Choosing The Right Lens Thickness For You

When ordering your glasses you may be asked what lens index you want to choose. The lens index is a number that represents the refractive index of lens material. It is used to measure how much a lens material bends light, and can affect the thickness and weight of the lens.

When choosing your glasses, it is important to understand the different lens index options available, as they can greatly impact the appearance, comfort, and performance of your glasses, so here is a brief rundown of the different lens index options you can choose from.

picture of lenses

Standard (1.5)

This lens index is ideal for the majority of prescriptions, particularly those with weaker strength. However, if your prescription strength exceeds +3.00 or -3.00, the lenses may start to appear bulkier.

Thin (1.6)

The 1.6 lens index is a suitable choice for prescriptions within the range of +4.00 and -4.00. These lenses are approximately 23% slimmer than standard plastic lenses. However, if your prescription exceeds this range, the lenses may begin to appear thicker.

Thinner (1.67)

The 1.67 lens index is one of the most commonly selected lens options. It is about 15% thinner and 25% flatter compared to the 1.6 option. It is well-suited for prescriptions ranging from +6.00 to -6.00. However, prescriptions beyond this range may appear noticeably thicker.

Thinnest (1.74)

The thinnest plastic lens available on the market. It is around 50% thinner than the 1.5 standard plastic lens and 30% lighter than the glass equivalent. It is ideal for medium to high prescriptions, providing a slim and lightweight solution for those with strong corrective needs.

Picture of different lens thicknesses

So now you know the different types, what are the actual benefits of having thinner lenses?


  • Aesthetics - Thinner lenses with a higher index look a lot thinner and lighter. This can be an attractive option for people with strong prescriptions. Perfect if you want to avoid the 'coke bottle' effect that can result from thick lenses.
  • Comfort - Thinner lenses are often more comfortable to wear. They put less weight on the nose and ears and can reduce pressure around the eyes.
  • Clarity - High-index lenses are made from materials that bend light more efficiently. This reduces lens distortion and improves visual clarity compared to traditional lenses.

In conclusion, if you have a strong prescription, choosing a thinner lens index can result in a more comfortable, clearer, and stylish pair of glasses.