What Is a Lazy Eye?
A lazy eye is when the vision of one of your eyes doesn’t develop the way it should. Doctors also call this amblyopia.
Signs of a Lazy Eye
Amblyopia starts in childhood, usually between ages 6 and 9. Identifying and treating it before age 7 brings the best chances of fully correcting the condition.
Common symptoms include:
- Trouble telling how near or far away something is (depth perception)
- Squinting or shutting one eye
- Head tilting
Lazy Eye Causes
Doctors don’t always know what’s behind some cases of amblyopia. Causes may include:
- Refractive errors. One eye might have much better focus than the other. The other eye could be nearsighted or farsighted. Or it could have astigmatism (distorted or blurry vision). When your brain gets both a blurry image and a clear one, it starts to ignore the blurry one. If this goes on for months or years, vision in the blurry eye will get worse.
- Strabismus. This is when your eyes don’t line up the way they should. One could turn in or out. People who have strabismus can’t focus their eyes together on an image, so they often see double. Your brain will ignore the image from the eye that isn’t aligned.
- Cataracts. A cloudy lens inside your eye can make things look blurry. The vision in that eye might not develop the way it should.
- Droopy eyelid (ptosis). A sagging eyelid can block your vision.
Lazy Eye Risk Factors
A child might be more likely to have a lazy eye if they:
- Were born early (premature)
- Were smaller than average at birth
- Have a family history of amblyopia or other eye conditions
- Have developmental disabilities
Lazy Eye Diagnosis
All children should have vision tests before they are school-age. Your child's doctor or the vision program at school will check to make sure that:
- Nothing blocks the light coming into their eyes
- Both eyes see equally well
- Each eye moves the way it should
If there's any problem, the doctor or school nurse may suggest that you take your child to an eye specialist. If you feel like something is wrong with your child's vision -- even if nothing shows up at the vision check -- make an appointment with a pediatric eye doctor.
Some eye care experts say kids should get an eye exam at 6 months old, 3 years old, and then every year while they’re in school. Ask your doctor what’s right for your child.
Eye doctors test babies and young children by watching how well their eyes follow a moving object. They may also cover one eye at a time and check the child’s reaction.
In older kids, the doctor will cover one eye and use pictures and letters to check their vision.
Lazy Eye Treatment
It’s important to start treatment for amblyopia as soon as possible. Depending on the cause, it might involve:
- Correcting any underlying vision problems such as nearsightedness, farsightedness, or astigmatism. Most kids with amblyopia also need glasses to help their eyes focus.
- Surgery, if a cataract is blocking light from their eye or if strabismus keeps their eyes from moving together the way they should
- Wearing a patch over the strong eye to force their brain to use the weak one. At first, your child will have a hard time seeing. Their vision will get better, though it might take weeks or months. After that, they won’t have to wear the patch all the time. But sometimes, when kids go back to using both eyes, they lose some vision in the weak eye. If that happens, they might have to wear the patch again.
- Eye drops with a medication called atropine, which blurs the strong eye so your child won’t need to wear a patch. This also forces their brain to use the weak eye.
- A Bangerter filter worn over the eyeglass lens of the stronger eye to blur their vision so they have to use the weak eye
Lazy Eye in Older Children and Adults
Some teenagers and adults with lazy eye have successful treatment. But it may not work as well after a child’s vision has fully developed, around age 7 to 9. If one eye remains blurry and they lose vision in their stronger eye later in life, they could have lifelong problems.
Lazy Eye Complications
If treatment starts too late, the vision loss of amblyopia might be permanent because links in the body’s visual system don’t form the way they should.
Lazy Eye Outlook
With early diagnosis and treatment, most children will regain almost all their vision. Make sure your child gets eye exams early on. Follow your doctor's advice about treatment, even when it’s hard to make your child do things like wear a patch every day.