I'd prolly best stick with my optician,. He knows how to adjust them just right, so they 're not so tight as to as to trigger my TN, but not so loose as to keep falling off (unless I bend down) . On the other hand, some less -than-ideal spares would be a boon, if affordable
And I don't think my oprician would mind. if I didn't get all my glassses from him. He's an incredibly nice guy , who does his best to save me money where he can.