How Sunglasses Work & Things You Should Know Before Buying Them

The most efficient way of protecting your eyes from harmful UV and HEV rays is by wearing good quality sunglasses when outdoors. Sunglasses that block 100 percent of UV rays and absorb most HEV rays are something you should look for. Also look for sunglasses with large lenses or wraparound style to protect as much of the delicate skin around your eyes as possible.

The color and darkness of the lenses has nothing to do with the amount of UV protection that sunglasses provide - a light amber-colored lens can provide the same UV protection as a dark gray lens. However, when it comes to HEV protection, color does matter. Most sunglass lenses that block a significant amount of blue light will be bronze, copper or reddish-brown. These sunglasses are also known as ‘blue-blockers’ and are popular among skiers, hunters, boaters and pilots who use them to heighten contrast. Also, although some contact lenses provide UV protection, they don't cover your whole eye, so you still need sunglasses.

Today, there are many different lens options are available, so it would be wise to consult your optician when choosing sunglasses.

Prescription Sunglasses are more convenient and more practical if you’re a contact lens wearer. Since you may not want to wear your contact lenses on the beach where your eyes can become itchy and watery as you battle with sand, sun, wind and water. Prescription sunglasses are available for almost any lens prescription, including bifocal and progressive lens options if you are presbyopic and need lenses to help you read that magazine or book at the pool.

When buying prescription sunglasses your main concern is that the lenses block 100 percent of the sun's harmful UV rays. UV protection is unrelated to the color and density of the tint in sunglass lenses, so you can choose any lens color and darkness you like, as long as your optician verifies that the lenses provide 100 percent UV protection.

Occasionally, eye allergies require medical intervention, such as when there are extreme pain and redness, heavy discharge and/or when over-the-counter and home remedies are not alleviating the situation. This usually involves prescription eye drops as pills and liquid eye solutions are less effective in treating eye allergies. For added glare protection from light bouncing back from reflective surfaces, prescription polarized sunglasses also are available.

In addition, prescription sunglasses are available in all lens materials, including high-index, polycarbonate, regular (CR-39) plastic, Trivex (a lightweight material similar to polycarbonate) and glass.

They are universally popular. Choices of frames and lenses in this category are almost endless. You often have the option of having your regular eyeglass prescription incorporated into a sunglass frame. But many designer sunglasses that can be purchased “over-the-counter” are called “plano”, which means without prescription.

They are a good option if you often participate in outdoor activities or if you work outdoors and do a lot of driving. Sport sunglasses are one of performance-oriented sunglasses developed to provide the best vision possible under extreme conditions. They are made of lightweight, flexible, durable materials, no-slip components that do not fail in the heat of the moment. And of course, many lens tints such as brown, green, gray, yellow and orange are available, with each color suitable for specific circumstances.

Polarized sunglasses have many benefits, especially for people who spend a lot of their time outdoors. Since these glasses contain a special filter that blocks this type of intense reflected light, reducing glare, they are perfect for skiers, bikers, golfers and joggers since all of these activities require the elimination of glare for optimum safety and performance. Polarized sunglasses can be helpful for driving, too, because they reduce glare-causing reflections from flat surfaces, such as the hood of the car or the road's surface. Additionally, polarized lenses may reduce the visibility of images produced by liquid crystal displays (LCDs) or light-emitting diode displays (LEDs) found on the dashboards of some cars or in other places such as the digital screens on automatic teller machines and self-service gas pumps.

To increase comfort and performance of polarized lenses add anti-reflecting coatings that reduce glare caused by light reflecting off the back surface of your sunglass lenses. This will eliminate distracting reflections when the sun is behind you (and can potentially reflect off the back surface of the lenses and into your eyes).

They are another option and are primarily for outdoor wear. They are not as clear indoors as other photochromic lenses, but they provide extra comfort in bright sunlight and behind the wheel. Sunglasses with photochromic lenses start from an already relatively dark tint and get even darker based on the light conditions. Some manufacturers also call these kind of lenses ‘Drivewear’.

Photochromic sunglasses do not darken when exposed to any kind of light. The molecules in the lenses change shape when exposed to UV radiation. The change in the molecules allows them to absorb more light and causes the lenses to darken. This technology can be used in lenses of different materials, but most commonly they are made from glass or polycarbonate. The more UV Radiation the lenses are exposed to, the darker they become. Most photochromic sunglass lenses will begin to significantly darken within about a minute and may continue to get darker for 15 more minutes. They normally take a little bit longer to return to their lighter tinted state.

Tinted from the top down, so that the top of the lens is darkest. This design is ideal for reading outdoors or driving, because they shield your eyes from overhead sunlight and allow more light through the bottom half of the lens so you can see your dashboard clearly.

Also called flash coating, are highly reflective coatings applied to the front surface of sunglass lenses to reduce the amount of light entering the eye. This makes them especially beneficial for activities in very bright conditions, such as snow skiing on a sunny day. Popular choices in mirror coatings include all colors of the rainbow, as well as silver, gold and copper metallic colors. Hot pink, blue — almost any color is available. Choosing the color of a mirror coating is a purely cosmetic decision. The color of the mirror coating you choose does not influence your color perception. The color of the tinted lens under the coating determines how mirrored sunglasses affect your color vision.

Frames are typically made of plastic, nylon, a metal or a metal alloy. However, in recent years various types of woods, such as bamboo, ebony, rosewood, pear wood, walnut and zebrawood have been used to make frames for sunglasses.

Nylon frames are usually used in sports because they are lightweight and flexible. They are able to bend slightly and return to their original shape when pressure is applied to them. This flex can also help the glasses grip better on the wearer's face. Metal frames are usually more rigid than nylon frames, and this is why they can be more easily damaged when the wearer participates in sport activities. Because metal frames are more rigid, some models have spring loaded hinges to help them grip the wearer's face better. The end of the resting hook and the bridge over the nose can be textured or have rubber or plastic material to improve hold. The ends of the resting hook are usually curved so that they wrap around the ear.

Wooden frames are non-toxic and nearly allergy free. Their look can vary according to the color, type and finishing. With wooden sunglasses, various shades of brown, beige, burgundy or black are most common. Wooden sunglasses come in various designs and shapes. However, these sunglasses are usually more expensive than the conventional plastic, acetate or metal frames and require more care.

Frames can hold the lenses in several different ways. Three common styles include full frame, half frame, and frameless. Full frame glasses have the frame go all around the lenses. Half frames go around only half the lens. Usually the frames attach to the top of the lenses and on the side near the top. Frameless glasses have no frame around the lenses and the ear stems are attached directly to the lenses. There are two styles of frameless glasses: those that have a piece of frame material connecting the two lenses, and those that are a single lens with ear stems on each side.

Today, sunglasses come in many different shapes and forms and colors. Feel free to check out the most popular sunglass colors for this summer. Depending on your preferences you can choose from a lot of types and shapes of sunglasses.

• Aviator style sunglasses have a dark metal frame and reflective or smoked lenses. The large lenses were designed to block the sun from all angles (which is why they were worn by pilots back in the day).

• Retro square style sunglasses have boxy shape and super-thick frames. They are available in a variety of prints and colors for both sexes, and the good thing is that they fit every face shape and size.

• Browline sunglasses have a thick top frame that runs across your brow (thus the name) and extra-thin rims around the bottom half of the lens.

• Wayfarers were created in the 50’s and now are back in trend since 2000’s. They are now in radically new shape. The lens is almost similar to squared shaped glasses but has a curve on the lower portion. They also offer full eye protection.

• Round style sunglasses have a full-rim with a plastic frame around and the lens is round in shape, but the frames can be small or large, skinny or thick, and metal or plastic.

• Cat eye style sunglasses have upswept outer edges and are retro feminine sunglass. Cat eye sunglasses were originally made famous in the ’50s by stars like Marilyn and Audrey. With feminine vibes and feline prints theses sunglasses never go out of style.

• Wrap Around sunglasses have frames that curve around the head from the front side. If you are planning to run or cycle a few miles, wear these wrap around glasses that will look sporty and at the same time give your vision complete protection.

• Oversized sunglasses have cut-out detail on the outer edge of a full plastic frame. The oversized sunshades that are in vogue since 70’s. They come in square or rectangular frame shape and cool lens that also provides protection from UV rays