CRT (Corneal Refractive Therapy) - FAQs

“What is CRT?”

Corneal Refractive Therapy (CRT), also known as Orthokeratology, is a technology that uses special gas-permeable lenses to gently reshape the front surface of the cornea while you sleep, for the purpose of temporarily correcting myopia (near-sightedness) and in some cases astigmatism. The principle is similar to the use of a dental retainer used by an orthodontist to realign crooked teeth. The CRT lenses are worn only at night while sleeping. They are removed upon awakening to provide corrected vision without the use of glasses or contact lenses during the day!

“How new is the technology?”

The concept of CRT is not new. Paragon CRT was actually the first therapeutic lens design to be approved by the FDA for overnight corneal reshaping and received the final FDA approval on June 13, 2002. The FDA approval signifies the completion of the most extensive clinical study to-date to establish the safety and efficacy of contact lens corneal reshaping in overnight use.

“What does the CRT procedure involve?”

A free CRT screening visit with us can determine if you are a good candidate to use the CRT lenses. During the screening, a corneal topographer is used to obtain a very precise computerized “map” of the cornea’s shape, which aids in the calculation of the diagnostic retainer. If you are a good candidate, a comprehensive eye health exam will be necessary to obtain further calculations for your own vision retainers. It takes about one week for the retainers to be custom made and delivered. Once your retainers are ready, you will be instructed on how to use and care for them. The maintenance is very easy. We will see you the first morning after you wear your retainers, and additionally on several follow-up visits throughout the year to ensure your cornea is adapting well to the retainers. The majority of patients achieve excellent vision in only a few days - many after a single night of wear!

“What are the advantages of CRT over glasses or soft contact lenses?”

Studies have shown that CRT slows the rate of progression of nearsightedness when compared to children wearing glasses or soft contacts. Children, especially those with rapidly increasing nearsightedness, can benefit from the help of CRTs to reduce myopia progression.

With CRTs most can see clearly during the daytime. Advantages of CRT correction are not having to deal with the daytime dryness and daytime discomfort of contact lens, not having glasses interfere with sports and other activities, and not having the worry of losing glasses or CL during the day.

“Does CRT have any advantages over Laser Surgery?”

There are several. CRT is less than half the cost of most Laser Vision Correction Surgery. It does not involve any post-operative pain. Both eyes can easily be done at the same time with CRT. Also, prescription changes are easy to deal with using CRT. There are no strong steroid or antibiotic drugs needed with CRT as there are during the post-operative period for laser surgery. Lastly, and perhaps most importantly, CRT is reversible. Laser surgery is not.

“What are the disadvantages of CRT?”

You must be prepared to allow 3 - 5 visits over a one month period. Should you stop wearing your retainers, your vision will slowly return to its’ original state. While the degree of success is very high, it cannot be guaranteed. However, when the corneal topography and computer software indicate a patient will be successful, it is rare that patients don’t do well with CRT. Rates and amount of improvement vary from one person to the next.

“Is CRT for everyone? What determines a good candidate for CRT?” The CRT 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). You will need to have a CRT evaluation before determining if CRT is right for your visual requirements.

“Is the therapy permanent?”

No. It’s temporary. In order to retain clear vision throughout the day, nightly wear of the lenses while you sleep is required. If you stop wearing the lenses, your vision will return to its original state in as little as 72 hours.

“How long does the therapy take to reach 20/20 vision?” Most patients show rapid improvement in their vision within the first week of treatment and achieve nearly their optimum vision in under 14 days.

“Does Health or Vision insurance cover this procedure?”

Unfortunately, most insurances consider CRT as a cosmetic procedure and will not cover for CRT.

“Do all eye doctors perform CRT?”

CRT is an advanced technology that requires specific training and the necessary diagnostic equipment and computer software to perform. CRT requires custom fitting and needs to be performed in a precise manner. Dr.Chang has had extensive experience in fitting patients in Paragon CRT.

“What is the cost of the CRT program?”

The entire program for the first year CRT wearers ranges from $1100- $2500 plus the cost of the comprehensive eye exam. Fees depend on the individual’s prescription and complexity. The CRT program fee includes all of the recommended professional visits throughout the year and the first set of CRT lenses. Replacement for lost or broken lenses or spare lenses are available at a cost of $225-375 per lens. Usually it is recommended that the CRT lenses be changed once per year to achieve optimal vision. Please contact us for more information.