Diagram of eye surface profile

Orthokeratology or ortho-keratology also referred to as “Ortho- K”, “overnight vision”, and “Corneal Refractive Therapy”. Is a lens that is prescribed in cases of nearsightedness, astigmatism, hyperopia, childhood myopia and in some mild cases of presbyopia. Ortho keratology takes the place of daily wear and use of glasses and contact lenses by lens wear overnight to temporarily re-shape the cornea.

Ortho-keratology acts like a retainer for the eyes it helps to reshape the cornea and how the light is refocused at the retina while you sleep providing you with clearer, crisp vision when you wake up. Through the process of reshaping the corneal tissue Ortho- K RGP lenses help to better control myopia so the patient is able to see without the daily use of contact lenses or glasses.

Who is a good candidate for ortho-k?

The best candidates for Orthokeratology are people who have mild to moderate myopia with/without astigmatism. The best candidates are those patients with an Rx less than -4.00 and astigmats lower than -1.50 .Children and Teenagers that want to be glasses free but are too young for refractive surgeries.  Also patients who are physically more active are great candidates as well because they are able to see clearly and not worry about contacts or glasses.

To determine whether or not a patient is a good candidate for these therapeutic lenses, the first step is to have a visit with an optometrist and from there will be referred to an orthokeratologist who will overview the overall ocular health of the eye and also takes a map of your cornea using a machine called a topographer.

With measurements and a map of your cornea, a computer controlled lathe shapes the lens with various specialized curves which further helps to reshape the corneal tissue.


Child fitting and Myopia.

Orthokeratology is also a great alternative for children as it may be a struggle of consistently making sure that the child is wearing their glasses or contacts during the day to further reduce myopia.  With the help of ortho-k it makes it easier on the parents as most myopia control involves the cooperation of not only the child but most importantly the parent/guardian of the children. As a child the cells in the eye tend to regenerate and grow more rapidly than an adult’s eye would progress.  It has been proven to be more effective because the more a child ages the possibility of becoming more myopic increases.

Benefits of Ortho- Keratology

The benefits of ortho-k is that it is a non-surgical method, no need for daily contacts or glasses wear. And an overall vision improvement.


Takes longer to see results, currently only for myopia patients, not a permanent solution to vision correction. The ortho-K lenses are more expensive to start compared to glasses and contacts.

Side effects

Ortho-k has been proven to be effective but can only be as effective if the candidate is consistent with wearing time. Upon removal of lenses for an extended period of time the eye will return to original shape and refractive error will come back. As this procedure is reversible there have been reported side effects of blurry and fluctuating vision. As these are a variation of an RGP lens the same risks and side effects still apply.





Works Cited


“Overnight Ortho-K in Children Significantly Reduces Peripheral Myopia.”Healio: Medical News, Journals, and Free CME. N.p., n.d. Web. 27 May 2016.


“Orthokeratology: Reshaping Your Eyes With Contact Lenses.” All About Vision. N.p., n.d. Web. 04 May 2016.

“What Is Orthokeratology?” AAOMC. N.p., n.d. Web. 04 May 2016.

“What You Should Know About Orthokeratology (ORTHO-K).”EyeHealthWeb.com. N.p., 26 Jan. 2013. Web. 24 May 2016.