Corneal Refractive Therapy(CRT)
While fitting contact lenses, Optometrists noticed that hard contact lenses or rigid gas permable lenses (RGP) caused a change physical and subjective change in the refractive ability of their patients. This change occurs because the RGP adjusts or reshapes the cornea. Corneal Refractive Therapy lenses are a type of RGP lens that has been specially designed to be worn throughout the night. It is during our sleep that these lenses gently reshape the front surface of your eye (the cornea) and thus correct your vision. In the morning, you remove the lenses so that you can see clearly without glasses or contact lenses. This effect is temporary however, so you must wear the reshaping lenses each night in order to maintain good acuity throughout the day.
What is a Certified Orthokeratologist?
A certified Orthokeratologist is an eye care specialist who has completed specialized training on how to fit specific contact lenses that are responsible for the corneal reshaping during corneal refractive therapy.
Who is CRT For?
Corneal Refractive Therapy lenses are usually a good option for near sighted individuals who are too young for LASIK surgery or for a variety of other reasons are not able to pursue vision correction surgery. As long as your eyes are healthy CRT can be a good treatment option for you because the treatment can be discontinued without permanently changing the eye. CRT is particularly well positioned for people who participate in sports, or who work in dusty environments that can make contact lens very difficult to wear. CRT is not as good though for individuals with high degrees of hyperopia and astigmatism.
What results can be expected from CRT?
The goal for corneal refractive therapy is to correct your vision to 20/20 without eyeglasses or contact lenses during the day. In the FDA trials, more than 65% of patients were able to achieve 20/20 visual acuity after wearing the lenses with the proper overnight wear. More than 90% were able to see 20/40 or better (the legal vision requirement for driving without glasses in most states). Success rates for CRT tend to be better for mild prescriptions however.
How long does CRT take?
Though you may see some improvement in your vision after a day or two, it may often take several weeks for the full effect to become apparent. During this time, your vision will not be as clear as it was with glasses or contacts, and you are likely to notice some glare and halos around lights. It is possible that you may need a temporary pair of eyeglasses for certain tasks, like driving at night, until your vision is fully corrected by the CRT lenses. This possibility is accessed during periodic routine eye examinations.
Is CRT comfortable?
Some people have comfort issues when attempting to wear gas permeable contact lenses during the day. But since CRT lenses are worn during sleep, comfort and lens awareness are generally not a problem.