Amblyopia

Answer 1

Definition

Amblyopia, or "lazy eye," is the loss of one eye's ability to see details. It is the most common cause of vision problems in children.

Alternative Names

Lazy eye

Causes, incidence, and risk factors

Amblyopia occurs when the brain and eyes do not work together properly. In persons with amblyopia, the brain favors one eye.

The preferred eye has normal vision, but because the brain ignores the other eye, a person's vision ability does not develop normally. Between ages 5 and 10, the brain stops growing and the condition becomes permanent.

Strabismus is the most common cause of amblyopia, and there is often a family history of this condition.

Other causes include:

• Astigmatism in both eyes
• Childhood cataracts
• Farsightedness
• Nearsightedness

Symptoms

• Eyes that turn in or out
• Eyes that do not appear to work together
• Inability to judge depth correctly

Signs and tests

Amblyopia is usually easily diagnosed with a complete examination of the eyes. Special tests are usually not required.

Treatment

The main treatment involves patching the normal eye to force use of the lazy eye. Sometimes, drops are used to blur the vision of the normal eye instead of putting a patch on it.

The underlying condition will also require treatment. If the lazy eye is due to a vision problem (nearsightedness or farsightedness), glasses or contact lenses will be prescribed.

For treatment of crossed eyes, see: Strabismus

Children whose vision cannot be expected to fully recover should wear glasses with protective lenses of polycarbonate, as should all children with only one good eye caused by any disorder. Polycarbonate glasses are shatter- and scratch-resistant.

Expectations (prognosis)

Children who receive treatment before age 5 usually have a near complete recovery of normal vision.

Delaying treatment can result in permanent vision problems. After age 10, only a partial recovery of vision can be expected.

Complications

• Eye muscle problems that may require several surgeries, which can have complications
• Permanent vision loss in the affected eye

Calling your health care provider

Call for an appointment with your health care provider or ophthalmologist if a vision problem is suspected in a young child.

Prevention

Early recognition and treatment of the problem in children can help to prevent permanent visual loss. All children should have a complete eye examination at least once between ages 3 and 5.

References

Olitsky SE, Hug D, Smith LP. Disorders of the uveal tract. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 628.

Doshi NR. Amblyopia. Am Fam Physician. 2007;75(3):361.

Answer 2

Definition

Amblyopia, or "lazy eye," is the loss of one eye's ability to see details. It is the most common cause of vision problems in children.

Alternative Names

Lazy eye

Causes, incidence, and risk factors

Amblyopia occurs when the nerve pathway from one eye to the brain does not develop during childhood. This occurs because the abnormal eye sends a blurred image or the wrong image to the brain.

This confuses the brain, and the brain may learn to ignore the image from the weaker eye.

Strabismus is the most common cause of amblyopia. There is often a family history of this condition.

The term "lazy eye" refers to amblyopia, which often occurs along with strabismus. However, amblyopia can occur without strabismus and people can have strabismus without amblyopia.

Other causes include:

• Childhood cataracts
• Farsightedness, nearsightedness, or astigmatism, especially if it is greater in one eye

Symptoms

• Eyes that turn in or out
• Eyes that do not appear to work together
• Inability to judge depth correctly
• Poor vision in one eye

Signs and tests

Amblyopia is usually easily diagnosed with a complete examination of the eyes. Special tests are usually not needed.

Treatment

First, any eye condition that is causing poor vision in the amblyopic eye (such as cataracts) needs to be corrected.

Children with a refractive error (nearsightedness, farsightedness, or astigmatism) will need glasses.

Next, a patch is placed on the normal eye. This forces the brain to recognize the image from the eye with amblyopia. Sometimes, drops are used to blur the vision of the normal eye instead of putting a patch on it.

For treatment of crossed eyes, see: Strabismus

Children whose vision will not fully recover, and those with only good eye due to any disorder should wear glasses with protective polycarbonate lenses. Polycarbonate glasses are shatter- and scratch-resistant.

Expectations (prognosis)

Children who get treated before age 5 will usually recover almost completely normal vision, although they may continue to have problems with depth percention.

Delaying treatment can result in permanent vision problems. After age 10, only a partial recovery of vision can be expected.

Complications

• Eye muscle problems that may require several surgeries, which can have complications
• Permanent vision loss in the affected eye

Calling your health care provider

Call for an appointment with your health care provider or ophthalmologist if you suspect a vision problem in a young child.

Prevention

Early recognition and treatment of the problem in children can help to prevent permanent visual loss. All children should have a complete eye examination at least once between ages 3 and 5.

Special techniques are needed to measure visual acuity in a child who is too young to speak. Most eye care professionals can perform these techniques.

References

Olitsky SE, Hug D, Smith LP. Disorders of vision. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 620.

Olitsky SE, Coats DK. Amblyopia and its management. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 15th ed. Philadelphia, Pa: Lippincott Williams & Wilkins. 2009:chap 10.

Reviewed By

Review Date: 08/12/2010

David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.