Sunglasses protect your eyes from harmful ultraviolet (UV) rays, reduce eyestrain in extreme conditions, and protect you from flying insects and debris. Buying a pair with the right lenses is key to your comfort, whether you’re driving to work, or climbing a mountain.
This article can help you navigate the world of sunglass lenses by explaining some of the terminology and science behind the different types of lenses, materials, ad their purpose.
Polarized lenses substantially reduce glare. They are essential if you enjoy water sports, winter activities, or are especially sensitive to glare. TALEX polarized lenses are made with a patented iodine filter that reduces up to 99% UV. In some instances, polarized lenses react with the tints in older windshields, or diminish the visibility of LCD screens.
Photochromic lenses automatically adjust to changing light intensities. These lenses actually get darker on bright days, and lighter when conditions get darker. However, 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.
Blue Light Lenses
Blue light filtering lenses combat digital eye strain by reducing your exposure to blue light from smartphones, tablets, computer screens, televisions, energy-efficient lighting, and the sun. This near-clear coating also optimizes visual performance, improves visual comfort, and extends the life of your lenses. All TALEX lenses have blue light filtering to different degrees.
Anti-reflective LensesAnti-reflective lenses can reduce eye strain caused from glare, reflections, and the "halos" you see around lights. This coating makes your vision sharper and your eyes appear clearer behind your lenses. It also helps protect your lenses from scratches and smudges, and can repel dust and water. All TALEX lenses come with anti-reflective coatings that reduce the amount of reflected UV from the back of your lenses, providing the best overall UV protection possible.
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 listed in our lens guide), 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:
10–20% VLT: Ideal for bright, sunny conditions.
20–35% VLT: Good for all-purpose use.
35+% VLT: Best for overcast and low-light conditions.
80+% VLT: Virtually clear lenses for very dim and night conditions.
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 lenses won’t distort colors, while green and brown lenses may cause minor distortion.
Lighter colors (copper/amber/orange/purple) excel in moderate light conditions. They are great for skiing, snowboarding and other snow sports. They also provide excellent depth perception, enhance contrasts in tricky, flat-light conditions, and improve the visibility of objects.
Light colors (green/yellow) make your surroundings appear brighter.
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, anti-scratch coating to improve durability, and anti-fog coating for humid conditions or high-energy activities. Mirror 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. Mirror coatings make objects appear darker than they are, so lighter tints are often used to compensate for this.
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 heavy and expensive. Glass can also break on impact. Polyurethane provides superior impact-resistance and good optical clarity. It’s flexible but expensive. Polycarbonate has excellent impact-resistance and very good optical clarity. It’s more affordable, extremely lightweight, and reasonably scratch-resistant (especially with lens coatings). Acrylic is an inexpensive material best suited for casual or occasional-use sunglasses. It’s less durable and optically clear, with some image distortion.
All TALEX polarized lenses used in our Shinzo Tamura sunglasses are made from CR39 polycarbonate.