Hello, it still depends on your conditions. If your computer screen has anti-glare and the video brightness isn't too high or too low and your vision is quite normal, then your eyes can not be affected. However, it can still cause some eye strain if you stay near to it for a long time, so just stay at the right distance and have a rest when your eyes are tired.
Our eyes need sufficient light to function, so they'll be harmed when you always stay at a dark room. Situation can be serious when you use computer in a dark room because the strong light of computer would make your eyes more tense.
Your eyes focus on that narrow screen which in contrast with the dark can make eye sight drop rapidly.