So, you've just had an eye exam and your optometry and optician has given you an eyeglass prescription. He or she probably mentioned that you are nearsighted or farsighted, or perhaps you have astigmatism.

But what do all those numbers on your eyeglass prescription mean? And what about all those abbreviated terms, such as OD, OS, SPH and CYL?

This article will help you read and understand your eyeglass prescription so you can discuss it with an optician when you buy new eyeglasses .