Deciding between the many different types of glasses lenses available is an important step within your vision-correction journey. Whether you need a high-strength prescription lens or a milder correction, it’s likely you’re going to have a long conversation with your optometrist before landing on a new pair.
Being prepared while discussing options is the best way to avoid discomfort or dissatisfaction with your new pair of glasses, and in this guide we’ll be covering the most common and useful lenses you may be able to wear.
Why is wearing the right type of lens important?
Finding the best type of lens for your glasses is just as important as figuring out which shape you should choose. Picking the wrong lens could mean headaches or eye strain in your future, so make sure you understand all of your prescription options before picking out a new pair.
Your glasses lenses should last just as long as your frames if you take good care of them – luckily, some of the most common modern day lens materials are naturally scratch-resistant and hard to shatter.
Different types of glasses lenses
Glasses lenses were historically made from glass, as their overall name implies. However, over time plastic lenses have become immensely popular due to their reliable, cheap, and modular nature. In fact, most lenses are now made from plastic instead of glass; but let’s begin by first going over the different types of lenses before covering what they’re made from:
Single-vision lenses
Single-vision lenses are known for being super versatile – depending on your unique situation and depth-perception ability, you’ll likely be able to use single-vision prescription glasses whether you’re nearsighted, farsighted, or have astigmatism.
These can be manufactured to work with eyes that have trouble seeing things up close or far away, and are often the go-to choice for reading glasses and computer glasses.
Bifocal and trifocal lenses
If you have trouble seeing both at a distance and up close, there’s a pretty good chance you’ll end up with some bifocal lenses. These lenses feature a section to help you see things at a distance, but also have a smaller magnifying lens situated on top that aids with difficulty seeing things up close.
Trifocals, on the other hand, are separated into three different sections. In other words, they help you see things up close, at a distance, and in between – perfect for someone who really just struggles to see things at any distance.
The defining feature of multifocal lenses is that they have a physical line on the lens that separates the magnification; this dividing line can be bothersome for some, as it does tend to look a bit dated compared to progressive lenses.
Progressive lenses
One of the most popular modern options, progressive lenses are designed for eyes with issues seeing objects at varying distances without the need for distinct lines or sections on the lens itself. Basically, these prescription lenses blend multiple together, offering you a more aesthetic and comfortable version of multifocal lenses.
Progressive lenses accomplish the same thing as multifocal lenses, but tend to do so in a more fluid manner – instead of having to move your head or glasses around to focus on something up close or far away, you can enjoy a seamless blended lens experience.
Other prescription lenses
If you have more unique vision issues that are difficult to fix, your doctor may prescribe you rarer kinds of lenses. These types of lenses for glasses are important, but most of us with standard vision issues will not have to wear them.
For example, prism lenses are triangular shaped lenses added to glasses to improve eyesight issues like double vision, binocular vision, or even problems brought on by neurological conditions.
What materials are eyeglass lenses made from?
Not only are the frames of most types of glasses manufactured using plastic nowadays, their lenses are as well. Plastic frames and prescription lenses are cheaper and easier to adjust – and they also tend to last longer than glass. Because plastic reflects more light than glass, most optometrists consider it superior in terms of clarity and usefulness in correcting whichever vision issues you may have.
There are are main two things to be aware of when discussing lens materials:
- Refractive index: the lens index of glasses describes the light bending abilities of a specific lens material, with higher values correlating with more powerful vision correction
- Abbe value: this number is what we measure the ability of a lens to disperse light with – higher values resulting in clearer pictures
CR-39 lenses
CR-39 is the standard kind of lens most eyeglass companies use, as it’s not only affordable but also works quite well in a variety of situations. Made from poly allyl diglycol carbonate (PADC),
CR-39 lenses are naturally scratch resistant, easy to combine with other lens treatments, and offer an overall clear picture. Compared to glass, CR-39’s ability to present optically clear images is almost the same – you would most likely be unable to tell the difference based on sight alone.
CR-39 eyeglass lenses have a high Abbe value of 58 and a mid index value of 1.5, making them one of the best choices for those who want consistently clear peripheral vision.
Polycarbonate lenses
Not quite as common as CR-39 lenses, polycarbonate lenses are a softer type of plastic popular for glasses with UV protection or lightweight models that can still remain shatter-resistant (but not as soft as contact lens plastic). As a softer plastic, polycarbonate is easier to scratch compared to CR-39, so if you’re used to different lenses it may take awhile to get used to your new pair with polycarbonate lenses.
Polycarbonate lenses come with an Abbe value of 30, which means you will experience more peripheral blurriness when wearing these lenses compared to CR-39.
Trivex lenses
Trivex is another type of plastic (big surprise there) with a high-impact resistance rating, similar in many ways to polycarbonate lenses. Compared to polycarbonate, Trivex lenses weigh less and are capable of presenting clearer peripheral vision – however, CR-39 still beats them both in that category.
This material also offers a high UV-protection rating due to its composition, making it a good choice for those who work outside in the sun. Not only that, but its impressive impact resistance rating means it’s often the favored material among construction workers or other occupations involving lots of wear and tear.
Trivex lenses have an Abbe value of 42-45, which is lower than CR-39 but higher than polycarbonate.
High-index lenses
High index lenses are designed with a higher refractive index in mind – these lenses are thin, lightweight, and comfortable to wear. Unfortunately, high prescriptions often result in thick, unsightly lenses; high index lenses aim to solve this discomfort through their thin but effective design.
One downside to wearing high index lenses is that as you increase the index, you’re more likely to begin seeing peripheral aberrations on the sides of your lens, which can be annoying for some people.
High-index lenses come with an Abbe value between 32-36, depending on your prescription.
Glass lenses
Glass is still used today to make lenses, but it is much less common than the options mentioned above. A material with lots of pros and cons involved, the main benefits of using glass include its level of optical clarity and its ability to resist scratching – glass has the best optics overall.
It’s also very easy to manufacture thin glass lenses compared to plastic lenses, which is often necessary as glass also happens to be the heaviest material. Aside from its weight, another downside of using glass is that it’s much easier to break or shatter, even if it’s resistant to scratches.
Glass lenses have an Abbe value of around 58, but it can be lower depending on the overall index being used.
Other lens features to be aware of
There are plenty of add-ons, lens coatings, and other features you can have tacked on to your glasses nowadays, many of which serve specific purposes for those with unique vision issues that require correction, including:
- Anti reflective coating: a type of coating that helps improve the ability of a lens to reflect light and improve the overall image quality
- Hydrophobic coating: also known as fog-proof or waterproof eyeglass lenses, hydrophobic coatings are made up of a thin layer of water-repellent that keeps your glasses dry
- Scratch resistant coating: coatings that are specifically designed to reduce the chance your lenses will be scratched up or marked, which can make them nearly unusable if bad enough
- Clear blue light filter: blue light filters help specialized blue light glasses reduce eye strain and other issues associated with staring at digital devices and screens for long periods of time
- Amber blue light filter: similar to the above, blue light can also effectively be filtered using amber-tinted glasses that feature stylish lenses
- UV filter: sunglasses and other related lenses use special UV filters which are more effective at protecting your eyes from harmful UV rays than standard glass or plastic
- Polarized lenses: along the same vein as UV filters, polarized lenses for glasses are a kind of treated lens that block light and glare from reaching your eyes once filtered through a tinted chemical coating
Final thoughts
If you aren’t an optometrist, it’s likely you never considered the real differences between various types of lenses for glasses. But, if you’re going to be wearing them everyday it’s nice to have a general idea of what’s going on behind the scenes – for more information related to your vision and what can be done to correct it, make sure to check out the rest of our blog content.