The latest technology has provided many high performance sun lenses designed to enhance your vision while outdoors. There are basically 4 types of sunglass lenses: Polarized, Photochromic, Mirror, and Constant Density.
Polarized lenses are specially designed to filter out the components of light that cause glare. These lenses are available in polycarbonate, plastic and glass. Suitable for activities near water and snow.
Photochromic lenses change from light to dark and back again based on varying light conditions. These lenses are recommended for people who wear sunglasses in a variety of light conditions.
Mirror lenses have a shiny metallic coating applied to the front lens surface that creates the mirror look. The mirror reflects some of the light and adds an extra buffer against glare.
Constant Density lenses remain constant in color and in the amount of light that they transmit. They provide excellent glare protection for sports and outdoor activities.
What are the differences in lens color or tints? The color of the lens is usually a personal decision, but here are some facts to keep in mind:
Gray or green-tinted: Offer the least amount of color distortion; good for all-purpose use and clear days.
Amber and orange: Block blue light, offering a brighter view on cloudy, hazy, or foggy days.
Gold and yellow: Add contrast; best in flat and dim-light situations.
Brown: Best for enhancing depth perception.
Rose: Has the highest contrast and best low-light image resolution.
Mirrored: Reduces the amount of light that reaches the eyes; good at high altitudes.
Gradient: Shaded from top to bottom. (A double-gradient lens is dark at the top and bottom, and lighter in the middle.) Driving glasses are often gradated so that you can see the dashboard clearly.
Photochromic: Automatically darkens and lightens as light conditions change. Photochromic (transitional) lenses won't get very dark, and take some time to adjust to changes in light. Heat also hinders the photochromic (transitional) lenses from getting dark.
Tip: Darker doesn't necessarily mean better. The darker the lenses, the more visible light they block. Brighter conditions demand darker lenses. It's important to keep in mind where you'll be wearing them most. Sunglasses designed for mountain climbing, for example, generally have lenses too dark for everyday wear.
What do the numbers located on the bridge and temples of the frames mean?
Example: The numbers on the frame reflect the SIZE MEASUREMENTS in millimeters (mm).
THE FIRST NUMBER (ex.54) = the width of the lenses
THE SECOND NUMBER (ex.38) = the distance between the Top of the lenses to the bottom.
THE THIRD NUMBER (ex.59) = the diagonal distance of the lens
THE FOURTH NUMBER (ex.18) = the distance of the bridge between the lenses
THE FIFTH NUMBER (ex.140) = the length of the temple arm including the portion going behind the ear
There are three major types of sunglass lenses: glass, polycarbonate and plastic.
• Glass lenses are the most scratch-resistant and distortion-free, but they are also heavier, more expensive and more likely to shatter.
• Polycarbonate lenses are tougher than plastic and are shatterproof, making them ideal for sports and outdoor activities.
• Plastic lenses cost much less, but are easily scratched and generally come with cheaper, flimsier frames.
What is the benefit of Polarized Lenses?
Polarized lenses are great for reducing glare from water, sand, snow or highway pavement that can cause temporary blindness, eyestrain, headaches, and impair night vision. They contain horizontal filtering strips that virtually eliminate the glare of reflected light. Polarization alone, however, does not block UV rays. UV protection comes from an invisible chemical applied to the lens. When buying polarized sunglasses don't forget to check the UV rating too.
What is ultraviolet radiation?
1. UV, or ultraviolet radiation, is part of the invisible light spectrum that falls between 100 and 400 nanometers (nm). UV is divided into three ranges - UV-A, UV-B and UV-C. UV-C, the range below 280 nanometers, is not considered a threat because most of it is filtered by the earth's protective ozone layer (although air pollutants are degrading the ozone, thus increasing UV exposure). Prolonged exposure to the higher-ranged UV-A and B rays, however, can cause significant eye damage, ranging from temporary discomfort to long-term vision problems such as cataracts. So check the labeling on your shades to make sure they protect against UV-A and B rays.
2. UV radiation is most intense between 10 a.m. and 3 p.m. and is stronger at high altitudes and closer to the equator. Sunglasses are particularly critical gear for mountaineers, climbers and anyone heading for the tropics.
3. The reflective qualities of snow, sand and water amplify the effects of UV radiation, harming unprotected eyes over even a brief period time. Thus it's especially important to wear the right sunglasses while skiing, boating, climbing or while hanging out on the beach or in the desert.
4. While clouds block solar brightness they can still allow up to 80 percent of UV light to reach your eyes and skin. So don't forget your shades on those cloudy days.
5. Dark lenses that don't block UV light can actually cause more damage than wearing none at all because they dilate your pupil, allowing more light in without blocking the damaging rays.
6. In addition to UV-blocking shades, wear a brimmed hat when in sunny conditions. Fifty percent of sunlight comes from directly overhead and can reach your eyes over the top of your sunglasses. Look for "wraparound" sports sunglasses, with specially curved lenses and frames that hug the contours of the face.
7. Babies and young children are more susceptible to UV damage because they have more translucent corneas and lenses. Protect them with hats and sunglasses.