Myopia or nearsightedness is reaching epidemic proportions. In a single generation the incidence of myopia has doubled. What is more startling is that researchers predict the incidence will increase an additional 40% over today’s numbers by the year 2050. Although genetics play a role in myopia development, studies are showing more evidence of behavioral and environmental factors contributing to the increase. The most prominent of them being less outdoor play during a child’s developmental years and more screen time both at play and at school.
While there is no outright cure for myopia, there are now options available to treat it. Instead of giving our children thicker glasses or stronger contacts every year, we are able to slow down or even halt its progression ensuring better vision for life. At the same time, we can reduce their risk for serious eye diseases associated with high myopia such as retinal detachments, early cataracts, and glaucoma. The chart below details these health risks associated with myopic progression.1
1. Flitcroft, D. I. (2012). The complex interactions of retinal, optical and environmental factors in myopia aetiology. Progress in retinal and eye research, 31(6), 622-660.
There are three treatment options available which have proven through research to be most effective in myopia control. These are: compounded atropine eyedrops; orthokeratology; and specialized daily soft contact lenses. While the efficacy of each method has proven to be essentially equal, there are advantages and disadvantages to each method when it comes to lifestyle for the child. These are outlined below along with their respective cost. Methods can be combined if a child still shows myopia progression on a single method.
Atropine drops have been used for many years especially in other countries to slow myopia progression. Atropine works on relaxing the accommodative or focusing mechanism of the eye. There is belief that progression occurs due to “focusing fatigue” from all the sustained near work children are doing. The problem with commercially available full-strength atropine is that it has the undesirable side effects of pupil dilation, as well as too much relaxation of the eye’s ability to focus. These side effects leave children light sensitive along with having difficulties reading without bifocals or reading glasses. This has led researchers to study diluted or compounded atropine. Multiple clinical studies have shown Atropine 0.01% to be as effective in controlling progression as full-strength atropine without giving children the negative side effects. In fact, it was found that low strength atropine provided better sustained control of progression. There was also no evidence of a rebound effect after stopping atropine treatment with the low dosage. This effect was found in some studies with the full-strength atropine.
Orthokeratology or ortho-k is a method where a variation of a gas permeable contact is placed on the eye before sleeping. It harnesses the tear film to apply a gentle pressure causing a measured amount of flattening to the central cornea. This flattening allows the image to be aligned on the retina providing clear vision in much the same way LASIK does. This allows the patient to see clearly during the day without glasses or contacts. The difference between ortho-k and other treatment is that the effect is reversible. The effect must be maintained by continued nightly wear of the lenses, much like a retainer for the eyes. Once the patient stops wearing the molds, the eye returns to its pretreatment level within a few days or weeks depending on how long the lenses have been worn. The technique has been around for decades, but improvements in lens design and material, as well as its ability to control myopic progression, have caused in rise in usage. It still remains a specialty practice however, due to the time and skill level required to properly fit the lenses.
Control of myopic progression through ortho-k is achieved through a process known as “myopic defocus” as illustrated in the diagram below.
In the myopic eye, traditional spectacle or contact lens correction pushes the image back to the central retina to allow us to see. However, it does so in a single focal plane. Due to the fact that the eye is curved causes the peripheral light rays to be focused behind the retina. This leads to an area of hyperopic defocus as illustrated by the blue line. The theory is this area of hyperopic defocus acts as a stimulus for the eye to grow longer, causing it to become more myopic due to the fact that the eye wants to “catch up” to that peripheral image. With ortho-k, the central cornea is flattened to allow vison correction resulting in a slight steepening of the mid-peripheral cornea. This results in the peripheral light rays being refracted to land in front of the retina causing an area of myopic defocus as illustrated by the red lines in the diagram above.
Research has shown that while hyperopic defocus of the peripheral retina acts as a stimulus for progression of prescription, myopic defocus of the peripheral retina does the opposite. It acts to slow down or even halt progression since the eye no longer needs to “catch up” to that peripheral image.
Recently, a soft contact lens has come onto the market that optically mimics what ortho-k does as far as creating myopic defocus of the peripheral retina. It controls the progression of myopia in this same manner. Most children notice no difference in vision when wearing this lens as compared to a normal contact lens.
All three methods of myopia control have their advantages and disadvantages. There is no correct or incorrect choice, it just depends on what you feel would best fit your lifestyle and the lifestyle of your child. The important thing is, whichever choice you make, you are doing something to help stop their eyes from getting worse.
Despite mounting research to support its efficacy, all methods of myopia control are currently considered “off label”. For this reason, insurance companies do not cover the cost of the programs. Insurance allowances can be used towards the cost of materials for ortho-k and the NaturalVue lenses, but not toward the program fees.
There is a wealth of information available online. A quick google search of myopia control yields multiple results. One website we find particularly informative and well done is www.treehouseeyes.com. This is a practice which is completely dedicated to myopia control. Under the myopia resource tab, there are videos and links to research articles for your review and learning.
Certainly, we welcome you to email us directly with any specific questions.
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