Are contact lens and glasses prescriptions the same?

On the surface, contact lens and glasses prescriptions might seem the same. After all, they’re both designed to improve your vision through a single lens. However, there are actually a few key differences between the two optical prescriptions that you should be aware of.

In this guide, we take a look at these differences and whether or not you can convert your contact lenses prescription to a glasses prescription – and vice versa.

What’s the difference between a glasses prescription and a contact lens prescription?

With your glasses, the vision correcting lenses are positioned away from your eyes by around 1-2cm, whereas contact lenses sit directly on your eyes. For this reason, the two prescriptions read very differently. When undertaking an eye test, your optician will test your eyes differently based on this.

First things first, you’ll need to get to grips with your contact lens or glasses prescription. Our guide to understanding your glasses prescription might help.

When it comes to contact lenses, the strength of your prescription may occasionally differ to your glasses prescription. Contact lens prescriptions also contain additional parameters that are not included on a glasses prescription. These differences are demonstrated with the below example prescriptions.

Example glasses prescription

  Sphere (SPH) Cylinder (CYL) Axis
DISTANCE R -1.00 -0.25 140.00
L -1.25 -0.25 120.00


Example contact lens prescription

  Power Base Curve (BC) Diameter (DIA) Brand 
R -1.00 8.8 14.0
L -1.25 8.8 14.0


Can I convert my contact lens prescription to a glasses prescription – or vice versa?

Sphere and Power display the strength of your prescription and often remain the same regardless of a contact lens or glasses prescription. However, it is not possible to accurately convert one into the other as you will be missing other important parts of the prescription, such as CYL or AXIS data. Most contact lens prescriptions follow a similar base curve and diameter, however, we would always recommend getting your contact lenses professionally tested – particularly if you’re a first-time wearer as there are many different brands and materials to choose from.

Deciding which is right for you

There’s often much debate around contact lenses or glasses and making the decision really depends on your lifestyle factors. There are certainly pros and cons to both. For example, glasses are really easygoing and there are plenty of styles to choose from, but contact lenses are virtually invisible and most people won’t even know you’re wearing them. To decide which is right for you, read our guide to glasses vs contact lenses.

If you’re a glasses convert, then you’re in the right place. Buying glasses is serious business – and that’s why we’re here to help. When it comes to buying your first pair online, there can sometimes be too many to choose from. However, our range of women’s glasses and men’s glasses are available to try on at home – for free!

With our try before you buy glasses service, you can choose up to four pairs of glasses (or sunglasses) to try on at home for an entire week. Show them off to your friends and family before deciding which pair (or pairs) you’d like to buy. There’s no commitment and no fuss. We’ll even pack a returns label in the trial set for you.

Take a look at our Instagram to see how other customers like you have enjoyed our try before you buy service!