Who Develops Myopia (Nearsightedness)?
Myopia, or nearsightedness, is a common condition affecting almost 30 percent of Americans. Both children and adults can be nearsighted, but myopia is normally first diagnosed in school-aged children. Nearsightedness tends to advance in the teens, as the eye continues to grow during this time. The condition levels off and generally stabilizes in adulthood.
Causes of Myopia
Nearsightedness happens when your eye is longer than normal, or, less often, when your cornea is too curved. Objects focus in front of the retina instead of on the retina, causing it to be blurred. The exact cause of myopia is not known.
Research about myopia supports two key risk factors:
- Family history. If one or both parents are nearsighted, the chance of their children developing it increases.
- Working up close. Long hours of near work such as reading or computer work may be at increased risk for developing myopia.
Temporary nearsightedness can also occur due to visual stress and disease:
- “Night” Myopia: Some people experience blurred distance vision only at night. When it’s dark, the eye may simply not be receiving enough light to focus, or too much light from the sides may be entering the naturally dilated eye, making it hard to focus.
- “False” Myopia: Some people cannot focus far after long periods of near vision tasks. Usually the focusing ability of the eye will return after some rest.
- Myopia symptoms could also be a sign of variations in blood sugar levels in people with diabetes or an early indication of a cataract.
Your eye care professional can evaluate your eyes to determine the reason and severity of your myopia.
What Is High Myopia?
The National Eye Institute defines High Myopia as “a severe form of myopia in which the eyeball continues to grow and becomes very long from front to back. It can increase the risk for retinal detachment, early development of cataracts and glaucoma.“
An eye care professional can diagnose myopia after a comprehensive eye exam. A standard vision test will be used, where the person is asked to read letters on a chart placed at the other end of the room.
If the standard vision test determines nearsightedness, the eye care professional will use various devices to learn about the state of the eye, what is causing the myopia, and the best way to correct it:
- A retinoscope shines a special light into the eyes to see how light reflects off the retina. As the light is reflected back from inside the eye, it can indicate whether a person is nearsighted or farsighted.
- A phoropter measures the amount of refractive error you have to determine the proper prescription for corrective eyewear and contact lenses.
- An ophthalmoscope is used during a retinal exam. Eye drops are often given to enlarge (dilate) the pupils so the eye care professional can have a better view of the back of the eye.
Treatment Options for Myopia
There are many ways to treat myopia including glasses, contacts, and LASIK, or other kinds of refractive surgeries. Ask your eye doctor which option may work best for you.