Reviewed by: Dr. Matthew Miller, OD on May 13th, 2020

High Index Lenses

Lens index is a number that describes how thick or thin your lenses are. The higher a lens' index is, the thinner it becomes. Higher prescriptions require higher index lenses, while lower prescriptions require lower index lenses.

Lens Indexes at EyeBuyDirect

Lens Indexes

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What are high index lenses and what's the difference?

High index lenses are thinner, more powerful lenses. They're lightweight and stylish, but are mostly reserved for those with higher vision correction needs. While most prescriptions are compatible with more than one specific index, it's up to you to decide which one fits your personal needs!

The difference between your glasses' lens index can make a huge impact. Deciding which you should get depends on your prescription and your lifestyle. Thicker lenses are more affordable, but can only accommodate lower vision correction needs. Thinner lenses are lightweight (and more stylish!) and can accommodate MANY kinds of vision needs, including higher prescriptions. In terms of balancing price and quality, 1.59 index polycarbonate lenses accommodate most prescriptions and are extra durable.

Lens thickness comparison

Recommended lens index

Lens index Features SPH CYL
Lens index 1.5
1.5 INDEX LENS Conventional single-vision lenses. Available starting from $0. + 2.25 to -2.25 +/- 2.00
or below
Lens index 1.57
1.57 INDEX LENS For people with moderately-strong prescriptions. Thinner and lighter than standard lenses. -2.50 to -5.00
or
+2.50 to +5.00
+/- 3.00
or below
Lens index 1.59
1.59 INDEX LENS Made with premium polycarbonate. Features 100% UV protection. Durable and impact-resistant. -4.25 to -6.75
or
+4.25 to +6.75
-2.25 to -3.00
or
+2.25 to +3.00
Lens index 1.6
1.6 INDEX LENS Stylish and extra-thin. Great choice for stronger prescriptions. -4.25 to -6.75
or
+4.25 to +6.75
-2.25 to -3.00
or
+2.25 to +3.00
Lens index 1.67
1.67 INDEX LENS Extremely thin. Good choice for extra-strong prescriptions. -7.00 to -9.00
or
+7.00 to +9.00
-3.25 to -4.00
or
+3.25 to +4.00
Lens index 1.74
1.74 INDEX LENS As thin as possible Best for the highest prescriptions. +/-9.25 and above -4.25 to -6.00
or
+4.25 to +6.00

What lens thickness should I get?

The lens thickness you should get depends on your prescription and your lifestyle. Thicker lenses are more affordable, but can only accommodate lower vision correction needs. Thinner lenses are lightweight (and more stylish!) and can accomodate ALL kinds of vision needs, including higher prescriptions! A good compromise lies in 1.59 index polycarbonate indexes, which accommodate most prescriptions and are extra durable.

How do I measure my PD?

Measuring your pupillary distance (PD) is super simple. While you can probably have your local optometrist help you measure it, you can also do it yourself! Just follow these easy steps on our special "How to Measure Pupillary Distance guide". The only thing you need is our free-to-print PD ruler.

How do I measure my PD?

You’re all set!

Now you’re all clear on the best lens index for your prescription; you’re ready to explore our massive range of men and women’s frames.

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FAQ

What are high index lenses made of?

High index lenses are made with a particular type of plastic that refracts light more effectively than standard index lenses. This usually means that they can be cut thinner than other lenses while providing perfect vision correction for stronger prescriptions.

Do high index lenses make eyes look smaller?

High index lenses cause less distortion than lower index lenses with the same prescription. If your prescription is high and your lenses are large, it can result in your eyes looking smaller or larger, depending on whether you are near or farsighted. High index lenses reduce this effect.

Why are high index lenses so expensive?

High index lenses are usually more expensive than lower index lenses because they’re made with more costly materials. The benefits of high index lenses make the extra cost worth it, though!

Why are my glasses lenses so thick?

If your eye prescription is high, your lenses will need to be cut thicker to correct your vision correctly. Luckily, choosing higher index lenses for your glasses means they can be thicker and still correct your vision perfectly.

Do I need high index lenses?

If you have a high eyeglasses prescription, high index lenses are recommended to ensure that your lenses are as thin as possible. As well as looking good, thin lenses reduce the total weight of your eyeglasses, making them more comfortable to wear for long periods of time.

How thick are polycarbonate lenses?

EyeBuyDirect’s polycarbonate lenses are cut at a 1.59 lens index. We recommend these lenses for medium-strength prescriptions. Polycarbonate lenses are naturally 100% UV blocking and extra durable.

How thick will my lenses be?

You can select the thickness of your lenses at EyeBuyDirect by choosing a lens index. The stronger your prescription is, the higher the lens index available to you. If you want your lenses to be as thin as possible, it’s a good idea to choose the highest lens index available to you.