Amblyopia, commonly called lazy eye, is a condition in children when vision does not develop properly, usually in one eye. If it’s left untreated, a child’s vision will never develop correctly in the affected eye. Vision impairment becomes permanent, because as the child’s brain matures, it will “ignore” the image coming from the poorly seeing eye. That’s why it’s essential to have a child with amblyopia regularly tested by an eye doctor.
What Causes Amblyopia?
Amblyopia usually starts when one eye has much better focus than the other eye. For example, one eye might be very farsighted or have a lot of astigmatism, while the other does not. When a child’s brain is confronted with both a blurry image and a clear one, it begins to ignore the blurry image. If this goes on for months or years in a young child, the vision in the eye that sees the blurry image will deteriorate.
Another cause of amblyopia is strabismus, which is an ocular misalignment, meaning that one eye turns inward or outward. This prevents the eyes from focusing together on an image and may cause double vision. To combat this, the child’s brain generally chooses to ignore the image from the deviated eye, causing the vision in that eye to deteriorate. It’s this misalignment of the eyes that leads some people to call amblyopia “lazy eye.”
In other cases, a child cannot see well in one eye because something blocks light from getting through, such as a cataract or a small amount of blood or other material in the back of the eye.
How Is Amblyopia Diagnosed?
All children should be screened before they are school-age. Your child’s doctor or the vision program at school will check three aspects of your child’s eye health:
- Your child’s eyes let light all the way through.
- Both eyes see equally well.
- The eyes move normally.
If there’s a problem in any area, the doctor or school nurse may recommend a visit to an eye specialist. If you feel that something could be wrong with your child’s vision, call your doctor even if your child has been screened at school.
Some eye care experts recommend an exam by an eye doctor at 6 months, 3 years, and then every two years in the school years. Ask your doctor or eye doctor which is right for your child.
A family history of amblyopia is a risk factor for the condition. Parents cannot tell just by looking at their child if they have amblyopia. Early diagnosis and treatment are the keys to the best visual outcome.
How Is Amblyopia Treated?
The most common treatment for amblyopia is to force the brain to start using the “bad” eye. This is done by first correcting any underlying problems in that eye and then by putting a patch over the “good” eye. At first, the child will have a hard time seeing with just the weaker eye. However, it is very important that your child wear the patch diligently because this will eventually improve vision. It can take weeks or months for an eye patch to improve vision. Follow your doctor’s instructions carefully and follow the schedule to bring your child to the eye doctor to be monitored closely during treatment.
As the child keeps using only the eye with amblyopia, his or her vision will continue to improve. After the doctor determines that vision is back to normal, your child will not have to wear the patch on a full-time basis. Some children may again lose some vision and need to undergo another round of wearing a patch. In cases of mild amblyopia, the doctor might recommend using an eye drop called atropine in the “good” eye instead of a patch. Atropine dilates the pupil and blurs the vision in the “good” eye, forcing the “bad” eye to do most of the work while the child is playing with toys, eating, drawing, or reading.
Most children with amblyopia will also need glasses to help focus. If there is something such as a cataract blocking light from getting into the eye, the doctor may recommend surgery to remove the blockage. If strabismus is preventing the eyes from moving together correctly, your doctor might recommend surgery on the muscles of the eye. Your doctor will discuss with you what treatment is most appropriate for your child.
What Is the Outlook for Children With Amblyopia?
If existing underlying problems are treated and the amblyopia is detected and treated early, most children will gain vision. Amblyopia becomes much more difficult to treat after about 7-9 years of age, so stick to the recommendations about early childhood exams.
Follow your doctor’s advice about treatment even when it’s difficult — many children do not want to wear an eye patch every day. With the use of atropine as an alternative method of treatment, success is now possible in a larger proportion of children with amblyopia.