|Strabismus in Childhood|
Strabismus or squint/crossed eyes , occurs
when there is a misalignment or lack of co-ordination between the two
eyes. Generally with this condition, the two eyes point in different directions.
The misalignment is a result of the failure of the eye muscles to work
together properly, caused by muscle weakness in the eye (leading to uneven
muscle development), injury, other eye diseases, a brain tumour, or a
tumour in the eye (cf. ).
It is usually diagnosed in childhood, but can also occur later in life.
An estimated 4% of American children have some degree of crossed eyes
and it affects boys and girls equally. Most children with crossed eyes
are otherwise normal, but there is a high incidence of this disorder in
children with cerebral palsy and hydrocephalus. Crossed eyes often worsen
when eye muscles are tired-for example, late in the day, in bright sunshine,
or during the course of an illness. Crossed eyes sometimes cause double
vision in children, but more commonly does in adults. If untreated, crossed
eyes are likely to worsen with age. Crossed eyes are classified by the
way the eye deviates:
- Esotropia or convergent strabismus . The
most common form, which occurs when the eye turns in toward the nose.
More than 50% of children with crossed eyes have this form.
- Accommodative esotropia is a variation
in farsighted children whose eyes cross because of the effort to focus.
- Exotropia or divergent strabismus , sometimes
called walleye , occurs when the eye drifts
outward. Sometimes eyes will drift up or down.
- False or pseudo-strabismus is a condition
in infants that looks like crossed eyes but is not. In fact, the appearance
of crossed eyes is caused by an extra fold of skin that some children
have near the inner eye, a broad flat nose, or eyes that are unusually
close together. Pseudo-strabismus will disappear as the child's face
Symptoms and Signs
The most common symptoms and signs of strabismus include:
- Mis-aligned eyes and uncoordinated eye movements, either constant
- Tilting head to look at things
- Frequent eye movements
- Rubbing of eyes
- Double vision
Diagnosis and Treatment
The doctor will usually check for deviations in eye movement, if the
child has an inability to keep one eye fixed on an object and if visual
acuity is poor in one or both eyes, to confirm a diagnosis of strabismus.
Treatments range from glasses to surgery. Glasses can be used to correct
mild crossed eyes, by improving focusing and redirecting the line of vision.
Sometimes an eye patch over the strong eye helps the weak eye focus. Exercises
may also be prescribed to strengthen the weak eye. In some cases, drops
are put in one eye, clouding vision and forcing the weaker eye to take
Surgery either strengthens or weakens an eye muscle in order to balance
a pair of muscles.
In a relatively new medical technique, a medication called botulinum (Botox)
is injected into an eye muscle. This temporarily weakens and relaxes the
muscle and allows the opposing muscle to tighten. The effect of the medication
wears off in several weeks, but the correction may be permanent.
With timely and appropriate treatment, the prognosis is excellent. Most
of the time crossed eyes can be corrected, both for visual and cosmetic
The information in this page is presented in summarised form and has been taken
from the following source(s):
Intelihealth.com, Children's Health Section: http://www.intelihealth.com/
(def;articles & more)