The rest have some useful vision, which they can use in their daily lives. With imperfect or no sight, visually disabled people often have to learn to understand about their world in different ways from sighted people.
Sighted people receive most of their information about their surroundings through seeing.
People with visual disability must learn to make use of other senses, usually hearing and touch. What sighted people may find out very quickly, visually disabled people may need help to discover. Sighted people use their vision to confirm what other senses may tell them - they look to see that a dog is barking at them, or turn their heads to be sure that the fruit smell comes from an orange rather than a lemon. They may not see a smile to encourage them, or notice anger on someone's face. They may be unaware that the person with them is sad and crying- unless they are told.