For the last time, reading in dim light does NOT give you myopia. At least, if the NIH can be believed: There is no way to prevent nearsightedness. Reading and watching television do not cause nearsightedness.

Now, some evidence suggests that maybe lots of close-up work (which includes almost all activities of modern humans, except driving) might increase incidence of myopia, and there is some evidence that young children who sleep in rooms that are too brightly lit might have an increased tendency toward myopia, but these are both kind of inconclusive and may not be true at all.

But you know, being told I'll "ruin my eyes" by reading in light that is too dim for the person TELLING me that to read comfortably has been one of my pet peeves for ages. Look, (fill in name of older relative here), if it's too dark for you to see, go ahead and turn on a light. I won't stop you. I won't even mind. But if it were too dark for me to read comfortably, I would already have turned on the light.

It's particularly strange when it's somebody I don't even know. I was sitting in the Co-op's cafe reading. I had been there a while, taking advantage of free refills on coffee. This old guy came up just to say "you'll ruin your eyes doing that." I was confused -- I thought he meant reading a book and wondered what the heck he was talking about. So I gave him a puzzled look. Then he started babbling about lumens, and I realized what he meant. I said that I hadn't noticed any eye fatigue. He said, "you're ruining your eyes even if you don't notice. It's like truckers falling asleep -- they don't think they're tired until their eyes start to close." I said, "I'll take it under advisement," meaning, "what are you anyway, a retired optometrist?" He left. I looked around, and wondered how bad your eyes had to be to think that the present light level was too dim to read in.

So, for the last time. I can see just fine. The fact that you can't is not my problem. I'm sorry your eyes are deteriorating with age, but then, so are mine. I get a lot of eye fatigue using computers. But you know, they're my eyes. I know when they're tired. Really.