No matter what you stare in a long time, bad effects on eye sight must happen. So staring at anything for too long wouldn't be a good idea. But seriously, you have gotten eye fatigue and one eye twitches uncontrollably by playing 15+ hours on the computer. You also will suffer an occasional headache, etc. The old CRT's emitted radiation that was suspected to help cause eyesight problems in people with long term exposure. But mostly eye problems come from not exercising them enough, and staring at one focal point for many hours a day can cause that. So there is nothing to do but stay away old computer monitors and TV screen. But not get far away from then forever, you still can play them for a while. If you feel tired and fatigue, you can drink a cup of tea and eat some fruits. Also, you can place cucumber slices on eyes to reduce fatigue.
