Your eyeglasses prescription explained, what each term means.
So you have had your eye exam and you have your latest prescription and you are wondering which glasses to buy.
We will explain what all those numbers mean. It does not matter if you have worn glasses for a long time, or this is your first eyeglasses prescription we will explain what all the numbers mean.
A good understanding of the prescription will tell you how healthy your eyes are, and what would be the best lens choice for you.
Prescriptions are usually written like the examples below.
Usually you will see abbreviations along the left side.
OD- This stands for Ocular Dexter, a latin term for Right Eye.
OS- This means Ocuclar Sinister, meaning left eye.
Then on the top there is:
Sphere (SPH) This is the overall eyeglasses prescription power, this is how strong your lenses need to be to correct your vision.
Cylinder (CYL) indicates astigmatism, a condition where the cornea is irregularly shaped, causing blurred and distorted vision. It also gives the lens strength needed to correct it.
Axis- This is extra power added to the lower part of a multifocal lens. It corrects a condition called presbyopia, which is when the eyes cannot focus on near things due to age.
Each optician’s shop will have different prescription forms, but they should all hold the same information.
You can either upload your prescription directly to us, or you can enter it prescription box on our website, when you are ordering your frames.
How to read your Prescription?
So, you have had your eye test and have been given your glasses prescription, but what do all the numbers mean?
In this example, the first number is called the “spherical power,” (SPH) and this is what tells us if you are short sighted, (-) like this example, or (+) long sighted.
The second column ( CYL ), is cylinder power. This tell us how much astigmatism is present.
The next column is ( AXIS ). This will always be a value between 1 to 180 and relates to the orientation of the CYL power.
If your prescription does not contain a PD (Pupillary Distance) value, then check out our ” How to measure your PD”