Amblyopia
What is amblyopia?
amblyopia is widely known as Lazy Eye. Lazy Eye or Amblyopia is an eye
condition characterized by reduced vision, which cannot be corrected by
glasses or contact lenses.
In this condition, the brain does not fully acknowledge the images seen
by the Amblyopic Eye. Amblyopic usually affects only one eye but in
some instances may manifest itself with reduced vision in both eyes.
The majority of Lazy Eye sufferers are young children. Amblyopia tends
to occur most often during the first years of life when eye sight is
still developing.
What causes Amblyopia?
The visual system of the child is not fully developed at birth. The
visual brain cells of a child are developing during their first decade
of life. Any insult to the child's vision during this time period can
lead to amblyopia.
Following are the common causes of amblyopia:
- Squint - This is the commonest cause of amblyopia. The
brain to avoid double vision ignores the image from the deviating eye.
This leads to poor visual development of the deviating eye and hence
amblyopia.
- Unequal refractive error (anisometropia) - In this
condition, the two eyes have different refractive errors. Because the
brain can not "balance" this difference, it picks the eye that is
"easier" to use and develops a preference for this eye only. The eye
with greater refractive error is suppressed and thus gets amblyopic. An
early treatment by giving the right glasses for correction can prevent
and correct this problem.
- Stimulus deprivation - Any form of stimulus derivation to
either one or both eyes in early childhood may lead to a severe form of
amblyopia. These causes for stimulus deprivation may be ptosis,
cataract, glaucoma, patching or any other obstacle that blocks the
vision in the eye.
Amblyopia is a neurological condition brought on by any one or more of
the above causes. The brain will start to suppress or block the weak
eye and this inhibition process can result in a permanent decrease in
the vision in that eye that can not be corrected with glasses, lenses,
or lasik surgery.
How can we detect if the child has amblyopia?
Detecting amblyopia in child is difficult, as the child may not be
aware of having one weak eye. If the child has a squint or some other
abnormality, the parents may notice that something is wrong. The vision
of the child can be tested by the ophthalmologist by special tests.
Poor vision in an eye may point towards a possibility of amblyopia.
Can anything be done to treat amblyopia and prevent vision loss?
With early diagnosis and treatment, the sight in the "lazy eye" can be restored.
When should treatment for amblyopia begin?
The earlier the treatment, the better the opportunity to reverse the vision loss.
Why is it important to treat amblyopia?
If an amblyopic eye is not treated by 10 years of age, the amblyopic
eye may permanently stay weak. This has many disadvantages like:
- Both eyes can not be used simultaneously and hence depth perception
(three-dimensional vision) is not present. Many occupations are not
open for people who have good vision in one eye only.
- It is important to give best possible vision to the amblyopic eye
even if the other eye is seeing well. The importance of this becomes
obvious, in case the person loses the other (better) eye, sometime
later due to some injury or disease.
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 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:
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.
How many people have amblyopia?
It is estimated that two to three percent of the general population suffers from this form of visual impairment.
What are the factors that determine the success of treatment?
The success of amblyopia treatment largely depends upon the motivation
of parents and the cooperation of the child. Patching of the better
eye, especially when the amblyopic eye has very poor vision is not
tolerated well by the child. The parents have to understand the
importance of this treatment and should explain the same to the child
to ensure better cooperation.
The other factors that determine the success of treatment are:
- The severity (depth) of amblyopia
- The age at which the treatment is started: The earlier the treatment is started, the better are the results
- Any other complicating factor in the eye preventing sufficient gain
of vision, e.g., glaucoma, cataract, retinal or optic nerve disorders
My child has squint and amblyopia. Which should be treated first?
Amblyopia has to be treated first in all these cases. Once the
amblyopia has been taken care of, the surgery may be done for squint
correction. Top
|
