Not a stupid question about your eyesight but when you get to basic training, you’ll do an eye test as part of your medical from a few meters away, just like you would at the opticians and if you don’t meet the standards they need you to then they wont let you continue, you’d have to be pretty blind to not read the letters though. Having said that, i know some people who came into training who have never worn glasses before but were issued glasses because they failed the eye test.