Sunglasses are eyewear designed to help protect the eyes from excessive sunlight. Eyes are extremely light sensitive and can be easily damaged by overexposure to radiation in the visible and nonvisible spectra. Bright sunlight can be merely a distracting annoyance, but extended exposure can cause soreness, headaches, or even permanent damage to the lens, retina, and cornea. Short term effects of sun overexposure include a temporary reduction in vision, known as snow blindness or welders' flash. Long-term effects include cataracts and loss of night vision. In both cases, the damage is caused by ultraviolet (UV) light, which literally burns the surface of the cornea.
Sunglasses were originally invented to reduce distracting glare and allow more comfortable viewing in bright light. Early sunglasses were simply tinted glass or plastic lenses that were primarily meant to reduce brightness. Darker lenses were considered to be better because they screened out more light. As our understanding of the damaging nature of sunlight evolved, the need for better eye protection was recognized, and technology was developed to help sunglasses better screen out the harmful rays of the sun, especially UV rays. 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. Unfortunately there is no way to tell from the color or darkness of the lens how well it will screen out UV light. Similarly, there is little relationship between price of glasses and their ability to block UV light.
Sunglasses consist of a pair of light-filtering lenses and a frame to hold them in place. The vast majority of lenses are made of colorized plastic, such as polycarbonate. However, glass is still employed for high quality brands. The highest quality lenses are optically accurate and do not distort shapes and lines. These lenses, like camera lenses, 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 by tempering it with various chemical treatments.
Soluble organic dyes and metallic oxide pigments are added to the lens material to absorb or reflect light of certain frequencies. These additives must not distort colors excessively, however; for example, badly colored lenses may make it difficult to discern the correct color of traffic lights. Gray lenses produce the least distortion for most people, although amber and brown are good too. Blue and purple tend to distort too much color. The additives also should block at least part of the blue light which is part of the lower frequency UV rays. Brown or amber screen out blue light the best, but at the cost of some color distortion. Various chemical coatings which are added to the lens can enhance viewing by reducing reflection or screening out polarized light.
Sunglass frames are made from metal or plastic. Metal frames, particularly expensive ones, are often made of mixtures of nickel and other metals such as silver. These frames have precisely engineered features, such as sculpted and gimbaled nose-pads, durable hinges with self-locking screws, and flexible temples. Upscale manufacturers use combinations of nickel, silver, stainless steel, graphite, and nylon in their leading-edge designs.
There are two key elements to consider regarding sunglasses design, fashion and function. In the last few decades sunglasses have become a high fashion item, and the current design process reflects this status. Upscale clothing designers, fragrance marketers, and sporting goods vendors custom-design sunglasses to promote their own specific image. By and large these design changes are not functional; they are intended to increase the fashion appeal of the glasses. Stylized frames, uniquely shaped lenses, and embossed logos are all part of this designer mystique. While some designs are considered "classic" and timeless, others must be continually updated to satisfy the public's constantly changing tastes. The children's sunglasses market is another area which requires frequent redesign, since the style of the glasses changes from season to season based on merchandising tie-ins with popular cartoon or other characters.
From a functional standpoint, sunglasses are designed specifically for a variety of outdoor activities. Sports enthusiasts have specific requirements that are reflected in sunglass design. For example, sunglasses designed for trap shooters are designed to provide maximum contrast to allow better viewing of their clay pigeon targets. On the other hand, sunglasses for skiers are designed to counter the light reflected of snow-covered surfaces. Lenses of the this types are known as blue blockers, because they filter out violet, blue, and some UV rays. Fisherman and boaters have their own special needs that must be addressed as well. Today there are custom-designed sunglasses for these activities and many more.
Sunglasses can protect the eyes in several ways. The glasses can either absorb or reflect certain frequencies of light, for both reduce the amount of light that enters the eyes. The absorbing types use various substances that are added to the lens material to selectively absorb light of specific frequencies. This range of frequencies can be controlled by changing the mixture of colorizing additives. The strength of the absorption is controlled by adjusting the amount of additive. Reflecting lenses have multi-layer antireflective coatings, consisting primarily of metallic particles. These metallic coatings reflect all colors of light and UV radiation equally well. There are reflective types with non-metallic coatings, which create a coloring effect. By varying the type and amount of colorant additive or coating, a large variety of lenses can be produced. The color of the finished lens indicates which portion of the visible spectrum is being transmitted. For example, if the lenses are dark yellowish, they absorb violet, blue, and probably some UV rays.
A special type of absorbing lens filters out polarized light. Light actually consists of two waves, one propagated in the horizontal plane and one in the vertical plane. When light bounces off a flat surface, such as snow, roadways, or a shiny metallic objects, the horizontal component is seen as glare. Polarized lenses are made using a special optical filter which absorbs the horizontal component of light and transmits only the vertical component. As a result bright reflected light is eliminated and eye strain is reduced. However, polarized lenses do not block UV light, so they require additional coatings or coloring agents to provide complete eye protection.
Another type of lens, the photochromatic lens, contains silver salts like those used in photographic film. These lenses darken out-doors and lighten indoors. In this way the lenses change color in response to UV exposure. However, the range of lenses' color change is not broad enough to be effective against most light frequencies, and although they are widely used, photochromatic lenses are not universally accepted by optometrists.
- 1 Colorant can be added to lenses in two primary ways, either by adding color to the molten lens material before the lens is formed, or by chemically post-coating the finished lens to achieve the desired hue. In the former method, the colorant additives are incorporated into the lens while the plastic or glass is at high temperatures and still liquefied. Soluble organic dyes or metallic oxide pigments are added to plastic. Metallic oxide or metal particles are incorporated into glass.
- 2 After the appropriate additives have been blended in, the molten plastic or glass is then cast into the general lens shape, or "puck." Inexpensive lenses are simple pucks that placed into frames. Expensive lenses are prepared in a manner similar to the method by which prescription lenses are made. First the appropriate lens puck is placed in a lensometer, an instrument that is used to find the optical center of the blank.
- 3 The lens is then put in a curve generator, which grinds out the back of the lens according to the patient's prescription. An edge grinder then grinds the outer rim to its proper shape and puts a bevel on the edge, allowing the lens to fit properly into the frames.
- 4 Lenses may now be coated with an anti-reflective material. The post-coating method produces lenses that are more evenly coated regardless of the lens configuration. It also allows for the coating to be removed and recoated after the lens is made. Such coating may be applied through a vacuum coating method, used to deposit an antireflective layer on the lens surface to reduce internal reflections. This faint bluish coating is also commonly used on camera lenses and binoculars.
- 5 The finished lenses are now ready to be mounted in eyeglass frames. Frames are constructed to hold the lenses in place using either a tension mount or screw mount design. Tension mounting is typically used in plastic frames. In this type of frame, the dimensions of the lens opening on the front surface of the frame are somewhat smaller than the lens itself. In this way the lenses can be pressed into their respective openings through the front edge of the frame without falling out its rear edge. A groove is formed in the periphery of each of the openings, and these mate with a ridge formed on the periphery of the respective left and right lenses. The plastic frame material permits sufficient stretching or elongation to allow the lenses to snap into these grooves.
- 6 Metal frames use a screw mount design because metal tends to deform easily and cannot hold the lenses as well. The metal structure of the frames has thin extruded sections that are bent into desired shapes. The frame structure surrounding the lens openings forms an open loop into which the lens is inserted. After the lens is inserted, the loop is closed by attaching a screw to the two open ends.
Beyond the regulations that ensure the glass and plastic used in lenses is shatterproof, there is little governmental regulation of sunglasses. Labeling of the absorbance rates of both types of UV light, UVA and UVB, is voluntary, but the American National Standards Institute (ANSI) has established transmittance guidelines for general purpose and special lenses. According to these standards, general purpose cosmetic lenses must block 70% of UVB, general purpose must block 95% of UVB and most UVA light. Special purpose must block 99% of UVB.
To a large extent, the degree of quality control imposed on sunglasses manufacture is a function of the type of sunglasses. Inexpensive plastic models have little concern with optical perfection; they may contain flaws which will distort the wearer's vision. On the other hand, expensive glass lenses strive for high optical quality and are checked accordingly. There are a variety of instrumental methods used to evaluate distortion of the finished lens, but one simple test is to simply hold the glasses at arms' length and look at a straight line in the distance. Slowly move the lenses across the line. If the lens causes the line to sway or bend, the lenses are optically imperfect. For best results, look through the outer edges of the lens as well as the center.
There are no particular byproducts resulting from sunglasses manufacture. Waste materials include plastic, glass, and metallic scrap from grinding the lenses and making the frames.
Sunglasses manufacturing processes have become increasingly sophisticated in response to greater demand for high quality, stylish glasses. New coatings and colorants which deliver better protection against UV radiation continue to be developed. Improvements in the way frames are manufactured continue to be made. For example, U.S. patent 5,583,199 discloses a new way to make frames from a single piece of metal. New types of high performance sun-protective eyewear will be developed as advances are made in the fields of optics, surface chemistry, metallurgy, and others.
Where to Learn More
Ahrens, Kathleen. Opportunities in Eye Care Careers. VGM Career Horizons, 1991.
Gourley, Paul and Gail Gourley. Protect Your Life in the Sun. High Light Publishing, 1993.
Zinn, Walter J. and Herbert Soloman. The Complete Guide to Eyecare, Eyeglasses, and Contact Lenses. Frederick Fell Publishers, 1986.
Berkeley Wellness Letter 9. The University of California, Berkeley, June 1993, p. 5.
"Sunglasses." How Products Are Made. . Encyclopedia.com. (November 29, 2018). https://www.encyclopedia.com/manufacturing/news-wires-white-papers-and-books/sunglasses
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sun·glass·es / ˈsənˌglasiz/ • pl. n. glasses tinted to protect the eyes from sunlight or glare.
"sunglasses." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (November 29, 2018). https://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/sunglasses-0
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Sunglasses, spectacles with tinted lenses, were originally a purely practical safety device, designed to protect the eyes from excess sun and glare. In the twentieth century, however, they became an important fashion accessory, whose use and meaning continues to evolve.
Sun Glasses to Sunglasses
Tinted spectacles were made in Europe as early as the seventeenth century, but were used because they were thought to be beneficial to the eyes, or to conceal the eyes of the blind, and were not "sunglasses" in the modern sense. The need for eyewear to protect the eyes against sun and glare first became apparent in the mid-nineteenth century, when early polar explorers and high-altitude mountaineers experienced snow-blindness, and spectacles and goggles with tinted lenses were developed, some with side shields of glass or leather. (The Inuit used slit snow-goggles of wood or bone, which covered the eyes.) As increasing numbers of Europeans and Americans were exposed to the strong sun of tropical and equatorial colonies and territories, dark glasses began to be worn there as well.
Sunglasses became more widely available in the 1880s, when bathing and holidays by the sea became popular with the general public; by 1900, inexpensive tinted glasses (now known as "sun glasses") were sold by seaside vendors, and worn by English tourists in Egypt to reduce the desert glare. The invention of the automobile, and the popularity of motoring as a fashionable leisure activity, also brought protective eyewear into common use, and tinted motoring goggles were available by the 1910s.
Hollywood Style and Glare Control
In the 1920s, sunglasses were occasionally worn for active outdoor sports such as golf and tennis, and for the newly fashionable activity of sunbathing. They did not truly enter the fashion sphere, however, until the early 1930s, when Hollywood stars such as Bette Davis and Marlene Dietrich were photographed wearing them between takes on the set, attending tennis matches and horse races, or trying to appear in public incognito. Sunglasses began to symbolize the glamour of life in Hollywood, but there was little variation in style at first; most 1930s sunglasses, for both men and women, had round, flat glass lenses, with narrow celluloid frames. The only fashion decision lay in choosing the color of the frames; these were usually translucent and in colors close to tortoiseshell, but opaque white frames were also considered chic.
Toward the end of the decade, the demand for sunglasses, and the variety of available styles, increased dramatically; in 1938 the number of pairs sold went almost overnight from the tens of thousands into the millions, and manufacturers rushed to come up with new colors and styles. Sunglasses began to be shown with street clothes, in addition to ski and beach wear, and Vogue suggested styles, such as the white pair featured on the cover of the 1 August 1939 issue, with "wide rims and earpieces, giving the approved 'goggly' appearance" (p. 81). Sunglasses, being less expensive than prescription eye-wear, and associated with vacation and leisure activities, were quickly embraced as a "fun" fashion accessory, and even bizarre novelty styles soon found a market.
The quality of sunglasses also improved in the 1930s, and both of the major U.S. optical companies introduced lines of sunglasses with optical glass lenses (ground and polished like prescription eyeglasses). Taking advantage of the public appeal of daring aviators such as Charles Lindbergh and Amelia Earhart, Bausch & Lomb introduced the metal-framed "Anti-Glare Aviator" sunglasses in 1936, and the following year gave them the more appealing brand name "Ray-Ban" (to emphasize protection from harmful infra-red and ultraviolet rays). American Optical teamed up with the Polaroid Corporation in 1938 to produce the first polarized sunglasses, with glass lenses incorporating a polarizing film. World War II brought new popularity to military-style sunglasses, especially Ray-Ban Aviators (worn by Navy pilots and General Douglas MacArthur), and lent them the air of toughness and competence that has kept the style popular ever since.
To See and Be Seen
After the war, the craze for sunglasses quickly resumed in full force. Advertisements began to emphasize smart styling over eye protection, and distinct men's and women's styles were developed. Sunglasses could now be purchased in drug, variety, and department stores, at prices from 25 cents to 25 dollars. With growing competition, established manufacturers increased their advertising and diversified; American Optical launched the "Cool-Ray" trademark, and in 1948 introduced inexpensive Polaroid plastic lenses. It became fashionable to have multiple pairs for sport, everyday, and even evening wear, and in colors to match particular outfits. Eyeglass wearers could have sunglasses made with their prescription, or choose from a variety of clip-on styles.
In the 1950s, to boost sales, sunglass manufacturers began coming out with new models every year, following the lead of the automobile industry. As with eyeglasses, the harlequin, or "cat-eye," shape was the dominant style for women, but sunglasses took the style to much more fanciful extremes. Sunglasses were made with carved, laminated frames shaped like flames, flowers, and butterflies, studded with rhinestones, imitating unlikely materials like bamboo, or trimmed with false "eyelashes" of raffia. Even relatively conservative frames were produced in bold and unusual shapes, colors, and patterns, and were given model names such as "Torrid," "Vivacious," and "Peekini." For men, new styles with clean lines and heavy plastic frames were popular, the most famous being the Ray-Ban "Wayfarer," introduced in 1952.
Whatever the frame style, sunglasses were also worn because of the air of mystery they imparted to the wearer. One could still hope to be mistaken for a celebrity such as Grace Kelly or Rita Hayworth, but sunglasses also offered, as a 1948 ad for the first mirrored sunglasses put it, "the wonderful fun of looking out at a world that can't see you" (Saks 34th St. advertisement for "Mirro-Lens" sunglasses, New York Times, 28 March 1948, p. 30). Dark "shades" contributed considerably to the "cool" of bebop jazz musicians and beatniks, who wore them even in dark nightclubs. Once the fad for wearing sunglasses at night caught on, however, it became harder to tell the "hip" from the "square"; as one observer told the New York Times in 1964, "If you're really 'in' you wouldn't be caught dead wearing them indoors or at night because you'd look like someone who is 'out' but is trying to look 'in'" (Warren, p. 66).
By the early 1960s, sunglasses were more popular than ever, with an estimated 50 million pairs per year sold in the United States by 1963. They were also available in more styles than ever before; Ray-Ban advertised "the see and be-seen sunglasses, [in] all kinds of designs—bold, shy, classic, crazy, round, oval, square, oriental" (Evans, p. 17). President Kennedy often appeared in public wearing sunglasses, and Jacqueline Kennedy started a fad for wraparound sunglasses when she began wearing them in 1962. Similar sleek, futuristic styles from Europe inspired Polaroid to launch the French-sounding C'Bon brand,
featuring "the St. Tropez look." Sunglass advertising was also taken to new and imaginative heights; the famous "Who's that behind those Foster Grants?" campaign of the mid-1960s, in which celebrities such as Vanessa Red-grave and Peter Sellers were shown transformed into a series of exotic characters by Foster Grant sunglasses, were highly successful in promoting the power of sunglasses to "subtly alter the personality," (Foster Grant advertisement, 1964, available from www.fostergrant.com) and release the wearer's inner tycoon or femme fatale.
In 1965, André Courrèges's sunglasses with solid white lenses and viewing slits were the first designer sunglasses to receive wide attention. They soon inspired other space-age designs such as Sea-and-Ski's "Boywatcher," a seamless slit goggle that could also be worn as a headband, and a variety of alien-looking "bug-eye" styles, with frames in day-glo colors or shiny chrome. Socalled "granny glasses" were also popular, as were large round wire-rims with lenses in pale psychedelic tints. Enormous round dark glasses, such as those designed by Emilio Pucci, were another style favored by celebrities late in the decade.
In the 1970s, the trend toward oversized designer frames continued. In keeping with the fashionable "natural" look, lenses became paler, with gradient tints in the same rosy shades fashionable for eye makeup. The eyes were now visible, and in the April 1977 issue of Vogue sunglasses were declared "the new cosmetic" (p. 146). As the decade progressed, expensive sunglasses by designers such as Pierre Cardin and Givenchy became sought-after status symbols, and were frequently worn on top of the head like a headband when not in use. Sporty mirrored styles were also popular, especially for men.
New Optical Identities
In the early 1980s, the trend to harder-edged styles in black and bright colors coincided with the revival of Ray-Ban's Wayfarer style, which was given a high profile by the Blues Brothers, the 1983 film Risky Business, and the TV series Miami Vice. Heavy black sunglasses with conspicuous designer logos harmonized with the era's penchant for "power dressing," and similar flashy styles were reproduced for every price range. Oddly shaped, futuristic "new wave" styles were another trend, and the mirrored aviator style was revived once again by the 1986 film Top Gun. High-tech "performance" styles designed specifically for outdoor sports, by makers such as Vuarnet and Revo, first became popular in the 1980s, and started a craze for iridescent mirrored lenses.
In the late 1980s and 1990s, in sunglasses as in eyeglasses, minimalism, industrial design, and revivals of earlier styles were the dominant themes. Designer logos fell out of favor early in the decade, and pared-down fashion and hairstyles required clean-lined, sleek frames with meticulous detailing. New sports styles by Oakley, so close-fitting that they seemed to merge with the face, were popularized by athletes such as Michael Jordan and Olympic speed-skater Bonnie Blair. These high-tech glasses, using novel materials such as magnesium alloy and gold iridium, were highly influential, and began to blur the line between sports and fashion eyewear.
At the turn of the century, sunglasses are more important than ever as an individual fashion statement, but there is no dominant style, unless it is "freedom of choice." After a series of "retro" revivals, and trends started by musical celebrities, avant-garde designers, athletes such as Lance Armstrong, the NASCAR circuit, and films such as The Matrix, the sunglass market has fractured into many specialized niches. An unprecedented variety of designer collections is available to choose from in the early 2000s, and larger makers such as Ray-Ban feature several smaller "themed" collections, each with its own distinct aesthetic. Over the course of the twentieth century, sunglasses have become an essential part of the fashion and image-making vocabulary, and they seem likely to continue to fill this role in the future.
See alsoEyeglasses .
Baker, Russell. "Observer—New Upward Movement in Clothing." New York Times (16 June 1964): 38.
Evans, Mike, ed. Sunglasses. New York: Universe, 1996. Brief, popular introduction.
Warren, Virginia Lee. "Dark Glasses After Dark: For the Eyes or Ego?" New York Times (10 Dec. 1964): 66.
Foster Grant. "Foster Grant History." Available from <http://www.fostergrant.com/history.html>.
Ray-Ban. "Ray-Ban History." Available from <http://www.rayban.com>.
Whitman, Anne. "Retro-Specs." Eyecare Business. December 1999. Available from <http://www.eyecarebiz.com>.
"Sunglasses." Encyclopedia of Clothing and Fashion. . Encyclopedia.com. (November 29, 2018). https://www.encyclopedia.com/fashion/encyclopedias-almanacs-transcripts-and-maps/sunglasses
"Sunglasses." Encyclopedia of Clothing and Fashion. . Retrieved November 29, 2018 from Encyclopedia.com: https://www.encyclopedia.com/fashion/encyclopedias-almanacs-transcripts-and-maps/sunglasses