Sunglasses, like Ray Bans, are a type of protective eyewear designed to prevent bright sunlight and high energy visible light from damaging or causing discomfort to the eyes. The sunglasses industry has made some incredible innovations over the last few years; new brands, styles, colors and functions have all surfaced recently.
Healthcare professionals and experts recommend eye protection whenever the sun comes out in order to shield the eyes from ultraviolet radiation and the blue light. The sun is very powerful and can have a detrimental and damaging ramifications on the cornea and retina of our eyes. Bright sunlight can be merely a distracting annoyance, however over exposure can cause soreness, headaches, or even permanent damage to the lens, retina, and cornea.
Short term effects of sun overexposure include a temporary vision impairment, while long term overexposure effects cataracts and loss of night vision. In both cases, the damage is caused by ultraviolet light, which is actively burning the surface of the cornea.
When considering purchasing sunglasses there are certain features you should be familiar with. For instance: sunglasses should provide optimal protection from the sun’s harmful rays. A high quality pair of sunglasses can protect you from any UV rays. Another consideration to take into account is the degree the glasses shield from strong lights. When a powerful light comes in contact with the eyes the iris closes and can cause squinting. eventually this extra light can cause significant damage to the retina. Effective sunglasses can eliminate up to 97% of light.
Damage to the eyes due to light is not exclusively from the sun. Other lights can do harm to our eyes as well. For example reflective light and light frequencies can also result in eye damage. Light reflections off of water or a mirror can distract you and prevent you from seeing an object. The prevention of light reflection is referred to as polarization. Certain light frequencies can blur vision and make it difficult to see at in certain circumstances.
It is imperative to know the benefits of high quality sunglasses before you purchase a pair. Having the right protection can make all of the difference in the world when it comes to sunglasses. Buying the appropriate kind of sunglasses you need for the situation gives you the most protection and performance out of a pair of sunglasses. From inexpensive models with plastic lens and frames to costly designer brands with ground glass lenses and custom-made frames, sunglasses are available in a staggering array of styles and prices.
Functions of Sunglasses
Due to all of the latest innovations in sunglasses there are a multitude of functions that can be associated with a pair of sunglasses. From visual clarity to increased protection, there are many features and functions that come with wearing sunglasses. Below are several of the important features and functions you can benefit from while wearing sun glasses, like the Ray Ban Warfarers.
The protection aspect of sunglasses could be the most important feature. A good pair of sunglasses should offer optimum protection against excessive exposure to light, in both visible as well as invisible components.
The most integral protection offered by sunglasses is the protection against ultra-violet radiation. UV radiation causes short-term and long term eye problems. Problems such as photokeratitis, cataracts, pterygium and certain form of eye cancer are results of overexposure to UV radiation. Health professionals recommend sunglasses that reflect or filter out up to 99% of UVA and UVB light for best protection. Pairs of sunglasses which offer this protection are referred to as UV400
Visual Clarity and Visual Comfort
an important benefit to wearing sunglasses is the improvement of visual clarity and comfort you get through the anti-glare protection. The lenses of sunglasses that are polarized work to reduce the glare reflected of objects, that can distract or temporarily blind you. These types of sunglasses are popular among fishermen who want to prevent the glare that reflects of the water’s surface. This feature is also popular in the disposable models given out to patients after eye exams.
Avoiding Eye Contact
At times sunglasses are worn to conceal a person’s eyes and prevent eye contact. The most effective type of sunglasses to hide a person’s eyes or mask their emotions are mirrored sunglasses. For instance: many poker players where tinted sunglass to make it more difficult for other players to read their emotions or facial expressions and gain an advantage.
In general sunglasses are made up of three parts; the frames, lenses and nose bridge. Each component plays a big part in defining the way the sunglasses look as well as the amount of protection you receive from them.
The frames for sunglasses consist of either plastic, nylon, a metal or a metal alloy. Nylon frames are commonly used in sports and activities because they tend to be lightweight and flexible. They have bending capabilities which make them more difficult to break and help its grip to the wearers face.
Metal frames are more solid than nylon ones and are easier to damage. Many metal frames include spring loaded hinges which help them achieve a better grip. The end of the resting hook and the bridge over the nose can have rubber or plastic material to improve their hold. In addition, the ends of the resting hooks on many metal frames are curved so they are able to wrap around the ears.
Metal frames, usually expensive ones, commonly consist of mixtures of nickel ad other metals like silver. Upscale manufacturers of these metal frames use combinations of nickel, silver, stainless steel, graphite, and nylon in their designs.
Frames can be designed to hold the lenses in several different methods. There are three different styles when it comes to holding the lenses; a full frame, half frame or frameless. Full framed glasses have a frame which completely surrounds the lenses, such as the Ray Ban Aviator or the Ray Ban Wayfarer. Half frames surround only half of the lens, in most cases using the top of the lens. Frameless glasses contain no frame and the lenses are attached directly to the ear stems.
Frameless sunglasses are broken down into two styles, a single lens with ear stems on both sides or ones that have a piece of frame material connecting the two lenses.
Some sunglasses, like those made for sports use have options for interchangeable lenses. In these glasses lenses can be removed and changed with other ones, giving the wearer the ability to choose color and style depending on light conditions. This is convenient because the wear does not have to bring more than one pair of sunglasses with him. In addition lenses can be cheaper than a whole new pair of sunglasses. The most common type of sunglasses with interchangeable lenses has a single lens or shield that protects both eyes.
Sunglasses consist of a pair of light-filtering lenses and a frame to secure them in place. A large majority of lenses consist of a colorized plastic material. However, some higher quality brands still use glass for their frames.
The highest quality lenses do not distort visible shapes and lines. These lenses, simlar to the lenses in a camera, are made from distortion-free ground and polished optical glass. The borosilicate glass used in these lenses is scratch resistant and is made impact resistant through the use of various chemical treatments.
Sunglass lenses are made of either glass, or plastic. Plastic lenses are typically made from acrylic, polycarbonate, CR-39 or polyurethane and are lighter and shatter-resistant, but are more prone to scratching. Polycarbonate plastic lenses are the lightest, and are also almost shatterproof, making them good for impact protection. Glass lenses have the best optical clarity and scratch resistance, but are generally heavier than plastic lenses.
Lenses come in a wide variety of colors depending on the style and purpose. For general use and to avoid color distortion red, grey, green, or brown are recommended
Soluble organic dyes and metallic oxide pigments are added to the lens material in order to reflect and absorb light of specific frequencies.
- Brown or amber screen out blue light the best, but at the cost of some color distortion.
- Gray lenses produce the least distortion for most people, although amber and brown are good too.
- Orange and yellow lenses increase both contrast and depth perception. They also increase color distortion. Yellow lenses are used by pilots, boaters, fishers, shooters, and hunters for their contrast enhancement and width perception properties
- Blue or purple lenses are mainly cosmetic. Blue and purple tend to distort too much color
- Turquoise lenses are good for medium and high light conditions, because they are good at enhancing contrast, but do not cause significant color distortion.
- Some models contain polarized lenses, made of Polaroid polarized plastic sheeting, in order to minimize glare caused by light reflected from surfaces such as water or by polarized diffuse sky radiation
A mirrored coating can also be applied to the lens. This mirrored coating deflects some of the light when it hits the lens so that it is not transmitted through the lens where it can reach the eye, making it useful in bright conditions. However ,mirrored coated lenses do not necessarily reflect UV radiation. Mirrored coatings can be made in any color by the manufacturer for styling and fashion purposes. The color of the mirrored surface does not have to match the color of the lens. For example, a brown lens can have a blue mirror coating, and a grey lens can have a silver coating. Sunglasses of this type are sometimes referred to as mirror shades. A mirror coating does not heat up when in the sunlight and it prevents scattering of rays in the lens bulk
Any of the above features, color, polarization, mirroring, and materials, can be combined into the lens for a pair of sunglasses.. Corrective lenses or glasses can be manufactured with either tinting or darkened to serve as sunglasses. An alternative is to use the corrective glasses with a secondary lenses such as oversize sunglasses that attach over the regular glasses, or a clip-on lens that are placed in front of the glasses.
Nose bridges provide the support between the lens and the face. They also prevent pressure marks on the face and cheeks caused by the weight of the lens or the frame. People with larger noses may need a low nose bridge on their sunglasses for support. Though people with smaller noses may need sunglasses with high nose bridges to allow clearance.
How to measure the standards of sunglasses
There are three major sunglass standards for measurement. These standards vary depending on what country you are in. In the United States the standard is ANSI Z80.3-2001, which includes three transmittance categories. According to the ANSI Z80.3-2001 standard, the lens should have a UVB (280 to 315 nm) transmittance of no more than one per cent and a UVA (315 to 380 nm) transmittance of no more than 0.3 times the visual light transmittance. The ANSI Z87.1-2003 standard includes requirements for basic impact and high impact protection. In the basic impact test, a 1 in (2.54 cm) steel ball is dropped on the lens from a height of 50 in (127 cm). In the high velocity test, a 1/4 in (6.35 mm) steel ball is shot at the lens at 150 ft/s (45.72 m/s). To pass both tests, no part of the lens may touch the eye
Measuring the protection of Sunglasses
The only method in measuring the protection you can get from a pair of sunglasses is to have the lenses measured by an optician or the manufacturer. What you can measure in relation to protection is the fit of the glasses. Lenses should fit close enough to the face that minimal light can reach the eyes from the sides.
Darker lenses do not automatically filter out a higher level of UV radiation. In fact, many people say that darker sunglasses could be more harmful than lighter lenses. This is because the darker glasses encourage the pupil to open wider and allows for more unfiltered radiation to enter.
How Polarization Works
Polarized sunglasses are becoming very popular as of recent. While in the beginning a majority of the people using polarized lenses were fisherman because of the anti-glare technology, more people have started realizing to benefits of having polarize sunglasses. These sunglasses can be used for driving and can help eliminate glare from flat surfaces like the hood of a car. Polarized sunglasses also can be worn indoors by light-sensitive people, including patients who have had post-cataract surgery and those continually exposed to bright lights through windows.
Light that is reflected from surfaces is horizontally polarized. This means that reflected light generally travels horizontally, as opposed to standard light which is scattered in many directions. Polarized sunglasses work to cut the glare to give your an opportunity to comfortably see better. The lenses contain a filter that is designed to block intense reflected light and in turn reduces glare.
The reduction in glare makes polarized lenses favorable for most sports and activities. Many lenses are even available with other features designed to enhance outdoor sports and activates.