August 2013

 

NEWS & OPINION

 

A fresh look at orthokeratology


by Ellen Stodola EyeWorld Staff Writer
   

Orthokeratology lenses have developed to address complications and become an effective way to treat myopia

Orthokeratology is a term that has been around for several decades, but the technology of today may be different than what you would expect. The contact lenses associated with orthokeratology have changed over the years. Over time, this treatment has been shown to be an effective way to treat myopia with moderate levels of astigmatism and has been gaining legitimacy and attention through published data.

Bruce Koffler, MD, Koffler Vision Group, Lexington, Ky.; and Cary Herzberg, OD, president of the International Academy of Orthokeratology and the Orthokeratology Academy of America, Herzberg Optical, Aurora, Ill., spoke on the topic, their work, and views of orthokeratology today.

The technology and change over time

This technology was basically invented by accident in the 1960s, Dr. Herzberg said. It was discovered that hard contact lenses made out of polymethylmethacrylate (PMMA) tended to flatten the cornea over time as patients wore them. This led to intentional flattening to treat the cornea and improve myopia; however, there were limitations of technology and design to produce lenses that would always center no matter how flat the base curve was fit.

Dr. Koffler said these hard contact lenses used during the day would attempt to flatten the central cornea, but often took weeks to months, with not very good results. In the 1990s, newer technology helped evolve these orthokeratology lenses. Advancements were made with new materials that allowed for higher oxygen permeability. "We went to gas permeable materials, rather than just hard materials," he said. As a result, it was possible to wear the lenses safely overnight.

Other new technology in the 1990s allowed for computerized cutting of the contact lenses, which allowed for reverse geometry lenses where "instead of the lens being steep centrally and gently flattening in the periphery, now we could create a lens that was flat centrally and a little steeper in the periphery." This advancement led to a more specialized design of the lenses.

Dr. Koffler said this culminated in an FDA study by Paragon Vision Sciences (Mesa, Ariz.), which resulted in the approval of their lens design and overnight wear for all ages in 2002. It was at this time that the term "corneal refractive therapy" was coined for the technique.

Dr. Herzberg said that advances in the field helped to propel the technique forward, especially advances in topography, which "allowed you to measure the elevation of the cornea more accurately." He also mentioned that new computerized lathing systems became available in the 1990s, meaning that "lenses could be manufactured without human involvement."

Appeal of the lenses

These lenses were appealing for a number of reasons. They offered a non-surgical approach to help myopia. They were also approved as a possible treatment for children. Dr. Koffler said the effect of the lenses is evident overnight and that most people get full correction within a week.

"The overnight wear does a couple of things," Dr. Koffler said. "Number one, these lenses don't move much, so the patients are comfortable when they're sleeping." Though they require six to eight hours of sleep, they could still work if someone wore them for the first couple of waking hours.

Candidates for the lenses

Dr. Koffler said orthokeratology lenses are particularly effective in myopes from about 1.0 D to 5.0 D, and with astigmatism up to about 1.5 D. He said he likes to offer this option to anyone who is a candidate and is looking at treatments beyond glasses. "We custom fit every individual and we can custom fit the central curve, we can custom fit in the mid-periphery of the cornea, and we can custom fit where the lens lands on the limbal or scleral area of the cornea," he said.

He said this type of overnight treatment could be particularly helpful in patients with certain lifestyles. For example, swimmers who can't wear contacts when swimming may benefit from this, or it could help those with allergies to be contact lens free during the day.

"We fit everybody, but the highest peaks are in the teenage population because they're so active and also in women and men who are getting into their early 40s and starting to lose their reading vision," Dr. Koffler said. Dr. Herzberg said that he uses this treatment for a variety of patients, fitting a lot of patients for the lenses very young. "Today in a practice, you can do a number of different treatments with orthokeratology, many that have been documented in controlled studies, including myopia, astigmatism, hyperopia, presbyopia, and myopia control," he said.

He also said that this type of treatment for myopia control could fit hand-in-hand with LASIK. For younger patients looking for myopia control, they can be treated with orthokeratology before they are eligible for LASIK. Later on, they may be a good candidate for LASIK or could use orthokeratology as a non-surgical alternative.

Studies on orthokeratology

There have been a number of studies on orthokeratology and these lenses, and statistically significant conclusions suggest that wearing them helps to slow myopia progression, as well as reduce axial length. These studies have been done in a variety of patient populations, comparing the lenses to eyeglass use and other contact lenses. "As soon as the message gets across of what this is all about, I think we're going to see a whole different attitude," Dr. Herzberg said. "It's a great way to control myopia. It's a safe and efficacious way to control this kind of problem." He said that results have shown orthokeratology to be no less safe than daily soft contact lenses.

Current state of orthokeratology

"I think it's important to understand that we are pro-ophthalmology, we're pro-optometry; orthokeratology is not selective to any one specialty or field," Dr. Herzberg said. He said there is still a lot of misinformation circulating about orthokeratology that creates a negative outlook for some, but practitioners who are familiar with the current studies and the safe, efficacious outcomes attained by the procedure are embracing the specialty in their practice.

Dr. Koffler said one of the reasons that people are negative about the topic is because there have been past instances of infections. These problems were mostly related to compliance issues, such as people not using proper solutions to store the lenses, not washing their hands, and improper water supply. "Those issues have been addressed with more oversight by the government agencies to certify practitioners," he said. Now, before a company will allow access to their lenses, a practitioner must complete a certification course. "I personally have been doing corneal refractive therapy since 2002 and have never had an infection in my patient population," he said.

Dr. Koffler said orthokeratology continues to come up and will be a topic of a refractive therapy symposium at next year's Contact Lens Association of Ophthalmologists meeting in Toronto. In addition, there are plans for two 90-minute symposia at the World Ophthalmology Congress in Tokyo next year.

Editors' note: Dr. Koffler has financial interests with Paragon Vision Science. Dr. Herzberg has no financial interests related to this article.

Contact information

Herzberg: oaadoc@gmail.com
Koffler: bkoffler@aol.com

A fresh look at orthokeratology A fresh look at orthokeratology
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