Is it possible to calculate the diameter of the eye from front to back when you what kind of glasses the person needs? Like if someone needs -2 type of glasses is it possible to calculate the eye diameter? If not would it be possible to determine someones eye diameter by determine the closest point at which the person can see sharp? Thanks in advance, ive searched everywhere but couldnt find an answer. This is what someone gave me to help but i dont know if its useful? I cant contact that person right now. Thanks in advance.