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Orthokeratology (CRT & VST)

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Orthokeratology is overnight vision correction using corneal reshaping lenses.

It is also called corneal refractive therapy.

This is a reversible method of treatment for myopia (near-sighted) patients and generally works for prescriptions up to -4.00D if there is not too much astigmatism (less than -1.25D). The treatment involves wearing a rigid gas permeable lens while sleeping. With good success, most patients have very stable vision and find they can miss an occasional overnight cycle without any vision loss after approximately 3 weeks of lens wear.

Sometimes it doesn’t work. Some corneas are too rigid and don’t respond adequately to the moulding design of the lens. Sometimes during sleep, the position of the eye, the tension of the eyelids and the sleep posture can affect the orientation of the lens on the cornea.

For this reason, we monitor the results with a corneal topographer so we can measure more accurately what is happening to the front part of the eye.

Today’s Orthokeratology lenses are based on a specific design that was approved for overnight wear in 2002 and are much more successful than earlier designs. Dr. Ben Giddens is an authorized fitter of Paragon CRT lenses (Paragon Vision Sciences) and Vision Shaping Treatment lenses (Bausch and Lomb).

Talk to our optometrists in Georgetown, Ontario to see whether Ortho-K makes sense for you or click here to learn more about it.



Due to the COVID-19 emergency the office will be closed until further notice for all routine activities.

We will be addressing only our patients with urgent eye problems. Please phone for consultation from Monday to Friday in the morning only.

Our office doors will be unlocked only for those patients with pre-booked urgent eye problems. We cannot provide walk-in service at this time.

Thank you.