 percent,” Dr. Davidorf pointed out. “However, the particular study [in Ophthalmology] by Joseph Colin, MD, that is often quoted is based on just 52 eyes of 30 patients with preoperative myopia greater than –12 D.”2
Dr. Davidorf cited the fact that the surgeons performed phacoemulsification through a 3.2-millimeter-wide incision, widened the incision to 6.5 mm and implanted a one-piece PMMA IOL. During the seven-year follow-up, 30 eyes (61.2 percent) required capsulotomy for opacification, and the incidence of retinal detachment during the seven years was four of 49 eyes, or 8.1 percent. (Two of the original 30 patients were lost to follow-up, leaving 49 eyes.) “While this is a commendable study, one patient had bilateral detachment. If he is excluded from the study, then you have two retinal detachments in 47 eyes, which is 4 percent,” Dr. Davidorf pointed out. “Additionally, the advances in lens technology and surgical methodology no doubt make the incidence lower than 8 percent.” While Dr. Davidorf continues to consider seriously the risk of retinal detachment in high myopes, and counsels his patients accordingly, he still includes clear lens exchange in his treatment options.
Other Clinical Considerations
Two other issues of relevance to the clear lens exchange discussion are astigmatism management and accurate IOL calculations, Dr. Davidorf said.
Astigmatism. A select group of patients with high levels of astigmatism undergoing refractive lens exchange may require LASIK or PRK following lens implantation to correct astigmatism that cannot be addressed by this procedure.
IOL calculation. “We also like to counsel our patients that while the IOL calculations are very good, they are not perfect,” he said. “The biggest calculation errors tend to occur in patients with eyes that are extremely long and extremely short. Indeed, the population that seeks clear lens exchange is the exact group for which it is the biggest challenge to obtain accurate calculations. There is a chance that they will need laser vision corrections after the lens correction.”
While the potential benefits of clear lens extraction can be successfully argued, the Ophthalmic Mutual Insurance Company, which insures more than 3,500 policyholders (35 percent of whom perform refractive surgery), takes a conservative approach. According to OMIC’s Betsy Kelley, the company has offered coverage for clear lens extraction since 1999 and revisited its guidelines when the Crystalens was approved by the FDA for use in cataract surgery.
Refractive surgery. “We did a mass mailing in June 2004 reminding physicians that even though clear lens exchange is similar to cataract surgery, it is still considered refractive surgery,” she said. “We do recognize that while refractive lens exchange may be the best alternative for certain patients, our concern is that it is not the best alternative for all patients. Just because the patient comes in with the simple of goal of getting rid of reading glasses, the refractive lens exchange option may not be appropriate. These patients are going to have higher expectations but may not fully comprehend the risks of intraocular surgery.”
Ms. Kelley added that OMIC is concerned with the potential for patients not understanding that refractive lens exchange is intraocular surgery, which carries risk. While the frequency may not be great, the seriousness of the possible risks is an issue. “Ophthalmologists may have a difficult time getting in front of a jury or judge to defend this procedure in the event of an adverse outcome, especially if the patient is relatively young with minimal refractive error and no evidence of cataracts,” she said.
Patient expectations. OMIC is also concerned about patient expectations. “Although accommodative lenses are certainly a huge improvement,” Ms. Kelley said, “patients may have unrealistic expectations and be very disappointed with the ultimate results. It is not a natural lens, and doesn’t provide the same type of accommodation as do the eyes at age 30. Thus they may not be satisfied with the outcome.”
The company generally provides coverage only for cases performed on patients with more than –10 D of myopia or between +3 and +15 D of hyperopia, ranges for which other refractive procedures are not as effective as they are for lower refractive errors. OMIC also is willing to consider exceptions to these patient selection criteria on a case-by-case basis due to special situations.
“I want to add that our position is developing,” Ms. Kelley said. “We are not trying to make a judgment or develop a standard of care. Our primary focus is protection of OMIC insureds.”
1 Visit www.omic.com and click “Refractive Surgery Information,” then “Guide to OMIC Refractive Surgery Requirements.”
2 Ophthalmology 1999;106:2281–2284.
|Dr. Fine noted that a variety of lenses are being developed that will make refractive lens exchange safer, more effective and, ultimately, more widely accepted in the ophthalmic community.|
One such lens is Calhoun Vision’s light-adjustable lens, a foldable, three-piece IOL with a cross-linked photosensitive silicone polymer matrix, a homogeneously embedded photosensitive macromer, and a photoinitiator that, when exposed to a low-intensity beam of light from a digital light delivery device, can correct higher-order aberrations in addition to sphere and cylinder.
Another is the SmartIOL (Medennium), an injectable silicone polymer with the potential for light-adjustable properties similar to the Calhoun lens.
The Medennium lens, which involves reinflation of the capsular bag with an adjustable polymer, may one day reduce the risk of vitreous detachment and subsequent retinal detachment risk following lens surgery in patients with high myopia, Dr. Fine pointed out.
“All of these advances really compel us to continue seeking intraocular solutions for refractive errors,” Dr. Fine said. “It is important to remember that in presbyopia, there is nothing wrong with the cornea. It is the lens that needs addressing.”
|MEET THE EXPERTS|
|D. Michael Colvard, MD Assistant clinical professor of ophthalmology at the University of Southern California and director of the Colvard Eye Center, Encino, Calif. Financial interests: Clinical investigator and consultant with AMO, Eyeonics and Medennium.|
Jonathan M. Davidorf, MD Assistant clinical professor of ophthalmology at the University of California, Los Angeles, and director of the Davidorf Eye Group, West Hills, Calif. Financial interests: None.
I. Howard Fine, MD Clinical professor of ophthalmology at Oregon Health & Science University in Eugene. Financial interests: Consultant to AMO, Bausch & Lomb, Carl Zeiss Meditech, with travel and research support from Alcon, Eyeonics, Staar Surgical and Rayner.
Ron P. Gallemore, MD, PhD Assistant clinical professor of ophthalmology at the University of California, Los Angeles, and partner with the Retina Vitreous Associates Medical Group, Los Angeles. Financial interests: Consultant to Eyetech, ScienceBased Health, Alcon and Pfizer.
Betsy Kelley Product executive with OMIC. Financial interests: Employee of OMIC.
Carl V. Migliazzo, MD Private practice at the Kansas City Eye Clinic, Overland Park. Financial interests: None.
James J. Salz, MD Clinical professor of ophthalmology at the University of Southern California and director of Laser Vision Medical Associates, Los Angeles. Financial interests: Consultant to Alcon and on the board of directors of OMIC.