I have 20/30 vision in one eye, 20/50 in the other. With glasses, I get 20/20 in both. What are the visual acuity requirements for a PPL? Presumably (hopefully?) someone with my visual acuity can't fly without glasses? (I definitely wouldn't even drive a car, let alone fly a plane, without glasses, even if it wasn't legally required. I could probably see the instruments in a plane fine, and I could see outside well enough to avoid hitting another plane, but I would probably have a hard time finding a runway to land on.)
If you're correctable to 20/20, then you'll pass the vision test just fine (unless there are other issues beyond what you've described). If you require glasses in order to pass, your medical certificate will have a note to the effect that you have to wear (or, "have available" in many cases) glasses while flying; that's very common, especially among pilots older than about 45, which is when presbyopia typically starts to set in.
Even 20/20 isn't strictly necessary; if you have 20/25 distant vision and good near vision, there's no need for glasses. The flight surgeon can tell you the exact limits, but since you're correctable to 20/20, that answers the specific question for your case.
The FAA has pretty straight-forward rules for vision acuity for 3rd class medical certificates, which (unless you're flying under Basic Med) is required to exercise private pilot privileges:
Near Vision: 20/40 or better in each eye separately (Snellen equivalent), with or without correction, as measured at 16 inches.
Distant Vision: 20/40 or better in each eye separately, with or without correction.