Your Eyeglass Prescription Made Simple
Now that you just finished having your eye exam, you have your prescription in your hand and you’re wondering what style eyeglass frames will look best on you. You also happen to look at your prescription and start to wonder what all those letters and numbers exactly mean. Whether you’ve worn glasses for years, or this is your first time, understanding your prescription will give you an insight into the health of your eyes as well as your overall health.
DEMYSTIFYING YOUR EYEGLASS PRESCRIPTION
Most of the time you will find that your eyeglass prescription is written in a grid-like format. It will contain terms, abbreviations, and numbers.
Along the left-hand side, you might see these abbreviations. Here is what those abbreviations mean:
O.D.: This is oculus dexter, meaning right eye.
O.S.: This is oculus sinister, meaning left eye.
O.U.: This is oculus uterque, meaning both eyes.
Along the top, you might see different verbiage that generally has to do with measurements related to different aspects of your vision.
SPH: This is short for sphere, and basically tells you how powerful your prescription needs to be in order to correct your vision.
If you happen to see the letters ADD, this is how much more power you need if you are getting bifocals or progressive lenses.
CYL: This is short for cylinder. If you see this, this indicates astigmatism. This is a condition where the cornea is irregularly shaped and causes blurred or distorted vision. It also tells the lens strength needed to fix it.
AXIS: This describes the direction and degree of your astigmatism.
ADD: This is the added magnifying power you need in the lower part of a multi-focal lens. It’s used to correct presbyopia (the inability to see up close).
UNDERSTANDING THE NUMBERS
There will be a number included on your prescription for each aspect of your vision that needs to be corrected. The further from zero that the numbers are, the more correction you need.
You will see a plus sign or minus sign in front of your eyeglass prescription, and that number is shorthand for farsightedness or nearsightedness.
A “+” means that you are farsighted (trouble seeing things close up).
A “-” means you’re nearsighted (trouble with seeing far away).
DO YOU HAVE A SINGLE VISION OR MULTI-FOCAL PRESCRIPTION?
Prescriptions look different depending on if you have a single or multi-focal prescription.
If you have single vision correction, this means your vision is corrected for either farsighted or nearsighted, but not both.
For single vision prescriptions, the “ADD” column will be blank. For bifocal or progressives (multi-focal) prescriptions, your lenses will correct your vision for both near and far, and often times intermediate as well. For these prescriptions, you will see a number in the “ADD” column.
To keep your eyes in optimal health, you should have an annual eye exam. This will also ensure that your contact or eyeglass prescription is up-to-date.