What is a cataract?
A cataract is a cloudy or opaque area in the lens located
directly behind the iris inside the eye. Normally, the lens is clear and allows
light entering the eye to clearly focus an image on the retina. When cataracts
develop, the light rays become scattered as they pass through the cloudy lens
and the retinal image becomes blurred and distorted.
What causes cataracts in children?
Cataracts can be present at birth (congenital) or can develop
later in life. It has been estimated that one in every 250 children will develop
a cataract either prior to birth or during childhood. While the exact cause of
some cataracts found in both eyes (bilateral cataracts) is unknown, many are
hereditary. Bilateral cataracts have also been associated with a number of
genetic disorders.
Cataracts found in only one eye (unilateral cataract) are
usually not associated with a particular disease. Trauma is another cause of
unilateral cataract.
How will cataracts affect my child’s vision?
Many of the cataracts that are discovered in newborns are small
and allow for excellent development of vision. More extensive ones can lead to
severe loss of vision.
What treatment is available for children who have cataracts?
Cataracts that obscure vision should be removed as early as
possible, even in the first weeks of life, to allow a clear retinal image.
Surgical removal of a cataract is done under general anesthesia using an
operating microscope. The lens is broken into small pieces with a microsurgical
instrument and removed through a small incision. Once the cataract has been
removed, focusing power may be restored in one of the following ways:
- Contact lenses — used after surgery for bilateral or unilateral
cataracts in children under two years of age. Contact lenses are recommended
for this age group because the eye and focusing power change rapidly during
early infancy. Contact lenses can also be used in older children.
- Intraocular lenses — artificial lenses may also be implanted to
replace natural lenses in children. This method is still under study for
infants, but early results have been excellent.
- Glasses — used in selected cases when the cataract surgery involves
both eyes and contact lenses have failed, or if intraocular lenses are not
appropriate.
The final step in the treatment process is to treat amblyopia
that develops if one eye is stronger than the other, as in the case of a
unilateral cataract. In patients with unilateral or asymmetric cataracts (one
cataract is more severe than the other), it is necessary to patch the good eye
to stimulate vision in the eye that had the cataract surgery. All patients who
undergo cataract surgery also require bifocal glasses to correct the residual
error of refraction and to allow focusing at distance and near.