Corneal Refractive Therapy (CRT)
Corneal Refractive Therapy is a non-surgical process clinically developed and FDA approved to reshape the cornea while you sleep. The result is the temporary correction of myopia with or without moderate astigmatism.

Similar in appearance to standard contact lenses, Paragon CRT therapeutic lenses gently reshape the corneal surface during sleep. When the Paragon CRT lenses are removed in the morning, the treated cornea allows light to focus on the retina. The result is clear, natural vision for all or most of your waking hours.

Because Paragon CRT offers freedom from glasses and the hassle of wearing contact lenses during the day, this leading-edge technology can enhance the lifestyle of those requiring vision correction. Active individuals can freely participate in sports without the interference of glasses or bother of contacts. Eye irritation or dryness, sometimes associated with contact lens wear due to outside dust and pollutants, is eliminated.

Here are some Frequently Asked Questions with respect to CRTs:

Is Corneal Refractive Therapy Permanent?
No. It’s temporary. If you stop wearing the lenses regularly while you sleep, your vision will return to its original state in as little as 72 hours.

Can everyone wear Paragon CRT?
Not everyone can wear Paragon CRT. This lens is designed for individuals with low to moderate myopia (nearsightedness up to –6.00 diopters) with or without astigmatism (up to –1.75 diopters). Paragon CRT therapeutic lenses are not yet available in bifocal prescriptions for presbyopia (which requires reading glasses or bifocals). At your doctor’s discretion you may be fitted in a monovision mode (one eye corrected for near vision and one corrected for distance vision). You might still need reading glasses. However, since there are variations in patient physiology and visual needs, the decision for CRT, at any age, can only be made after a thorough eye exam and the recommendations of the eye care professional. At this time, hyperopia (farsightedness) is not correctable with CRT.

Are there age restrictions for Corneal Refractive Therapy with Paragon CRT?
No. The FDA placed no age restrictions on candidates for Corneal Refractive Therapy with Paragon CRT.
CRT is being successfully performed on children 12 years old and younger. It can be a great option for children and teens that are active in sports activities or any other extra curricular activities. Those who are older and presbyopic (requiring reading glasses or bifocals) may still be candidates for CRT.
They may correct their distance vision with CRT and wear near-vision reading glasses for close work. At the doctor’s discretion you may be fitted in a monovision mode (one eye corrected for near vision and one corrected
for distance vision). Visual requirements due to age or activities can only be assessed after a thorough eye exam. Your Paragon CRT certified eye care professional will recommend what is best for you.

How long does it take to reach good vision?
Most patients have rapid improvement in the first few days of treatment and achieve nearly their optimum vision in 10 to 14 days.

What do I do to see adequately in the period of time between when I start Corneal Refractive Therapy with Paragon CRT and when I achieve full treatment?

It’s important to understand that for a time after you have begun treatment, but before sufficient treatment is realized, your old glasses or contacts will no longer be the appropriate prescription. It may involve insertion of your Paragon CRT lenses for part of the day or some use of temporary soft lenses in different prescriptions as an option. Your eye care practitioner will discuss your options for visual correction during that transitional period of time.

Are there any risks involved with wearing Paragon CRT?
There is a small risk involved when any contact lens is worn. It is not expected that the Paragon CRT lenses for contact lens Corneal Refractive Therapy will provide a risk that is greater than other contact lenses. There were no serious adverse events reported in the Paragon CRT FDA clinical study.

Can I see with my Paragon CRT lenses in?
Yes. One of the great features of the Paragon CRT lens is that if you have to get up in the middle of the night, you will be able to see where you are going. Or, if during the initial treatment phase, you find you need some form of vision correction, you can put in your Paragon CRT lenses and see clearly.

How often will I have to replace my Paragon CRT lenses?
Generally speaking the Paragon CRT lenses will have to be replaced once a year. However, depending on factors such as protein build-up, how well the lenses are taken care of, etc., the lenses may have to be replaced more frequently.

Is Corneal Refractive Therapy painful?
The therapy is not painful. Initially, you may have a slight awareness of the therapeutic lens. You will not feel the lenses when you sleep and there is no sense of physical corneal change…. just visual improvement when the
lenses are removed. If I discontinue CRT, will my vision to return to normal?
There are no recorded permanent corneal changes post-treatment. Generally, the more myopia being reduced, the longer it will take for the corneal curvature to return to normal. For instance, if your pretreated correction was - 4.50D, it would take a few days longer to return to normal than if the pretreated correction was -1.50D.

What happens if I lose or damage a lens?
Corneal Refractive Therapy is different than wearing regular contact lenses. If you discontinue wear for one night, your vision may be impaired the next day. Previously worn glasses or contact lenses may not help. Immediate replacement is necessary! Having a spare pair of lenses is strongly recommended.

Questions? Contact our CRT Coordinator at

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Paragon Vision Sciences has taken the recent advancements in computerized corneal mapping , computerized manufacturing, and oxygen permeable contact lens materials and produced a therapeutic contact lens design that is like no other.

This has allowed Paragon CRT to become the one corneal reshaping modality that truly stands out and the first to earn FDA approval for nighttime Corneal Refractive Therapy.

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Infographic: Myopia Facts