Non-24 in Sighted vs. Blind People
Although the majority of people with Non 24-Hour Sleep Wake Disorder (Non-24) are blind, it also occurs in a small number of sighted individuals. As many as half to three-quarters of totally blind patients (i.e., having no light perception) are considered to have Non-24, representing approximately 65 to 95 thousand Americans. The number of sighted people with Non-24 is unknown.