I spend a lot of time on the computer, but I understand doing such is unhealthy. It would be best to just take an hour or so to get away from the computer or just go outside for a while.
Some LCD monitors may emit a small amount of UV radiation, but these amounts are rather small, so there is virtually no risk to the human body. The biggest computer usage risk is eye strain, from to much use, and maybe long term issues as well.
That is now the problem, if you prevent one problem, another one again emerges. You guard against stray radiations, eye strain problems emerges.
I do get health issues every now and then. I can't help it though. I mean it can be pretty tense playing too much games.
If you are playing game on your phone or the computer then there are several apps and software to remind you take rest. Some apps even tell you about the exercises to avoid the health issues with your body and brain.