I have no idea why I pronounce it glARSes ... just my upbringing. Neither is wrong or right, just different.
In my little gang.. we call them Sasssssses... But when I'm in public I'm known to add an R into every word on the planet
My 'home counties' accent indicates that it's "glarses" all the way... :H .. which I have a plan to ditch and go back to my loverly contacts.