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Strabismus is a problem caused
by one or more improperly functioning eye muscles, resulting in a misalignment
of the eyes. Normally, each eye focuses on the same spot but sends a
slightly different message to the brain. The brain superimposes the two
images, giving vision depth and dimension. Here's an easy way to see how
the eyes work together: hold your finger at arm's length. While
looking at your finger, close one eye, then the other. Notice how your
finger changes position. Even though the images are slightly different,
the brain interprets them as one.
Each eye has six muscles that
work in unison to control movements. The brain controls the eye muscles,
which keep the eyes properly aligned. It is critical that the muscles
function together for the brain to interpret the image from each eye as a
single one.
Strabismus must be detected
early in children because they are so adaptable. If a child sees double,
his or her brain quickly learns to suppress or block out one of the images to
maintain single vision. In a very short time, the brain permanently
suppresses vision from the turned eye, causing a weak or amblyopic eye.
Children may also develop a head tilt or turn to compensate for the problem
and eliminate the double image. Unlike children, adults with a newly
acquired strabismus problem typically see double.
There are many causes of
strabismus. It can be inherited, or it may be caused by trauma, certain
diseases, refractive errors and sometimes eye surgery.
Signs and Symptoms
Adults are much more likely to
be bothered by symptoms from strabismus than young children. It is
unusual for a child to complain of double vision. Children should
undergo vision screening examinations to detect problems early. The younger the
child is when strabismus is detected and treated, the better the chance of
normal vision. The following are common signs and symptoms:
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Turned or crossed eye
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Head tilt or turn
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Squinting
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Double vision (in some cases)
Detection and Diagnosis
Strabismus is detected with a
comprehensive eye examination and special tests used to evaluate the alignment of the
eyes.
Treatment
The appropriate treatment for
strabismus is dependent on several factors including the patient's age, the
cause of the problem, and the type and degree of the eye turn. Treatment
may include patching, corrective glasses and prisms, together with vision
therapy or, as a last resort, surgery.
Vision therapy, together with
possible refractive error correction, attempts to teach the brain to utilise
both eyes together as a team. For this
treatment to be effective, it must be done at a young age before the child can
develop amblyopia.
Surgery is sometimes performed
for both adults and children to straighten a crossed eye. The procedure
may be done with local or general anaesthesia. There are several
different surgical techniques used to correct strabismus. The
appropriate one is dependent on the muscle involved and the degree of the eye
turn.
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