Testing the Effectiveness of an Evening Blue-depleted Light Environment in an Acute Psychiatric Ward

"A 20-bedded ward with tunable light emitting diode (LED) lamps. At 18:00h the lighting undergoes a 30-minute transition during which the green and blue LEDs are dimmed to produce blue-depleted amber colored lighting. At 06:50h a new 10-minute transition changes the light color to ordinary indoor lighting. From 07:00h to 18:00h, there is ordinary indoor lighting (3000K colour temperature). The light intensity is dimmed to 20% of the maximum from 23:00h to 6:50h.~Blue-blocking window filters are deployed also in the evening. All TV sets have permanent blue-blocking filters and individuals are provided with blue-blocking screens that can be attached to the front of personal electronic devices. If the patients leave the blue-depleted unit after 18:30 they are offered blue-blocking glasses to wear. The light spectrum in the ward was assessed prior to commencing the RCT and is well-matched to what has been shown in laboratory settings to minimally suppress melatonin."

"The other half of the unit (20 patient rooms and their corresponding bathrooms and common areas) have ordinary indoor light installed (Glamox, Norway). This has a 3000K color temperature. The light is dimmed to 20% of max in the night, similar to the blue-depleted condition.~The light in the normal light condition and the blue-depleted light condition have similar levels of photopic lux throughout the 24h cycle, but different levels of melanopic lux between 1830h and 0700h."