If an infant is born unable to see or with severe visual impairment, he is said to have congenital blindness. A number of different conditions can cause congenital blindness, including certain diseases and genetic factors. The term "congenital" simply means that it is present from birth, and does not provide information as to while a child might be born blind. Blindness can also sometimes occur with other conditions, such as autism spectrum disorders and mental retardation.
There are many things that may cause a person to be born with congenital blindness. One of them is a physical defect in the eyes or an abnormality in the brain. Some people are born blind because of infections their mothers developed while they were pregnant. For example, German measles, a viral illness, can affect developing babies and cause congenital blindness. Others may be born blind because of an inherited condition or due to an injury that happens during childbirth.
One cause of congenital blindness is Leber congenital amaurosis (LCA), a rare degenerative disease in which the retinas do not function properly. Retinopathy of prematurity, a condition in which the retina of a baby born prematurely has not had time to develop properly, can cause blindness in severe cases. It is also possible for a baby to be born with congenital cataracts, meaning that the lens of the eye is clouded, causing loss of vision.
When children have congenital blindness, their learning and development needs are different. Barring any other conditions, they can learn and develop in much the same way as other children can, but they may need the help of special teachers or materials to help them do so without normal sight. There are many learning and developmental programs that emphasize using touch, hearing, and even taste and smell to learn.
Eventually, the sense of touch plays a very important role in learning. Blind children and adults can use braille to read books, even though they cannot see them. This involves feeling small bumps or dots that represent letters and words, reading with the hands instead of the eyes.
A blind person's hearing can also play a critical role in his ability to learn and read. There are devices designed to read information on a written page, allowing blind people to listen to books and written materials rather than using braille. In fact, some of these devices make it possible for blind children to attend regular school if they wish.
The idea of being born without sight or with significantly impaired vision can seem frightening to sighted individuals. It may be difficult to imagine how a blind individual can perform daily tasks most people take for granted, such as going for a walk or running errands. One of the resources a blind person may have is a guide dog. These dogs are specially trained to help visually impaired people move about and even cross streets safely.