Despite genetic tendendies, outdoor play may help children avoid glasses
Have you wondered if you can help your children avoid wearing glasses? Myopia is the most common reason for wearing glasses for activities that involve distance viewing; such as driving, watching TV, and going to the movies. Thirty percent of the population is afflicted with myopia, and old wives tales abound as to the causes, prevention, and the best treatments. Most recent studies dispel the myths and provide guidelines for myopia and the best course of action to set our kids on their way to seeing well throughout their lives.
Risk factors for myopia:
Myopia is, likely, caused by a combination of factors. Here are specific risk factors that have been associated with myopia.
• Family history – Six in ten children whose parents are myopic develop the condition. The chance of myopia increases if both parents have myopia.
• Asian ethnicity – A prevalence of myopia exists in urban settings, such as Hong Kong and Singapore. Because it is higher than rural communities, it suggests that there is also an environmental contribution to development of myopia.
• Near work – Recent studies of a theory that dates back a century has proven a correlation between near work and myopia. The Sydney Myopia Study showed that close reading distance (<30 cm) and continuous reading (> 30 minutes) increased the risk of myopia in school children.
• Not spending enough time outdoors –a recent study published in January 2009 issue of Optometry and Vision Science, found that in engaging in enough (at least 14 hours) of outdoor activity can help to counteract the heightened hereditary risk of having two myopic parents.
• Eye disease – such as diabetes and cataracts, for example, can be associated with myopia
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Treatment of myopia:
• Glasses – The most common method of correcting myopia is glasses. As soon as the disorder is diagnoses, the child needs to be placed in glasses.
• Contact lenses – Typically during teenage years, contact lenses are introduced. Most myopes do well with soft contact lenses. Occasionally, rigid gas permeable lenses are used. Exceptional care needs to be applied to make sure the lenses are kept clean and not worn overnight.
• Orthokeratology / Corneal Refractive Therapy (CRT) – Special contact lenses are worn overnight to reshape the cornea while a person is sleeping. The cornea retains its new shape temporarily during the day. Patients may be at risk for reduced corneal sensitivity and corneal infection that may result in scarring. The cornea can also become irregular to the point of preventing the patient from undergoing corneal refractive surgery or laser vision correction in the future.
• Laser vision correction (LASIK and PRK) – Laser vision correction is FDA approved for patients starting 18 years of age and older. Refraction needs to be stable for one year prior to undergoing laser vision correction. Stability is defined by a change of no more than 0.5 diopters (D) within a year.
• Phakic IOL's (ICL) – Implantable collamer lenses are ultra-thin layers of collagen shaped in a way to correct myopia and inserted behind the iris. ICL’s are typically used for patients with very high myopia or those who are not candidates for laser vision correction.
What can be done to prevent myopia?
• Increase outdoor activity – Higher levels of total time spent outdoors, not including sports, is associated with less myopia and a more hyperopic mean refraction, after adjusting for near work, parental myopia, and ethnicity. While 6 in 10 children with parental myopia develop the condition, when outdoor activity tops 14 hours a week, this risk drops down to just 2 in 10. California-based Orinda study supports this finding and so do the studies from Ohio State University College of Optometry and Singapore study in children of Chinese, Malay, and Indian ethnicity.
• Keep near objects more than 30 cm away from your eyes
• Take frequent breaks from near work – Walk away from your desk at least every 30 minutes to allow your eyes a chance to focus on ojbects at a distance.
Do’s and don’ts of myopia detection, prevention, and treatment:
• Do make sure to have your child’s vision tested every year.
• Do have each eye tested separately. It is possible to see small letters on a vision chart with both eyes open and have only one eye seeing well. The other eye can be nearsighted, farsighted, or astigmatic. If the vision is not corrected in that eye while the child is young, the eye may not develop neurologically, resulting in a condition called amblyopia, or “lazy eye.” Once amblyopia develops, the eye can never see well, even if it is later corrected with glasses or contact lenses. Poor depth perception may result. Strabismus, or “cross eyes” may develop as well.
• Do have your child hold their near work more than 30 cm away from their eyes.
• Do encourage frequent breaks from near work – every 30 minutes, look up and into the distance.
• Do make sure that your child spends at least 14 hours a week outdoors.
• Do consider vision correction surgery starting at 18 years of age, especially, when contact lenses are worn too much, hygiene is poor, or there is already evidence of contact lens-related corneal problems, such as scarring, blood vessels, and inflammation.
• Don’t worry that wearing glasses or contacts will accelerate progression of myopia in your child. Studies show that it will not. Myopia either will progress or it won’t, regardless if they wear glasses or contacts. The good news is that prescription stabilizes in many youngsters even by 18 years of age.
Pacific Vision Institute www.pacificvision.org
American Academy of Ophthalmology www.aao.org
American Society of Cataract and Refractive Surgery www.ascrs.org
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