Why do blind people sleep differently?

Over the past 25 years, chronobiological research has largely elucidated the functioning of our internal clock. We now know quite precisely how the primary circadian regulator, light, acts directly on the internal clock via the eye and how the internal clock controls sleep, wakefulness, and a variety of other processes in response to this. This control factor, light, is missing in blind people who cannot perceive light. As a result, more than 50% of people who cannot perceive light suffer from a serious condition (Non-24) in which the internal clock usually runs in rhythms > 24 hours. This causes the biological sleep readiness phase to continuously “shift” backwards. This results in severe, intermittent disturbances of sleep and wakefulness, which can have pronounced physical and psychosocial consequences. The lecture will clearly explain the function of the internal clock and present approaches for possible treatments when light cannot fulfill its controlling function for the internal clock.