I had towear both ear plugs and muffs for most of the time I was working on flight lines while in the USAF. I have a hi frequency hearing loss from all the jet engines small gas turbine engines and unmuffled gas or diesel engines that I worked on or was around all day.
Wearing any type of glasses does make muffs a lot less effective.
From 15 years of wearing both, I strongly recomend a properly fitted set of ear plugs. Keep them clean. Any time you are going to be in a noisy area wear them.
Even now after almost 20 years after leaving the USAF, I still have some ringing in my ears at times. I know it will never change and have gotten used to it but hope you do not have to.
