Intensive Care patients experience severe alterations of sleep. They may develop a circadian rhythm sleep disorder, characterized by an irregular sleep/wake pattern. The presence of abnormal sleep/wake cycles may be a risk factor for delirium, which would link it to higher morbidity, mortality and longer ICU stay. Bright light therapy is the treatment of choice for circadian rhythm sleep disorders and may be helpful in handling delirium. The objective of this study is to determine whether bright light therapy is effective for reducing the incidence and duration of delirium in the Intensive Care Unit.