Diagnosis of Lazy Eye (Amblyopia)
A diagnosis of amblyopia is made with a complete eye examination including a physical exam of the eye, a medical history, and a vision test. An optometrist or an ophthalmologist can perform the examination.
A basic eye exam usually begins with a medical history and questions about the patient's health and past and current eye problems. The parent of an infant or young child answers these questions. School-aged children may be able to specify if they have problems seeing out of one eye, or if they have problems reading or seeing the blackboard.
Eye movement is tested by moving a light or object through the patient's field of vision and assessing the eye's ability to follow it. This allows the doctor to determine if the eye muscles are working properly. Tests that access binocular visionhow the eyes work togetherare also done. In strabismus, the stronger eye may do all the looking, or the weaker eye may align itself intermittently.
If the patient is old enough, a vision test involving reading letters from an eye chart may also be utilized. This helps determine if either eye has a refractive error (e.g., nearsightedness). If the patient is not old enough to know letters, other objective methods are used to determine the refractive error.
Other tests may be performed if disease is the suspected cause. These tests depend on the results of the initial exam, symptoms, and the appearance of the eye.
Treatment for Lazy Eye (Amblyopia)
Treatment depends on the underlying cause and how early the condition is diagnosed. It was previously believed that only young children could benefit from treatment, because the brain's vision system is completely developed by age 8 to 10. Detection and correction before the age of 2 offers the best chance for normal vision.
However, current research has concluded that effective treatment can take place at any age. The longer the condition goes uncorrected, the longer the length of treatment required. Treatment can be as simple as a pair of eyeglasses or as complex as surgery.
Surgery is used to treat amblyopia caused by strabismus, cataracts, and other blockages on the cornea. For strabismus, surgery is performed on the eye muscle to force the eyes into alignment. Sometimes surgical results are cosmetic; the eyes look straighter, but they are still not aligned and require further treatment. Early surgery is often recommended, so that infants can develop normal sight as their eyes mature.
Eyeglasses are used to correct the visual imbalance if amblyopia is caused by a refractive error. Glasses or bifocals are also sometimes used to straighten strabismic eyes.
Vision therapy uses exercises to help both eyes work together. It also trains the brain to use the amblyopic eye, improving its vision. Vision therapy can be used alone, before or after surgery, and with eyeglasses.
Patching involves covering the good eye and forcing use of the amblyopic eye. The weaker eye becomes stronger with use. The problem with eye patches is that some children do not like wearing them. A patch can be worn all day or for a few hours a day, depending on the child's age and vision. It is used until the eye has strengthened and vision has normalized or until improvement plateaus.
Preventing Lazy Eye
Amblyopia is caused by another eye condition, so diagnosing and treating visual problems as early as possible can prevent its onset. An initial eye examination is recommended at age 3 to 6 months and then periodically. An eye problem detected in infancy, such as strabismus, can be corrected before it causes amblyopia.