|AGE Present at birth||GENDER Not significant factors|
|LIFESTYLE Not significant factors||GENETICS Sometimes runs in families|
Congenital blindness is severely impaired vision that is present from birth.
Vision plays a very important part in a child's early development. Impaired vision at birth can cause serious delay in certain aspects of development and may lead to learning disabilities, particularly when it is associated with other difficulties, such as congenital deafness.
About 9 in 10 children considered blind from birth do have some vision, even though it may be as little as recognition of light and dark or shapes.
What are the causes of congenital blindness?
In the developed world, half of all cases of congenital blindness run in families and may be due to a genetic disorder. Other important causes are congenital infections such as the protozoal infection toxoplasmosis and the viral infection rubella. These infections are transmitted from the mother to the developing fetus during pregnancy and may lead to impaired vision in a newborn baby. However, congenital rubella is now rare in the developed world due to routine immunization. A baby's eyes may also be affected by cataracts, in which the eye lenses are opaque, or glaucoma, in which the optic nerve is damaged due to increased pressure within the eyes. Congenital blindness may also be caused by damage to the brain as a result of lack of oxygen during birth.
What are the symptoms of congenital blindness?
Parents usually become aware that their baby has a vision problem within a few weeks of birth. He or she may be less responsive than other babies, lying quietly to make the most of his or her hearing. Parents may also notice that their baby:
- Is unable to fix his or her eyes on a close object.
- Has random eye movements.
- Does not smile by the age of 6 weeks.
- Has abnormally large, cloudy eyes if glaucoma is present.
Parents may find it difficult to bond with a quiet baby who does not smile.
How is congenital blindness diagnosed?
If congenital blindness is not suspected by the baby's parents, it will probably be picked up during a routine examination in infancy. A child suspected of having impaired vision will be referred to a specialist for an examination and tests (see Vision tests in children). His or her hearing will also be tested (see Hearing tests in children) because, if the child is severely visually impaired, he or she will rely more on hearing.
What is the treatment?
It is possible to improve vision in only a small number of babies, such as those with cataracts or glaucoma. Early treatment of these conditions is important. Cataracts are usually removed surgically within the first month of life (see Cataract surgery). Glaucoma may also be treated by surgery to allow fluid to drain from the eye.
If vision cannot be improved, much can be done to help a child to make maximum use of other senses or what little vision he or she has. If your child is diagnosed as blind, a team of specialists, including a teacher for the blind, will be available to give you and your child support and care. You will also be given advice on how to stimulate your child using speech, sounds, and touch and how to adapt your home so that your child is able to explore it safely and develop self-confidence. Some children require special schooling to learn braille, a system of raised dots that allows blind people to read and write.
Genetic counselling is available for parents of an affected child who wish to have more children or for prospective parents who are blind.
What is the prognosis?
Children treated for cataracts or glaucoma will probably still have impaired vision but often have enough sight to perform most activities unaided. Many blind or visually impaired children with no other disabilities go on to have successful personal and professional lives.
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