Turning on the light to sleep not only wastes energy, but also affects the quality of sleep. The biological rhythm of human body, including biological clock, is naturally formed in the process of adapting to the environment, and "sleeping in the dark" is a routine of human life. If you break this routine, turning on the light at night or sleeping in strong sunlight will cause a kind of "light pressure" on the human body, which will affect the normal metabolic function of the human body, including the normal physiological and biochemical reactions in the body, and even make the heartbeat, pulse and blood pressure of the human body abnormal, leading to diseases. Recently, medical researchers have confirmed that turning on the light while sleeping will inhibit the secretion of a substance called melatonin in the human body and reduce the immune function of the human body. The incidence of cancer is twice that of normal people, such as flight attendants, telecommunications, doctors, nurses and so on. Medical scientists warn that turning on the light to sleep not only affects human immunity, but also easily causes cancer. It is especially bad for babies to sleep with the lights on. Any artificial light source will produce subtle light pressure. The long-term existence of this kind of light pressure will make people, especially infants, feel restless and restless, so it is difficult to fall asleep and the quality of sleep is not good. At the same time, letting infants sleep under the light for a long time will further affect their eye reticular activation system, shortening their sleep time every time, making their sleep depth shallow and easy to wake up. Babies sleeping in the light for a long time is greatly detrimental to their vision development. When the eyeball is exposed to light for a long time to sleep, the stimulation of light on the eye will continue, and the eyeball and ciliary muscle will not be fully rested, which will easily damage the retina and affect the normal development of infant vision.