Sleep hygiene. I'm in college and I know too many people that waste away online until 3am and are always tired and then down coffee after coffee during the day.

Other than that,

> sitting in a dark room with your screen as your only light source

is also really not great for your eyes, in the same way that having a bright light source in your field of vision (e.g. a window without blackout shades directly behind your monitor) isn't either.

I call bullshit.

I'm using computers/TV/Phones in dark room, on an average 12h+ a day, for ~20 years. My eyes are just fine. Last time (and only time) I went to an eye doctor two years ago because people like you keep saying my eyes are damaged, the doctor asked me why am I wasting my money going to eye doctor.

Just because someone stays up till 3AM (which I have done for years), doesn't mean they need to sleep less or feel always tired. This has nothing to do with using computer in dark room which is possible even at 3PM.

Also, I don't drink coffee (less than 5 times a year). There are plenty of people who sleep at proper time and still drink a lot of coffee all day.