Depending on the severity of their vision loss, people will be either registered as sight impaired or severely sight impaired (which is also known as blind). The terms "blind" and "partially sighted" are more generally used in every day conversations.
However, how someone chooses to describe themselves in relation to their eye condition is very individual and the term they use will depend on their personal preference.
Everyone is different and manages their sight loss condition in a unique way. Sight loss can vary significantly. This includes total blindness, better vision in light or dark areas, long distance and short distance, and that's just highlighting a few!
Never make assumptions of what people can and cannot see, as each blind and partially sighted person's background to sight loss is different.