It may be overkill but I carry around a stupid amount of eyewear with me in my flight bag.
I have the "must wear corrective lenses" endorsement on my licence.
I wear contacts, my AME informs me I have to carry glasses with me as well.
So I wear contacts & carry spare glasses. I also, of course have sunglasses, but I need two types. Non prescription to wear with my contacts and prescription in case I ever lose a lens and require sunglasses.
As far as I know I can't get away with just carrying the prescription sunglasses but to my mind , seeing as I wear sunglasses for about 95% of my flights, wearing ordinary prescription glasses with no tint would be almost as bad as wearing no lenses at all.
I'm lucky in that eye prescription hasn't changed since I was sixteen , so I just throw my deeply unfashionable old glasses in my flight bag!