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For years, boaters and fishermen have used polarized sunglasses to reduce reflected glare from the water surrounding them, but now that many others who spend time outdoors have discovered the benefits of polarized lenses such as skiers, golfers, bikers, drivers, hunters and joggers. Polarized lenses are used in sunglasses to reduce glare from reflective surfaces such as the surface of a lake or the hood of a car. Sunlight bouncing off a horizontal surface will strike the viewer's eyes at a similar angle. This means the glare from the surface of the water or the road or the car hood will be strong. Polarized lenses improve contrast and visibility while reducing squint and eyestrain. Our board certified opticians will offer you suwnwear products so you can enjoy life with a clearer view along with elimination of glare.
These changeable lenses automatically darken and lighten to provide the right level of protection and comfort over a wide range of light conditions. Transitions lenses are available in many lens designs, material, and prescription. Performance features include advanced variable-tint technology that allows rapid darkening when you go outside (and rapid return to clear when you go in), and 100% UV protection. They come in regular, lightweight plastic materials as well as in high-index plastic and polycarbonate. They have a front-surface coating that changes color (to gray or brown) when exposed to ultraviolet light. The changeable coating means that the color darkens evenly regardless of lens prescription or thickness.
Transitions also makes a few niche products including for Drivewear, which features a lens that remains dark behind the windshield of a vehicle. As a general rule, photochromic lenses won't darken behind the windshield because the glass blocks out the UV rays that cause the lenses to change color.
Reflective sunglasses often have a mirrored look. The lenses in these sunglasses have a reflective coating applied in a very thin, sparse layer -- so thin that it's called a half-silvered surface.
Often, the mirror coating is applied as a gradient that gradually changes shades from top to bottom. This provides additional protection from light coming from above while allowing more light to come in from below or straight ahead. What that means is that if you are driving, the sun's rays are blocked but you can see the dashboard. Sometimes the coating is bi-gradient, shading from mirrored at top and bottom to clear in the middle. The key problem with reflective sunglasses is that the coating is easily scratched.
While glass is naturally scratch resistant, most plastics are not. To compensate, manufacturers have developed a variety of ways to apply optically clear hard films to the lens. Films are made of materials such as diamond-like carbon (DLC) and polycrystalline diamond. Through a process of ionization, a thin but extremely durable film is created on the surface of the lens. See Patent 5,268,217 for details.
A common problem with sunglasses is called back-glare. This is light that hits the back of the lenses and bounces into the eyes. The purpose of an anti-reflective (AR) coating is to reduce these reflections off the lenses. AR is made of a very thin film that is layered on the lens. It is made of material that has an index of refraction that is somewhere between air and glass. This causes the intensity of the light reflected from the inner surface and the light reflected from the outer surface of the film to be nearly equal, minimizing the glare you see. AR coatings are also applied to the front of prescription eyewear and some sunglasses to eliminate the "hot spot" glare that reflects off the lens. See Anti-Reflective treated lenses.
Several of the most serious eye problems can be linked to one cause: UV light. A good UV coating on your sunglasses can eliminate UV radiation, and you should check to make sure that your sunglasses filter out 100 percent of both types of UV rays.
There are anti-reflective coated lenses and there are anti-reflective treated lenses. So what's the difference? In a word - QUALITY. Dr. Uzick & Associates highly recommend Crizal brand anti-reflective lenses. Crizal lenses eliminate reflections that cause eyestrain and fatigue, especially from fluorescent lighting, computer screens, and glare from headlights, taillights, traffic lights and neon signs. The latest generation of Crizal no-glare lenses does more than provide clearer vision—they practically take care of themselves. All Crizal lenses go through an eight step treatment process to ensure you will have the clearest vision possible with the highest quality of protection for your lenses. Annoying glare cannot only keep you from seeing the world, it can keep the world from seeing you. When glare does not reflect off your lenses, they appear virtually invisible. This allows you to see better, look better, and feel better about your glasses.
