How do I select reading glasses before I have an eye exam?

Answer:
Assuming healthy eyes that see well without glasses at distance, you can determine the correct power by trying on differently powered readers at your local drugstore. When you find a power that gives you clear reading vision when holding your book or phone at a comfortable distance, go ahead and purchase. You would need an ophthalmologist if you wear glasses for distance, have an irregularly shaped cornea (astigmatism) or other eye disease. It is considered good practice to have an eye examination by an ophthalmologist when you enter your 40s—the time when reading glasses usually become necessary anyway. This will establish a baseline for you and protect your eye health as you age.