Amblyopia is a condition that occurs when there is a reduction of vision in one eye. Amblyopia, which is often called “lazy eye,” is most common in infants and children, but it can also occur in adults. Amblyopia is not contagious.
There are two common types of amblyopia:
- Anisometropic amblyopia occurs when the vision in one eye differs from the other. For example, one eye is very nearsighted (myopic), a visual defect where distant objects appear blurred; and the other eye is very farsighted (hyperopic), an abnormal visual condition where vision is better (more focused or clearer) for objects that are farther away than for objects that are close. In general, people who have anisometropic amblyopia are often asymptomatic (showing no signs of the condition).
- Strabismic amblyopia occurs when there is a visible misalignment (crossing) of one eye.
If you suspect that you or your child has this condition, contact your doctor. The sooner amblyopia is treated, the more favorable the outcome.
Amblyopia is caused when the brain prefers (favors) one eye to the other. The brain’s preference (liking) for one eye over the other can weaken and reduce vision in the eye that is less used.
There are no apparent genetic or environmental factors that can be attributed to causing amblyopia.
A risk factor is something that increases your chance of getting a disease or condition.
The following factors increase your chances of developing amblyopia. If you have any of these risk factors, tell your doctor:
- Age: children six years old or younger and adults under the age of 40
- Heredity: A family history of eye disorders or diseases, such as cataracts, excessive nearsightedness, or farsightedness
- A history of corneal scarring
The symptoms for amblyopia vary from person to person. Some people might be asymptomatic (showing no signs of the condition) while others are symptomatic (showing signs of the condition). If you experience any of these symptoms do not assume it is due to amblyopia. These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your physician.
- Double vision (seeing multiple images when both eyes are focused on only one image)
- A droopy (the inability to fully-open) eyelid that blocks the pupil
- Dizzy spells
- Blurred (objects appear fuzzy) or distorted (objects appear twisted or out of focus) vision
- Excessive squinting or closing of the eyes
- A misalignment (crossing) of one eye, generally the eye that is less used will excessively turn toward the nose
Your doctor will ask about your symptoms and medical history, and perform a physical exam. You may also be referred to an ophthalmologist, a doctor who specializes in the medical and surgical treatment of eye disorders and vision measurement. Since amblyopia tends to occur in young children, the types of tests an ophthalmologist will perform will be determined by the patient’s age and their ability to respond to the ophthalmologist. Tests may include the following:
- Visual acuity assessment testing (VAT), such as the Lea Symbols test that is used to assess distant vision.
- Cycloplegic refraction test, which is performed to determine how the eyeball displays and receives images produced by the lens of the eye. To perform the test, eye drops are used to dilate (widen the pupil) for a better view of the eye. To determine the direction of light the eye receives and displays, the dilating drops briefly paralyze (impair movement or make inactive) the eye muscles that control focusing.
Talk with your doctor about the best treatment plan for you. Treatment options include the following:
Atropine drops or ointment is placed in the non-amblyopic eye (the eye that is favored by the brain or the sound eye). This causes the sound eye to become unfocused and forces the patient to use the lazy eye.
Corrective lenses, such as glasses, are prescribed to offset the eye’s visual abnormalities or defects, such as excessive nearsightedness or farsightedness.
Occlusive Therapy (Patching)
A patch is placed over the non-amblyopic eye (the sound eye), which forces the patient to use the lazy eye.
To reduce the chances of amblyopia going undetected (unidentified), children under the age of six should have a comprehensive eye exam by their third birthday. There are no known preventive measures that will reduce your chances of getting amblyopia. However, routinely getting a comprehensive vision exam, early detection, and an immediate treatment plan for amblyopia will lead to more favorable outcomes.