Orthokeratology

Myopia an normal vision showing enlongated eyeball and long axial length in the myopic eye

Myopia

 

Myopia is also known a nearsightedness. Myopia is quickly increasing around the world and is one of the leading causes of blindness in the world. It is estimated that 30% of the Canadian population is myopic.

 

Many young people have the unnerving experience of having their eye-glasses prescription go up every time they go to the eye doctor. 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. Therefore, any treatment that can slow or stop the progression of myopia is welcome.

 

Orthokeratology for Myopia Control

 

Orthokeratology has been studied and used for over 20 years and has been shown to stop or slow the progression of myopia in a number of studies, some of which are listed below. Many studies use the term corneal re-shaping, which is another name for orthokeratology.

 

REIM (2003). Tom Reim OD,FOAA and colleagues first reported the potential of myopia control in 2003 with a retrospective study that reported that corneal reshaping experienced about a sixty percent reduction in myopic progression.

 

LORIC (2005). The Longitudinal Orthokeratology Research in Children(LORIC) study was conducted in Asia, and found a much slower rate of myopia and axial elongation(47%) among young progressive myopes who underwent corneal reshaping compared to those who wore eyeglasses.

 

CRAYON (2007). The Corneal Reshaping and Yearly Observation of nearsightedness(CRAYON) study, conducted by Jeff Walline OD,FAAO at Ohio State University, also found lower rates of myopia progression and axial elongation (57%) among patients who used orthokeratology (Walline, 2008).

 

SMART The Stabilization of Myopia by Accelerated Reshaping Technique(SMART) study, a large scale(300 patient), five year longitudinal, multicenter evaluation of the effectiveness of orthokeratology for young progressive myopes. The study found that after three years, there was a statistically higher increase in myopic progression for children who wore soft contact lenses group compared with the Ortho-K group.

 

CRIMP(2010) . Corneal reshaping inhibits myopia progression(CRIMP) is a ten year retrospective study out of Australia that demonstrated control of myopia progression over a ten year time frame. Fully 70% of all participants in the corneal reshaping control group did not progress in degree of myopia over the period studied.

 

MCOS in progress. " The Myopia Control with Orthokeratology contact lenses in Spain (MCOS) Study, in which continued documentation of safety outcomes for corneal reshaping in a pediatric population was evident by no changes in best-corrected visual acuity or significant adverse health effects from ortho-k wear" (Gregory,2010).

 

 

 

Newer reserach also provides some hope that increasing time spent outdoors might help slow the progression of myopia. Drops of a pharmaceutical agent called Atropine have also shown some promise in recent studies.

 

The dangers of myopia

 

Retinal detatchments

 

Myopia and the eye disorders that arise when myopia progresses can cause abnormal or adverse changes in a patient's eyes. Myopia causes abnormal stretching or elongation of the eye which may induce 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 process may result in a detatched retina - a medical emergency that requires immediate attention and often surgery. Retinal detatchments often lead to blindness.

 

There is a second mechanism whereby the elongating process associated with myopia can cause blindness. Elongation can also cause holes to form in the edges of the retina, leading to a retinal detachment. This can cause bindness and requires emergency surgery to try to save the patient's vision.

 

Glaucoma

 

Myopia can also lead to glaucoma. Moderate to highly myopic people are twice as likely to develop glaucoma. (Mitchell 2000). Glaucoma causes permanent vision loss if it is not diagnosed and treated early. It sneaks up on the victim because it causes no pain and moves so gradually that the victim usually does not know that they have already lost portions of their peripheral vision. An eye doctor's comprehensive eye examination is the only way to to catch glaucoma before it does permanent damage.

 

The myopia epidemic

 

The statistics on myopia show that it is a world-wide epidemic.

 

Research on Myopia in Canada from the University of Waterloo’s School of Optometry and Vision Science and the CNIB Foundation found that myopia in children increases dramatically from Grade 1 to Grade 8. An equally troubling finding was that 30% of the myopic children in the study did not have glasses to enable them to see clearly. The study also showed that kids are becoming myopic and an earlier age, at 6-7 years of age when in the past children did not become myopic until 12-13 years of age.

 

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