Sunglasses. You shouldn't leave home on a sunny day without them. Even stepping outside to let the dog into the yard can leave you squinting on a bright day. For many, sunglasses have become more of a fashion accessory than the piece of protective equipment they are intended to be. But more research is showing that having a quality pair of sunglasses is essential to the health of your eyes. Luckily, there are ever-increasing numbers of sunglasses that are protective and trendy. Unfortunately, a lot of them are also pricey. With all the options that are out there, it can be difficult to know which are the right pair for you. Here we walk you through the most important factors to consider when selecting your sunnies.
Why Invest in Sunglasses?
You worry about your skin getting sunburnt when you spend a lot of time outside, right? Well, your eyes are no different when it comes to needing sun protection. The Skin Cancer Foundation reports that UV rays are just as damaging to your eyes as they are to your skin. UV exposure has been linked to a myriad of eye afflictions from cataracts or macular degeneration to melanoma or eyelid and other eye-related cancers. The American Academy of Opthalmology also links UV rays to growths on the eye, permanent retinal damage, and even temporary blindness, which is sometimes referred to as snow blindness.
UV Protection Isn't Enough
But UV isn't the only culprit. A growing body of evidence suggests that high-energy visible light, aka blue light, can also damage our eyes. Here's how it works. Light is a spectrum of waves of differing lengths, some of which we can see. This is called visible light and makes up the rainbow as we know it. Shorter wavelengths --like violet and blue — contain more energy. Red light has the longest wavelengths of any visible light.
Sandwiching the visible light spectra are UV (ultraviolet) and infrared waves. UV light has shorter wavelengths than visible violet or blue light and is more damaging than either of them. However, one-third of visible light is made of short, high-energy violet and blue wavelengths. This chunk of the visible spectrum is blue light and is frequently referred to as HEV, or high-energy visible light. Too much exposure to them can be harmful to our eyes.
According to the latest research, blue light is beneficial in small amounts, boosting alertness, helping memory, and elevating mood as well as regulating our circadian rhythms. Getting this blue light naturally from the sun can be quite helpful to our normal daily function. In fact, The National Institute of Health states that blue light is frequently used in therapy for Seasonal Affective Disorder, a type of depression that's related to the change of seasons and amount of available sunlight.
Blue light is everywhere, and much more prevalent in our technology-driven lives than ever before. Fluorescent and LED lights contain blue light, as do many of the devices we use for hours each day such as flat-screen TVs, computers, tablets, and smartphones. According to the market research group, Neilsen, adults in the US are now spending an average of 11 hours each day consuming media, which significantly increases the amount of time our eyes are exposed to blue light even without being outdoors. With so much indoor exposure, it's becoming more important to protect our eyes while out in the sun, by investing in sunglasses that limit or eliminate HEV transmission.
Should I Worry About Infrared Light?
Infrared light carries less energy than visible light. Infrared hasn't been linked to as many damaging effects as UV radiation or blue light, but some research suggests overexposure to infrared radiation may be linked to increased frequency of cataracts. However, certain sunglasses do help protect against infrared light. If you have sensitive eyes, these glasses may be worth a gander.
Too Much of a Good Thing
Even when narrowed down to wavelengths that aren't harmful to human eyes, it's easy for our eyes to be overloaded by sheer brightness. Whether from the angle of the sun, from light bouncing off of surfaces around us, or from being at high altitude, sometimes it's just too bright. One of the most basic functions of sunglasses is to cut down on the amount of visible light entering the eye — simply put, to dim things down.The amount of light sunglasses let through is referred to as Visible Light Transmission (VLT). Glasses can be tinted to 0% VLT (think total blackout) or not tinted at all, with 100% VLT (think prescription eyeglasses or readers). VLT percentages have been sorted into five different Protection Index categories. Each is meant for different ideal light conditions. They are:
- Cat 0 (80-100% VLT): Virtually no tint, used mainly for safety glasses or eyeglasses when you need to see what you're doing clearly.
- Cat 1 (46-79% VLT): For casual use or to be used as a comfort filter (such as extended screen time), also used in cosmetic and fashion eyewear.
- Cat 2 (18-45% VLT): Common in some casual and technical sport sunglasses, good visibility and UV protection for average, daily use, and in cloudy conditions.
- Cat 3 (8-17% VLT): Extra UV and visible light protection for everyday use in brighter light conditions, such as driving, boating, or in open mountain ranges.
- Cat 4 (3-8% VLT): High level of visible and UV ray protection, not intended for everyday purposes like driving. Made for extremely bright conditions such as high altitude trekking and mountaineering.
Why Polarized? Reflected Light Hurts Too
Additionally, glare from reflective surfaces such as snow, water, or even pavement can cause eye strain and eye fatigue, leaving you with tired eyes and impaired vision that may impact your safety. Fortunately, polarized lenses help combat most types of surface glare.
Polarization works by physically blocking horizontal waves of light that bounce off of objects all around us, while still allowing vertical waves of light from direct light sources to pass through the lenses and enter your eyes. This not only helps keep your eyes from tiring out so quickly but can also help you see better while driving or when spending time on water or snow. Additionally, polarized lenses tend to increase the clarity and color of what you see, as they block superfluous light that may overload your eyes' capacity.
Confusingly, there's no perfect answer for whether or not you need polarized lenses. In general, they are great for blocking extra light and are an excellent choice for water and snow sports, driving, and other high-glare environments. But if you want to see more trail detail for something like mountain biking, you may opt-out of polarized lenses to get all the light you can. This is a preference that varies from person to person — some people find the polarization helpful in every situation while others find it to be too visually restrictive for activities requiring detailed vision.
Many sunglasses can also be purchased with polarized lenses, though many others do not provide the option. Whether or not you should use polarized lenses for your active eyewear is ultimately up to you, but there are a few things to consider. Polarization is more beneficial for people in very bright light environments where you may experience a lot of glare. For most people's everyday lives, polarized lenses are helpful and useful but not absolutely necessary. But polarization can also make it hard to read many types of electronics screens from your smartphone to your bike computer to your in-car audio display. So while there are benefits, it's a very personal choice based on your desires.
To help you decide, consider how sensitive you feel your eyes are and the amount of glare you'll be experiencing while wearing your glasses. In general, for anyone planning to spend time around reflective surfaces while driving, walking around town, boating, fishing, or hanging out on the snow, polarized lenses are a great way to make your experience more comfortable.
Types of Sunglasses
With so many harmful rays of light entering our eyes at any given moment, it's incredibly important to give those sensitive little organs the same care and protection we would give to any other part of our bodies during hazardous activity. We wear seatbelts when we drive and helmets, when we ski and bike, so wearing adequate sunglasses is a no-brainer. But with literally thousands of options available, how do you decide which sunglasses are best for you?
Decide how you're planning to use your sunglasses. Are you simply hoping to protect your eyes during average, everyday activities like driving, spending time out on the town, or for light recreation like yardwork or walking? If you're searching for more performance-based shades, for example, to wear mountain biking, you'll want to check out our cycling sunglasses review or read our full sport sunglasses review.
Many sunglasses are made of other materials and conglomerates that aren't glass. While some sunglasses do still sport glass lenses, many high-quality models are made of plastics like polyurethane, polycarbonate, or acrylic. There are pros and cons to each type of lens construction.
- Glass lenses provide the best clarity and are naturally scratch and chip resistant. However, they are also heavier than their plastic counterparts and will shatter with enough force.
- Polyurethane lenses offer supreme impact resistance while providing excellent optical clarity. They are lightweight and flexible and tend to come with a higher price tag.
- Polycarbonate lenses are very impact resistant and offer very good optical clarity. They are lightweight and tend to be more affordable, though they are also less scratch-resistant.
- Acrylic lenses are less durable and offer decreased optical clarity, which sometimes includes image distortion. However, they are an inexpensive alternative to polycarbonate lenses and are easily mass-produced.
It's possible to find sunglasses in a whole rainbow of colors these days. Beyond their appeal in fashion, different lens colors also affect how well you see in a range of light levels and conditions. Here we outline the common lens colors and their ideal applications.
Many sunglasses companies have developed their proprietary lens technologies. Digging past the trademarked names you can discover a wide variety of features both built into and coated on top of lenses. At the most basic level, you should always seek a pair of sunglasses that offer 100% UV protection. You'll also want polarized lenses if you will wear them driving or around water or snow.Beyond that, there are many coatings and features to choose from. The following is a list of the more common options.
- Scratch-Resistant Coating is a good idea for scratch-prone lenses made of plastic or polycarbonate.
- Anti-Reflective or Mirrored Coatings improve the filtration of visible light and, when applied to the inside of the lens, reduce interference glare.
- Anti-Fog Coating prevents condensation from accumulating during exercise.
- Hydrophobic Coating helps water bead and roll off lenses more efficiently, which is excellent for water sports or rainy locations.
- Oil-Repellent Coating reduces fingerprints and streaks from hair while making cleaning easier.
- Photochromic Lenses change tint levels based on the lighting. They are helpful in variable light situations but they shift slowly in colder temperatures.
- Interchangeable Lenses can be easily interchanged within the same frame. They are helpful for high-performance sports and not often found in casual or water-sport sunglasses.
While lenses are arguably the most important part of any pair of sunglasses, they also aren't worth much without a good frame to keep them on your face and protecting your eyes.
Frames are made from a seemingly endless number of materials from metals to plastics to organics. Each has its appeals and drawbacks.
- Nylon is an inexpensive, lightweight, and durable plastic that is also commonly used to make sunglass frames. There are many blends and variations of nylon, some of which are incredibly impact-resistant, flexible, and strong, making them an excellent choice for high-velocity sports glasses.
- Castor-based frames are also becoming more common on the market. Derived from castor oil (yes, from castor beans), this plastic is light, durable, and appeals to the eco-conscious consumer as a non-petroleum-based plastic.
It's also important to consider the hinge construction on your new sunglasses. Namely, if they are rigid or offer a flex fit. Flexible hinges allow the hinge to overextend, which may give a more comfortable fit for a wider face or over a long period. Flex-fit hinges also tend to be more durable and are more able to withstand impacts. They're also great for narrow-fit glasses and can provide some extra security keeping glasses more stable on your face.
No pair of sunglasses is worth it if they don't offer you the comfort and coverage you need. Because we all have a unique head and face shape and size and specific desires, this largely depends on you. Being able to go into a store to try on sunglasses is ideal, but if you're shopping online (as so many of us do these days), take note of the return policy of your new glasses just in case.
Trying your new glasses fresh out of the box, you can shake your head vigorously from side to side, or use a head-banging motion to see how much they move on your head. Too much motion is indicative of a poor fit. Just like buying clothes or shoes online, most sunglass websites provide measurements for each pair. You can compare these to a pair of sunglasses or eyeglasses that you already own to judge if they will be a good fit for your face.
Most glasses and sunglasses have their size printed on the inside of one bow. For example, our main tester's prescription sunglasses read 55 18 145 inside the left bow. This translates to 55mm wide lenses, an 18mm wide bridge, and 145mm long bows. Her regular prescription glasses are 52 18 145 - 52mm wide lenses, an 18mm wide bridge, and 145mm long bows. If you have a smaller head (like she does), shorter bows will provide a more secure and comfortable fit. If you have a narrower face (like she does) or a narrow nose, a narrower bridge will do the same. These measurements, of course, don't tell the whole story, but they're a helpful place to start when choosing the right pair for you.
The coverage you want from your sunglasses will likely change based on what type of activity you plan on doing in them. However, there are some basic considerations that you can take into account when shopping for and trying on any pair of sunglasses. You'll want to judge the overall size, shape, and curvature of the glasses and their effectiveness at keeping out dust and debris and preventing the sun from entering in the side of the glasses.
Glasses and sunglasses are often listed with a "base curve" number. This translates to the literal curve of the front of the glasses around your face. Models with a base curve of 5 are essentially flat across the front. A base curve of 6 is one of the most common builds of everyday and casual sunglasses. Several offer a base curve of 8, which is closer to a wraparound style, offering more peripheral coverage and are much more face-hugging. Glasses with a base curve of 9 are very face-hugging and often feel almost like a pair of goggles. They offer some of the best coverage of any glasses.
Knowing what base curve you need is especially important if you're planning to tackle super bright or overly windy or dusty activities, like paddling under the bright sun or visiting a desert. Considering the sunlight that will be entering from around the sides of your glasses is crucial for high-elevation expeditions and even in environments with lots of glare such as snow or open water.
Comfort is a highly subjective topic. That said, there are a few guidelines that can help you when appraising the comfort of a pair of shades. For example, it's important to consider the weight and balance of your new sunglasses. Heavy or front-loaded glasses may slide down your nose easily or cause undue strain on your ears. Additionally, you don't want the sunglasses to touch your eyelashes and maybe not want them to touch your eyebrows.
Make sure that your glasses are snug without being tight, particularly where they hug you around your ears. Some frames can be adjusted easily by an optometrist or eyeglass technician to make minor adjustments. Not all frames are adjustable though, and professionals use specific techniques to make adjustments that you shouldn't try at home, lest you damage or break your new sunnies.
Style and Versatility
The amount of stock you put into what you look like in your sunglasses is is completely up to you. You may find that it's important that your pair of everyday shades is more fashionable than the sporty sunglasses you wear to your tennis match or on your mountaineering expedition. Or you may not care at all. But most people do.
There are a million resources to search for the right sunglass shape for your face online. We like Sun Hut's interactive face shape tool. And most online sources say that aviators look good on just about everyone, so there's that.
Most high-quality sunglasses come with a protective storage case or bag. Often this is in the form of a soft microfiber cleaning/storage bag, a rigid or semi-rigid case, or possibly both. Casual, lifestyle, and water sport sunglasses are most likely to come with either a flex or clamshell-style rigid or semi-rigid case and a cleaning cloth or cleaning bag. A case of any kind is a bonus with a pair of sunglasses that will help you keep your investment protected when not in use.
With so many sunglasses to choose from, it's just a matter of searching to find a pair that matches your activity level and style and provides the eye protection you desire. While there are many things to consider while making this choice, we hope that this guide helps you understand the options that are available and find your perfect pair of shades.