Vision disabilities and instruction
When sight is impaired, it can have a detrimental effect on a child's physical, neurological, and emotional development. Legal blindness is defined as visual acuity in both eyes of less than 20/200 or a visual field of less than 20 degrees despite the best correction with glasses. The overall incidence of blindness in children is 1 in 3000; 46% of these children were born blind, and an additional 38% lost their sight before 1 year of age. Among children who are blind, approximately 25% are totally blind, 25% have some light perception, and the remaining 50% may have enough vision to read enlarged type. In childhood, the causes of blindness are many and varied. Blindness can be an isolated disability or part of a condition involving multiple disabilities. About half of children who are totally blind have other developmental disabilities. Even with typical intelligence, a child who is blind from birth or early childhood is developmentally delayed. However, if visual loss is identified early, various methods of treatment and education improve developmental outcomes.