I had PRK done when I was 40.
The dr recommended he undercorrect one eye and overcorrect the other slightly and I knew it wouldn't "bother" me 'cos I once went a couple of months with just one contact lens in (don't ask

).
One of the reasons he did this was because I told him I was a book-a-holic: I read 2-3 books a week.
He also said that most people need reading glasses starting at around 40 and I would need them sooner or later regardless.
Anyway, it's now 9 years later. To this day, I have to close one eye and "look" with the other (and then repeat) before I can remember which eye is overcorrected and which is undercorrected.
I am just beginning to need reading glasses. When I went for my last eye exam, the doc told me to pick up the "1s" from the discount rack and only use it when necessary. I've used them maybe 3 times, in 7 months or so, only to read fine print in not perfect light.