Welcome to Professional VisionCare Orthokeratology


Welcome to our website! Orthokeratology, also known as Corneal Refractive Therapy (C.R.T.), is a popular and effective way to correct your vision overnight and be glasses or contact lens free during the day. Read on to find out more about this life changing treatment and if this could be ideal for you!

Corneal Refractive Therapy (C.R.T.) Facts

What is C.R.T.?

C.R.T. (also known as orthokeratology, or ortho-k) is an FDA-approved, nightly rigid contact lens treatment designed to improve your vision.  This reversible, non-surgical treatment gently reshapes your eyes while you sleep, and reduces or eliminates the need for corrective lenses during your waking hours.

What vision problems can C.R.T. treat?

C.R.T. is designed to treat nearsightedness, farsightedness, and low amounts of astigmatism.  

What does C.R.T. use to correct vision?

C.R.T. uses rigid, oxygen permeable contact lenses that are custom designed with various curvatures to correct your specific prescription by gently remolding the front surface of the eye.

What are the benefits of C.R.T.?

C.R.T. corrects your vision so you can be glasses and contact lens free during the day. It is an excellent alternative for athletes, patients who lead an active lifestyle, poor candidates for refractive surgery, and anyone who finds wearing glasses or contact lenses inconvenient during the day.  In addition, research shows that C.R.T. can slow or stop the progression of nearsightedness in children.  To learn more about myopia control, click here.

C.R.T. and Myopia

Check out this short video on what myopia is, and how C.R.T. can help!

C.R.T. and Myopia Control


How does C.R.T. slow or stop myopia progression?

C.R.T. reshapes the front surface of the eye, creating a flatter central area and a raised peripheral ring around the flattened area.  The new flat surface focuses light perfectly at the central retina in the back of the eye, correcting vision and making distance objects look sharp.  The steep peripheral ring focuses light in front of the peripheral retina, reducing the stimulus for eye elongation and thereby slowing myopia progression. 

How effective is C.R.T. in slowing or stopping myopia progression?

While individual results may vary, studies have shown C.R.T. to slow myopia progression by up to 50%. (Example: Progression of 0.50D/year instead of 1.00D/year.)  Researchers agree that single vision glasses and soft distance contact lenses have no effect on slowing myopia progression.  

What is the C.R.T. treatment process?


See us for a C.R.T. consultation

We will help you determine if C.R.T. is a good option to correct your prescription.  This process includes taking a computerized "map" of the eye surface, checking your glasses prescription, and evaluating the health of your eye.  


Take your C.R.T. lenses home and wear them overnight

If C.R.T. is a good option, you will likely receive your lenses that same day.  We will train you how to insert, remove, and clean the contacts and send you home with an initial supply of contact lens solution.  Wear the lenses overnight for at least 6-8 hours, and return the next morning for a follow up appointment to see how much your vision improves!


Follow up with us to find out how C.R.T. is working for you

Wear your contacts on the morning of your first follow up visit.  We will check your vision, lens position, eye health, take a new "map" of the eye surface, and make any necessary changes to the design of the lenses. Follow up visits thereafter are 1-2 weeks, 1 month and 3 months. Once we determine that the lenses are giving your eyes the proper treatment, you will receive a spare pair. We recommend yearly follow up visits after completion of the C.R.T. process.

C.R.T. Patient Testimonials

Frequently asked questions about C.R.T.


How long does it take for C.R.T. to improve my vision?

In most cases, there will be a noticeable improvement in your vision the first morning after wearing C.R.T.  However, full visual improvement can take a few weeks of consecutive nightly wear.  

How long does my vision stay corrected during the day?

Most patients will enjoy clear vision the entire day, but may notice mild blurriness at night time.  The therapeutic effects of C.R.T. generally last about 1 to 2 days, although results can vary.  We recommend wearing the lenses every night to maintain excellent day time vision.  

Is the vision improvement from C.R.T. permanent?

No.  C.R.T. treatment is 100% reversible.  Once you discontinue wearing the lenses overnight, your eye shape will return to its pre-treatment form.  

Can children wear C.R.T. lenses?

Absolutely!  In fact, C.R.T. is one of the recommended treatment methods if your child is nearsighted and has a prescription that is progressively getting worse.  With adult supervision, children can successfully undergo C.R.T. treatment.  

What are the risks of C.R.T. treatment?

In general, the risks of C.R.T. are similar to any contact lens wear.  These risks can be minimized by following the proper handling and wearing instructions given by our office.  Common adverse side effects include redness, tearing, pain, discharge, light sensitivity, abrasion of the surface of the eye, and distorted vision.  Extremely rare side effects include scarring of the eye, abnormal blood vessel growth, microbial infections and ulcers, and permanent vision loss. If you are experiencing any abnormal symptoms with your C.R.T. lenses, discontinue wear and call our office immediately.

Find out if C.R.T. is right for you

Send Message

Send us a message and schedule a phone consultation with Dr. Nancy McBride!  She will gladly discuss whether or not you or your child could be a good candidate for CRT.  She is available Monday through Thursday at 5:45pm.  Please specify in the message that you are interested in discussing CRT candidacy and list two days you are able to speak with Dr. McBride.  It may be helpful to have the most recent prescription on hand for the consultation.  Please allow 24 hours for a response.

Professional VisionCare Associates

14607 Ventura Blvd, Sherman Oaks, California 91403, United States



Monday - Thursday: 8:30am - 5:30pm

Friday: 8:30am - 5:00pm

Saturday: 8:00am - 2:00pm

Sunday: Closed

Photo credit:

1. orthokeratology