What Are High-Index Lenses, and Do You Need Them?

What Are High-Index Lenses, and Do You Need Them?

You’ve just had your annual visit with your optometrist, and you’re headed to your optician to get your new frames. You already know you’re going to be shelling out some dough for your new eyeglasses, but you might not know whether you need some of the available options your eyewear retailer offers. 

One such option is high-index lenses. These sound high-tech, and they’re usually offered with some type of marketing phrase that includes the words “thinner lens.” Thinner lenses seem like they’d be lighter weight, more comfortable, and less noticeable, so you might be thinking of pulling the trigger and paying more than double the cost of standard lenses to get them. 

Not so fast. High-index lenses do have an important seat at the vision correction table, but it’s important to understand that not everyone needs them. The eye care experts at Stoggles appreciate the fascination with the latest and greatest innovations, but we also know that not every new technology is right for every person (or even necessary).

We’ll give you the skinny on these thinner lenses and let you know what they are and what they do, and help you decide whether or not you actually need them. First, a little backstory about how eyeglasses work (trust us, this is important).

How Do Eyeglasses Work?

Eyeglasses help correct refractive errors. Refractive errors are caused by issues with the shape of the cornea or the length of the eyeball, or issues from aging lenses. These issues usually lead to four main problems: nearsightedness, farsightedness, astigmatism, and age-related vision impairment:

  • Nearsightedness. Also known as myopia, this is the most common type of refractive error. It causes objects far away to appear blurry, but objects close up to be clear. 
  • Farsightedness. Also known as hyperopia, this is like the counter-error of myopia. It causes distance vision to be clear and near vision to be blurry.
  • Astigmatism. This type of refractive error happens due to a misshapen cornea. This causes light to refract incorrectly and hit the retina (where your vision actually happens) in a way that is misaligned. This causes issues with all fields of vision (near, far, and intermediate).
  • Presbyopia. Like hyperopia, presbyopia causes near vision to decline while distance vision remains sharp. However, the cause of presbyopia isn’t an issue with the length or shape of the eye but rather a decline in the lens with age. 

Eyeglasses and contact lenses work by bending light properly so that it hits your retina square on, and not above, behind, or beside it. How hard the lens has to work to correct your error is referred to as the lenses’ refractive index

The more significant your refractive error, the more powerful your lenses’ refractive index. A higher refractive index typically equates to a thicker, heavier lens. Before you start thinking your strong prescription will mean you have to wear Coke bottle glasses, keep in mind that modern technology has significantly reduced the weight, thickness, and visibility of vision correction on lenses themselves. 

Bottom line: Even if your prescription is +4.00 or higher and corrects several refractive errors, you don't have to wear thick bifocals to see clearly. 

What Are High Index Lenses?

Eye care innovations have come a long way, and lens material is now thinner, more lightweight, and better at correcting your vision. There are numerous different types of lenses available to correct your vision and offer some unique bonus features, like darkening when you are exposed to UV light. 

High index lenses are unique because they’re able to bend and refract light more effectively than other types of lenses. This means they’re capable of a stronger refractive index, allowing someone with a very high prescription to get the vision correction they need without the bulk of a heavier lens.

How Do High Index Lenses Work?

High index lenses are typically plastic lenses. You can get glass high index lenses, but they’re rarely recommended over high-index plastic. During the manufacturing process, the plastic used in high index lenses is treated so that they have a higher index than standard plastic lenses.

Who Needs High Index Lenses?

The main benefit of high index lenses is that they correct stronger prescriptions with less material. If your prescription is +/- 4.00, you could benefit from high index lenses, which will probably be the thinnest option. 

If your script is lower than +/-4.00, high index lenses aren’t really necessary. If you want to be able to say, “I have high index lenses,” that’s probably the extent of the benefits you’ll really appreciate. 

How Does High Index Stack Up Against Other Lenses?

For all their ability to correct your vision with a thinner lens, high impact lenses don’t offer the same benefits as other lens types, which may make them a non-viable option for some users. 

Polycarbonate Lenses

These types of lenses are impact-resistant, provide crystal clear vision, and are able to correct strong prescriptions. They aren’t quite as thin as high index lenses, but they’re a solid option for eyewear that won’t shatter the first time you drop them. 

Conventional Plastic Lenses

Most plastic lenses aren’t as impact-resistant as polycarbonate and not nearly as thin as high index. These types of lenses offer some impact resistance and are good for correcting weaker prescriptions, but for higher prescriptions and more shatter resistance, you’ll want to consider polycarbonate and/or high index. 


The highest index available comes in the form of glass. It’s superior in optical quality to any other material but not so superior that the average person is going to notice. The reason why most people opt out of glass lenses is because they break easily and weigh more, making them fragile and uncomfortable… and downright dangerous. Imagine a glass lens breaking right in front of your eye — although it’s rare, why take the chance when the alternatives are pretty great, too? 

If you need the highest level of optics available, glass is your go-to. If you aren’t repairing watches or inspecting diamonds all day, you can probably opt for a high index plastic or even conventional or polycarbonate which still gives you clear vision and excellent optics.

What Should You Know About Single-Vision and Multivision Lenses?

If you have more than one refractive error to correct, you’ll need multivision lenses. These lenses originated as bifocals, evolved into trifocals, and are now available as progressive lenses. 

Progressive lenses have a gradient that helps blend the fields of vision correction from one to the other, but it still takes a little practice learning to use these types of eyeglass lenses. You can find progressive high index lenses, polycarbonate lenses, and glass lenses. 

Single-vision lenses correct one type of refractive error only. If that refractive error is strong and your prescription requires a higher index of refraction, high index lenses might be a good option. 

What Are the Disadvantages of High-Index Lenses?

They’re powerful, lightweight, and a great way to avoid thicker lenses, but there are some disadvantages of high-index lenses. 

They’re Pricey

We don’t mean just a few bucks extra, either. You can expect to pay more than double the cost of regular lenses if you opt for high index. Even lower-end retailers still add on anywhere from $50 to $150 for selecting the high-index option. 

Durability Is An Issue

You know yourself best, and if you tend to be hard on your eyewear, these might not be the best option. High index lenses are more fragile than other types of plastic. You might also notice scratches sooner than you do with other types of lens material. There’s usually an option to add an anti-scratch coating to your lenses if you still decide on the high index option. 

They Reflect Light More Easily

High index lenses tend to reflect light more easily than other types of lenses, which can be problematic. If you’re in bright light or if you’re driving, the glare from reflected light might make it hard to see. If you decide on high-index lenses, it would be worth it to spring for the anti-reflective coating, which will add about $50-$100 to your total prescription glasses bill. 

Bottom line: If you have a higher prescription, high index lenses are a life saver, unless, of course, the think lenses look appeals to you. They’ll cut down on lens thickness, feel comfortable, and prevent you from thick, “bug-eye” looking lenses. If you don’t have a high prescription, you can get thin lenses in the form of a less expensive material, like polycarbonate. 

At Stoggles, we use polycarbonate for our lenses and frames to create lighter lenses that are impact-resistant and protective. We also go to great lengths to make sure your safety eyewear never looks or feels like safety eyewear. 

Stoggles: Safety Eyewear That Slaps

Keeping your eyes safe is important, and Stoggles does it in style. Every pair of Stoggles we create comes standard with safety features you need and style you also need. 

Let’s be honest; if your safety eyewear isn’t attractive, you won’t wear it, and that makes it incredibly unsafe. 

ANSI Z87.1-2020 Certification

Our Stoggles are made from polycarbonate material that is incredibly durable and shatter-resistant. We test it to meet ANSI Z87.1-2020 standards, which means it has passed high-velocity impact tests with flying colors. 


Your lenses might be high index, but do they fog? Fogging lenses are unsafe and annoying. We coat every pair of Stoggles we make with an anti-fogging compound so you never have to remove your eyewear to wipe them down.

Side and Top Shields

It only takes one injury to realize you should’ve opted for safety eyewear. Regular glasses leave your eyes vulnerable by the temples and near the eyebrows. Stoggles gives you protection in these areas with side and top shields which are low profile and streamlined so you can still look stylish and don’t have to take on the dreaded safety glasses look.

UV and Blue Light Blocking

Intrusive light can damage your eyes, which is why you’ll find every pair of Stoggles comes with blue light-blocking lenses that also block UV light. 

Style Superiority

We don’t mean to brag, but we will anyway. Our style is second to none. We offer unexpected frame shapes and colors that match your personality. No matter what you love in terms of shape and color, you can find it at Stoggles and finally break up with those bargain bin safety glasses once and for all. 

High Impact Safety

High index lenses might be a good option for you if you have a strong prescription, but safety eyewear is always a good option. Only Stoggles gives you the ability to keep your eyes safe and your style protected at the same time. 


Refractive Errors | National Eye Institute

Astigmatism, Hyperopia, and Myopia | Boston Children's Hospital

What Is Astigmatism? Symptoms, Causes, Diagnosis, Treatment | American Academy of Ophthalmology

Refractive Index - StatPearls | NCBI Bookshelf

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