Lazy Eye
The common term for amblyopia, in which a child’s reduced vision is not caused by any eye disease and is not correctable by glasses or contact lenses. Instead, the problem is caused by the brain’s refusal to acknowledge the images seen by the lazy eye, causing reduced vision. This almost always affects only one eye, although vision may be reduced in both. It is estimated that three percent of children under six have some form of amblyopia. If not detected and treated early in life, amblyopia can cause a permanent loss of vision. Detection and correction before the age of two is the best way to restore normal vision. Between 2 and 3 percent of all children have lazy eye.
Cause
All babies are born with poor eyesight, but as they grow, their eyesight improves. Good eyesight needs a clear, focused image that is the same in both eyes. If the image is not clear in one eye, or if it is not the same in both eyes, the vision pathways will not develop correctly, or may get worse.
Amblyopia usually is caused by either a misalignment of a child’s eyes (such as crossed eyes) or a difference in image quality between the two eyes (one eye focusing better than the other). In both cases, one eye becomes stronger, suppressing the image of the other eye. If this condition persists, the weaker eye may become useless. Anything that interferes with clear vision in either eye during the critical period from birth to six years of age will cause amblyopia.
Amblyopia vs. Strabismus
Although many people call strabismus (crossed eyes) “lazy eye,” in fact they are two different conditions; strabismus is one cause of amblyopia. Amblyopia can result from a constant strabismus in which the right or left eye turns all of the time, but alternating strabismus in which an eye only sometimes turns rarely causes amblyopia.
Diagnosis
Since amblyopia usually occurs in only one eye, children may not notice the condition, and because many parents do not have their infants or toddlers take a comprehensive vision exam, many children go undiagnosed until they have their eyes examined later. The most important diagnostic tools are special visual acuity tests.
Treatment
The earlier the treatment, the better the opportunity to reverse the vision loss. Amblyopia can be treated between the ages of two and six, but the success rate decreases with age. The best results from treatment occur between six months and two years.
Glasses are commonly prescribed to improve focusing or misalignment of the eyes. Surgery may be performed on the eye muscles to straighten the eyes if other means have not been successful.
Eye exercises may be recommended either before or after surgery to correct faulty visual habits associated with strabismus and to teach comfortable use of the eyes. The correction may be followed by patching or covering one eye for a few weeks to as long as a year. The better-seeing eye is patched, forcing the “lazy” one to work, thereby strengthening its vision.
Eye drops or ointment may be used to blur the vision of the good eye in order to force the weaker one to work, although this is generally a less successful approach than eye patching.
Although true amblyopia cannot be cured after the age of six, treatment for older children still can usually improve vision. Treatment of amblyopia after the age of six requires more effort and includes vision therapy. If not treated early enough, an amblyopic eye may never develop good vision and may even become functionally blind.
Cause
All babies are born with poor eyesight, but as they grow, their eyesight improves. Good eyesight needs a clear, focused image that is the same in both eyes. If the image is not clear in one eye, or if it is not the same in both eyes, the vision pathways will not develop correctly, or may get worse.
Amblyopia usually is caused by either a misalignment of a child’s eyes (such as crossed eyes) or a difference in image quality between the two eyes (one eye focusing better than the other). In both cases, one eye becomes stronger, suppressing the image of the other eye. If this condition persists, the weaker eye may become useless. Anything that interferes with clear vision in either eye during the critical period from birth to six years of age will cause amblyopia.
Amblyopia vs. Strabismus
Although many people call strabismus (crossed eyes) “lazy eye,” in fact they are two different conditions; strabismus is one cause of amblyopia. Amblyopia can result from a constant strabismus in which the right or left eye turns all of the time, but alternating strabismus in which an eye only sometimes turns rarely causes amblyopia.
Diagnosis
Since amblyopia usually occurs in only one eye, children may not notice the condition, and because many parents do not have their infants or toddlers take a comprehensive vision exam, many children go undiagnosed until they have their eyes examined later. The most important diagnostic tools are special visual acuity tests.
Treatment
The earlier the treatment, the better the opportunity to reverse the vision loss. Amblyopia can be treated between the ages of two and six, but the success rate decreases with age. The best results from treatment occur between six months and two years.
Glasses are commonly prescribed to improve focusing or misalignment of the eyes. Surgery may be performed on the eye muscles to straighten the eyes if other means have not been successful.
Eye exercises may be recommended either before or after surgery to correct faulty visual habits associated with strabismus and to teach comfortable use of the eyes. The correction may be followed by patching or covering one eye for a few weeks to as long as a year. The better-seeing eye is patched, forcing the “lazy” one to work, thereby strengthening its vision.
Eye drops or ointment may be used to blur the vision of the good eye in order to force the weaker one to work, although this is generally a less successful approach than eye patching.
Although true amblyopia cannot be cured after the age of six, treatment for older children still can usually improve vision. Treatment of amblyopia after the age of six requires more effort and includes vision therapy. If not treated early enough, an amblyopic eye may never develop good vision and may even become functionally blind.
