Sunglasses protect your eyes from harmful ultraviolet (UV) rays, reduce eyestrain in bright conditions and protect you from flying debris and other hazards. Finding the right pair is key to your comfort, whether you’re driving to work or climbing a mountain.
Most sunglasses block 100% of ultraviolet light. UV protection information should be printed on the hangtag or price sticker of any sunglasses you buy, no matter where you buy them. If it isn’t, find a different pair.
Types of Sunglasses
Casual sunglasses: Best for everyday use and basic recreational activities, casual sunglasses do an excellent job of shading your eyes from the sun while you drive to work and walk through town. Casual sunglasses are typically not designed to handle the intensity of action sports.
Sport sunglasses: Designed for activities such as running, hiking and biking, sport sunglasses offer light weight and an excellent fit for fast-paced adventures. High-end frame and lens materials are more impact-resistant and flexible than casual sunglasses. Sport sunglasses also typically feature grippy nose pads and temple ends, a feature that helps keep the frames in place even when you’re sweating. Some sport sunglasses include interchangeable lenses so you can make adjustments for different light conditions.
Glacier glasses: Glacier glasses are special sunglasses designed specifically to protect your eyes from the intense light at high altitudes and sunlight reflecting off snow. They often feature wrap-around extensions to block light from entering at the sides.
Sunglass Lens Features
Polarized lenses: Polarized lenses substantially reduce glare. Polarization is a great feature if you enjoy water sports or are especially sensitive to glare.
In some instances, polarized lenses react with the tints in windshields, creating blind spots and diminishing the visibility of LCD readouts. If this occurs, consider mirrored lenses as a glare-reducing alternative.
Photochromic lenses: Photochromic lenses automatically adjust to changing light intensities and conditions. These lenses actually get darker on bright days, and lighter when conditions get darker.
A couple of caveats: The photochromic process takes longer to work in cold conditions, and it doesn’t work at all when driving a car because UVB rays do not penetrate your windshield.
Interchangeable lenses: Some sunglass styles come with interchangeable (removable) lenses of different colors. These multi-lens systems allow you to tailor your eye protection to your activities and conditions. Consider this option if you need reliable performance in a wide variety of situations.
Visible Light Transmission
The amount of light that reaches your eyes through your lenses is called Visible Light Transmission (VLT). Measured as a percentage (and usually listed in the product specs), VLT is affected by the color and thickness of your lenses, the material they’re made of and the coatings they have on them. Here are some general guidelines for choosing sunglasses based on VLT percentages:
- 0–19% VLT: Ideal for bright, sunny conditions.
- 20–40% VLT: Good for all-purpose use.
- 40+% VLT: Best for overcast and low-light conditions.
- 80–90+% VLT: Virtually clear lenses for very dim and night conditions.
Sunglass Lens Colors (Tints)
Lens colors affect how much visible light reaches your eyes, how well you see other colors and how well you see contrasts.
Dark colors (brown/gray/green) are ideal for everyday use and most outdoor activities. Darker shades are intended primarily to cut through the glare and reduce eyestrain in moderate-to-bright conditions. Gray and green lenses won’t distort colors, while brown lenses may cause minor distortion.
Light colors (yellow/gold/amber/rose/vermillion): These colors excel in moderate- to low-level light conditions. They are often great for skiing, snowboarding and other snow sports. They provide excellent depth perception, enhance contrasts in tricky, flat-light conditions, improve the visibility of objects and make your surroundings appear brighter.
Sunglass Lens Coatings
The more expensive the sunglasses, the more likely they are to have several layers of coatings. These can include a hydrophobic coating to repel water, an anti-scratch coating to improve durability and an anti-fog coating for humid conditions or high-energy activities.
Mirrored or flash coating refers to a reflective film applied to the outside surfaces of some sunglass lenses. 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.
Sunglass Lens Materials
The material used in your sunglass lenses will affect their clarity, weight, durability and cost.
Glass offers superior optical clarity and superior scratch-resistance. However, it’s heavier than other materials and expensive. Glass will “spider” when impacted (but not chip or shatter).
Polyurethane provides superior impact-resistance and excellent optical clarity. It’s flexible and lightweight, but expensive.
Polycarbonate has excellent impact-resistance and very good optical clarity. It’s affordable, lightweight and low-bulk, but less scratch-resistant.
Acrylic is an inexpensive alternative to polycarbonate, best suited for casual or occasional-use sunglasses. It’s less durable and optically clear than polycarbonate or glass with some image distortion.
Sunglass Frame Materials
Choosing a frame is nearly as important as the lenses, since it contributes to your sunglasses’ comfort, durability and safety.
Metal is easy to adjust to your face and less obtrusive to your field of vision. It’s more expensive and less durable than other types, and it’s not for high-impact activities. Keep in mind that metal can get too hot to wear if left in a closed-up car. Specific metals include stainless steel, aluminum and titanium.
Nylon is inexpensive, lightweight and more durable than metal. Some nylon frames have high impact-resistance for sports. These frames aren’t adjustable, unless they have an internal, adjustable wire core.
Acetate: Sometimes called “handmades,” these variations of plastic are popular on high-style glasses. More color varieties are possible, but they are less flexible and forgiving. Not intended for high-activity sports.
Castor-based polymer is a light, durable, non-petroleum-based material derived from castor plants.
Sunglass Fit Tips
Here are some tips when trying on a pair of sunglasses:
- Frames should fit snugly on your nose and ears, but not pinch or rub.
- The weight of sunglasses should be evenly distributed between your ears and nose. Frames should be light enough to avoid excess friction on these contact points.
- Your eyelashes should not contact the frame.
- You may be able to adjust the fit of metal or wire-core frames by carefully bending the frame at the bridge and/or temples.
- You may be able to adjust nosepieces by pinching them closer together or farther apart.
Shopping online? Look for product descriptions that include fit guidelines such as “fits smaller faces” or “fits medium to large faces” for guidance. A few brands offer temples that are adjustable or come in several lengths.