Near-sightedness makes you more likely to notice them, but I don't think it's a serious sign of anything unless you're seeing them so much that it's a problem. They're always there in healthy eyes, your brain just tunes them out most of the time. I would assume that changes in the way your eye focusses - either because of a change in the actual eye like the person above describes or because of a change in the prescription of glasses changing the light that enters your eye - just makes it more likely for your brain to not tune them out because they suddenly look a bit different to what your brain got used to