Whether or not you can wear contacts after Lasik depends upon the same factors as it does before the surgery. My understanding is that with people whose prescriptions are less than 10 diopters 95% have vision correction to 20/40 or better after the surgery (meaning you can drive without glasses).
My doctor has a great webpage that explains a lot about the different types of surgery and what they are doing today that is at the forfront of medical technology.
I work with a guy who had -13 in one eye and -15 in the other. He is now -2 & -3. He is sad that he doesn't have perfect vision but he can walk around without glasses on now, whereas he never could before.
It is amazing what they can do. Hopefully, by the time I get presbyopia they will have a cure for that too!
Laura