Frequently Asked Questions: Amblyopia
What is amblyopia?
Amblyopia, or "lazy eye," is a common vision problem in children and is responsible for vision loss in more children than all other causes combined. Amblyopia is decreased vision of a child that results when one or both eyes send a blurry image to the brain. The brain does not learn to see clearly. Amblyopia may occur even when there is no observable structural abnormality of the eye. If amblyopia is not treated in a timely fashion, the vision loss may be permanent into adulthood.
What are the signs of amblyopia?
Amblyopia is present when a structurally normal eye doesn't see normally, even with the correct glasses. Because there are typically no outward signs of amblyopia, the only way to detect it is with an age-appropriate vision test. An assessment of the vision can be performed at any age by a pediatric ophthalmologist and by a pediatrician for children three years of age and older. For more information, visit the AAPOS Web site.
How is amblyopia detected?
A parent or primary care physician may notice either poor vision or strabismus. Primary care physicians routinely screen for amblyopia. Amblyopia is sometimes detected on pre-school vision screening.
What are the types of amblyopia?
The types and causes of amblyopia are: strabismic amblyopia, deprivation amblyopia, refractive amblyopia or a combination of the three. All forms of amblyopia result in reduced vision in the effected eye(s).
Are the signs for amblyopia similar to those of Strabismus?
Not necessarily. Strabismus can lead to amblyopia, but many cases of amblyopia do not have strabismus and are therefore not noticeable, even to the most observant parent. Strabismus is a condition in which the eyes do not stay straight in relation to each other and is a non-specific term for eye muscle imbalance. The eyes may be crossed in relation to each other (esotropia) or outward in relation to each other (exotropia). Less commonly, one eye may be elevated compared to the other (hypertropia). Children with strabismus may also have amblyopia, but most children with amblyopia do not have strabismus. Unlike strabismus, there are no outward signs of amblyopia.
What is strabismic amblyopia?
Strabismic amblyopia develops when the eyes are not aligned. When an eye turns in, out, up or down, the brain may "turn off" the eye that is not aligned and the vision subsequently decreases.
What is deprivation amblyopia?
Deprivation amblyopia develops when a cataract or similar condition "deprives" a child's eye of visual input. If not treated very early, vision loss may be severe and may affect both eyes.
What is refractive amblyopia?
Refractive amblyopia occurs when a child has a large or unequal amount of refractive error (need for glasses). Usually the brain "turns off" the eye that has the larger refractive error. Parents and primary care physicians may not notice a problem because the eyes are often aligned and the good eye vision is normal. Therefore, this kind of amblyopia may not be detected unless the vision is tested.
Will glasses help a child with refractive amblyopia see better?
Sometimes, but glasses alone may not correct the vision to 20/20. Glasses are prescribed initially and vision monitored until there is no further improvement. Any remaining amblyopia is then treated.
Can both eyes have amblyopia?
Yes. When there are equal amounts of high refractive error, both eyes may have poor vision (bilateral amblyopia) even when wearing glasses. Constant wear of glasses is very important, and vision is checked frequently. Vision typically improves but may take several years.
When and how is amblyopia treated?
Amblyopia is treated during childhood, and the earlier the age, the better the treatment result. Usually, by the age of 9-10 years the visual system is stable, and the vision does not improve much with treatment. However, vision improvement can occur at up to 17 years of age in some cases.
The underlying cause of the amblyopia is treated (correction of refractive error with glasses or contact lenses, removal of cataract, etc.) and then vision reassessed. If vision is still reduced, consideration is given to amblyopia treatment. The main forms of treatment are patches and drops. Occlusion treatment involves patching the better-seeing eye to stimulate vision in the poorer-seeing eye. The ophthalmologist prescribes the hours per day to patch based on the age of the child and the severity of vision deficit. Follow-up exams assess vision in the poorer-seeing eye for improvement and in the better-seeing eye to confirm no decrease in vision (occlusion amblyopia). In addition to an ophthalmologist, an orthoptist may be involved in the assessment and management of amblyopia. Orthoptists are allied health professionals that specialize in amblyopia and strabismus.
What kind of patch should be used?
The classic patch is an adhesive "Band-Aid®" type that is applied directly to the skin around the eye. These are available in different sizes for younger and older children. For children wearing glasses, a cloth patch slipped onto the glasses may be utilized. "Pirate" patches on elastic bands are not recommended due to easy removal by children.
What if a child refuses to wear the patch?
Many children resist wearing a patch at first. Successful patching requires persistence and much encouragement from family members, neighbors, teachers, etc. Children often throw a temper tantrum but eventually learn not to remove the patch. A reward to the child for successful patching can be helpful. Usually cooperation improves as the vision improves.
Reward calendars can encourage cooperation. The use of arm guards, which are gentle restraints, may help during the difficult phases of patching therapy. You can visit the Snuggle Wraps™ and Pedi-Wraps® web sites to order arm guards to assist you in keeping your child from removing the patch.
Is there an alternative to patching to treat amblyopia?
Sometimes the stronger eye can be "penalized" or the vision blurred to below the level of the poorer-seeing eye. This can be done by using an eye drop (atropine) in the better-seeing eye and possibly changing the glasses prescription. Ophthalmologists sometimes use this treatment for mild and moderate degrees of amblyopia. Penalizing eye drops work less well when the better-seeing eye is nearsighted.
How will atropine drops affect my child?
Atropine blurs close-up vision in the better-seeing eye. This encourages use of the poorer-seeing eye and improves vision in that eye over time. With atropine penalization, you will not have to fight constantly with your child to keep a patch over the better-seeing eye.
Do the drops hurt?
No. Unlike other types of eye drops, atropine drops usually do not sting.
How do I apply the drops?
With your child lying down and looking up to the ceiling, hold the eyelids apart and place the drop anywhere between the lids. If the child is frightened, try giving the drop before he or she wakes up. In some children it is necessary for one adult to hold the child while the other gives the drop. Eventually a routine will be established, and it will get easy to apply the drops. Remember to wash your hands before and after giving the eye drops.
What are the side effects?
Rarely, a child can develop fever, facial flushing or redness and swelling around the eye. If this occurs, stop using the drops and contact your ophthalmologist.
I gave a drop of atropine five days ago, and my child's pupil is still dilated. Is something wrong?
No. A single drop of atropine may dilate the pupil for up to one week. Although the pupil remains dilated, the blurring effect of the atropine wears off in one-to-three days.
Should my child wear sunglasses, since the pupil is always dilated by the atropine?
Outdoors on a sunny day, your child will be more comfortable wearing sunglasses. If your child already wears glasses, they can be coated with a clear ultraviolet filter, which will help.
How can my child function at school with the better eye blurred?
The atropine blurs the good eye for near work. This forces the child to use the poorer eye for reading. Allow the child to hold reading material close.
How long will I need to use the atropine?
Treatment may be continued for months or even years, depending on the age of the child and the severity of amblyopia.
My appointment is next week. Should I continue using the atropine drops?
Discontinue the atropine drops one full week before your appointment (or before any surgery) unless your doctor says otherwise.
I put atropine drops in my child's eye, but now my own pupil is dilated. What happened?
You most likely forgot to wash your hands after giving the eye drops. Be careful not to get the atropine in your own eye. You could have blurred vision and a dilated pupil for up to one week.
What are appropriate goals of amblyopia treatment?
In all cases, the goal is the best possible vision in each eye. While not every child can be improved to 20/20, most can obtain a substantial improvement in vision. Realistic goals depend on the age of the child and the level of vision when the amblyopia is diagnosed. Your ophthalmologist can give you an estimate of vision potential.
How long does amblyopia treatment last?
Vision usually improves within a few weeks, but optimal results may take several months and depend on the level of vision and age. Once vision has been maximized, maintenance treatment until 9-10 years of age may be required to keep the vision from regressing.
What happens if amblyopia treatment does not work?
In some cases, treatment for amblyopia may not succeed in substantially improving vision. It is a difficult decision to discontinue treatment, but sometimes that is best for both the child and family. Children who have significant amblyopia in one eye should utilize protective eyewear to protect the better-seeing eye from injury. As long as the better-seeing eye remains healthy, normal daily function is expected.
Can surgery be performed to treat amblyopia?
No.
Where can I learn more about amblyopia research?
More information about past and ongoing clinical studies regarding amblyopia can be found at the National Eye Institute web site.