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
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 lens index
High lens index
Low lens index
Low lens index
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
Choosing a frame for low-index lenses
Recommended glasses frames for high-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 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
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
Round
Round frames are ideal as they have a smaller lens space which disguises your low index lens.
Plastic
Plastic is an ideal material choice for heavier low index lenses as it is lightweight.
Recommended glasses frames for low-index lenses
Round
Round frames are ideal as they have a smaller lens space which disguises your low index lens.
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
How to shop for lenses with the best index for you:
Can’t find what you are looking for or need advice?
Talk to one of our Opticians
Can't find what you are looking for or need advice? Talk to one of our 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.
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.