Blindness can be partial, with loss of only part of the vision. It can also be complete, in which case there is no perception of light.
Blindness has many causes, yet the incidence of true blindness in the United States remains low.
Accidents, diabetes , and macular degeneration account for most blindness in the United States. Worldwide, vitamin A deficiency is the leading cause of blindness. There are other causes of blindness. This list is not all inclusive, and the causes are not presented in order of likelihood. The causes of this symptom can include unlikely diseases and medications.