Lens materials – what’s best for your eyes?

When it comes to shopping for a new pair of glasses, wondering what kind of lens material you’ll choose generally isn’t the first thing that comes to mind.

In fact, using the term ‘glasses’ is a bit of a misnomer nowadays – it’s rare that lenses are made with real glass anymore. Since glass lenses are heavy and generally considered unsafe because of how easily they shatter, they’re typically reserved for people with extremely high prescriptions because it offers the highest index available (1.9).

So, what are lenses made of? Well, that might depend on where you’re buying your glasses.

We’re not going to name names, but we are going to take a stand: if you care for your eyes, please do not choose polycarbonate lenses. Polycarbonate lenses became enormously popular because they are the complete opposite of glass: they’re virtually shatterproof. They became the standard choice in eyewear for people like police officers who needed uncompromising eye protection. They made their way into the mainstream because, well, who wouldn’t want shatterproof lenses? They were also marketed as feather-light and scratch-resistant. Again, who wouldn’t want that?

There are two major catches, though. Optically speaking, polycarbonate offers relatively poor clarity when stacked against other options. And that scratch-resistance we mentioned? It turns out that the core of the lens is the most durable part, but the exterior is actually not particularly scratch-resistant at all – which defeats the purpose for eyewear.

The best option for lens material is plastic. We know, it doesn’t sound very fancy. But it really is true.

If you’ve got a light prescription, CR39 plastic with a high-quality coating is your best bet. For higher prescriptions, high-index plastic (1.6, 1.67, and 1.74, depending on the Rx) will provide the best visual clarity, scratch-resistance, and lens thinness.

There is just one other lens material you may need – depending on your frame choice – that you may be less familiar with: trivex. Trivex is a special blend of materials designed for semi-rimless and rimless glasses. Standard CR39 lenses (especially in light prescriptions) can’t be made with a groove or drilled into, and it doesn’t always make sense to use a 1.6 lens for this purpose. With trivex on the market, there’s truly no reason to compromise on quality with polycarbonate.

Your optician will tell you exactly which index of lens you need based on your prescription, but now you know which material is the best for your eyes!