I know plenty of guys that still wear glasses or eventually got corrective surgery. I don't think it's a show stopper.
You may get called port holes, nerd, or 4 eyes though. So make sure you got some thick skin to go with that prescription eye wear
On a more serious note it's usually a requirement that your vision be no worse than whatever is in writing for the medical standards, and correctable to whatever the standards may be. In training youll just wear glasses when you shoot and take them off when you swim. Most of the guys that needed corrective surgery did it when they got to their teams, or between selection and the pipeline. I can't speak how other branches do their business, but we typically had faster turn around times/priority for the corrective eye surgery appointments