Low light
There was a show on the Discovery Channel about things your mother told you that weren't true. One of the topics it discussed was dim light being hard on the eyes. Their conclusion was "Dim light can't hurt your eyes any more than it can hurt a camera."
My first year away from home I read an article suggesting that you should read with a 100 watt bulb. It puzzled me because it didn't say at what distance the bulb should be from what you are reading. The distance is actually more important than the wattage in affecting the light on the page.
That should have been a clue that the person didn't know what he was talking about, but because "it was written" I went out and got a 100 watt bulb. My impression from the start was that it was too bright from about 4 feet away, and after awhile I replaced it with a dimmer one.
I practically enjoy turning out the lights in an office where I work. If it is daylight it isn't as bright but it is so much more beautiful, and always different. The dimmer part is not the slightest problem to me even if I am reading.
I counted the lights on one floor of that building. 153 lights at 80 watts each, comes out to just over 12,000 watts, or 12 KWH every hour. In one day just lighting this floor uses more electricity than my house does in 2 weeks. If everyone shared my taste in lighting, hardly any of them would be needed.
The new Kindle, readable in bright sunlight (6" Display, U.S. Wireless)
If you do wind up in front of the computer for hours at a time, one thing that has helped me is adjusting the monitor brightness as low as it will go. You do want your monitor to be about as bright as the background lighting, or you will have a bright spot in your field of vision and that is hard on my eyes.
Most people are a bit enthusiastic about the brightness they set their TV or monitors to. They seem to think more is good that way and it is like trying to read something typed on a lampshade instead of just normal daylight on a page. Also the color is richer and looks better when it isn't washed out by light. My experience and opinions of course, yours might vary.
I keep the brightness on my monitor set to 0%. It isn't actually 0% because when I was turning it down, from 40% down the brightness didn't decrease at all, but I would personally like it a bit lower. That has been a serious help for eyestrain. I don't expect to buy another monitor for years but if I do I will want to try out the model first and see how dim I can set it.
I might have thought that if I could open my eyelids, seeing would be covered. The intricate detail that makes up life is amazing.
It's a repeated lesson in life, stay wide awake for anything you do. Even if the light is dim. 
