Contact Lens Prescription vs Glasses: Complete UK Guide

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         Contact Lens Prescription vs Glasses: Complete UK Guide   March 14, 2026   
             SEO Tapita 

        Contact lens and glasses prescriptions are not interchangeable. While both correct vision, contact lens prescriptions include additional measurements (base curve and diameter) because contacts sit directly on your eye's surface, unlike glasses which sit 12mm away. You cannot use one prescription for the other without a proper contact lens fitting.

Got your glasses prescription and ready to order those gorgeous colored contact lenses you’ve been eyeing? Hold on you’ll need a different prescription first. This isn’t just a technicality; it’s a legal requirement in the UK and crucial for your eye health.

This comprehensive guide explains exactly why glasses and contact lens prescriptions differ, what those mysterious abbreviations mean, how to get your contact lens prescription in the UK, and everything you need to know about prescription requirements for colored contact lenses. Whether you’re switching from glasses to contacts or simply curious about the differences, you’ll have complete clarity by the end.

Aspect

Glasses Prescription

Contact Lens Prescription

Distance from eye

12mm away from eye

Directly on eye surface

Measurements included

SPH, CYL, AXIS, PD

SPH, CYL, AXIS, BC, DIA

Validity period (UK)

2 years

1 year

Fitting appointment required

No

Yes (legally required)

Colored lens options

N/A

Requires prescription even for 0.00 power