Before the invention of the eye glasses, how (if at all) did civilizations diagnose vision issues, how were these people treated, & what did they determine to be the cause of near and far sightedness?

by neunietoons
grandpohbah

You might find this excellent answer by u/sunagainstgold helpful: https://www.reddit.com/r/AskHistorians/comments/8cvbs2/how_did_humans_cope_with_poor_eyesight_in_the/