LAZY
EYE/ AMBLYOPIA
Amblyopia ("am-blee-oh-pee-ah") is an eye problem
that causes poor vision in children. This refers to diminished vision in one or
both otherwise anatomically normal eyes.
Reasons
for Amblyopia
Amblyobia can happen in young children when there is a big
difference in the degree of myopia (minus numbers for distant vision) between
the two eyes. The brain ignores the image from the weaker eye to prevent blurred
vision. As a result, the weaker eye does not develop properly. This results in
decreased or poor vision if the condition is not detected and treated early. Amblyopia
results if vision from one eye is consistently suppressed and the other eye becomes
dominant.
Undetected myopia before the age of 9 years
can lead to amblyopia (lazy eye).
This can also happen when the eyes are not
aligned or have 'crossed eyes or strabismus or squint'. The brain then receives
two different images, resulting in double vision. In young children the visual
system has not reached full maturity and the brain is able to suppress the image
from one eye to avoid double vision.
About 5% of children have amblyopia.
Diagnosis
of Amblyopia
Since amblyopia usually occurs in one eye only, many parents
and children may be unaware of the condition. Far too many parents fail to take
their children in for an early vision examination and many children go undiagnosed
until they reach a much later age.
The most important diagnostic tools are
the special visual acuity tests other than the standard 6/6 or 20/20 letter charts
used. Examination with cycloplegic drops can be necessary to detect this condition.
Treatment
of Amblyopia
Since there are numerous causes of amblyopia, the treatment
must match the problem. Early treatment is usually with the need to use glasses,
vision therapy, and/or eye patching. While detection and correction before the
age of three is considered to offer the best outcomes, children up to age 9 years
can also be successfully treated.
Surgery may be needed for co existing eye
conditions such as cataracts, droopy eyelids or crossed eyes.
After the cause
of the amblyopia is found, the child will need to use the weaker eye most of the
time, so it will get stronger. To make the child use the weaker eye, a patch can
be put over the stronger eye. This makes the weaker eye become stronger. Patches
may be used all day or part of the day, depending on the child's age and vision.
The
treatment usually lasts until vision is normal, or until vision stops getting
better. For most children, this takes several weeks.
Eye
Patch Therapy
The best results in amblyopia therapy occur when total visual
deprivation of the stronger eye is allowed. For this reason, eye patches that
stick to the skin around the eye are most effective. Strap-on "pirate's patches"
and patches worn over glasses are less effective.
Particularly if a child is
resistant to patching therapy, "atropine" eye drops may be helpful in
certain conditions. Atropine is instilled onto the dominant eye creating a temporary
blurring effect which may allow the child to use the other eye with amblyopia
- thus "patching without a patch."
Our ophthalmologist will prescribe
the appropriate number of hours that the patch should be worn each day. While
undergoing patching therapy, it is critical that your child return for a vision
check at the recommended time intervals! This is to safeguard against the development
of amblyopia in the eye being patched.
Generally, the younger the child, the
quicker the desired results are obtained with amblyopia therapy.
FREQUENTLY
ASKED QUESTIONS
What if my child refuses to wear
the Patch?
It is not uncommon that children with amblyopia refuse to wear
the patch and may also remove it when left unsupervised.
Patching should begin
during a time when you can devote all of your attention to your child (e.g. a
weekend). Typically, the first few days are the most difficult. Keep your child
occupied with games or television when wearing the patch. If your child removes
the patch, promptly replace it.
Can surgery correct
amblyopia?
No. Surgery may be needed for cataracts, droopy eyelids or crossed
eyes.
If not treated, can my child outgrow amblyopia?
No.
In fact this may result in permanent irreversible visual loss if untreated
If
my child is amblyopic, should his/her siblings be evaluated by an ophthalmologist?
It
is reasonable that all siblings of children diagnosed with amblyopia have a routine
examination by an ophthalmologist at age 3-4 years
I
have been informed of some drugs being used instead of patching?
The only
drug treatment I can think of is when some doctors put eye drops (Atropine) in
the good eye which makes the vision of this eye hazy, so the child is forced to
see with the weaker eye. This works kind of like 'patching' but not very effective
as the eye (with drops) still gets stimulated with light. Patching works more
effectively in our experience.
How many hours of
patching are necessary?
3 hours to 4 hours of 'patching' is what is required
to be effective. But this need not be during school hours as some parents' fear
that their child will be bullied and can be done at home, when he is doing some
activities at home.
What activities would you recommend
to help 'exercise' the weak eye?
The recommended games / sports to help
stimulate the weak eye include 'ball games or sports requiring a ball such as
Tennis, Cricket etc so that this improves his stereoscopic (3 dimensional vision)
and body to eye coordination.
Even work such as; doing
puzzles improves the linear activity. You may also give him multicolour grains
and ask him to segregate the same, string beads in the thread etc.
The doctor
may want to give some synaptophore exercises; however, the above exercises will
help.
How often does my child need to visit the eye
doctor?
Ideally your child has to see the doctor every month or at least
once in two months until he achieves 20/20 or 6/6 vision in both eyes. The follow
up visits are to check his progress and change any treatment plan that is being
followed.
Why is early treatment important?
The
vision pathways in the brain must become strong early, when children are very
young. The first few years of life are the most important not only for eyesight
but since also for development of the brain and ability to learn. After a child
is 8 to 10 years of age, the brain's vision system is complete. It cannot develop
anymore. If the amblyopia has not been treated by this age, the child will have
poor vision for life.