Recent studies have shown that even a little light at night can interfere with your body's production of Melatonin, an important immune system modulator, and the hormone associated with the feeling of getting a "good night's sleep". Eye Pajamas Sleepmasks allow no light to reach your eyes to help insure your body's uninterrupted production of this important hormone while you sleep, particularly if you have to sleep during the day. The supply of Melatonin is interrupted if the eye's light glands detect any small amount of light, therefore, it is neccessary to give your eyes total darkness for optimum sleep. Eye Pajamas Sleepmasks provide an effective, comfortable and cost effective way to sleep in the dark. They promote greater sleeping comfort, giving your eyes the total darkness they need.