Bottom line. to FLY, you need 20/40 or better UNcorrected. Whether this be natural, or waivered through an appropriate PRK procedure, this is the requirement. You must also correct to 20/20 if you are worse than 20/20.
Let's say you get PRK and you after your recovery from surgery, you are 20/20 or better. But then time passes and your eye sight worsens to 20/40 before SNA selection. You could correct this with glasses back to 20/20. Would this still be ok from the NOMI perspective even though you had been waivered for the surgery?