Lens index page

Lens Index

Discover which lens thickness is best for your vision needs

What is lens index?

Lens index or refractive index is a numerical representation of the thickness of your lenses. As this number increases, the lenses become thinner. The index indicates how efficiently light is bent as it passes through the lens.  

Lens Index

Lens
Index

What is lens index?

Lens index or refractive index is a numerical representation of the thickness of your lenses.

As this number increases, the lenses become thinner. The index indicates how efficiently light is bent as it passes through the lens.  

High Index
High lens index
Thinner lenses, besides being lighter, more comfortable, and visually pleasing, cater to a wider range of vision needs, including high prescriptions.
High index lenses
High lens index
Thinner lenses, besides being lighter, more comfortable, and visually pleasing, cater to a wider range of vision needs, including high prescriptions.
Low Index
Low lens index
Lower-index lenses are more affordable, but the thicker the lens, the more you compromise on comfort. Also, they are only suitable for lower vision correction requirements.
Low lens index
Lower-index lenses are more affordable, but the thicker the lens, the more you compromise on comfort. Also, they are only suitable for lower vision correction requirements.
low index lenses

Which lens index is best for you?

The choice between lenses depends on your prescription and lifestyle. When reading your prescription note that the SPH value indicates the amount of lens power prescribed for (-) or (+). The CYL value is not always included in prescriptions; it indicates the power of your astigmatism correction.

Which lens index is best for you?

The choice between lenses depends on your prescription and lifestyle. When reading your prescription note that the SPH value indicates the amount of lens power prescribed for (-) or (+).

The CYL value is not always included in prescriptions; it indicates the power of your astigmatism correction.

Check out our lens comparison guide below to see the qualities of each lens.

Lens thickness based on prescription

Lenses can be thickest in the center or at the edges, depending on the prescription. Our aspheric lenses reduce central thickness as they have a flatter curve.

Plus lenses

These lenses are thickest in the center, like a magnifying glass. They are used to correct farsightedness (hyperopia). The numerical prescription is always marked with a plus (+) symbol.

Minus lenses

These lenses are thickest on the edges. They are used to correct nearsightedness (myopia). The numerical prescription is always marked with a minus (-) symbol.

Lens thickness based on prescription

Lenses can be thickest in the center or at the edges, depending on the prescription. Our aspheric lenses reduce central thickness as they have a flatter curve.

Plus lenses

These lenses are thickest in the center, like a magnifying glass. They are used to correct farsightedness (hyperopia). The numerical prescription is always marked with a plus (+) symbol.

Minus lenses

These lenses are thickest on the edges. They are used to correct nearsightedness (myopia). The numerical prescription is always marked with a minus (-) symbol.

Recommended glasses frames for high-index lenses

As a high index prescription holder, you can choose from a range of thinner frame styles, check out our recommendations.
Wire frame
Wire frame

Slim wire frames work with high-index prescriptions as there is no excess thickness.

Rimless
Rimless

As you are not disguising thick lenses, why not try rimless elements?

Semi rimmed
Semi-rimless

Still want the style of having a frame? Experiment with semi-rimless glasses.

Recommended glasses frames for high-index lenses

As a high index prescription holder, you can choose from a range of thinner frame styles, check out our recommendations.
Wire-Frame
Wire frames

Slim wire frames work with high-index prescriptions as there is no excess thickness.

Rimless

As you are not disguising thick lenses, why not try rimless elements?

Rimless
Semi-Rimmed
Semi-rimless

Still want the style of having a frame? Experiment with semi-rimless glasses.

Do

Consider the thickness of the lens: low-index lenses are thicker than high-index lenses, so choose a frame that’s thicker.

Prioritise frame size: smaller frames ensure a comfortable fit and a lighter weight.

Consider aesthetics: your glasses should match your style and face shape. There are many frame options available.

Don't

Choose rimless or semi-rimless frames: these styles may not support the weight of low-index lenses effectively.

Disregard lens treatments treatments like anti-reflective coatings can make lenses appear thinner by reducing glare.

Overlook the fit: if your glasses are too loose or too tight, they can cause discomfort.

Choosing a frame for low-index lenses

Choosing a frame for low-index lenses

Do

Consider the thickness of the lens: low-index lenses are thicker than high-index lenses, so choose a frame that’s thicker.

Prioritise frame size: smaller frames ensure comfort and a lighter weight.

Consider aesthetics: your glasses should match your style and face shape. There are many frame options available.

Don't

Choose rimless or semi-rimless frames: these styles may not support the weight of low-index lenses effectively.

Disregard lens treatments: treatments like anti-reflective coatings can make lenses appear thinner by reducing glare.

Overlook the fit: if your glasses are too loose or too tight, they can cause discomfort. 

Recommended glasses frames for low-index lenses

As a low-index prescription holder, there are fewer frames suitable for the thickness of your lens. We advise the following frame styles.
FUll rim
Full-rim

Full-rim glasses create a smaller lens space, hiding your thicker lenses.

Round frames
Round

Round frames are ideal as they have a smaller lens space which disguises your low index lens. 

Plastic
Plastic

Plastic is an ideal material choice for heavier low index lenses as it is lightweight.

Recommended glasses frames for low-index lenses

As a low-index prescription holder, there are fewer frames suitable for the thickness of your lens. We advise the following frame styles.
Full-Rim
Full-rim

Full-rim glasses create a smaller lens space, hiding your thicker lenses.

Round

Round frames are ideal as they have a smaller lens space which disguises your low index lens. 

Round
Plastic
Plastic

Plastic is an ideal material choice for heavier low index lenses as it is lightweight.

How to shop for lenses with the best index for you

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How to shop for lenses with the best index for you:

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Our optical experts

Our optical experts

Speak to a certified optician

Got questions about eye care? We’re here to help.

For guidance you can trust, ask our in-house opticians.

Speak to a
certified optician

Got questions about eye care?

We’re here to help. For guidance you can trust, ask our in-house opticians.

FAQs

A 1.50 index lens refers to a type of lens with a refractive index of 1.50. In the case of a 1.50 index lens, it means that the lens material has a moderate level of light-bending capability. These lenses are generally thicker than higher-index lenses. They are often used for prescriptions with moderate levels of correction.

In terms of lenses we have everything from high to low index with add-ons and coatings such as anti-scratch and Impact X resistance. For more information about everything from lens materials to progressive lens options, check out our Lens Hub.

Our thinnest lens is the Ultra Thin 1.74 index lens. It is 60% thinner than the basic lens making it more lightweight and comfortable.

High-index lenses such as our Ultra Thin 1.74 lens are considered an investment due to the sleek thinness of the lens and the longer labour process. As it is our most premium package, the price reflects this.