You are welcome to wear your glasses when paddleboarding, we suggest an older pair though as sometimes they fall off. If you would like to wear glasses then it is at your own risk but we do have some glasses leashes available for you to borrow.
For surfing it is harder to keep glasses on, if you really need to see then some people have used prescription goggles!
We have had many people wear contact lenses for both activities and generally these seem to fare better! (you do need to keep your eyes closed when in the water though!)