Eyes That Cross
The belief that crossed eyes in a child will straighten
themselves is a tragic misconception; a child does not outgrow crossing. If an
infant's eyes "float," momentarily turning in or out, there is
usually nothing to worry about. It may take the first three months of life for
eyes to become coordinated. After that, however, crossing (strabismus) warrants
immediate attention. Without attention, there may be loss of vision in the
turned-in eye. When eyes cross, each views an object from a different angle.
The brain then receives two different images. Since seeing double is highly
disturbing, the cross-eyed child will squint and tilt his head in an effort to
combine the two images.
Finally, he will give up, resort to using just one eye,
and the sight in the other will deteriorate for lack of use. When a child is
helped early, simple treatment may be effective. One cause of crossing is
farsightedness, which may lead to such excessive use of the eye muscles that
the eyes overconverge. Sometimes glasses alone, to correct the farsightedness,
may be enough to straighten the eyes.
A qualified orthotic technician in an eye doctor's office
can help many children by teaching them eye exercises and how to use them at
home. Special devices allow each eye to see only half a scene; the eye muscles
are strengthened while the child practices fusing the two images into a whole
picture-for example, putting the dog he sees with one eye into the doghouse he
sees with the other.
Even when surgery is necessary, the operation to bring the
eye muscles into proper balance is virtually free of risk. A muscle that does
not pull enough may be shortened; or excessive pull may be reduced by
reattaching the muscle at a different point on the eyeball. In most cases, the
child experiences little or no pain, is up the day after operation, and goes
home in another day or two.
Lazy Eye Lazy eye, or amblyopia, affects children who are
cross-eyed and also those who have one normal and one nearsighted or farsighted
eye, or one nearsighted and one farsighted eye.
Here again the brain gets two
dissimilar images and may shut out one. Even when sight in one eye has
deteriorated to a considerable extent, there is a good chance it can be
restored. But it has been estimated that as many as 100,000 children a year in
this country are on the way to joining the untreatable ranks. Amblyopia is a
major reason why every child should have a thorough examination of the eyes by
the age of four, f or the learning ability of the eye is at its height up to
age seven, and thenfails off.
Treatment for lazy eye before age seven-and in
some cases, later can be effective. Eyeglasses and a patch over the good eye
may be needed. The patch forces use of the weak eye so that, with increased
work, its vision builds up. Glaucomaoften insidious, glaucoma is a leading
cause of blindness. The most common form develops when the fluid that normally
fills the eyeball, the aqueous humor, fails to drain properly. Ordinarily, the
fluid is produced continuously within the eye, and excess amounts drain off through,
the small duct near the iris.
But aging, infection, a tumor, congenital
defects, and other causes can constrict or block the drain. Fluid pressure then
builds up and the pressure, if great and of long duration, may damage the optic
nerve. In the acute type of glaucoma, vision may dim suddenly, the eyeball
becomes painful, and the victim feels quite ill. But the insidious type of glaucoma
causes no pain, injuring vision very slowly. Sometimes it may make itself known
by the appearance of colored rings and halos about bright objects or by dimming
of side vision. Much can be done to preserve vision in most cases, provided
glaucoma is diagnosed in time. Surgical enlargement of the drainage ducts may
be used, or medicine may be effective in constricting the pupil enough to allow
the canals to open by themselves. Glaucoma is easily recognized by an eyedoctor.
