Amblyopia is a condition where central visual acuity of an apparently healthy eye isreduced because of lack of use during early childhood. Sometimes known as "lazy eye", often it occurs because the "good" eye is preferred.
What is amblyopia?
Normally the images sent by each eye to the brain are identical. When they differ, double vision occurs. Rather than go through life with double vision,
the brain soon learns to ignore the distorted image sent by one eye and "sees" only with the good eye, that is, the one that is stronger and more accurate.
The eye that is ignored becomes weaker from disuse. It is for this reason that the condition is also known as "lazy eye". It is unrelated to any eye health
problem and is not correctable with spectacles alone.
The amblyopic eye is not blind in the sense of being entirely without sight. Amblyopia affects only the central vision of the affected eye. Peripheral awareness
will remain. Since it is quite difficult to correct amblyopia when the affected eye is not used at all, early detection and treatment are extremely important.
Who is likely to develop amblyopia?
Amblyopia is generally the result of poor early visual development, and as such, usually occurs before the age of five or six. It is estimated that two
to four percent of children under the age of six have amblyopia. The chance of amblyopia developing during adulthood is very small.
What causes amblyopia?
It has many causes. Most often, it results from either a misalignment of a child's eyes, such as crossed eyes, or a difference in image quality between
the two eyes (as one eye focuses 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.
Can anything be done to treat amblyopia and prevent vision loss?
A comprehensive eye examination by an eye specialist can determine the presence of amblyopia. The earlier it is diagnosed, the greater the chance for a
complete recovery. That is why it is important to have a child's vision examined before the age of three and again when entering school. Since amblyopia
occurs only in one eye, the good eye takes over and the individual is generally unaware of the condition.
With early diagnosis and treatment, the sight in the "lazy eye" can be restored. Corrective lenses, prisms, contact lenses and/or vision therapy are often
used to treat amblyopia. In less developed cases, patching the good eye often stimulates and strengthens the amblyopic eye. In more advanced situations,
other vision therapy techniques are used.
When should treatment for amblyopia begin?
Just like with any disease or disorder of the body, the earlier the treatment, the better the opportunity to reverse the vision loss.
What treatments are available?
Before treating amblyopia, it may be necessary to first treat the underlying cause.
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 non-surgical means are unsuccessful. Surgery can help in the treatment of amblyopia
by allowing the eyes to work together better. Eye exercises are a limited form of treatment. 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.
What treatment follows the correction of the underlying cause?
The correction may be followed by:
list of 2 items
• Patching or covering one eye may be required for a period of time ranging from 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.
• Medication - in the form of eye drops or ointment - may be used to blur the vision of the good eye in order to force the weaker one to work. This is generally
a less successful approach.
What happens if amblyopia is left untreated?
If not treated early enough, an amblyopic eye may never develop good vision and may even become functionally blind.