3 correction options for presbyopes

May 31, 2014

The treatment choices presented to presbyopic patients will depend on many factors, including lifestyle, profession, general attitude toward vision, and levels of disposable income. The first step is ascertaining which two of the three visual acuities are most important to them: near, intermediate, or distance vision. For example, you probably wouldn't recommend a multifocal intraocular lens (IOL) to a professional airline pilot because those lenses may compromise nighttime distance vision.

The treatment choices presented to presbyopic patients will depend on many factors, including lifestyle, profession, general attitude toward vision, and levels of disposable income. The first step is ascertaining which two of the three visual acuities are most important to them: near, intermediate, or distance vision. For example, you probably wouldn't recommend a multifocal intraocular lens (IOL) to a professional airline pilot because those lenses may compromise nighttime distance vision.

However you, the doctor, and the patient decide to move forward, it is important that presbyopes understand that some aspect of their vision will have to be at least slightly compromised. Tradeoffs are inevitable. Despite many recent technological advancements, no one modality can give a presbyope simultaneously flawless near, intermediate, and distance vision.  

That having been established, there are still a number of viable options for patients losing their accommodation, ranging from traditional-but still effective-progressive addition lenses (PALs) to the most leading-edge surgical procedures.

Spectacles

They don't grab headlines the way contact lenses and surgeries do, but spectacles are still the go-to option for millions of presbyopic patients, not to mention a reliable profit center for eyecare practitioners. And like contact lenses and surgery, spectacle technology continues to advance.

Generally speaking, flat-line bifocals are giving way to PALs. “There are still people who wear bifocals,” says Ryan H. Powell, OD, in northwestern Missouri. “But they tend to be people who turned presbyopic back in the 1990s, tried the 'no-line' lenses, they weren't successful, so they stuck with the straight lines.”

Dr. Powell fits most of his newly presbyopic patients into progressive lenses, which he makes a point of calling “no-line lenses” rather than progressives or PALs. “We have learned over time that if you say the words 'progressive lens,' patients have no idea what you are talking about. No-line bifocals is more descriptive,” he says.

The major technological advance among PALs over the past 10 years or so has been the extent to which newer designs have all but eliminated peripheral distortion, Dr. Powell says, which historically has been a frequent patient complaint. “The newer designs have really taken care of that problem,” he says.

Progressive lenses can be divided broadly into three categories, according to Dr. Powell: commercial, brand name, and customized. Commercial lenses tend to have a low success rate. “We have a lot of patients tell us they tried no-lines and were not successful with them. Our first question is 'Well, where did you get them?'” he says. “And if they have tried what I consider to be a commercial style no-line, those have a low success rate. If I can get patients into a brand-name or customized lens, they do fantastic.”

He adds that he has had great success with Essilor's Varilux 4D progressive lenses, which are custom designed around the patient's dominant eye. Just as people are right or left-handed, they also have a leading, dominant eye. This is the eye that reaches the object being viewed first when we change gaze direction. The Varilux 4D factors in the movement of the patient's leading, dominant eye, which results in a faster visual reaction time, according to the company.

Next: Contact lenses

 

Contact lenses

Although monovision continues to be a fallback option for presbyopic contact lens wearers, most practitioners now say they prefer to start off patients in a multifocal lens if possible. The big news in this field is that there are now three daily disposable multifocal lenses to choose from: Alcon Dailies AquaComfort Plus Multifocal and Focus Dailies Multifocal; CooperVision Proclear 1 Day Multifocal; and Sauflon clariti 1day multifocal.

“A lot of patients want to wear these lenses only part time,” says Optometry Times Editorial Advisory Board member David I. Geffen, OD, FAAO. “So it's a great deal for them to be able to wear them and just throw them away at the end of the day. My patients are loving this.”

For monthly presbyopic wear, Dr. Geffen's go-to lens is Bausch + Lomb's PureVision 2 Multifocal. “I think the optics on that lens are just excellent. And the company has redesigned the entire lens to improve its comfort, and that is working out great for us,” Dr. Geffen says.

One of the reasons multifocal lenses are eclipsing monovision modalities is that the multifocal lens manufacturing process has been improved, according to Dr. Geffen. “I think manufacturers have been able to create more quality control. They are now able to reproduce the lenses much better. It's not like you put one lens in one time and you can see, and then you put the next one in, and you can't. They are able to produce those aspheric designs more uniformly. You now know that each lens is going to be pretty much the same.”

Some practitioners avoid multifocals because they think fitting times are prohibitively long. This is no longer true, says Dr. Geffen. “With the advent of these better lenses, we are finding much less discrepancy in fit, so they don't take as much time. One of the keys is not to overdo it. If these lenses are going to work, you'll know it in two visits. You don't want to keep going until you are fitting 10 lenses. Feedback is pretty quick.

Next: Surgery

 

Surgery

The newest class of presbyopic correction, surgical options have existed for about only 10 years or so. So, many of these technologies do not have large patient cohorts exhibiting long-term results. Indeed the only U.S. Food and Drug Administration (FDA)-approved corneal surgery for presbyopia is conductive keratoplasty (CK), and it has fallen out of favor in recent years. A non-ablative, non-incisional procedure that uses radiofrequency energy to steepen the cornea, CK may regress over time and to occasionally induce astigmatism.

Monovision induced by LASIK has been prevalent as an off-label procedure for several years and can produce success rates in the 70 to 90 percent range. A LASIK variation called presbyLASIK, which essentially carves a multifocal design on the cornea, may be less successful. It produces measureable near-distance improvement, but patient satisfaction has not been particularly high so far.

Another option, corneal inlays, are refractive optics implanted intrastromally. One of these, Kamra, made by Acufocus and up for FDA approval this summer, increases depth of field by employing the principal of small-aperture optics-i.e., the pin-hole optics you may remember from high school science class.

Another procedure focused on intrastromal corneal tissue is Intracor, which employs a femtosecond laser to ablate this tissue only, thus leaving the epithelium untouched. Initial data on this technique is promising, but additional studies are needed before it can achieve widespread use.

Perhaps the most successful surgical treatments for presbyopia have been IOLs implanted in conjunction with cataract surgery. Multifocal IOLs can correct for presbyopia and astigmatism or be employed to induce monovision. One FDA-approved IOL can even mimic the accommodative powers of a natural lens.

Of the 3.5 million cataract surgeries that occur every year, about five percent receive a multifocal or accommodative IOL, according to Richard L. Lindstrom, MD, founder of Minnesota Eye Consultants and a pioneer of refractive surgery. “It's a small percentage of patients, but because there are so many cataract surgeries, it comes pretty close to 200,000 a year,” he says. “So a lot of patients are opting for these lenses.”

An IOL likely to be approved for use in the U.S. soon uses a unique aspheric design to increase depth of focus, according to Dr. Lindstrom. Synchrony IOL, made by Visiogen and AMO, features a high plus anterior optic connected by spring haptics to a posterior optic with variable negative power. “It's not really a multifocal, but it improves depth of focus, so it does improve near vision,” he says.

At the American Society of Cataract and Refractive Surgery (ASCRS) meeting in April, Dr. Lindstrom learned of an experimental topical drop that causes pupils to constrict for about 8 hours, creating small aperture optics that increase depth of focus, without inducing the negative side effects of pilocarpine. “Maybe you can put the drop in when you get to work, and it wears off in time for your drive home at night,” he noted. “It might be a good stand-alone therapy, or act as a test run for patients potentially interested in small-aperture corneal inlays.”ODT

Mr. Celia is a freelance healthcare writer based in the Philadelphia area.