Orthokeratology Stops or Slows Progression of Childhood Myopia

Orthokeratology is one of the specialized treatments we provide at our Vancouver eye clinic.  Naturally, we are please to see the continual flow of research studies that support its effectiveness.

The July 2013 issue of the journal Eye & Contact Lens published the latest in a long line of studies that have shown that orthokeratology is effective in stabilizing or slowing the progression of myopia in children.

Orthokeratology is a doctor-provided vision correction treatment that reshapes your cornea while you sleep so thatyou have perfect vision during the day. No glasses, no contacts, no surgery. Orthokeratology is also sometimes caled "corneal reshaping", "corneal molding", "overnight vision correction" or "ortho-K".

Eye doctors will tell you that some young people dislike going to the eye doctor because their eye-glasses prescription goes up at every visit. This phenomenon is known as myopia progression. Myopia is commonly called nearsightedness.

Not only does myopia progression mean increased inconvenience as the patient's vision worsens and thicker or more expensive lenses, high myopia puts a patient at risk of serious eye diseases that may result in blindness, such as glaucoma and retinal detatchment. Therefore, any treatment that can slow or stop the progression of myopia is welcome.

Myopia is quickly reaching epidemic proportions world wide:

• The World Health Organization predicts that there will be 2.5 billion nearsighted people by year 2020.

• Approximately 80% of elementary students in Singapore are myopic.

• 90% of college students in China are nearsighted.

• The National Institutes of Health reports that in 1972, the frequency of myopia was 25% in U.S. individuals aged 12 to 54. By 2004, it had increased to 41.6%. (Roan,2010).

• In 2004 approximately 26% of all people living in the U.S. and Europe were myopic.

• The incidence of myopia in "hunter-gatherer" societies where children perform little near work, is about 1%.

Orthokeratology has been shown to stop or slow the progression of myopia in children in a number of studies. The latest study, published in the July 2013 issue of the journal Eye & Contact Lens sought to determine whether overnight orthokeratology has an impact on a child's specacles prescription over a period up to 8 years. In the study, a group of kids with no orthokeratology treatment was compared with a group that received the treatment.

The results shows that on the whole, the children treated with orthokeratology showed a significantly more stable specatcles prescription than the chidlren who did received orthokeratology treatment. An impressive 64% of the eyes treated wtith orthokeratology stopped getting worse all together. As the authors put it, they "demonstrated an apparent total arrest of manifest myopic refractive change."

The study's authors concluded that the study provides evidence that orthokeratology can reduce the rate of progression of childhood myopia over the long term.

Citation:
Eye & Contact Lens
Corneal Reshaping Influences Myopic Prescription Stability (CRIMPS): An Analysis of the Effect of Orthokeratology on Childhood Myopic Refractive Stability
Eye Contact Lens 2013 Jul 01;[EPub Ahead of Print], LE Downie, R Lowe

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New study confirms orthokeratology for slowing myopia progression

Yet another study, this one out of Australia, supports orthokeratology for slowing the progression of myopia.  The study was published in the journal Ophthalmic & Physiological Optics on January 24, 2013.   

The goal of the study authors was to describe the time course of changes in both peripheral refraction and corneal topography in myopic adults wearing myopic orthokeratology (OK) lenses.  That means that the researchers wanted to to see how the surface of the cornea - the clear dome that covers the colored part of the eye - changed over time and whether the focusing power of a subject's peripheral vision changed overtime when overnight orthokeratology lens retainers were worn.

The study design was simple.  Nineteen patients were fitted with ortho-k lenses and the researchers measured their peripheral focusing power and the contours of the surface of the cornea after 1, 4, 7 and 14 nights of ortho-k retainer lens wear.

The study reached the following conclusions:

Orthokeratology caused significant changes in both peripheral refraction and corneal topography. The greatest change in refraction and corneal refractive power across the horizontal corneal meridian occurred during the first night of OK lens wear. Subsequent changes in both peripheral refraction and corneal topography were less dramatic, in the same manner as reported changes in apical radius and central refraction after OK. This study confirms that with OK treatment, the peripheral retina experiences myopic defocus, which is conjectured to underlie the observed slowing of myopia progression.

The study adds to our understanding of the mechanism by which orthokeratology slows myopia progression.  The culprit in myopia is thought to be focusing power in an eye's peripheral vision.  This study explains how orthokeratology causes positive changes in this part of the eye that result in a slowing of myopia progression

The role of the peripheral retinal in causing myopia progression may be difficult for the lay person to understand.  One of the best explanations that we have read comes from the College of Optometrists in Vision Development blog post, "Its All About the Blur":

New theories on the development of myopia are evaluating the role of peripheral retina. When lenses are prescribed for any type of refractive error (myopia, hyperopia, astigmatism), those lenses put a clear and focused image on the fovea, which is essentially the “bullseye” on the retina. Whenever we want to see something clearly, we aim our eyes so the image falls on the fovea. The lenses allow us to see clearly precisely because the image is focused on the fovea. But those lenses (especially spectacles) have a different curvature than the retina. The result is a slight defocus on the peripheral retina. The further away from the central retina you are, the greater the amount of defocus. This is not something noticeable by the average patient, because the amount of blur is small, and because we don’t notice blur as well in the periphery. But it seems that our retinas DO notice, because there is significant evidence that this peripheral defocus drives the eye to elongate, and that elongation results in myopia.

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Orthokeratology is shown to be safe for correcting myopia in children

A new study on orthokeratology was just published in the August 2012 issue of the journal Optometry & Vision Science.  The purpose of the study was to find the rate of adverse events associated with orthokeratology use in children over a two year period.

Orthokeratology is doctor-supervised vision correction where the patient wears a custom designed and manufactured lens retainer while they sleep.  The lens retainer reshapes the cornea of the eye allowing it to focus light properly for clear vision.   In the morning, the patient awakes to perfect vision during the day without glasses, contacts or surgery.

The study tracked 61 children from the ages of 6 to 12 with myopia and astigmatism.  The researchers checked in with the children every six months and told them to contact the clinic as soon as any adverse event occurs.  

The study authors concluded that the relatively low incidence of adverse events and discontinuations with orthokeratology is conducive for the correction of myopia in children with orthokeratology lens retainers.

This is the latest is number of new studies showing that orthokeratology is safe and effective.  Here are some others that we have written about:

• Orthokeratology is shown to be effective in correcting astigmatism. Patients with astigmatism now have an alternative to glasses, contact lenses and laser surgery

• New study supports orthokeratology for myopia control and for astigmatism correction

New study supports orthokeratology for myopia control and for astigmatism correction

The Faculty of Health and Social Sciences at Hong Kong's Polytechnic University issued a press release today on the results from two studies on orthokeratology.  One, called the "ROMIO" study, was a single blind, randomized, controlled clinical trial on the effectiveness of orthokeratology for myopia control.  The other, called the "TO SEE" study, looked at the effectiveness of orthokeratology for astigmatism correction.

Brief description of orthokeratology

Patients who wish to receive orthokeratology must have a thorough eye examination to see if they are suitable for the treatment. The optometrist will specially designed and dispense a pair of rigid retainer contact lenses made from high oxygen permeable material to be worn during sleep. The lens will reshape the cornea resulting in perfect vision the next day without the need to wear glasses or contact lenses.

Orthokeratology is the only non-surgical treatment that allows you to be free of corrective lenses like eye-glasses and contact lenses.

Myopia

Myopia and its progression is a serious problem.  Not only does it cause progressively worsening eyesight, requiring thicker and more expensive lenses, it increases the risk of serious eye diseases such as glaucoma and retinal detachment which can cause permanent vision loss.

After 24 months of research, the ROMIO study found that the increase in eyeball length (also called "axial length" -the progression of myopia is measured by observing the elongation of the eyeball)  in a group of subjects that were treated with orthokeratology was 0.36mm.  In the group that was not treated with orthokeratology and only wore spectacles, the eyeball length was 0.63mm. The results indicate that orthokeratology slowed down the progression of myopia by 43%.

Astigmatism

Researchers at the same university also concluded the "TO-SEE" study which looked at 37 children aged 6 to 12 years to study the potential of orthokeratology for the reduction of astigmatism. The team found that toric design orthokeratology lens retainers effectively reduced astigmatism by 79% after one month of wear. At the end of 24 months, the eyeball length of the participants was 0.31mm which indicated that myopia was also being controlled.

Orthokeratology is a reversible treatment and can be stopped anytime. The results of these two studies show that orthokeratology is a safe and effective solution for refractive error correction, myopic control and astigmatism reduction.

I posted about the dangers of the myopia epidemic here.

The myopia epidemic: why it is so dangerous.

Myopia, also called nearsightedess, is increasing in the population at an alarming rate.  According to the National Institutes of Health in 1972, the frequency of myopia was 25% in Americans aged 12 to 54. By 2004, it had increased to 41.6%. (Roan,2010).

Even worse than the increasing frequency of myopia is that for affected individuals it has a tendency to get worse over time.  Some of you may say, "Who cares? People can wear glasses."  Corrective lenses may fix a myope's blurry vision but myopia is far more dangerous than blurry vision.

The danger of myopia is that it can lead to blindness due to the adverse ocular changes associated with it.  Myopia causes abnormal stretching or elongation of the eye which can cause thinning and weakening of the retina (the thin membrane at the back of the eye that contains the cells that send visual information to the brain).   This elongation may pull on the vitreous (the gel substance that fills the eye) which in turn pulls on the retina.  This proces can cause a retinal detatchment - a  medical emergency requiring immediate surgical attention.  A detached retina can lead to blindness.

Another problem with myopia is glaucoma.  Moderate to highly myopic people are twice as likely to develop glaucoma. (Mitchell 2000).  Threfore, it is important for myopic individuals to see thier optometrist regularly to ensure that glaucoma is not developing.

Because of the dangers of myopia, scientists have been working on ways to stop myopia progression.  Orthokeratology is one solution that has been shown to be effective in a number of studies from around the world.  Orthokeratology is a treatment where the patient wears a night-time retainer lens while sleeping.  The retainer changes the shape of the cornea so that the patient experiences clear vision during the day.  In addition to being an alternative to glasses, contacts and laser surgery, orthokeratology retainers can slow or stop the progression of myopia. 

Laser eye sugery makes you queasy?

I came across this news article from Houston, Texas on corneal reshaping, which doctors call orthokeratology (the article curiously used the term "corneal molding", which makes it sound like your cornea is past its expiry date...).

Orthokeratology reshapes your cornea while you sleep so that you have perfect vision during the day. No glasses, no contacts, no surgery. It is very popular with people who are active in sports, especially swimming, people who don't like the discomfort of contact lenses and people who are tired of wearing glasses. It is also a good option for people who are not good candidates for laser eye surgery or who just don't like the idea of having elective surgery on their eyes.

The patient will wear custom designed hard contact lenses while they sleep (they are very comfortable) and remove them in the morning. Sometimes there is a trial and error process to get the fit perfect and to ensure maximum effectiveness and comfort. During sleep, the lens reshapes the cornea of the eye resulting in 20/20 vision upon waking.

Orthokeratology should be done under doctor supervision to ensure that the lenses are doing their job properly, that the eyes are adapting well to the lenses and that there is no risk of damage is being done. The risks of orthokeratology are generally the same as those associated with regular contact lens use, namely that improper care and cleaning can cause infections.

New research even suggests that orthokeratology can stop the progression of myopia (near-sightedness). Many young people have the unnerving experience of seeing their glasses prescription get worse and worse every time they go to the eye doctor. Orthokeratology appears to be one way to slow or stop that process. Incidentally, I have also had success in my clinic with using vision therapy to stop the progression of myopia.

Many of my patients have opted for orthokeratology and I'm happy to say that the vast majority of them really love it. If you are interested in orthokeratology, go see your optometrist who will assess your eyes and determine if you are a good candidate for it.

To read the Houston, Texas article, click here.