Myopia Is An Epidemic
When we think of an epidemic, we think of a disease that can be transmitted from insects to humans (Zika virus), animals to humans (mad cow disease), or humans to humans (AIDS). There is another type of epidemic that is caused by the environment and changes in human behavior, namely myopia or nearsightedness. Much of what we know about the contagion of myopia comes from studies of school children in East Asia. In China, as many as 80% to 90% of school graduates are myopic, a fact which has stimulated a lot of interest in determining what can be done to stem the myopia tide. A similar interest in the U.S. is brewing due to the increases in rates of myopia development here.
Population-based studies have shown significantly greater prevalence of myopia across the generations. In China, one study demonstrated that 78.4% of 15-year-old students were myopic compared to only 19.8% of their parents when they were 15. An American survey completed by the National Health and Nutrition compared myopia development over 30 years to have increased from 25% to only 41.6%. Similar changes have been seen across other cultures worldwide.
Problems with Progressive Myopia
So, what’s the big deal about the increase in myopia across the world. Can’t these blurry-eyed patients just toughen up and wear glasses, get contacts, or be LASERed?
The answer, of course, is yes, but there is a cost to be paid. Dependence on glasses and contacts over the years can be substantial. The attendant risks of non-reversible LASIK and the cost are significant. Myopia is known to be accompanied by medical issues like the development of retinal detachments and degenerations, macular holes, and glaucoma. Asian populations get the worst of these co-morbidities…and they know it.
Why is this happening? Well, it used to be thought that you were a product of your parent’s genes, and whatever cards were dealt your way was the way it was going to be. It turns out that the classic “nature vs nurture” question exists in myopia development. Studies show a large environmental component exists that is related to cultural and social changes regarding our use of personal electronics (phones, tablets, gaming, computers). The closer working distances we use for sustained near work on our personal devices is taking its toll. Kids are not spending as much time playing outdoors in the daytime, thereby getting natural sunlight and relaxing the focusing muscles when looking at the horizon. Virtual activities and gaming have replaced personal interaction and physical activity for youth.
The Good News
What can be done to reduce myopia development? Many studies show that prescribing glasses or contacts to relax accommodation (focusing ability) may help some. Other studies show that low doses of focus-reducing ophthalmic drugs can be helpful used off-label to prevent over-focusing, but the dosages have not been standardized and the results vary.
Animal studies at the University of Houston have gotten us closer to why myopia is actually developing. In primate studies, it has been shown the blur, also known as defocus, in the mid-peripheral retina is the cause of retinal elongation that produces nearsightedness. Light that enters the eye centrally can be clear or blurry and have no influence on myopia progression. Mid-peripheral retina blur induced in animals is reversible if the stimulus to blur is removed. In other words, animal myopia goes away when the stimulus to blur is gone. Myopia in humans, however, does not reverse in the same way—we just have to prevent the mid-periphery from becoming blurry in the first place.
Overnight Corneal Reshaping (OCR)
A procedure called overnight corneal reshaping (also called orthokeratology, ortho-k, gentle molding, or CRT for corneal refractive therapy, and others) actually produces the clarification of the vision in the retinal mid-periphery. Special lenses are prescribed to gently and very-accurately reshape the central corneal shape to sub-micron level accuracy based on corneal topography-guided contact lens manufacturing techniques. While that is a mouthful, it means that any conceivable geometry of the contact lens can be custom-made to the doctor’s special design characteristics. These lenses are made to be worn overnight while sleeping due to the ability of current gas permeable materials that permit enough oxygen to the cornea unlike old “hard” lenses made from polymethyl methacrylate (PMMA). Simply, you wear lenses overnight, remove them in the morning, and see well all day long without the reliance on daytime glasses or contacts. This may seem to be too good to be true, but it really works well for appropriate candidates. With the mid-peripheral retinal clarity, axial elongation of the eye is slowed or ceased.
Overnight reshaping offers a lot of freedom to its wearers during activities like swimming and is safer in contact sports than dress glasses ordinary contact lenses. Doctors who practice OCR need special training and credentials to fit and manage patients with these lenses. Look for doctors who are Fellows in the American Academy of Orthokeratology and Myopia Control. Additionally, specialized equipment is required to measure and map the cornea for precise monitoring of the procedure.
Act Now to Beat Myopia Progression
In summary, while myopia progression is on the rise worldwide, there are things that can be done proactively. Eye drop drugs prescribed for reducing the focusing ability, as well as the implementation of overnight corneal reshaping to keep the mid-retinal periphery clear, will slow or eliminate the myopic creep over the years. It is also recommended to limit near vision activities on electronic devices and spend an hour or two a day outside to help children not get more myopic.
Contact Dr. Raymond Brill, a charter member and Fellow of the Orthokeratology Academy of America and Myopia Control, for a free 15-minute personal consultation to see if you or a family member is a candidate for OCR.