A Guide to High-Index vs. Polycarbonate Lenses

Whether it’s the first or umpteenth time, picking out new lenses for your eyeglass prescription can be a little overwhelming. After all, there’s a plethora of choices. You might need single-vision lenses to tackle myopia (nearsightedness), astigmatism (an irregularly shaped cornea), and hyperopia (farsightedness). There are also bifocals and progressive lenses for those who need to toggle between near and far vision.

And then there’s the lens material to think about. From high-index and polycarbonate lenses, there's a lot to consider when choosing a lens type.

That’s why we created this guide on high-index vs. polycarbonate lenses. Focusing on these two commonly used lens materials, you’ll learn their pros and cons to decide which eyeglass lenses you should choose.

High-Index vs. Polycarbonate Lenses 101

Let’s begin by finding out what high-index and polycarbonate lenses are.

What Are High-Index Lenses?

High-index lenses are made of plastic lens material with a high refractive index.

For those new to the concept, the index of refraction measures how light travels through the material, aka refraction. Different materials have different refractive indexes.

For example, standard plastic lenses — like Columbia Resin 39 (CR-39) lens — typically range from 1.48 to 1.54. Meanwhile, high-index and ultra-high-index lenses rank at around 1.64 and beyond.

What Are Polycarbonate Lenses?

Polycarbonate lenses, also called “Poly C” lenses, are a type of plastic lens widely used in prescription and non-prescription glasses. They are especially popular for kids’ eyewear, safety glasses, and sports accessories like swimming goggles because of their durability.

Similar to high-index lenses, polycarbonate lenses have a high refractive index of around 1.59. This makes them ideal for low-to-high prescriptions, like the ones at Pair Eyewear.

High-Index vs. Polycarbonate Lenses: Which Is Better for You?

If you’re having a hard time deciding on high-index vs. polycarbonate lenses for your new pair of glasses, here are some key factors to consider.

Prescription Strength

High-index lenses are favored for stronger prescriptions, thanks to their high refractive index.

Generally speaking, eyeglass lenses with a higher index need less material to bend light. That’s why most opticians and optometrists recommend normal index lenses for low to moderate prescriptions. High-index lenses allow you to wear higher prescriptions without thick lenses that give you a “bug-eyed” look.

Polycarbonate lenses also score relatively high on the refractive index, so this lens material is good for strong prescriptions, too. But they’re especially useful if impact resistance is at the top of your list of needs.

Impact Resistance

Wearing glasses doesn't mean you need to think twice before signing up for soccer camp or kicking up your heels on the dance floor. With the right lens choice, you can ensure your spectacles withstand your most energetic activities.

That’s where Poly C lenses triumph in the high-index vs. polycarbonate debate.

Polycarbonate lenses are highly revered for their formidable impact-resistant properties. For context, these lenses can hold up to five times the impact of CR-39 lenses, which are pretty durable themselves.

When pitted against the more brittle high-index lenses, polycarbonate lenses are much less likely to break and shatter. That’s why most eyewear for kids and sports are made with polycarbonate lenses.

Visual Clarity

When debating high-index vs. polycarbonate lenses, some may argue that one potential downside of the latter is their relatively low Abbe value of 30.

Abbe value refers to how well the lens disperses light. Lenses with lower Abbe values have higher dispersion, resulting in chromatic aberration. That means light rays of different wavelengths focus on different points when they pass through the lenses. This leads to unwanted color distortions — think rainbow-like glares around the lens’ edges.

For that reason, a high Abbe value is usually preferred if you want better visual clarity and comfort with your eyeglasses.

However, if you have your sights set on the impact resistance of polycarbonate lenses, you have options. Some manufacturers, like Pair,have a workaround solution in the form of an anti-reflective coating to cut down on visual distortions.

Still, if you think you’ll be better off with high-index lenses, we'd like to point out that these lenses also typically have a low Abbe value of around 32 to 42.

Lightness and Thinness

High-index vs. polycarbonate lenses — which is lighter and thinner?

Strictly speaking, high-index lenses are thinner than polycarbonate ones. In fact, high-index plastic lenses are some of the thinnest lenses on the market.

The reason? High-index lenses are flat in the front and the back to achieve their high refractive index. For nearsighted prescriptions, the eyeglass manufacturer can flatten the lenses even more to make the center as thin as 1.5 millimeters without compromising their impact resistance. For reference, the lens thickness of standard CR-39 lenses is around 2.0 millimeters.

That said, thinner lenses don’t necessarily weigh less. High-index lens material is actually heavier than polycarbonate. So, if lightness is something you prioritize in your eyewear, a lightweight pair of polycarbonate glasses might be less likely to cut into your nose and ears.

Scratch Resistance

You may have heard that glass lenses are the best at scratch-resistant protection and may extend the longevity of your eyewear. Unfortunately, this type of lens is also the most breakable and can be dangerous when shattered.

For safety purposes, it’s best to choose high-index plastic lenses, which are generally scratch-resistant. The plastic material is less likely to break upon contact.

Meanwhile, polycarbonate lenses are not very scratch-resistant. But that shouldn’t put you off them, given their impact resistance. You can always request an anti-scratch coating to protect your glasses.

Cost

Those on a budget may favor polycarbonate lenses over high-index ones.

The latter incurs higher costs during manufacturing. That's because high-index lenses need a greater degree of precision during cutting and grinding to create their distinctive curves. This, in turn, hikes up the prices for consumers like you.

On the other hand, polycarbonate lenses are much cheaper to produce, which means you pay less for the glasses. Case in point: Pair Eyewear’s frames start as low as $60, including the prescription lens options!

What Other Factors Should You Consider?

You’re officially an expert on high-index and polycarbonate lenses, but what other factors should you consider when buying new glasses?

Once you select your lens material, you have a few more choices to make before your new pair of glasses is set:

Frame Material and Shape

Now that you’ve decided on your lenses, it’s time to move on to the frames.

Glasses are commonly made of a few materials, namely metal, titanium, and plastic. Metal frames tend to be lightweight and thin — if you want a minimalist, frame-that-’s-barely-there effect, this might be the material for you.

Titanium — though technically a type of metal — is in a category of its own, as these frames have become especially popular in recent years. One of the biggest benefits of titanium frames is that they’re even light yet extremely durable.

They’re even hypoallergenic… but unfortunately, they can also be pricey.

The final material you’ll encounter in your search is plastic. Plastic frames are usually thicker than metal and titanium, which means they can support thicker lenses for higher prescriptions. They can also be designed to come in any color or pattern you can dream of.

Once your frame material is chosen, it’s time to consider frame shape. The rule of thumb here is the same as in romance: Opposites attract. That means that if you have a round or oval-shaped face, a square or rectangle frame shape will look great on you.

Conversely, a rounded frame can perfectly balance the angular features of a square or rectangular face.

Lens Customization

Even after you’ve picked out your lens and frame materials, chosen a shape that’s suited to your face, and reached the checkout stage, there are still more choices you have to make — this time, about lens customization.

Two common customizations are blue-light filters and light responsiveness. Blue-light filtering lenses can be a great choice if you spend a lot of time working on your computer or frequently experience digital eye strain. These lenses filter out the blue light emitted by the sun and electronics (such as smartphones, computers, and TVs).

Your other choice is light-responsive lenses. These lenses immediately start to darken when they’re exposed to UV rays, including both direct and indirect sunlight. Once you go back inside, they fade back to clear lenses.

If you hate the hassle of swapping between glasses and sunglasses or have a family history of eye disease, light-responsive lenses might be ideal. Conversely, if you spend a lot of time indoors and at a screen, consider blue light-blocking lenses.

Finally, if you’re somewhere in between, many manufacturers let you add both options.

Price Point

Just like when you’re clothes shopping, it’s a good idea to go into the process with a price point in mind. In terms of lenses, the most economical option is polycarbonate lenses. For frame material, look for a pair made of durable, high-quality plastic, such as cellulose acetate.

Regardless of the choice you end up making, try out the frames you’re thinking of buying before you make your purchase. It's crucial to get a sense of how they actually look on your face and if they match your personal style.

With Pair’s virtual try-on feature, you can now do this from the comfort of your home!

High-Index vs. Polycarbonate Lenses: The Choice Is Yours

There are various pros and cons for high-index and polycarbonate lenses that can help you determine the right fit for your next pair of glasses.

For instance, if you have a high prescription try high-index lenses for their thinness. That said, if you value lightness and durability, then polycarbonate lenses may be the wiser choice here.

No matter which type you end up with, high-index and polycarbonate lenses can be combined with an aspheric design to make the eyeglasses aesthetically thin. Those looking for UV protection may also be interested in transition lenses that darken in the presence of sunlight. And if you want to minimize the uncomfortable symptoms of computer vision syndrome (read: digital eye strain), opting for blue-light lenses may help.

For eyeglass wearers interested in polycarbonate lenses, Pair Eyewear will become your go-to brand in no time. We offer this as our standard lensoption in single-vision and progressive lenses treated with an anti-reflective and anti-scratch treatment. If thinness is what you desire, our Premium lenses boast 1.67 ultra-thin lenses made of lightweight glass. There are also our light-responsive lenses to protect your eyes from harmful UV rays.

And the best part? Our prices start as low as $60 with a huge collection of fun designs (aka our Top Frames) to suit everyone.