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How to Buy Sunglasses: Size, Style, & Lens Guide

We have one of the largest selections of accessories on the web, a super knowledgeable staff and expert guides to help you make an informed decision.

Believe it or not, people in Seattle buy more sunglasses than anywhere in the country. When you only have to pull out the sunglasses for a few months each, you often forget where you hid them last year. That being said, we know how hard it can be to find the right pair for your face, style, and emotional needs. This buying guide is designed to help you find the right pair of sunglasses for you.

UV Protection

Although there’s no way to deny how great you look in that killer pair of shades, there’s a real reason to wear them! On top of being an awesome fashion accessory, sunglasses protect you from various forms of ultraviolet light, increasing optical clarity in bright conditions while reducing the risk of damage to your eyes.

Sunglasses are essential for people exposed to high levels of Ultraviolet (UV) light during activities like snowsports, watersports and driving in bright weather. When purchasing sunglasses, one of the most important things to look for is 100% ultraviolet (UV) protection. Even though the sun is 93 million miles away, the ultraviolet (UV) rays it emits can be a factor in causing cataracts, macular degeneration and growths on the eye, including cancer.

There are two types of UV light you need to look out for:

UVB Rays
UVB are super intense and the primary cause of sunburns and cancer, and can be very hazardous to the eyes. UVB Rays vary in intensity throughout the year and are much stronger in the summer months between the hours of 10 am and 4 pm – this is the time of year when the earth’s axial tilt is angled towards the sun, causing UVB Rays to be more focused. Although UVB rays are more intense in the summer, they possess the capacity to burn or damage skin and eyes year-round, and their effect is amplified by snow.

UVA Rays
UVA account for 95% of the UV radiation reaching the Earth’s surface. UVA rays do not vary in intensity throughout the year and although they are much less intense, they are 30-50 times more prevalent than UVB rays. In recent studies, UVA rays have also been shown capable of contributing to the development of skin cancer and photoaging, and have been linked to the development of certain types of cataracts.

Frame Size

When picking out your new sunglasses the first thing to look at is face size. Sunglass frame size should closely mirror face size - smaller frames work better with smaller faces and vice versa. Frame size refers to the actual fit of the sunglasses. This is a general rule of thumb and not to be confused with the coverage of the sunglasses. They do make oversize stunner shade for small faces. For a more specific look at the size of a pair of glasses, look at the dimensions. This is often written as three consecutive numbers: (Eye Size) – (Bridge Size) – (Temple Size). Not every manufacturer provides this info, by we have tried to include in the specs of every pair of sunglasses we can on our site.

Eye Size
This is the horizontal measurement from the outside edge to the inside edge of one lens. Typical widths are 40–62 mm.

Bridge Size
The bridge is the distance between lenses. Typical widths are 14–24 mm.

Temple Size
This is the length of the temple piece, also known as the arm piece or ear piece. Typical lengths are 120–150 mm

Frame Material

Choosing a frame material that suits your purpose is critical as it plays a huge role in the comfort, safety and functionality of your new glasses. Different materials lend themselves to different functions, price ranges and styles, and with each comes distinct advantages and disadvantages.

Metal is one commonly used material in the manufacturing of sunglass frames due to its malleability, corrosion resistance, and ease of adjustability, making it very easy to tailor to many face shapes and frame styles. Metal frames typically tend to be more expensive, less durable and are not ideal for action sports.

Nylon frames should be your go-to for sports and performance activities. Nylon frames are very resistant to temperature fluctuations, and remain super flexible while still retaining the stiffness required for safety. Companies use different brand names for their frame nylons, including Grilamid (not company specific) and O-Matter™ (specific to Oakley). Nylon frames tend to be less expensive, lightweight and stronger than traditional metal frames.

Generally found in higher-end sunglasses, Titanium frames are durable (duhh), scratch resistant, and tend to be on the pricier side of things.

This versatile, tough plastic offers serious impact resistance and can be found in many sport and safety glasses. Despite their durability, they tend to be rigid frames and are not very flexible. If you have a kid, a polycarbonate frame is a good choice for them as the frames can take a beating.

Acetate is a plastic itself, but it is a little different. Compared to a standard plastic frame (usually Acrylic or Polyurethane), Acetate frames are stronger, more flexible and generally lighter. Acetate frames can come in a huge variety of colors and textures, and since the color is imbedded in the material itself instead of painted on, the color tends to stay.

Sunglasses can be made out of a wide variety of plastic frames, from Acrylic to Polyurethane. Plastic frames are generally the cheapest frames available and can be a great option if price is an issue.

Lens Material

Optical Glass
Optical Glass Lenses are ground and polished to exacting standards to assure distortion-free vision. Optical glass is extremely durable and very scratch resistant. The primary advantages to optical glass lenses are high levels of distortion free vision and scratch resistance. The downside however is that they tend to be more expensive and when impacted sometimes spider or break, which can be a hazard for active sports.

Polycarbonate plastic lenses are the best bet for individuals who will be movin’ and shakin’ in their sunglasses. Polycarbonate lenses are made from a similar material to that of aircraft windshields and are virtually indestructible. Polycarbonate is light and scratch resistant (not scratch proof), offers a high level of optical clarity, and is 50 times more impact resistant than optical glass making for a very strong, distortion free lens. The only disadvantages are a slightly lower level of scratch resistance and optical clarity that’s not quite as good as optical glass or NXT.

NXT Polyurethane
This lens material truly is the top of the line. Combining all the benefits of optical glass with all of polycarbonates performance capabilities making NXT Polyurethane lenses the best choice for anyone willing to shell out the cash to get them. NXT lenses are made with Trivex, an advanced polymer material whose advantages include extreme impact resistance, superior optical clarity and ultralight weight.

Acrylic Lenses
Acrylic lenses are the go-to for an inexpensive sunglass solution, and an ideal choice for casual or fashion sunglasses. The primary disadvantage of acrylics is that you sacrifice some durability and optical clarity.

Lens Tints and Coatings

Different lens colors add to the performance of the lens in different lighting conditions but do not contribute to increased UV protection. Different lens colors provide an array of different looks and cause your eyes to react differently to varying light making certain colors more suitable for certain activities and conditions.


These tints are color neutral and cut down on the intensity of light without changing colors, providing crisper contrast. The darker tints in this group are made to cut glare while reducing eyestrain in slightly above average brightness situations and enhancing depth perception. These lenses are good for activities where color can be important, like driving.


Brown tints enhance the quality of light, cutting out neutral brown tones and giving the wearer increase contrast and depth perception. They can cause color distortion.


These lenses provide excellent contrast and depth perception; however, that comes as a trade of for less protection from brightness. They work well in moderate to low light conditions because of their ability to amplify the available light. Because they increase contrast in low light conditions, like overcast weather or snow, they are ideal for skiing, snowboarding and other snow sports.


Sir Elton’s favorite tint, these lenses provide great lowlight image resolution and still enhance contrast. They work by blocking the “hazy” blue end of the color spectrum and are a good choice for most activities. Rose lenses can be worn for long periods, as they cause very little eyestrain over time.


Primarily for cosmetic wear, they don’t have much functional value. Note that this is very different compared to a blue or purple chrome, which are indeed functional and useful.

Mirrored or Flash Coating

This refers to a reflective film applied to the outside surfaces of some lenses that is highly desirable for people with high sensitivity to bright light. Also, if you don’t want people to be able to see your eyeballs - for some reason - then mirrored lenses are the way to go. They reduce glare by reflecting much of the light that hits the lens surface. Mirrored coatings make objects appear darker than they are, so lighter tints are often used to compensate for this.

Lens Technology

Polarized Lenses
When light reflects off flat surfaces such as water, snow, glass, sand or pavement it is reflected perpendicular to that surface. This reflective glare is very intense and has the potential to cause increased eye irritation, eye fatigue and in some cases restricted vision (It’s called Brewster’s Angle for you science folk out there). Polarized lenses, using horizontally aligned polarizing micro crystals, block all vertical light and protect your eyes from this glare. Polarized lenses are particularly suitable for water sports, cycling and driving where there tends to be a high degree of reflective glare, but they do not offer additional UV protection.

Photochromic lenses automatically adjust to changing light intensities to protect you in a wider range of conditions (science in action). These lenses actually get darker (to block more light) on bright days, and lighter when conditions get darker. A couple of caveats: The photochromic process doesn’t happen instantly, and it takes longer to work in cold conditions. Also, it doesn't work at all when you’re inside a car (the change in tint is activated by harmful UVB rays, which don’t penetrate your windshield).

Gradient Lenses
Gradient lenses are tinted from the top down, so that the top of the lens is darkest. These lenses are good for driving, because they shield your eyes from overhead sunlight and allow more light through the bottom half of the lens so you can see your dashboard display clearly.

Double Gradient
Double gradient refers to lenses that are also tinted from the bottom up: The top and bottom are darkest and the middle has a lighter tint. Double gradient lenses are a great choice if you want sunglasses that aren't too dark, but shield your eyes well against bright overhead sunlight and light reflecting off sand, water and other reflective surfaces at your feet. These lenses are a good choice for water sports.

This is evo. We are a ski, snowboard, wake, skate, bike, surf, camp and clothing online retailer with physical stores in SeattlePortlandDenver, Salt Lake City, and Whistler. Our goal is to provide you with great information to make both your purchase and up-keep easy.

evo also likes to travel to remote places across the globe in search of world-class powder turns, epic waves, or legendary mountain biking locations through evoTrip Adventure Travel Trips. Or, if you prefer to travel on your own, check out our ski & snowboard resort travel guides, and mountain bike trail guides


Still have questions? Please give our customer care team a call at 866-386-1590, Customer Care Hours. They can help you find the right setup to fit your needs.