Corneal Refractive Therapy begins with an initial consultation in which exams are performed to carefully measure your refractive error and to map the curvature of the eye. If you are a candidate for Orthokeratology and decide to start treatment, Dr. Vu will fit you with the lenses that will give you the best possible results. Once you begin wearing the lenses, CRT patients reach functional vision during the day within a week or two, and maximum effectiveness for most patients by 3 months. Initially, you may need weaker glasses or contact lenses to function in the daytime. 

The effect of the correction will wear off towards the end of the day initially, but will last longer the more you continue wearing the lenses at night. Usually the effect is stable for a 24-hour period in 2-3 weeks. CRT offers many advantages, including the ability to see clearly while wearing the lenses. Therefore, if patients need visual assistance during the first couple of days after starting CRT, they can wear their CRT lenses in the daytime and have great vision. CRT is a completely reversible process, so if you stop wearing the lenses regularly while you sleep, your vision will return to its original state within a few days. Because CRT is completely reversible, CRT users can still be candidates for LASIK in the future, when they are ready to consider the procedure.

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We are committed to helping you achieve your visual goals and guarantee that we will safeguard your interests at all times.

About Orthokeratology

Orthokeratology is a non-surgical method of decreasing mild to moderate myopia and astigmatism. Myopia, or nearsightedness, causes light to be focused in front of the retina rather than on it, resulting in blurry vision when looking at distant objects. Here at Linda Vision, Dr. Linda Vu, a board-certified ophthalmologist, uses a form of Orthokeratology called Corneal Refractive Therapy (CRT) by Paragon Vision Sciences. CRT was approved by the FDA in 2002, and has since improved the lifestyle and vision of people of all ages by reducing the need for glasses and daytime contact lenses.

CRT uses special gas permeable contact lenses to reshape the cornea while you sleep. Although the lenses are only worn at night, the cornea retains its altered shape and corrected focus throughout the daytime. This means that CRT patients no longer have to deal with the hassle of glasses or dryness and irritation caused by daytime contact lenses. The temporary correction of myopia not only allows patients to see clearly, but it may reduce changes in prescription. Our Corneal Refractive Therapy uses Paragon CRT lenses. These lenses are produced by Paragon Vision Technology, the first company to get FDA approval for overnight corneal reshaping lenses.


Your follow-up care is just as important to your vision as wearing the lenses. We offer unlimited follow-up exams with Dr. Vu for 12 months after beginning Corneal Refractive Therapy and it is important that you keep all scheduled appointments.

Ready to schedule an Appointment?

We are committed to helping you achieve your visual goals and guarantee that we will safeguard your interests at all times.


Is Orthokeratology Permanent?

No, it is temporary. If you stop wearing the lenses regularly while you sleep, your vision will return to its original state in as soon as 72 hours.

Can everyone wear CRT lenses?

This lens is designed for individuals with low to moderate nearsightedness (up to –6.00 diopters) with or without astigmatism (up to –1.75 diopters). The maximum treatment for any given eye is dependent on several patient features. Dr. Linda Vu is very experienced with Orthokeratology and can assess your eyes and give you an idea of what to expect. At this time, hyperopia (farsightedness) is not correctable with CRT.

What should I do to see adequately in the period of time between when I start & end Orthokeratology treatment?

It is important to understand that for a short time after you have begun treatment, but before sufficient treatment is achieved, your old glasses or contacts will no longer be the appropriate prescription. You may have to wear your CRT lenses for part of the day or some use temporary soft lenses in different prescriptions. Dr. Vu will discuss your options for visual correction during that transitional period of time.

Are there any risks involved with wearing Paragon CRT lenses?

There is a small risk involved when any contact lens is worn. The risk between regular wear contacts lenses and CRT is similar, but is minimized with proper care of the lenses. There were no serious adverse events reported in the CRT FDA clinical studies.

Can I see while wearing my CRT lenses?

Yes. One of the great features of the 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. Also, if during the initial treatment phase, you find you need some form of vision correction, you can wear your CRT lenses in the daytime and see clearly.

How often will I have to replace my CRT lenses?

Generally speaking, the CRT lenses will have to be replaced once a year. However, depending on factors such as protein build-up and how well the lenses are taken care of, the lenses may have to be replaced more or less frequently.

Is Orthokeratology painful?

The therapy is not painful. Initially, you may have a slight awareness of the therapeutic lens but you will not feel the lenses when you sleep and there is no sense of physical corneal change. You will notice visual improvement when the lenses are removed.

Is Orthokeratology covered by insurance?

Orthokeratology is an elective treatment which means it is not covered by your insurance. However we do offer interest free monthly payments that help make Orthokeratology more affordable to our patients.

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Our Los Angeles LASIK specialists have been performing LASIK surgeries for over 20 years combined, with very positive results. Linda Vision’s experience and dedication to each patient, along with the use of the Wavelight EX500 excimer laser, make Linda Vision the ideal place to have LASIK surgery. We offer unlimited LASIK follow-up exams for 12 months after your Custom Wavefront LASIK surgery.

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