UV radiation is nothing to take lightly. Chronic exposure to UV rays can cause premature aging of the skin, skin cancer, damage to the eyes including cataracts and can even suppress your immune system. Fortunately, even if you spend all day in front of a computer, there is little to be worried about. Most computer screens today don't emit UV radiation, although older monitors do.
UV Light Levels
Cathode ray tube, or CRT, screens like those that were once used for computer monitors and TV sets actually do emit low levels of UV radiation. However, these levels are significantly lower than that of the sun. The fluorescent light bulb above your head emit actually emits more UV light than a CRT monitor. Although the flickering light that CRTs use may cause eye fatigue, this is not the same as actual eye damage.
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Liquid Crystal Display, or LCD, flat-panel monitors, most commonly found on laptops, desktops, and mobile devices today do not emit any UV radiation.
Though UV light is not such a problem, computer monitors of all types and televisions have been found to emit blue light. While dangers associated with blue light are also mild to none, studies have shown that blue light causes the brain to be more alert, and sleep comes less easily. Because of this, it is best to stop using a computer at least an hour before bedtime and turn off any monitors that may be on in the bedroom for a better night's sleep.
While old CRT computer screens may not emit dangerous levels of UV light and LCD monitors don't emit it at all, eye-strain, fatigue and sleeplessness can still occur from overexposure to computer monitors. More than radiation, eye strain should be a concern if you spend long periods of time in front of a computer. The Mayo Clinic recommends the 20-20-20 rule to reduce eye strain. Every 20 minutes, look away from your computer and focus on something at least 20 feet away for at least 20 seconds.