12 May 2010
Vol 2, Issue 31

About The Cover

Cover image expansion

ONLINE COVER Light Matters. The wavelength of light that falls on our faces does more than just make us look sick or ruddy. All visible light is sensed by our rods and cones to create images of the world around us, but only light at the blue end of the spectrum has been thought to control our mood, our circadian clock, and other non–image-forming functions. New work by Gooley et al. now shows that cones also contribute to non-image light sensation, suggesting that the blue light now often used for therapy in depression or shift work should perhaps be replaced by green or white illumination. [CREDIT: CHRIS BICKEL/SCIENCE TRANSLATIONAL MEDICINE]