What kind of production facility do you have?
For high care or high risk, I have had wipes available for mobile phones. We only allowed company issued mobiles in which neatly got around any objections on potential damage. For glasses, we said no cases, but honestly didn't ask for them to be sanitised. It's a good point though, especially for reading glasses which you will be taking on and off repeatedly. Thinking outside of the box though, if you could keep your glasses in your high hygiene area, that would help. But then you'll be in the realms of buying them for your staff and providing storage.
I would say though that bigger risks exist in terms of barrier control than this (in almost every high care and high risk factory I visit I will find problems with their barrier control which are much more significant than this.) So I might be inclined to let the glasses things go on the basis of low risk. Phones, not so much. I tell you why... people use them on the toilet... 