How to Read an Eyeglass Prescription

Knowing how to read an eyeglass prescription could save you money and time when trying to purchase new lenses, especially if you're going to a new doctor or ordering online. To learn what your prescription means and how to read it, follow a few simple steps.

Instructions

• 1

  Take note of the numbers your doctor is writing down during your eye exam. Ask questions and ask what each measurement refers to. This will give you a better understanding of the numbers on your prescription.

• 2

  Ask your doctor for a copy of the prescription and ask to again go over what each of the numbers mean. Most prescription lens websites will offer a guide to help you understand the numbers as well.

• 3

  Look at the prescription. The OS means your left eye and the OD means your right eye. There will be a plus or minus sign in front of the numbers. A plus sign means you're farsighted and a minus sign means you're nearsighted. The higher the numbers, the more your vision needs correction.

• 4

  Check to see if you have an astigmatism. If you do, your prescription will look like this: S x C x Axis, where the S is the sphere (the negative or positive number used to determine the degree of nearsighted or farsightedness), C is the cylinder (the negative or positive number used to measure the focusing power of your lens), and Axis refers to the amount of curvature in the lens from 0 to 180 degrees. Your prescription should look something like this: -2.75 +1.00 x 45.

• 5

  Order your glasses by reading the different elements of the prescription. Make a follow-up appointment after you receive the lenses to make sure they work for you.