Orthokeratology

Ortho-K And Corneal Refractive Therapy: Overnight Contacts To Correct Myopia

Wouldn't it be great if you could correct your eyesight and reduce your dependence on glasses or contact lenses — without having to undergo eye surgery?

It might sound far-fetched, but it's a reality for many people. It's called orthokeratology, or ortho-k.

Here are the top 10 things you should know about orthokeratology:

1. What Is Ortho-K?

Ortho-k lenses are prescribed for two purposes:

• To correct refractive errors (primarily nearsightedness, but also astigmatism and hyperopia). In some cases, ortho-k also is used to correct presbyopia.
• To slow the progression of childhood myopia. (Read more about myopia control.)

Ortho-k lenses are also called "corneal reshaping contact lenses" or "overnight contact lenses to correct or control myopia."

One specific brand of ortho-k lenses and fitting technique is Bausch + Lomb's Vision Shaping Treatment (VST). But ortho-k can be safely and successfully performed with other gas permeable (GP) lenses and corneal reshaping fitting techniques.

2. What Is Corneal Refractive Therapy (CRT)?

Paragon CRT (Paragon Vision Sciences) is a specific brand of corneal reshaping lenses that has a proprietary lens design and fitting methodology, called corneal refractive therapy (CRT). Though technically different than orthokeratology, CRT is used for similar purposes and produces comparable results.

For simplicity, I'll be using the terms "orthokeratology" and "ortho-k" to describe all types of corneal reshaping lenses — including corneal refractive therapy lenses — in this article. Your eye doctor will determine which type of corneal reshaping lenses are best for you after examining your eyes.

3. How Long Does The Ortho-K Effect Last?

You should be able to see acceptably well without glasses or contact lenses for a day or two, sometimes longer. For best results, you should wear the ortho-k lenses every night.

4. Which Vision Problems Can Ortho-K Correct?

Orthokeratology is most frequently used to temporarily correct myopia (nearsightedness). Generally, ortho-k can correct upwards of -6.00 diopters (D) of myopia.

Ortho-k also can correct lesser degrees of astigmatism, hyperopia and presbyopia.

The type and amount of refractive error that can be effectively managed with orthokeratology differ on a case-by-case basis. Your eye doctor will be able to give you more specific guidance after examining your eyes.

5. Who Is A Good Candidate for Orthokeratology?

Most people with mild to moderate myopia (with or without mild astigmatism) are good candidates for ortho-k.

Because the corneal reshaping effect is temporary, little risk is involved, and you can discontinue wearing the lenses at any time — provided you are willing to start wearing glasses or contacts again when your myopia returns!

6. Who Fits Ortho-K Lenses?

In the United States, optometrists perform most orthokeratology lens fitting. But ophthalmologists also perform ortho-k fittings. In some cases, ortho-k may be performed by a contact lens technician under the supervision of an optometrist or ophthalmologist.

7. What Results Can You Expect From Ortho-K?

Eye care practitioners usually aim for 20/20 vision after ortho-k, but 20/40 vision (the legal minimum for driving in most of the United States) often is considered an acceptable outcome.

In the FDA clinical study for approval of Paragon CRT lenses, 93 percent of patients achieved 20/32 vision or better, and 67 percent achieved 20/20 or better. In the clinical study for FDA approval of one VST design, about 95 percent achieved 20/40 or better, and 73 percent achieved 20/20 or better. Both studies followed patients for at least nine months.

8. What To Expect When You Begin Ortho-K

When you begin to wear ortho-k lenses, you will likely have some awareness of the lenses on your eyes until you fall asleep. With time, the lenses typically become more comfortable immediately upon insertion.

9. How Long Does It Take For Maximum Ortho-K Effect?

This depends on many factors, especially the amount of nearsightedness (and possibly astigmatism) you have when you begin the ortho-k process.

10. How Much Does Ortho-K Cost?

Ortho-k prices in the U.S. generally range from $1,000 to $2,000 (for both eyes), making the procedure roughly half the cost of LASIK. But particularly difficult cases of ortho-k can cost as much as $4,000.

There are additional costs for replacement ortho-k lenses, lens care solutions and follow-up exams, which can total about $300 to $500 per year.