Plenty of folk with glasses do parades in the RAF and as I believe your dress regs are a direct extract from ours it'll probably be the same. ACP1919 is a little dated from what I can remember about the copy I've got gathering dust in Clothing Stores.
SWO's used to have a thing about folk who have to wear tinted glasses or only had 'defence specs'.
The new dress regs for the RAF are being sent out at the mo so that'd probably be your best port of call.
There is an electronic copy available via the MoD Intranet if you have access.