(See also Cataract.)
A congenital cataract is a painless clouding of the lens that is present at birth or shortly after birth.
Congenital cataracts have many causes. They may be inherited (multiple genetic or chromosomal disorders), related to disorders of metabolism (such as galactosemia), or caused by infections contracted while in the womb (such as rubella) or by another disease of the mother during pregnancy.
Congenital cataracts may affect only one or both eyes. They may not be noticed unless a complete eye examination is done at birth. As with other cataracts, the clouding of the lens sometimes blocks vision. Infants with cataracts should always be evaluated by a medical doctor who specializes in the evaluation and treatment of all types of eye disorders (ophthalmologist).
Some cataracts cover only part of the lens (partial cataracts), and cloudiness begins during the first 10 years of life. Vision will be better in eyes that have partial cataracts.
If necessary, ophthalmologists remove congenital cataracts through a small incision in the eye. In many children, doctors may implant a plastic or silicone lens (intraocular lens) after cataract removal surgery. After the removal procedure, doctors prescribe eyeglasses, contact lenses, or both to correct vision.
After a cataract is removed from one eye, the quality of the image in the treated eye is still poorer than that of the other eye (assuming the other eye is normal). Because the better eye is preferred, the brain suppresses the poorer-quality image, and amblyopia develops. If doctors cannot correct the vision sufficiently in the treated eye, they often "handicap" the good eye with a patch or drops that blur vision. The handicapping helps the treated eye to develop normal sight.
After cataracts are removed from both eyes, children who had image quality that was similar in both eyes more frequently develop equal vision in both eyes.