If you want something that you can fit glasses under, you will probably not have luck with the standard accurate sized helmets from TE2, AP, ATA, MRCE, etc.
There is however some accurate styled helmets that are scaled up slightly. RT-Mod makes one as well as the ANH v2.5.
You will probably want to stay away from the FX, yes it's the largest, but it's also the least accurate.
I feel your pain, being a glasses-wearing-melon-headed trooper myself