Nearsightedness Has Become More Common
Myopia (nearsightedness) may have been more common in Americans than it was 30 years ago, according to a new study in the December issue of Archives of Ophthalmology.
Susan Vitale, PhD MHS and colleagues at the National Eye Institute compared U.S. population prevalence estimates for myopia in over 4,400 participants in the 1971-1972 National Health and Nutrition Examination Survey (NHANES) to over 8,000 participants in the 1999 to 2004 surveys. The prevalence for those aged 12 to 54 was significantly higher in recent years than in the 1970’s.
From the earlier NHANES data, 25% were diagnosed with myopia, a common condition in which the image of an object seen in the distance is out of focus. Most recently, 41.6% of those participating in the surveys have been diagnosed with nearsightedness – an increase of 17%.
Nearsightedness is more common in white Americans than in blacks, but the overall increase in prevalence has occurred in both races. No other ethnic group was included in the data. Gender differences were not noted.
Myopia occurs if the eyeball is too long or if the cornea has too much curvature. The condition typically begins in childhood and continues to worsen until early adulthood.
Heredity is a factor in the development of myopia, but environmental factors contribute as well. Researchers think one of the reasons for the decline in vision is related to more time spend doing close-up work, such as computer and telephone texting, which would cause the eyeball to grow longer. Americans are also decreasing time spent outdoors, in which they are more likely to focus on objects at a distance, relaxing the eye.
The blurred vision of myopia can be treated with corrective lenses, such as eyeglasses or contact lenses, or surgeries such as LASIK. Myopia can increase the risk of other eye diseases, such as glaucoma, retinal detachment and blindness due to the thinning of the retina.
Prevent Blindness America recommends the following tips to reducing computer eye strain:
1. Position the computer screen slightly lower than eye level at about 60 centimeters from the eye.
2. Use a non-glare filter to reduce glare and reflections, which will help the eye relax.
3. Alternate computer work with other tasks that do not require as much close-up work
4. Take breaks often to relax the eyes. Go for a walk, or look at objects that are outside the window