Children with a family history of significant childhood eye
problems should be examined early in life for the presence of similar problems.
A screening evaluation is completed by the pediatrician, but a detailed
examination is best performed by the pediatric ophthalmologist.
What is a lazy eye and how is it treated?
The term "lazy eye" is a misnomer for poor
vision in one eye, though the eye appears to be normal. If a condition causes a
child to favor one eye, poor vision might occur in the eye that is not being used.
The medical term for this condition is amblyopia.
Amblyopia can result from crossed eyes (strabismus). The brain
turns off the image coming from the deviated eye to avoid double vision, since
this image cannot be superimposed on the image coming from the other eye. Over
time, the part of the brain receiving the image from the deviated eye loses the
capacity to see small targets and vision is reduced in that eye. This condition
is called strabismic amblyopia.
Amblyopia can also result from uncorrected high errors of
refraction, such as astigmatism (an irregularity in the curvature of the
cornea), or from unequal errors of refraction between the two eyes (anisometropia).
The child's brain will favor the clearer image coming from the eye with the
lesser error of refraction, thus leading to disuse of the other eye and hence to
anisometropic amblyopia. Blurry images from hazy structures in the eye, such as
from the cornea or the lens of the eye, can also lead to so-called deprivation
amblyopia.
Amblyopia is treated by:
- Correcting the underlying eye problem, such as giving the
appropriate glasses, aligning the eyes surgically, or clearing the ocular media
- Allowing the amblyopic eye to be used more through the
penalization of the better-seeing eye with patching or dilating eye drops
Amblyopia is reversible in the first nine to 10 years of life but
is best treated very early. The younger the child is at the beginning of
therapy, the faster the recovery of vision.
When is strabismus surgery necessary?
Strabismus surgery is performed to realign deviated
eyes and to allow for the use of both eyes in vision (binocular vision). With a
few exceptions, ocular deviations that are either constant or very frequent are
best treated surgically. Accommodative esotropia (inward deviation of the eye),
for example, is best treated with glasses. Children with this disease are very
farsighted (hypermetropic) and their eyes deviate inward as they accommodate or
focus to see clearly. Glasses are given to relieve the accommodative effort,
hence allowing the eyes to remain aligned.