What is myopia?
People who have myopia (also known as nearsightedness) have difficulty seeing distant objects, but can see objects that are near clearly. For example, a person who is nearsighted may not be able to make out highway signs until they are just a few feet away.
Myopia affects a significant percentage of the population. It’s an eye focus disorder that is easily corrected with eyeglasses, contact lenses or surgery.
How common is myopia?
Myopia is very common. According to the American Optometric Association, more than 40% of Americans are myopic, a number that is rapidly rising, especially among school-aged children. Eye experts expect this trend to continue in the coming decades.
Today one in four parents has a child with some degree of nearsightedness. Some eye experts believe that if your child spends an extraordinary amount of time engaged in “near” activities, such as reading or using smartphones and computers, it may raise the risk of developing myopia.
Can myopia lead to blindness?
Usually, myopia is a minor nuisance that can be corrected with eyeglasses, contact lenses or surgery. But in rare cases, a progressive type called degenerative myopia develops that can be very serious and is a leading cause of legal blindness. Degenerative myopia affects only about 2% of the population. It is believed to be inherited and is more common in Jewish, Japanese, Chinese and Middle Eastern people.
What causes myopia?
If you have myopia, more than likely at least one or both of your parents did, too. Eye experts are still unsure of the exact cause of myopia, but believe it to be a mix of hereditary and environmental factors. It’s possible that you can inherit the ability to be myopic and then if your lifestyle produces just the right conditions, you’ll develop it. For example, if you use your eyes for a lot of close-up work, such as reading or working on a computer, you may develop myopia.
Myopia usually appears in childhood. Typically, the condition levels off, but it can worsen with age. Because the light coming into your eyes is not focused correctly, images appear to be unclear. Think of it a little like a misdirected spotlight. If you shine a spotlight on the wrong spot in the distance, you won’t be able to see the right object clearly.
What is refractive error?
When the shape of your eye doesn’t allow light to focus correctly on the retina, eye experts call this a refractive error. Your cornea and lens work together to bend light onto your retina, the light sensitive part of the eye, so that you can see clearly. If either your eyeball, cornea or your lens isn’t the right shape, light will bend away from or not focus directly on the retina as it normally would.
If you are nearsighted, your eyeball is too long from front to back, or your cornea is too curved or there are problems with the shape of your lens. Light coming into your eye focuses in front of the retina instead of on it, making faraway objects look fuzzy.
When an eye care provider develops your eyeglass prescription for nearsightedness, it will be a negative number, depending upon your degree of nearsightedness, such as -2.00. The higher the number, the stronger your lenses will be.
What are the symptoms of myopia?
If you are nearsighted, you may notice:
- Faraway objects look blurred or fuzzy.
- Close items appear clear.
- Eye strain.
- Tiredness when driving, playing sports or looking more than a few feet away.
Some additional symptoms of myopia to watch for in your children include:
- Poor school grades.
- Shortened attention span.
- Holding objects close to the face.
Most cases of myopia are mild and easily controlled with eyeglasses, contact lenses or refractive surgery. However, in rare cases more severe disorders develop.
High myopia: A rare inherited type of high-degree nearsightedness is called high myopia. It happens when your child’s eyeballs grow longer than they should or the cornea is too steep. High myopia is usually defined as myopia with a refractive error greater than -6. It can progressively worsen to higher powers of myopia. High myopia usually stops getting worse between the ages of 20 and 30. It can be corrected with eyeglasses or contact lenses, and in some cases, refractive surgery, depending on severity. High myopia may raise your child’s risk of developing more serious sight conditions later in life, such as cataracts, detached retinas and glaucoma. Left untreated, high myopia complications can lead to blindness, so regular eye exams are critical.
Degenerative myopia: A fairly rare but serious form that usually begins in early childhood is degenerative myopia. This form is severe because it damages the retina and is a leading cause of legal blindness.
Does myopia get worse with age?
Yes, it can. Especially during growth spurts of the pre-teen and teen years, when the body grows quickly, myopia can get worse. At the age of 20, myopia usually levels off. It’s also possible for adults to be diagnosed with myopia. When this happens, it’s usually due to visual stress or a disease like diabetes or cataracts.
Visual stress can be caused by spending too much time doing up-close activities, such as reading or doing computer work. Eye experts believe that your focusing muscles may get stuck in “near gear” from overusing them this way.
If you are an adult experiencing sudden nearsightedness, floaters (sort of like spots floating through your field of vision), flashes of light or shadows, or sudden sight loss in one eye, contact an eye care provider immediately to rule out a more serious health condition.