Are contacts and glasses prescriptions the same?

Feb 28, 2019 in Glasses & Sunglasses

Close up of woman wearing glasses

Glasses and contact lenses work in the same way – correcting the path of light entering your eyes. So surely the prescriptions are interchangeable? We take a closer look.

If you’re reading this, there’s a good chance you’re wearing glasses or contact lenses – and we hope you’ve already had two different check-ups, giving you a glasses prescription and a contact lens specification. But you’ve probably wondered if it’s possible to convert your contact lens specification to glasses, or the other way around.

It’s certainly true that glasses and contact lenses both work on the same principle. They’re both lenses that correct focus misalignments with your eyes by properly directing light rays onto your retina. But as lenses are a medical device, things aren’t quite that simple.

Here’s why.

Are contacts and glasses prescriptions different?

The answer to this question is a definitive ‘yes’. Glasses and contact lens prescriptions are different, despite in some cases looking very similar.

Despite some online ‘experts’ telling you how easy and reliable it is to do so, we can assure you it is not recommended that you convert your prescriptions yourself. The simple reason is that contact lenses and glasses lenses are inherently different – glasses sit in front of your eyes, while contact lenses are in direct contact with your eyeball.

This fundamentally changes the way they refract light, and this affects their corrective power (or dioptre). The corrective power is only one aspect measured during your eye test – we also measure and note the shape and size of your eye.

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Some lenses will also have other details, a specification is not complete unless it contains the manufacturer, lens type. The three measures illustrated above and any other specific details allowing 100% accurate ordering and replication.

For contact lenses in particular, different brands use different materials, fittings and thicknesses, and these all impact the final prescription. In other words, don’t guess, estimate or convert your contact lens prescription. It might be tempting, but it shouldn't be done.

You need an eye test for each

If you wear glasses and are interested in contact lenses, or the other way around, pop into your local Leightons branch and have an in-depth chat with one of our experts. In the meantime, take a look at this article to help you choose between glasses and contacts. Let your optometrist use their expertise to guide you through the different lens options and find the right contact lens specification for you.

Book your contact lens or glasses eye tests today

If you’re ready to get going, you can book an appointment online at your nearest Leightons branch or call us on 0800 40 20 20.