What Does Your Eyeglass Prescription Really Mean?

You’ve just had your eye exam and walk out with that little bit of paper filled with numbers and abbreviations, but what does it all mean? We’ve developed a short guide to help you understand what all the jargon on your eyeglass prescription actually means to you.

First, your prescription probably has two rows, possibly three labeled with two digit abbreviations. These are normally labeled OD for oculus dexter and OS for oculus sinister. These are simply the Latin terms for the right and left eye. Some practices have actually updated their prescriptions to simply read, RE (right eye) and LE (left eye). The third row that sometimes appears is OU, which refers to both eyes.

Next, let’s tackle the other terms you may see on your prescription.

• Sph or Sphere denotes the prescription power or how strong the lenses must be to correct your vision. The number that appears under this heading will be preceded by a plus or a minus sign. A plus sign implies that you are farsighted meaning objects close to you appear blurry. The minus signs is for nearsightedness where objects far away appear blurry. Occasionally, the sign is left off. Not to worry, this simply means you are farsighted.
• Cyl or Cylinder refers to astigmatism. Astigmatism is a condition where the cornea is irregularly shaped which causes blurred and distorted vision. If there is nothing under this heading, you do not have astigmatism.
• Axis will describe the degree and direction of the astigmatism should it be present.
• Prism refers to the amount of prismatic power needed to compensate for eye alignment issues. It’s unlikely you will have a number in this column as only a very small percentage of people suffer from alignment issues.

Multifocal lenses also require a heading titled Add. Add is the magnifying power that is only applied to the bottom part of the multifocal lenses. It is intended to correct presbyopia. This number will always appear as a plus or positive number, most likely ranging from +.75 to +3.00 D and will be the same for both of the eyes.

Once you have a basic understanding of how to read your eyeglass prescription, you begin to have a better understanding of your overall vision health. It’s important to always keep your eyewear up to date to ensure you have the best vision possible. To update your look today, rx-safety.com to see some of the top brands at the best prices.