Prescription Glasses Lens Materials Explained
Standard Plastic

Often called plain 'plastic' or 'CR39'. No coatings with a refractive index of 1.5. (The higher the refractive index the more 'dense' the lens is, so the thinner it will be per unit of power) Can be easily tinted.
We use this index as standard and include a Scratch Resistant Coating on all lenses free of charge.
Hi Index Lenses.
These are lenses made from more dense plastics to make lenses thinner and lighter. They all come with the reflection free coating, so you don’t need to add that on to these lenses. With a starting price of only £30 they represent an excellent way to enhance your vision and the look of your new glasses.
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1.6 Index
Reduces thickness by up to 30%. Ideal for all prescriptions.
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1.67 Index
Reduces thickness by up to 40%. Ideal for prescriptions +/- 2 and over
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1.74 Index
The thinnest plastic lenses available, reducing thickness by up to 50%. Ideal for prescriptions +/- 4 and above. The thinnest and lightest lens material in the world.
Hi Index lenses can be tinted, but due to the technical difficulties of this, they are significantly more expensive. Please call for details.
