Effects of bright light at lunchtime on sleep in patients in a geriatric hospital II

Inpatients with sleep disturbances in a geriatric hospital received 1 h of exposure to approximately 8000 Ix bright light per day for 3 weeks. Polysom nogram was recorded for four female patients. Two (aged 68 and 87 years) we re non-demented patients with weak cataracts and the other two (aged 92 and 93 years) were demented patients with severe cataracts. Electroencephalogr am results showed that light exposure decreased the proportion of Stage W. while increased the proportion of Stage 2, and these effects continued for at least 3 weeks after the cessation of light exposure. These results sugge st that exposure to bright light is effective in improving the disturbed sl eep of patients.