Over the last 100 years, due to the invention of the light bulb, and more recently, artificial-light-emitting televisions, computers and smart phones, we are exposed to much more light at night than ever before. Prolonged exposure in the late evening delays our body clock, causing us to extend our bedtimes. Light is the most important factor that can affect your sleep, directly influencing your body clock. To significantly shift our sleep/wake pattern (circadian rhythm), we need to get as much as exposure to bright light in the mornings, at the time you want to be awake and alert, reduce light and specifically blue light exposure at night and also sleep in complete darkness. Exposure to blue light before bedtime, from digital devices and lighting, causes melatonin production to be blocked. Melatonin is a hormone that helps us fall asleep. You can use these Blue Light Blockers fit-overs during the day to help with visual comfort and eye fatigue when you are on any digital device including computers, tablets and phones (can be worn over glasses or on their own). Using these at night to block blue light in the evening may help with better sleep, better mood, general health and eye health. They will allow you to watch TV, use your computer, phone and tablet right up to bedtime, whilst minimising the awakening effect of the blue-light waves from these devices. These glasses are so effective that they must NEVER be used when driving. .