PhotonBoy said:
I read a lot of science fiction novels in my mid to late teens and I often wonder if that's what made me near-sighted.
Nope
This is an old wives tale furthered by my grandmother and thousands of others like her to get the kids to go to bed and stop reading
Just using your eyes doesn't make them get worse any faster. As we get over 40 most of us will need reading glasses. Regardless of what you did with your eyes. It's just the focusing muscles you're exercising when you read closeup, exercising a muscle doesn't make them get worse at their job
Our lenses just get harder and less able to be moved by the same muscles over time.
So your reading a lot did not make your eyes any worse.
However, over using those muscles can give you a headache!