If you have less than perfect vision, you might be wondering how to read your glasses prescription.
However, there are important reasons why the prescription is written the way it is.
Eyeglasses prescriptions use the same standard format and common notations.
Verywell / Alex Dos Diaz
This makes them universal, meaning that they can be read anywhere in the world.
The article will help you decipher an eyeglass prescription by walking you through what the terminology means.
OD vs. OS
Providers who write eyeglasses prescriptions may include Latin abbreviations.
While they have been used for a long time, Latin abbreviations are becoming less common.
OD is an abbreviation for the Latin termoculus dexterand refers to the right eye.
OS is an abbreviation for the Latin termoculus sinisterand refers to the left eye.
Nearsighted people have trouble seeing things that are far away.
Farsighted people have trouble seeing things at all ranges.
Cylinder (CYL)
The next number is the “cylinder” measurement.
On your prescription, “cylinder” might be abbreviated as “CYL.”
The cylinder measures the amount of astigmatism in your eye.
The number shows how much lens power will be needed to correct astigmatism.
This number is an angle in degrees from 0 to 180.
It is the part of your eye that does most of the focusing.
This addition helps a person see better for reading and other activities that they do up close.
Younger people’s prescriptions usually do not have an ADD number.
While some young people can have near-focusing problems, it usually develops as you approach 40.
ADD vs. To get the right number, you should probably do a little math.
To find the right reading glasses, add the sphere number to the ADD number.
Next, look at the cylinder measurement and the axis measurement.
Astigmatism is typically not corrected in over-the-counter reading glasses.
In addition to terms and abbreviations, eyeglasses prescriptions also include a lot of numbers.
These numbers indicate how much correction your vision needs.
The higher the number, the more correction your vision needs.
One of the numbers, the axis, refers to the location of your astigmatism.
If you don’t have astigmatism, you won’t see an axis number.
The plus sign refers to farsightedness and the minus sign refers to nearsightedness.
If you are farsighted, distant objects appear clearer than closer ones.
Your glasses will be designed to correct your specific problem.
The greater the number next to the plus or minus sign, the more correction you need.
Summary
Your eyeglasses prescription may include Latin abbreviations, numbers, and mathematical signs.
These numbers are used to describe thecorrection you needin your glasses.
A plus sign next to the number means you are farsighted, while a minus sign means nearsightedness.
The higher the number, the more correction your vision needs.
What is astigmatism?
Astigmatism is a curvature of the eye that makes your vision blurry or distorted.
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