How to Read Your Prescription

How to Read Your Prescription

How to read your prescription

There’s a lot of numbers and letters on an eye test prescription so to help you understand the jargon we’ve put together a quick guide below.

SPH - Sphere

This tells you the power of the lens needed to correct your vision. It will have either a + or a - before the number.

A minus sign ‘-’ indicates that you are short-sighted. A plus sign ‘+’ indicates that you’re long-sighted.

CYL - Cylinder

If you have an astigmatism, you will have a number under CYL. This tells you how strong your astigmatism is and how much correction is needed. The higher the number (e.g. above 4), the stronger the astigmatism. CYLs or Cylinders help to correct astigmatism by providing more power over one area of the lens.

Find out more about astigmatism here.


The axis will indicate where the CYL needs to be positioned on the lens to correct the astigmatism.

Near Add

If you have a number here on your prescription you will be wearing Varifocal lenses. It indicates the amount of correction that is needed on your distance prescription to give you your reading prescription.

Intermediate Add

Similar to the Near Vision Add, this is the amount of correction needed on your distance prescription to give you your intermediate prescription (for looking at something at mid-range, such as a computer screen).


Prisms are prescribed if you suffer from double vision. They can help the eyes work together and create one image instead of two.


The base is simply where the prism needs to be positioned in the lens when it is being made.


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If you have noticed any changes in your hearing quality or clarity, no matter how slight they may seem, visit your local M&S Opticians for your free hearing health check.


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