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Home » Contact Lenses » Ortho-Keratology (Ortho-K)

Ortho-Keratology (Ortho-K)

Ortho-K Q&A
Mississauga Vision Centre
By Dr. Sana Al-Imari

Please describe what Ortho-Keratology is and give a basic sense of how it works. Orthokeratology is a non-surgical procedure that reshapes the front surface of the eye to eliminate the need for glasses or contact lenses during the day. It makes use of a specially designed therapeutic contact lens to be worn only when sleeping, and removed in the morning to achieve clear, comfortable vision uncorrected. To get the general idea, think of it as braces for the eyes!

boy swimming in poolHow does Ortho-K assist in treating nearsightedness, and astigmatism? Nearsightedness (or myopia) and astigmatism are types of refractive errors that limit unaided vision and are mostly dependent on the shape of the front surface of the eye, or the cornea. Orthokeratology treatment targets exactly that, reshaping the cornea reversibly to allow light to bend correctly onto the back of the eye, or the retina.

Are there different types of ortho k, if yes which one do you recommend and why? Orthokeratology lenses have a very basic design that’s dependent on the material used. The material has to be very high in oxygen permeability to ensure corneal health. At present, there are two brands approved for overnight wear: Paragon Vision Sciences’ Corneal Refractive Therapy (CRT), and Bausch and Lomb’s Vision Shaping Treatment (VST). Both lens designs are excellent treatment options and can correct astigmatism up to -1.50 diopters, the only difference being, the VST lens corrects myopia up to -5.00 diopters, while the CRT lens corrects up to -6.00 diopters. Overall, they are equally effective and both require a certification program that demonstrates the understanding of this treatment.

How does Ortho-K slow the progression of childhood myopia? In general, the eye functions by using the cornea as a lens to focus light onto the back of the eye, or the retina. Myopia or nearsightedness is a condition where the eyeball is too long, causing images or light to focus in front of the retina. As the eye continues to grow, it will lead to poorer vision as well as physical sight-threatening changes like retinal detachments and glaucoma. Animals studies have shown that the trigger for the eye growth is found in the retina, particularly in the periphery (1). It was also found that light focuses differently on the central retina compared to the peripheral retina. Orthokeratology was designed to reshape the cornea in a way to allow equal focus of the light on the central and peripheral retina, thus helping to control the growth or progression of the myopia.

Are the effects of Ortho-K instant? The full effects of orthokeratology take approximately 1-2 weeks, however, most patients will notice a dramatic improvement in vision within just a few nights of wear. The rate of treatment is dependent on the prescription strength as well as the pliability or flexibility of the cornea. Should the treatment require a few nights of wear to achieve good vision, a temporary disposable soft contact lens may be prescribed for a few days.

What is it about this particular technology that you find most exciting, or the component that made you feel you need to use in this for your practice? The number of children that are becoming nearsighted has grown rapidly over the last 30 years, with the World Health Organization (WHO) estimating a worldwide incidence of 23%, projected to increase to 52% by 2050 (2). Once we learned the effectiveness of orthokeratology towards controlling the myopia progression, we felt it was necessary to embrace this technology and recommend it to all patients who are showing signs of progression. We also found it to be a great alternative to laser refractive surgery for those who are not good candidates, are not ready or don’t ever want to do eye surgery.

How effective is it? What results can a patient expect from being treated with Ortho-k?Once candidacy for orthokeratology is determined, clear, comfortable and unaided vision is guaranteed and can be maintained long-term with adjustment or replacement of the contact lens as needed. In regards to myopia control, consistent wear of the contact lens has shown halting of the eye growth by 43 percent in school-aged children over a 2-year period (3)(4)(5)(6). There are many on-going studies to determine the long-term efficacy of orthokeratology for myopia control.

Can you describe the patient experience when being treated with Ortho-K? When wearing the orthoK contact lens or retainer for the first time, the vision will be close to 20/20 but the lens will feel very uncomfortable. However, once the eyes are closed and the patient is ready to sleep, the sensation will be mild enough to allow uninterrupted sleep. Over time the cornea becomes less sensitized and the lens will become more comfortable. The morning routine will include removal, cleaning then proper storing of the contact lens, while the evening routine will include insertion and sleeping with the retainer nightly. After the first six months of wear, we can experiment with wearing the retainer every other night, however, vision will be compromised if discontinue wear more than 2 nights in a row.

boys with thumbs upWho is a good candidate for Ortho-k? From what age can a patient have Ortho-K?A good candidate for orthoK will need excellent corneal and lid health, free of infection, inflammation or allergies. Patients as young as 10 years old can be fit with these lenses, however, parental support is an absolute must. The Ortho-K retainers or molds are worn nightly so proper hygiene is crucial for the success and safety of this therapy. Another criteria of candidacy is the level of nearsightedness and astigmatism. All of this can be assessed during the consult visit.

Are there specific patients for whom the use of Ortho-K is particularly helpful or useful? Why? A good candidate for orthoK will need excellent corneal and lid health, free of infection, inflammation or allergies. Patients as young as 10 years old can be fit with these lenses, however, parental support is an absolute must. The Ortho-K retainers or molds are worn nightly so proper hygiene is crucial for the success and safety of this therapy. Another criteria of candidacy is the level of nearsightedness and astigmatism. All of this can be assessed during the consult visit.

Can you share a particular patient success story, in which by treating with Ortho-K, you were able to provide a patient with a solution which you would otherwise not have been able to provide? My first orthokeratology treatment patient was a 11-year-old boy who was showing signs of myopia progression. After a long discussion with his parents, we decided to try orthokeratology. As soon as I placed the lenses on his eyes and he realized he can see his parents without his glasses, a large smile formed on his face that I couldn’t help but mimic. It was a pleasure to bring him excellent vision without the aid of glasses. The treatment was an even greater success when his prescription stayed the same 1 year later.

What are some of the benefits of Ortho-k over glasses? There are many benefits of orthokeratology over glasses and each one depends on the preferences and lifestyle of the patient. One benefit would include being able to read the alarm clock upon waking. Another is being able to read the shampoo bottle in the shower. Thirdly, enjoying fast-paced sports or even water sports without worrying about glasses falling off.

Is Ortho-k good for athletes? Orthokeratology is an excellent option for athletes. The use of sports goggles can be cumbersome or unfashionable for some athletes and would prefer glasses-free correction. Although, soft contact lenses are a great alternative, they are not recommended for young athletes who are not mature enough to maintain proper contact lens hygiene unsupervised. For those patients specifically, orthokeratology lenses are only worn when at home, allowing the parents to have complete control on the handle and care of these lenses.

Is Ortho-K safe? Orthokeratology has been approved by many health and medical regulatory bodies around the globe including Health Canada and the Food and Drug Administration (FDA) in the U.S. As with any contact lens wear, there are few complications. One side effect of this treatment is the development of infection or microbial keratitis, which can lead to corneal scarring and vision loss. It can be avoided with diligent lens care, adhering to the prescribed wearing schedule and regular examinations.


1. Smith, E.L., III, et al. 2005. Peripheral Vision Can Influence Eye Growth and Refractive Development in Infant Monkeys. Invest Ophthalmic Vis Sci. 46(11): 3965-3972.

2. The impact of myopia and high myopia: report of the Joint World Health Organization–Brien Holden Vision Institute Global Scientific Meeting on Myopia, University of New South Wales, Sydney, Australia, 16–18 March 2015

3. Davis, R. et al. 2015. Stabilizing Myopia by Accelerating Reshaping Technique (SMART)-Study Three Year Outcomes and Overview. Adv. Ophthalmic. Vis. Syst. 2 (3): 00046.

4. Cho, P., Cheung, S.W. 2012. Retardation of myopia in Orthokeratology (ROMIO) study: a 2-year randomized clinical trial. Invest Ophthalmol Vis Sci. 53:7077-85

5. Walline, J.J., Jones, L.A., Sinnott, L.T. 2009. Corneal reshaping and myopia progression. Br J Opthalmol. 93(9):1181-56.. Si, J.K., et al. 2015. Orthokeratology for Myopia Control: A Meta-analysis. Optom Vis Sci. 92(3):252-7