Refractive Surgery
Considering refractive lens exchange

Experts explain when to do it and how to do it well

Orbscan: the thin corneas may mandate refractive lens exchange Source: William Trattler, M.D.

Patients with ectasia may warrant refractive lens exchange as well Source: William Trattler, M.D.

There are a few reasons why a refractive lens exchange is a better option than LASIK for patients looking to eliminate their need for glasses or contact lenses. Some patients may simply be poor candidates for LASIK because they are significantly hyperopic or myopic, have corneas that are too thin, have corneal ectasia, or have irregular astigmatism, according to Stanley Berke, M.D., associate clinical professor of ophthalmology and visual sciences, Albert Einstein College of Medicine, New York, and chief, Glaucoma Service, Nassau University Medical Center, New York.
In addition, for patients in their late 40s and early 50s found to be developing some nuclear sclerosis, even in mild cases, there will be some internal scatter, which optically is not ideal for the eye, said Jason Stahl, M.D., assistant clinical professor of ophthalmology, Kansas University Medical Center, Kansas City, Kan., and we understand their vision will progressively deteriorate over the years. For these patients and for those in that age range with no cataracts at all, the option to use a presbyopia-correcting lens to correct their refractive error, really has a four in one benefit, he said. A refractive lens exchange can correct their refractive error to give them both distance and near vision, it can eliminate any cataract surgery in the future and lastly because the lens is artificial, the procedure stabilizes the optics of the eye. It’s a long term solution as opposed to getting LASIK and then needing cataract surgery later on. According to Dr. Berke, it’s also always harder to determine the correct IOL power in someone who’s had laser vision correction but easier and more accurate to do it on a virgin eye that has not had LASIK.
Over the last 5 or 6 years, the ability to demonstrate to patients, through electronic medical records, scatter from nuclear sclerosis, has allowed patients to really have a better understanding of these progressive lens changes, which Dr. Stahl calls the functional lens syndrome. As such, they’re really embracing refractive lens exchange, not wanting to wait like their parents’ generation did for cataract surgery, he said.

Pre-op consultation and evaluation

“I like to discuss with the patient what their visual wants and needs are in terms of their activities [like] whether they drive at night, and whether they use a computer frequently,” said Dr. Berke. Patients who are suitable candidates for the surgery are usually younger and want to be able to see far away and close-up, he said, and they are good candidates for premium lenses as opposed to just standard monofocal lenses. A monofocal lens may give them good vision but just at one distance, he explained. So we discuss the various options, which are either the multifocal lenses such as the ReStor (Alcon, Fort Worth, Texas) or Tecnis (Abbott Medical Optics, Santa Ana, Calif.) multifocal, an accommodating lens like the Crystalens (Bausch & Lomb, Rochester, N.Y.), or even a toric lens, he said. Because this is technically an elective procedure, Dr. Stahl said surgeons really need to have very good understanding when it comes to patient education as far as explaining what the technology can do for them so they have an adequate expectation for the range of vision that we can achieve with these presbyopia lenses.
Making sure that the patient is a good candidate for surgery is important as well, so we need to evaluate if there’s any dry eye or blepharitis and treat that, Dr. Stahl said. “I get a retinal OCT [optical coherence tomography] in all my patients just to make sure there isn’t any retinal pathology that would affect their outcome,” he said.
The surgeon also needs to evaluate if there’s anything on the cornea that could cause light scatter and affect the outcome of surgery, such as scarring, anterior basement membrane dystrophy, and Fuchs’ dystrophy, he continued. Once it is determined that the patient is a good candidate, then very good measurements need to be taken such as keratometry and axial length measurements, Dr. Stahl said.
Very accurate pre-op IOL calculations are vital, Dr. Berke said, “I prefer to do at least two methods, one is the IOLmaster and the other is the A-scan and I like to make sure that the two correlate. If they don’t, then I’ll repeat it or at least rely on the one that seems to be more reliable.” Factoring in correcting astigmatism is important as well, Dr. Stahl said, so plan for limbal relaxing incisions if that’s an issue.

Tips for surgery

Prior to surgery, Dr. Stahl places all his patients on a fourth generation fluoroquinolone and a non-steroidal in an attempt to reduce the risk of cystoid macular edema.
During surgery it’s important to be meticulous about every step along the way, Dr. Berke said. The premium lenses all have to be implanted in an intact capsular bag and well centered, so if the situation is such that the capsular bag is disrupted, then you may need to switch from a premium lens to a standard lens and put it in the sulcus, he added.
“I typically just use topical anesthesia with these patients and my preferred technique is a clear corneal phaco wound, which is constructed in such a way that it’s self-sealing and therefore doesn’t require any sutures,” Dr. Berke said, “so visual recovery is very fast.” When it comes to creating the capsulorhexis, be very careful to make it the appropriate size and well-centered, Dr. Stahl said. At the end of surgery, Dr. Berke polishes the posterior capsule carefully and the patients are started out on a standard post-op cataract regimen consisting of Zymar (gatifloxacin, Allergan, Irvine, Calif.) four times a day for a week and Pred Forte (prednisolone acetate, Allergan) or Acuvail (Ketorolac, Allergan) for 1 month (2 months for premium lenses or clear lensectomies), basically a third generation antibiotic, a steroid eye drop and a non-steroidal anti-inflammatory drug, he said. I want to make certain that these patients don’t develop any CME at all because even a little bit of CME can degrade their vision and make them unhappy, he added.
Also, monitoring the posterior capsule for opacification in the early post-op period is important. A lot of these patients who tend to be younger patients with premium lenses may need a YAG capsulotomy earlier (within the first several months following surgery) than standard cases because younger patients tend to develop capsular opacification more rapidly than older patients and also they don’t tolerate it as well, Dr. Berke said.
Surgeons also need to make sure that post-op, if the refractive target has not been hit, if there’s still refractive error, that needs to be corrected, Dr. Stahl said. There will be a significant number of patients where some type of enhancement, whether it’s LASIK, PRK, limbal relaxing incisions, or secondary piggyback IOLs. These presbyopic lenses are wonderful but if we haven’t corrected their refractive errors, they’re not going to achieve the range of vision that we want for them, he explained. “So it’s more than just doing the surgery, we have to make sure we finish the job and correct any residual refractive error also,” he emphasized.

Editors’ note: Drs. Berke and Stahl have no financial interests related to their comments.

Contact information

Berke: 516-593-7709, sberke@ocli.net
Stahl: 913-491-3330, jstahl@durrievision.com