If your lens is glass, you can remove with a little acetone, which removes the nail polish.?But be careful not to touch the frame of the glasses, because you can despintarlos, or if plastic shell / mica is damaged.?If your lens is mica, not try to use acetone, do not resist.?A cotton can moisten with a little acetone, sizes not hard, try soaking the dried loctite.
I suggest you to put your sunglasses into warm water and then try to remove the loctite. Or you can take them to a nearby sunglasses store to ask some opticians to remove the loctite for you. Good luck!
This depends on which kind of material your sunglasses belong to. If the lenses of your sunglasses are made by glass, you can put them in warm water, different material will swell to different extend. So we can use this theory to help remove the loctite. But if the lenses are made by plastics, this way may not work. It will be very hard for you to remove them, and you may need to turn to an optician. And the UV coating may be removed from your lenses too.
Last time, I got some loctite stain on my lenses. I scratched them off by nails. But later I found that I shouldn't do that because my lenses get some scratches. Later, my friend told me that I should use sunglasses cloth other than napkins, toilet tissue or paper towels and I shouldn't use my nails to scratch the lenses. The best way is to ask for help from an optician.