Orthokeratology is a procedure of gently reshaping the cornea in order to temporarily modify or totally eliminate a refractive error. This non-invasive clinical technique is also known by the following names:

•    OK
•    Vision Shaping Treatment or VST
•    OrthoK
•    Corneal Refractive Therapy or CRT.

Orthokeratology involves the use of a rigid custom-made contact lens to mold the shape of the cornea to reduce or correct myopia. Continuous use of the lens is necessary as the cornea is highly elastic and will always return to its original shape. The effect will wear off after a few days if use is discontinued. The contact lenses are permanent and can last for up to three years.

Ideal Candidates for Orthokeratology

This procedure is recommended for the following persons:

•    Those with mild to moderate myopia or short sightedness of -0.75 to -5.00D.
•    Those with presbyopes for monovision corrections.
•    Those with hyperopes or long sightedness of up to +3.00D.
•    Those with contact lens allergies.
•    Those who easily misplace contact lenses.
•    Those whose work or lifestyles are not suited for use disposable contact lenses.
•    Those who are afraid of undergoing refractive surgery due to the risks they provide.
•    Those who suffer from dry eye syndrome due to prolonged computer use or exposure to air conditioning and dusty environments.

Orthokeratology Procedure

The following steps will be undertaken should you be found qualified to undergo this procedure:

•    Your eye doctor will check the prescription and health of your eyes.
•    Your cornea will be measured for customization of the lens using an instrument called a corneal topographer.
•    Once your contact lens is completed, you will be required to wear it overnight to temporarily alter the shape of your cornea.
•    You will remove the contact lens first thing in the morning and you will have clear vision throughout the day without the help of eye glasses or contact lenses.
•    You need to visit your doctor for follow-up consultations to monitor the effect of the lens on your vision.
•    Expect lens changes or adjustments for clearer vision.

A key issue to remember is that orthokeratology is a specialised procedure. Few practitioners are experienced in its implementation.  If you make a random request it is likely that you will be talked out of following up further.  Make sure you see an optometrist that has ample experience in this unique procedure.

Orthokeratology Risks

As with any medical procedure, there will also be concomitant risks when you undergo orthokeratology. Though these complications rarely happen, it would be beneficial for you to know some risks that accompany this procedure:

•    Cornea infections
•    Scarring of the cornea
•    Degradation of vision.

To avoid these complications, make sure to strictly follow the instructions of your eye doctor especially with regard to the schedule, handling, hygiene, wearing and caring for your contact lenses.

Indeed, this procedure is an innovative, convenient and comfortable way of correcting refractive errors. While it may sound like a serious and expensive procedure, its benefits definitely outweigh the costs. In the long run, it can even end up cheaper considering how long it lasts. So go ahead and explore the awesome gift of orthokeratology.


  • by Harry Posted July 1, 2012 5:24 am

    How much myopia can ortho k treat? I heard it was -10.00D is this true?

    • by Jim Posted July 1, 2012 7:51 am

      Hi Harry
      There are some novel orthokeratology designed lenses that can correct up to -10.00D of myopia but they suffer from a number of significant issues:
      1. The treatment zone they offer is quite small and this leads to significant optical aberrations, particularly in dim light.
      2. The pressure effect these lenses exert on the cornea are very significant and can easily compromise the epithelial surface of the cornea. This can in turn expose the eyes to infection, which ultimately can cause irreversible scarring if not monitored extremely carefully.

      What we need to remember is the following:
      a. With prescription sup to -2.00D success rate is nearly 100% and complication rate is very rare.
      b. As we increase the boundaries in particular over -4.00D success rate decreases significantly and complication rate increases signifcantly.
      c. Orthokeratology is a specialised treatment that only highly trained practitioners should be performing especially when it comes to prescriptions above -4.00D.

      Hope this helps.

      • by Harry Posted July 3, 2012 12:52 pm

        Thanks for replying Jim 🙂

        In regards to your second point about the pressure these different types of lens exerts on the cornea leading to compromisation of the epithelial surface, I found this video as I was looking into it on the internet. Now I’m no optometrist so I only understand partially what this optometrist is saying but I believe he states that the lenses don’t apply more pressure, but they actually provide more manipulation. He talk’s about Munnerlyn’s formula and the treatment zones and all that stuff….

        Here’s the link:

        Skip to about 18 minutes and 35 seconds of the video (00:18:35) and thats when he talks about what the lenses are actually doing. Or, you can just watch the entire video for yourself 🙂

        Once again, thanks for replying and I would love to hear your opinion on these lenses.

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