Saturday, November 28, 2015
When using iPad at night, study suggests orange tinted glasses for better sleep
Sleep quality and health can be affected by exposure to different light-emitting devices. Exposure to short-wavelength-enriched (blue-enriched) light in the evening increases alertness and suppresses the production of melatonin, which is only produced during sleeping hours and helps regulate the sleep-wake cycle.
In this study, Gringras et al reveals the spectral profiles of the most popular devices in 2014: the iPad Air, the iPhone 5s, and the Kindle Paperwhite 1st generation. The difference in light signals emitted from a popular game (Angry Birds) and e-book text was also compared. The default brightness levels were used for the iPhone and iPad, and 50% brightness was used for the Kindle based on convenience sampling from users. Irradiance was measured as an exact spectral power distribution (SPD) using a spectrometer. The spectral profiles were similar across all devices, and between Angry Birds and e-book text. The intensity level was higher for the iPad.
Two strategies to reduce the impact of short-wavelength enriched light emissions were tested. First, the blue-blocking, orange-tinted Pyramex Ztek Safety Eyewear was very effective in decreasing the intensity of the short-wavelength/blue light emissions. Second, the Kids Sleep Dr app, which allowed for selection of a “sleep-aware” palate of colors on the device, was also successful in reducing short-wavelength light emissions, but also changed the spectral profile completely.
Gringras P, Middleton B, Skene DJ, Revell VL. Bigger, Brighter, Bluer-Better? Current Light-Emitting Devices – Adverse Sleep Properties and Preventative Strategies. Frontiers in Public Health. 2015;3:233. doi:10.3389/fpubh.2015.00233.