Understanding UV Protection in Sunglass Lenses
You need a new pair of sunglasses—but where to even begin? Beyond the many choices in frame designs, materials and colors, there are a number of other lens terms you’ve likely encountered in your search: PC, TAC, polarized and more. Before you pick up your next pair of shades, it’s helpful to understand what’s what, so you can be sure you’re buying the very best sunglasses for your needs.
UV 101: Protecting Your Eyes from the Sun’s Rays
First thing’s first: why are there so many lens types, and why does it matter? Understanding the importance of protecting our eyes from the sun's harmful ultraviolet (UV) rays is crucial for maintaining overall eye health. UV radiation, which is present in sunlight, can have detrimental effects on our eyes without taking the proper precautions.
Here are just a few reasons why having UV protection from your eyewear is so essential:
- Shielding Against UV Damage: Prolonged exposure to UV radiation can lead to various eye conditions, from corneal damage and cataracts to macular degeneration and pterygium (also known as “surfer’s eye”), among others. These conditions can require medical intervention and may even result in vision loss. By wearing sunglasses with UV protection, you effectively create a barrier that shields your eyes from the harmful effects of UV radiation.
- Preventing Acute Conditions Like Photokeratitis: Photokeratitis, often referred to as "snow blindness" or "sunburn of the eyes," is a temporary but painful condition caused by excessive exposure to UV rays. It typically occurs in environments with high UV levels, such as snowy mountains or sunny beaches. Symptoms can include redness, tearing, sensitivity to light, and sensation many describe as burning or “gritty.” Sunglasses can help to prevent this unpleasant experience from happening to you.
- Long-Term Eye Health: UV damage accumulates over time, and repeated exposure can have a compound effect on your eyes. By consistently wearing sunglasses with proper UV protection, you can greatly reduce the long-term risks associated with UV radiation, including the development of age-related eye conditions that can flare up and impact your vision later in life.
- UV Reflection: It's important to note that UV rays can reflect off surfaces such as water, sand, snow, and even concrete. This means that even on cloudy or overcast days, UV radiation can still reach your eyes. Therefore, wearing sunglasses with UV protection is essential year-round, regardless of the weather conditions.
For a deeper dive into ultraviolet radiation, check out our guide to understanding the UV index, including an exploration of the types of UV rays and the best ways to understand your risk on any given day. The bottom line is that UV protection should go way beyond protecting your skin. Investing in high-quality sunglasses with proper UV-blocking protection is an effective way to safeguard your eyes from potential harm and maintain optimal eye health throughout your life.
Common Lens Terminology
Knowing that sun protection is key for both short- and long-term eye health, it’s time to pick out lenses. This is where an understanding of the basic types and terms comes into play.
Polycarbonate (PC) Lenses
Polycarbonate lenses are a sunglass lens type made from a thermoplastic material known for its exceptional durability and impact resistance. These lenses are thinner and lighter than traditional plastic lenses and are more shatterproof than glass lenses, making them ideal for a variety of sports and outdoor adventures. They also offer excellent UV protection, blocking harmful rays that can cause eye damage and vision loss.
The material's inherent resistance to scratches and other forms of damage makes it an excellent choice for individuals who enjoy an active lifestyle. Overall, polycarbonate lenses provide reliable eye protection, comfort, and durability, making them a popular choice for sunglasses.
Triacetate Cellulose (TAC) Lenses
TAC lenses are a type of multi-layer, polarized sunglass lens made from cellulose acetate, a material derived from wood pulp. These lenses feature a polarizing filter that reduces glare from reflective surfaces, such as water or snow, making them ideal for a number of outdoor activities—particularly high-octane summer activities, and winter sports like skiing and snowboarding. TAC lenses are also lightweight and shatter-resistant, providing superior protection against impact damage, and ensuring they are safe to wear during highly active pursuits.
TAC lenses are also designed to enhance color and clarity, allowing for more vivid and accurate vision, particularly in bright sunlight. Additionally, these lenses offer excellent UV protection, shielding the eyes from harmful rays that can cause long-term damage. Fun fact: all Panama Jack polarized lenses are made from TAC material, while our non-polarized sunglass lenses are made from PC.
So, wait—what exactly are polarized lenses then? This is a type of sunglass lens designed to reduce glare and enhance visual clarity. Polarized lenses feature a specialized polarizing filter that blocks reflected light, reducing the glare from shiny or reflective surfaces including water, snow, and even slick or otherwise “shiny” roads. This makes them ideal for outdoor activities, such as driving, fishing, or skiing, where excessive glare can be hazardous and visually distracting.
Polarized lenses are available in a range of colors and tints, each offering different amounts of light transmission and contrast enhancement. They also provide excellent UV protection, shielding the eyes from harmful rays that can cause long-term damage.
UV400 lenses are a type of sunglass lens that blocks nearly 100% of ultraviolet (UV) light with wavelengths up to 400 nanometers. These lenses provide superior protection and are designed to filter out both UVA and UVB rays, which can penetrate through the eyes and lead to long-term vision problems. They are available in a range of lens colors and tints, each offering different levels of visible light transmission and contrast enhancement. UV400 lenses are a desirable quality in a new pair of sunglasses, as they not only protect your eyes but also help reduce glare and enhance visual clarity.
Scratch-resistant coating is a protective layer applied to the surface of sunglass lenses to prevent scratches and other forms of damage. This coating is typically made from a hard, clear material that bonds to the lens surface, creating a barrier that helps to resist abrasions, smudges, and other types of wear and tear.
Scratch-resistant coating enhances the durability and lifespan of sunglass lenses, ensuring that they remain in good condition even with regular use. Although scratch-resistant coating does not make lenses completely scratch-proof, it does significantly reduce the risk of damage, making it a worthwhile investment for anyone who wears glasses on the regular.