What is Ortho-K overnight contacts for myopia control?

Discover the fascinating development history of orthokeratology (Ortho-K or the overnight contacts). And how it is an effective solution for children with myopia to leave their glasses behind and enjoy clear vision while preventing myopia from worsening.

What is orthokeratology (Ortho-K)? 

Orthokeratology, also known as Ortho-K or the overnight contacts, is a non-surgical vision correction procedure that uses specially designed contact lenses to reshape the cornea. 

These lenses are made of a rigid, gas-permeable material designed to gently reshape your cornea while you sleep and are removed in the morning, providing clear vision throughout the day. 

In the simplest terms, Ortho-K is a science that changes the curvature or shape of the cornea to adjust how light is focused on the retina at the back of one's eye, providing an excellent option for those who want to leave their glasses behind or not have to wear contact lenses all the time. 

Ortho-K can be used to correct nearsightedness (myopia), farsightedness (hyperopia), astigmatism, and presbyopia. It is most commonly used to prevent nearsightedness from worsening in children.

The fascinating history of orthokeratology 

The field of orthokeratology has a long and interesting history, dating back to the 1940s when doctors first discovered a reshaping phenomenon of glass lenses.

George Jessen created the first orthokeratology design in the 1960s, made from Polymethyl methacrylate (PMMA) material, which was described as "Orthofocus." Although these early designs had unpredictable results, leading to the belief that applied orthokeratology was more art or luck than science.

This was followed by a major breakthrough in the 1990s with the development of computerized corneal topography, which allowed for accurate mapping of the surface curvature of the cornea using a non-invasive, painless imaging procedure. This made it possible to create designs with repeatable results. 

The development of new materials for rigid gas permeable lenses also provided much higher levels of oxygen permeability, allowing for orthokeratology to become an overnight procedure rather than being limited only for daytime wear. 

In 1994, the FDA granted approval for daily wear of a type of lens indicated for orthokeratology called Contex OK-Lens. 

And in June 2002, FDA granted approval for overnight wear of a type of corneal reshaping called "Corneal Refractive Therapy" (CRT).

How does orthokeratology work? 

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Ortho-K lenses are designed to float on top of the eye tear film and apply gentle hydraulic force to the front layer of the cornea. The force causes some parts of the cornea to take in more fluid and some parts to take in less. This change in the cornea by only a few microns leads to a temporary reshaping of the cornea and correction of refractive errors such as myopia.

Ortho-K redirects the fluid within the corneal cells and doesn't cause pain.  And, it doesn’t squish your cornea.

The Ortho-K lenses are custom-made for each individual patient based on their specific eye measurements and prescription needs. They are gas-permeable contact lenses that are designed to be worn overnight. After removal, improved vision is generally noticed for 24 to 72 hours. 

Ortho-K is well suited for individuals, who are not appropriate to wear contact lenses during the day, are active in sports and water activities, or want a non-surgical and non-invasive alternative to surgery. 

Orthokeratology is relatively safe and has few side effects; however, it does require regular follow-up visits with an eye care professional for monitoring vision changes and lens fit adjustments if necessary. 

Ortho-K for myopia control in children

Unlike glasses or regular contact lenses, Ortho-K involves wearing custom-made lenses overnight that reshape the cornea. This allows for clearer vision during the day without having to put on glasses or lenses. 

Meta-analysis studies demonstrated Ortho-K could reduce myopia progression near 50%, similar to myopia-control glasses and soft contact lenses that are based on peripheral myopic defocus.

A 2017 study further demonstrated its effectiveness in slowing refractive error progression over a twelve-year period, with a clinically acceptable safety profile in myopic children aged seven to sixteen years. 

Ortho-K could work synergistically with other treatments that are not based on peripheral defocus for its mechanism of action. Studies demonstrated greater effectiveness in preventing myopia from progressing when combining Ortho-K with 0.01% atropine. 

Recently, a study found that when Ortho-K treatment alone is insufficient, adding 0.05% atropine to Ortho-K may enhance myopia control effectiveness.¹

Ortho-K use in children more than 6 years old was shown in studies to be effective and well-tolerated. However, there is no absolute age when children can begin wearing Ortho-K lenses in a real-world setting; factors such as acceptance level, sense of discipline, and responsibility in caring for the contacts should be taken into consideration. 

An important consideration when evaluating if Ortho-K is appropriate is if your kid is mature enough to ensure proper hygiene and handling of the lenses. 

Ortho-K is reversible. If you stop wearing your Ortho-K lenses, your vision should return to its original state, and the shape of your cornea will be restored within a few days or weeks, depending on how long you have been wearing them. 

Although generally safe, some Ortho-K related risks, which are similar to any soft contact lenses, should be considered beforehand. 

Common side effects include dry eyes, blurred vision, and eye discomfort when wearing the lenses overnight. 

Eye sensitivity, leading to difficulty in inserting the lenses, during the first few days was also reported. The eye sensitivity issue can be alleviated through desensitizing eye drops or allowing time to adapt to the rigid lenses – usually about one week. 

There are also rare but serious risks of infection or inflammation, which frequently are due to improper lens care or hygiene practices while using the lenses. 

The typical first-time cost of Ortho-K treatment usually runs around US$1,200 to US$2,000, depending on the refractive error and the region. An additional cost to include is the cleaning and disinfecting supplies, which could be about US$150 to US$200 per year.

Overall, Ortho-K is an excellent choice for myopia control in children due to its effectiveness in slowing myopia progression and the convenience of not needing to wear glasses. 

In order to ensure long-term success with Ortho-K treatment, it is important to have rigorous compliance to the lens care regimen, good adherence to routine follow-ups, and timely treatment of any complications that may arise.

Final Thoughts

Orthokeratology is a relatively safe, non-invasive, and reversible vision correction procedure that is an excellent choice for myopia control in children. It is an effective way to slow myopia progression, and the convenience of not having to wear glasses makes it even more attractive. 

While there are some risks involved with Ortho-K, such as infections or inflammation, these can be minimized with proper lens care and hygiene practices. 

With regular follow-up visits and timely treatment of complications – if they occur, Ortho-K can be an effective and reliable solution for your child to leave their glasses behind and enjoy clear vision throughout the day.

1. Wen L, Liu H, Xu Q, et al. Add-on effect of using 0.05% atropine in fast progressors of orthokeratology: A preliminary retrospective study. Cont Lens Anterior Eye. Published online July 27, 2024. doi:10.1016/j.clae.2024.102282.

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