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Free Laser Vision Screening
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Amblyopia is poor vision in an otherwise healthy eye that did not develop normal sight during early childhood. It is often called a "lazy eye." When one normal eye develops good vision while the other normal eye does not, the eye with poorer vision is called amblyopic. Usually, only one eye is amblyopic. The condition is common, affecting approximately 2-3% of people. The only time to correct amblyopia is during infancy or early childhood (before the age of about 10 years old). How does normal vision develop?Under normal circumstances, the brain "learns to see" and interpret what the eyes present as a child grows. If a child cannot use his or her eyes normally, the brain does not "learn to see" properly and vision may be decreased. If this abnormality is not corrected before the first nine or ten years of life, the inability of the visual system to properly use the eye is permanant, and usually cannot be changed. The development of equal vision in both eyes is necessary for the brain's ability to interpret what the eyes see. Many occupations are not open to people who have good vision in one eye only. Additionally, if the vision in one eye should be lost later in life from an accident or illness, it is essential that the other eye have normal vision. Without good vision in at least one eye, a person is visually impaired. For all of these reasons, amblyopia must be detected and treated as early in a child's life as possible. When should vision be tested?All children should have their vision checked by their pediatrician, family physician or ophthalmologist (eye M.D.) at or before their fourth birthday. Most physicians test vision as part of a child's medical examination. They may send a child to an ophthalmologist if there is any sign of an abnormal eye condition. New techniques make it possible to test vision in infants and young children. If there is a family history of misaligned eyes, childhood cataracts or a serious eye disease, your ophthalmologist can check vision even earlier than age three. What causes amblyopia?Amblyopia is caused by any condition that affects normal use of the eyes and visual development. In many cases, the conditions associated with amblyopia is inherited. Children in a family with a history of amblyopia or misaligned eyes should be checked by an ophthalmologist as early in life as possible. Amblyopia has three major causes:Strabismus (crossed eyes)Amblyopia occurs most commonly with misaligned or crossed eyes. The child's brain turns the crossed eye off to avoid double vision and the child uses only the better eye. Unequal focus (refractive error)Refractive errors are eye conditions that are corrected by wearing glasses or contact lenses Amblyopia occurs when one eye is out of focus because it is more nearsighted, farsighted or astigmatic than the other. The brain turns the blurred eye off and becomes amblyopic. The eyes can look normal but one eye has poor vision. Childhood cataractAn eye disease such as a cataract (a clouding of the eye's naturally clear lens) often leads to amblyopia. Any factor that prevents a clear image from being focused inside the eye can lead to the development of amblyopia in a child. This is often the most severe form of amblyopia. How is amblyopia diagnosed? It is not easy to recognize amblyopia. A child will not complain of having one strong eye and one weak eye. Unless the child has a misaligned eye, an obvious cataract, or other obvious abnormality, there is no way for parents to tell that something is wrong. Amblyopia is detected by finding a difference in vision between the child's two eyes. Since it is difficult to measure vision in young children, your ophthalmologist estimates visual acuity by watching how well a baby follows objects with one eye when the other eye is covered. Using a variety of tests, the ophthalmologist observes the reactions of the baby when one eye is occluded. If one eye is amblyopic and the good eye is covered, the baby will attempt to look around the patch, try to pull it off or get upset. Poor vision in one eye does not always mean that a child has permanant amblyopia. Vision can often be improved by prescribing glasses for a child. Your ophthalmologist will also carefully examine the interior of the eye to see if other eye diseases may be causing decreased vision. These diseases include:
How is amblyopia treated?To correct amblyopia, a child's brain must be forced to use the weak eye. This is usually done by occluding or covering the strong eye, often for weeks or months. Even after vision has been restored in the weak eye, part-time occlusion may be required over a period of years to maintain the improvement. Glasses are prescribed to correct errors in focusing. If glasses alone do not improve vision, then patching is necessary. Occasionally, amblyopia is treated by blurring the vision in the good eye with special eye medicines or lenses to force the child to use the amblyopic eye. If strabismus is also present, amblyopia is treated before strabismus surgery to correct misaligned eyes, and patching is often continued after surgery as well.If your ophthalmologist finds a cataract or other abnormality, surgery may be required. After surgery, glasses or contact lenses are often used to help restore focusing, while patching improves vision. Amblyopia cannot usually be cured by treating the cause alone. The brain has already "shut off" the weak eye and must be forced to "turn on" the weak eye. The weaker eye must be made stronger in order to see normally. Prescribing glasses or performing surgery can correct the source of amblyopia, but your ophthalmologist must also treat the amblyopia itself. If amblyopia is not treated, several problems may occur:
Your ophthalmologist can give you instructions on how to treat amblyopia, but it is you and your child's responsibility to carry out this treatment. Young children do not like to have their eyes patched, especially if they have been depending on the non-amblyopic eye to see clearly. But as a parent, you must convince your child to do what is best for him or her. Successful treatment mostly depends on your interest and involvement, as well as your ability to gain your child's cooperation. In almost all cases, parents play the most important role in determining whether their child's amblyopia is to be corrected. Loss of vision is preventable Success in the treatment of amblyopia also depends upon:
If the problem is detected and treated early, vision usually improves. Sometimes part-time treatment may have to continue until the child is about nine or ten years of age. After this time, the development in the visual system is permanant and amblyopia usually does not recur. If amblyopia is first discovered after early childhood, treatment may not be successful. Amblyopia caused by strabismus or unequal refractive errors may be treated successfully at a much older age than the amblyopia caused by a cataract or cloudiness in tissues in the eye. If you have additional questions or would like any further information, contact your ophthalmologist. |
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