Lol i Dont my friend. I dont know.
you know what i have always wondered that, also if they look through a window and use Amaterasu on a tree will the window or tree catch on fire? same with on mirror will they burn themselves or the mirror?
Sharingan genjutsu is just the transfer of chakra through ones eyes into the others. Glasses dont change the amount of chakra that gets transferred.
As for a mirror, it would be the same effect as casting genjutsu on a wall. Glass is just light reflecting material, it doesnt reflect chakra.
Would the lenses in the glasses increase or decrease the effect on the targeted individual?
Or what happens if they perform genjutsu on themselves in a mirror?