Technology, high success rates drive refractive cataract surgery

In this installment of a series marking OSN’s 25th anniversary, pioneers discuss techniques and tools that have enabled cataract surgeons to refine refractive outcomes.

In the last 2 decades, IOL innovations and new laser procedures have spurred the gradual but steady fusion of cataract and refractive surgery.

Whether undergoing refractive lensectomy or laser enhancement after cataract surgery, patients demand and expect better outcomes than ever, according to surgeons interviewed by Ocular Surgery News. In part, these expectations are fueled by dramatically improved technology and results.

Frank A. Bucci Jr., MD, OSN Cornea/External Disease Section Member Eric D. Donnenfeld, MD, OSN Chief Medical Editor Richard L. Lindstrom, MD, and OSN Refractive Surgery Section Member Marguerite B. McDonald, MD, shared their observations of how cataract surgery and refractive surgery have become so closely intertwined.

Dr. Lindstrom pointed to a “continuous incremental series of events” that have blended cataract and refractive surgery. The first key development was the advent of phacoemulsification, which allowed small incisions and lowered the risk of induced astigmatism, he said.

Later, in collaboration with OSN Cataract Surgery Section Member Robert H. Osher, MD, and others, Dr. Lindstrom helped popularize intraoperative astigmatic keratotomy.

“The next key event was the development of foldable IOLs, pioneered by Tom Mazzocco. Those were really the original events,” Dr. Lindstrom said. (See article, “Foldable IOLs ushered in new cataract and refractive paradigm” in the June 1 issue Ocular Surgery News.) “Then, what really got refractive surgery into the modern era and allowed acceptance by all of organized ophthalmology was the approval of the excimer laser. That gave us an extraordinarily refined enhancement tool for the cataract surgeon. That was the next big event.”

Advancements in IOLs have evolved the technology from foldable lenses to modern small-incision multifocal, accommodating and toric lenses, while surgical techniques such as intraoperative corneal or limbal relaxing incisions, along with LASIK or surface ablation, have evolved to where they can enhance refractive outcomes for almost any interested cataract patient, Dr. Lindstrom said.

“We’ve got multiple refractive cataract surgery channels now, corneal-based astigmatism correction, toric IOLs, multifocal IOLs and accommodating IOLs, and patients benefit from all these tools,” he said.

Safety improvements have made intraocular surgery a viable and attractive option for many surgeons and patients, Dr. McDonald said.

“That’s when it began to look like it was going to be a continuum instead of two separate, different practices,” she said.

Dr. Donnenfeld credited improvements in axial length measurement, IOL calculation software and small incisions for helping to improve refractive outcomes and reduce surgically induced astigmatism.

“In general, cataract surgery has always been a refractive surgery because, whenever you remove the lens of the eye, where cataract is an opacified lens, you have the opportunity to correct whatever spherical error is there, nearsightedness or farsightedness,” Dr. Bucci said.

Patient expectations

“Of course, with every passing year, the patient expectations have gotten higher, too,” Dr. McDonald said. “When you look at the early RK papers from the 1980s, 20/20 wasn’t even reported. The highest level reported for outcome was 20/40 or better. So patient expectations have increased as the technology has increased.”

Marguerite B. McDonald

Currently, between 10% and 30% of multifocal IOL cases need laser “touch-ups,” Dr. McDonald said. However, the rate of enhancement with laser procedures on virgin eyes has dropped from about 15% a decade ago to 5% to 7% or even lower, she noted.

“One’s enhancement rate is impacted by several factors, including the type of cases one takes on,” Dr. McDonald said. “If a laser surgeon has an unusually high percentage of challenging cases (eyes with high refractive errors, post-RK eyes, post-PK eyes, etc.), that surgeon is going to have a higher enhancement rate. Nevertheless, technology has helped us to drive the enhancement rate down. Ironically, multifocal IOLs have driven up the need for laser treatment in a population we never dreamed we’d be treating, the older patient who has just had an IOL. Perhaps these cases will partially compensate for the slow growth in the laser vision correction market that some have predicted.”

Rising success rates and resulting high expectations are a recent phenomenon, Dr. Donnenfeld said.

“I think that there’s been a significant shift in patient expectations that developed just over the last couple of years,” he said. Surgeons’ ability to enhance vision and the growing number of satisfied patients have “created a perfect storm for patients to come in looking for and expecting perfect visual results after their cataract surgery,” he said.

Older patients have generally lower expectations than younger patients, who are usually willing to pay for presbyopia-correcting IOLs, Dr. Bucci said.

Medicare does not cover presbyopia-correcting IOLs, which in the United States currently include the ReSTOR (Alcon), the ReZoom (Advanced Medical Optics) and the crystalens (eyeonics).

However, under a 2005 Centers for Medicare and Medicaid Services ruling, a patient may opt to pay out of pocket to “upgrade” to a presbyopia-correcting IOL in lieu of a conventional lens. The patient covers the portion of the facility charge that exceeds the charge for conventional IOL implantation.

“If it wasn’t for the CMS ruling, there would be a whole different landscape here because you can get away with a less-than-perfect presbyopia-correcting IOL in a typical cataract patient whose expectations are less for a whole host of reasons,” Dr. Bucci said.

Training and practice

Refractive surgeons generally face a steep learning curve in adopting cataract procedures, Dr. McDonald said.

“I think it’s harder for refractive surgeons to learn to do phaco than it is for cataract surgeons to learn to do PRK,” she said. “But going in both directions is a daunting task. Most people will probably say, ‘Heck, I’m just going to find somebody with the complementary skill set, inside or outside of my practice, and strike a deal with them.’”

However, cataract surgeons learn refractive procedures such as PRK relatively quickly, Dr. McDonald said.

“I think it’s easier for cataract surgeons to learn to do PRK,” she said. “And many people feel PRK is the preferred technique for enhancing an older patient who has had a multifocal IOL because it doesn’t induce or exacerbate dry eye for 2 years, as LASIK can. Most of them are already suffering from dry eyes.”

Eric D. Donnenfeld

PRK should ideally be performed 6 to 12 weeks after cataract surgery, Dr. McDonald said.

“I think it’s a harder skill set for the refractive surgeon to learn cataract surgery,” Dr. Donnenfeld said. “It takes years to develop really skilled cataract surgery.”

Cataract surgeons must be prepared to use PRK, LASIK or limbal relaxing incisions to correct small spherical refractive errors and astigmatism. Conversely, refractive surgeons need to learn cataract techniques and be able to offer good outcomes, Dr. Donnenfeld said.

However, cataract surgeons need to develop the refractive surgeon’s “emotional and psychological mindset,” which is focused on maximizing refractive outcomes, he said.

“I think that may be even harder to develop,” he said. “You have to have the mindset that you always have to be willing to treat any residual problem as long as it’s safe to optimize patient outcomes. And that mindset is probably the most difficult part for the cataract surgeon to adopt.”

Emerging innovations

New multifocal IOL technologies may enhance refractive outcomes, Dr. Donnenfeld said.

“The aspheric optics being adopted into multifocal IOLs are giving better quality of vision with multifocal lenses,” he said.

Limbal relaxing incisions improve refractive results and boost patient satisfaction after multifocal IOL implantation, he noted.

Dr. McDonald said accommodating lenses hold the most hope for optimal results.

“The holy grail of cataract surgery is to restore accommodation,” she said. “Multifocal IOLs are wonderful, but they will be seen someday as an intermediate step.

New accommodating IOLs will offer multiple benefits, Dr. Donnenfeld said.

“I think the next big thing we’re looking for is a better accommodating IOL,” he said. “There are some very promising new accommodating IOLs that are in clinical trials outside the United States that I’m very excited about. I think that’s the thing that’s going to move it to the next level, when we can really provide quality visual acuity at distance and near without a loss of contrast sensitivity or quality of vision.”

Accommodating lenses may offer unheard-of outcomes, Dr. Lindstrom said.

“With accommodating IOLs, we’ll be able to give people vision like the emmetrope has when they’re 35 years old,” Dr. Lindstrom said. “Basically, they’re 20/20 or better at distance, intermediate and near.”

New keratometry and IOL measurement technologies will also improve refractive outcomes, Dr. Donnenfeld said. Also, intraoperative aberrometry during cataract surgery will enhance the measurement of IOL power and help surgeons more accurately customize lenses to provide optimal outcomes, he said.

New phacoemulsification machines will continue to enhance cataract surgery, he said.

“I think anything that improves cataract surgery is going to provide safer visual rehabilitation,” Dr. Donnenfeld said.

Cutting-edge procedures, such as multifocal LASIK ablation and conductive keratoplasty, show much promise, the experts said.

Dr. McDonald was optimistic about multifocal ablation for hyperopic presbyopia.

“I think the multifocal ablation [procedures] that are going through the FDA approval process will be a great primary and rescue procedure, especially a rescue procedure, for people who have a multifocal IOL who are disappointed in how much near vision correction they’ve gotten,” she said. “In the world of laser vision correction, I see multifocal ablations as a breakthrough that will help combine cataract and refractive surgery.”

Dr. Lindstrom mentioned that conductive keratoplasty is also “a useful enhancement tool” for some surgeons and patients with astigmatism, hyperopia, hyperopic astigmatism or presbyopia who are seeking alternatives to LASIK, for example, in the face of a thin cornea or dry eye. The CK technology from Refractec uses radiofrequency energy to reshape the cornea.

Advanced implants and surgical procedures, including the use of femtosecond technology, have provided the means by which cataract surgeons may produce desired refractive outcomes, Dr. Lindstrom said.

“We’ve really got good tools today to enhance a patient’s refractive outcome to give most of them the outcome they want,” Dr. Lindstrom said.

For more information:

• Frank A. Bucci Jr., MD, can be reached at Bucci Laser Vision Institute, 158 Wilkes-Barre Township Blvd., Wilkes-Barre, PA 18702; 570-825-5949; fax: 570-825-2645; e-mail: buccivision@aol.com.
• Eric D. Donnenfeld, MD, can be reached at OCLI, 2000 North Village Ave., Rockville Centre, NY 11570; 516-766-2519; fax: 516-766-3714; e-mail: eddoph@aol.com.
• Richard L. Lindstrom, MD, can be reached at Minnesota Eye Consultants, 9801 DuPont Ave. S, Suite 200, Bloomington, MN 55431; 952-888-5800; fax: 952-884-2656; e-mail: rllindstrom@mneye.com. Dr. Lindstrom is a paid consultant for Advanced Medical Optics, Alcon, eyeonics and Refractec.
• Marguerite B. McDonald, MD, can be reached at OCLI, 266 Merrick Road, Lynbrook, NY 11563; 516-593-7709; fax: 504-232-3641; e-mail: margueritemcdmd@aol.com.

• Matt Hasson is an OSN Staff Writer who covers all aspects of ophthalmology. He focuses on regulatory, legislative and practice management topics.