If you cannot go without your glasses at reenactments, make period correct glasses your top priority. Most folks claim that reproduction glasses are difficult to find, or that they can't afford another pair of glasses. Fannie and Vera are here to help with a bushel of low-cost solutions. The Period Look in Eyewear Period styles did not have nose pads, but featured a contoured arch that rested on the nose for support. The temples on period eyeglasses were straight - they did not wrap around the ear.
Most photos show octagonal or oval frames.
Period frames were fashioned much like a piece of fine jewelry, with meticulous workmanship. Gold glasses were 14K gold, silver glasses were sterling. Although the thin frames seem very delicate, they were well made and sturdy. Some frames attached to a single wand in lieu of temples and were held up to the eyes for use. These glasses did not have temples, but used spring loaded nose pads that literally pinched the nose firmly to keep the glasses in place.