I have read that in certain, intense, high stress situations like a home invasion that your adrenaline is running so high that gun blasts don't hurt your hearing, or your eyesight.
I think it's more that you don't notice it, even though incremental damage is still being done. I know when I have a deer or pheasant in the sights that rifle/shotgun sounds like an airgun! But, a few unprotected blasts over the course of a lifetime probably won't cause much noticeable damage. I think it's the cumulative effect over time that's a problem.
