What Lens Thickness Should I Choose?

The lens thickness of your glasses is an important consideration when ordering your next pair of prescription glasses online. Your lens thickness will differ depending on your prescription - the stronger/higher your prescription values, the thicker your lens.

You can mitigate thicker lenses caused by a strong prescription or PD by choosing a lens with a higher refractive index. This index is an indicator of how much light is bent as it travels through the lens. The more the light is bent, with a higher refractive index material, the thinner the lens can be.

Your lens options

There are four different refractive index options (thicknesses) to choose from when ordering your next pair of glasses:

Our standard lens, which you receive when ordering a Value, Bronze, or Silver Pack, has an index of 1.499.

Our thin lens, which you receive when ordering a Gold Pack, has an index of 1.60.

Our thinner lens, which you receive when ordering a Gold+ Pack, has an index of 1.67.

Our thinnest lens, which you receive when ordering a Platinum Pack, has an index of 1.74.

What lens thickness should I choose?

Short-Sighted

If you're short-sighted (negative SPH values), the edge thickness of your lenses will be much more visible and you'll see a clear benefit from selecting a higher refractive index lens.

For Sphere values between -2.50 and -4.00, we would recommend selecting at least a 1.6 index lens (Gold Pack). For values above this and between -4.00 and -6.00 we strongly recommend selecting a 1.67 index lens (Gold+ Pack), and for any prescription over -6.00, a lens of index 1.74 (Platinum Pack).

Outside of your lens selection, we also recommend choosing a full-rimmed plastic frame which will hide the edge thickness much better than a metal one. And try to choose a frame with a lens diameter below 50mm. The larger the diameter, the larger the edge thickness will be.

Far-Sighted

If you're far-sighted (positive SPH values), the centre thickness of your lenses will be more prominent and you will also see benefits from selecting a higher refractive index lens.

For Sphere values between +2.50 and +4.00, we would recommend selecting at least a 1.6 index lens (Gold Pack). For values above this and between +4.00 and -6.00 we strongly recommend selecting a 1.67 index lens (Gold+ Pack), and for any prescription over -6.00, a lens of index 1.74 (Platinum Pack).

Outside of your lens selection, we also recommend choosing full-rimmed plastic frame which will hide the centre thickness much better than a metal one. And try to choose a frame with a lens diameter below 50mm. The larger the diameter, the larger the edge thickness will be.

You can select any of these packages with any strength of prescription, and the choice is entirely yours. However, if you have a +/-6.00  and above values with a bronze pack, your lenses may be thicker than you would wish for.

To keep your lenses as thin as possible and for best results - if your prescription is high, then stay away from semi-rimless frames or large frames where the lens diameter is large such as the aviators. This will always cause the lens to be thicker.

Please email us at or call us on 01489 572340 for any advice on which lens might be best.

Choosing Lens Thickness FAQs

What factors determine the thickness of my lenses?

The thickness of your lenses is mainly influenced by your prescription strength, the lens material's refractive index, and the size and shape of your chosen frames.

Higher prescription strengths usually require thicker lenses, but selecting a higher refractive index in our more premium lens packs (gold or platinum for the strongest prescriptions) will result in thinner lenses.

What is the refractive index, and how does it affect lens thickness?

The refractive index measures how efficiently a lens material bends light. Materials with a higher refractive index can bend light more effectively, allowing for thinner lenses even with stronger prescriptions.

Which lens thickness is suitable for my prescription?

For short-sighted (myopic) prescriptions, lenses with a 1.6 index are recommended for SPH values between -2.50 and -4.00, a 1.67 index for values between -4.00 and -6.00, and a 1.74 index for anything over -6.00. For far-sighted (hyperopic) prescriptions, the same index levels apply to corresponding positive SPH values.

Thinner lenses improve comfort and appearance by reducing obvious thickness and weight. Visible thickness is further reduced by using smaller lens diameters (less than 50mm) and full-rimmed plastic frames with higher index lenses.

Are thinner lenses more expensive?

Yes, lenses with higher refractive indices, which are thinner, generally cost more due to the advanced materials and manufacturing processes involved. At Glasses2You, we strive to offer high-quality, thinner lenses at prices that stay affordable, ensuring you receive exceptional value without compromising on performance or look.

Do thinner lenses affect visual quality?

Thinner lenses made from high-index materials provide excellent visual clarity. While high-index lenses may have slightly lower Abbe values, leading to minor chromatic aberrations in rare cases, the benefits of reduced thickness and enhanced aesthetics far outweigh these minimal effects.

Can I choose any frame style with high-index lenses?

While high-index lenses are compatible with most frame styles, selecting smaller frames is highly recommended, as they can help maintain a thinner lens profile, which is particularly helpful for higher prescriptions. This can help with the comfort and aesthetic appeal of your frames.

How can I reduce the weight of my glasses?

Choosing high refractive index lenses can decrease lens thickness and weight. Selecting smaller frames and materials can also reduce the overall weight of your glasses.

Will high-index lenses fit in rimless or semi-rimless frames?

Yes, high-index lenses are suitable for rimless or semi-rimless frames. Their durability and reduced thickness make them a good choice for these frame styles.

Feel free to contact us for advice or to learn more about the best lenses for your frame style. We're here to help!