Nearsightedness Rates Are on the Rise
Myopia rates in the U.S. are higher than ever and are continuing to increase. In fact, more than 40 percent of Americans are now nearsighted, according to the American Optometric Association's (AOA) 2018 American Eye-Q survey.
What Happens When You Have Myopia
Myopia makes it difficult to see objects in the distance clearly. Light rays must be focused directly on your retina for clear close and far vision. If you're nearsighted, the rays are focused in front of the retina, the light-sensing layer of cells at the back of the eye. The opposite happens if you're farsighted (hyperopic). Rays focus beyond the retina, which makes near objects look blurry.
Nearsightedness may be caused by eyeballs that are too long or corneas that curve more than normal. The clear cornea covers your iris and pupil and helps control the way light enters your eyes.
These Factors Play a Role in Myopia Rates
You or your children may be more likely to become more nearsighted if:
- Other People in Your Family Are Myopic. You're risk of myopia increases if one or both of your parents are nearsighted.
- You Spend a Lot of Time Reading or Using a Digital Device. The amount of time you spend viewing near objects and images can also increase the likelihood that you'll develop myopia. In fact, society's reliance on digital devices could be part of the reason that myopia rates are increasing. The rates have risen 25 percent during the past 40 years, according to the AOA.
- You Don't Get Enough Sun. Lack of sun exposure may be a factor in the development of myopia in children. Children who spend more than two hours a day outside have a lower risk of becoming nearsighted. Exposure to light may increase the release of dopamine in the retina, according to the National Eye Institute. Dopamine, a natural chemical that transports messages between brain cells, affects eye growth.
- You Have a Problem with Binocular Vision. Good binocular vision requires both of your eyes to work together as a team. Problems with eye teaming may increase stress, causing the eyeball to become longer.
Ways to Reduce the Risk
As myopia rates increase, more people are likely to develop high myopia, which occurs when your vision without glasses or contacts is 20/400 or worse. High myopia increases your risk of cataracts, glaucoma, retinal detachment, and macular degeneration. Although your likelihood of developing these eye diseases and conditions naturally increases with age, you may experience these problems at a younger age if you have high myopia.
Fortunately, these steps may prevent nearsightedness or keep it from worsening:
- Limit Screen Time. Decreasing the amount of time children and teenagers spend watching TV, playing video games, and surfing the Internet may lower the myopia risk. Limiting screen time may also prevent worsening myopia in adults. The World Health Organization recommends no screen time from birth to age 2 and no more than two hours of screen time daily for older children.
- Take Frequent Breaks. Restricting screen time to two hours may not be realistic for adults and teenagers who use computers and digital devices for work and school. Taking a 20-minute break after an hour or two of screen time and frequently looking at objects in the distance can reduce eyestrain.
- Encourage Your Children to Play Outside. Increasing the amount of time your children spend outdoors is a simple way to lower their myopia risk.
- Schedule Regular Comprehensive Eye Examinations. Both children and adults benefit from yearly eye exams. School vision screenings may not be accurate enough to determine if your child has a vision problem.
- See a Vision Therapist. Your vision therapist can treat problems with eye teaming and other issues that may cause or contribute to myopia. Therapy may involve the use of special lenses, prisms, activities, and games designed to improve and maximize your vision.
Sources:
World Health Organization: The Importance of Myopia and High Myopia, March 2015
National Eye Institute: Myopia: A Close Look at Efforts to Turn Back a Growing Problem, 10/2/17
JAMA: Effect of Time Spent Outdoors at School on the Development of Myopia, 9/15/15