Sleeping with lights or TV ON or even watching mobile screen LED for a long time just before going to sleep has a serious bad effect on our health. It increases the chance of developing cancer cells in our body and also leads to depression. The exposure to light causes a nerve stimulation from the eye to brain that controls hormones, body temperature and even decides whether we are fully asleep or wide awake. Since our body is not made to adapt in artificial lighting, it is a good practice to sleep in darkness as much as possible. So go to bed, stay away from your mobile, lights off, cover your windows with curtains or even wear eye masks and have a good night sleep.