Glasses, also known aseyeglasses,spectacles, or colloquially asspecs, arevisioneyewear with clear or tintedlenses mounted in a frame that holds them in front of a person'seyes, typically utilizing a bridge over thenose and hinged arms, known as temples or temple pieces, that rest over the ears for support.
Glasses are typically used forvision correction, such as with reading glasses and glasses used fornearsightedness; however, without the specialized lenses, they are sometimes used for cosmetic purposes.
Safety glasses areeye protection, a form of personal protective equipment (PPE) that are worn by workers around their eyes for protection. Safety glasses act as a shield to protect the eyes from any type of foreign debris that may cause irritation or injury; these glasses may have protection on the sides of the eyes as well as in the lenses. Some types of safety glasses are used to protect against visible and near-visible light orradiation. Glasses are worn for eye protection in some sports, such assquash.
Glasses wearers may use a strap to prevent the glasses from falling off. Wearers of glasses that are used only part of the time may have the glasses attached to a cord that goes around their neck to prevent the loss and breaking of the glasses.
Sunglasses allow for better vision in bright daylight and are used to protect one's eyes against damage from excessive levels ofultraviolet light. Typical sunglasses lenses are tinted for protection against bright light or polarized to remove glare;photochromic glasses are clear or lightly tinted in dark or indoor conditions, but turn into sunglasses when they come into contact with ultraviolet light. Most over-the-counter sunglasses do not have corrective power in the lenses; however, special prescription sunglasses can be made. People with conditions that havephotophobia as a primary symptom (like certainmigraine disorders) often wear sunglasses or precision tinted glasses, even indoors and at night.
Specialized glasses may be used for viewing specific visual information, for example,3D glasses for3D films (stereoscopy). Sometimes glasses are worn purely for fashion or aesthetic purposes. Even with glasses used for vision correction, a wide range of fashions are available, using plastic, metal, wire, and other materials for frames. Most glasses lens are made of plastic, polyethylene, and glass.
Glasses can be marked or found by their primary function, but also appear in combinations such as prescription sunglasses or safety glasses with enhanced magnification.
Askyline seen through a corrective lens, showing the effect ofrefractionMicrofiber cloth designed for cleaning corrective lenses without scratching sensitive glass
Corrective lenses are used to correctrefractive errors by bending the light entering the eye in order to alleviate the effects of conditions such asnearsightedness (myopia),farsightedness (hypermetropia) orastigmatism. The ability of one's eyes to accommodate their focus to near and distant focus alters over time. A common condition in people over forty years old ispresbyopia, which is caused by the eye'scrystalline lens losing elasticity, progressively reducing the ability of the lens toaccommodate (i.e. to focus on objects close to the eye). Few people have a pair of eyes that show exactly equal refractive characteristics; one eye may need a "stronger" (i.e. more refracting) lens than the other.
Corrective lenses bring the image back into focus on the retina. They are made to conform to theprescription of anophthalmologist oroptometrist. Alensmeter can be used to verify the specifications of an existing pair of glasses. Corrective eyeglasses can significantly improve thelife quality of the wearer. Not only do they enhance the wearer's visual experience, but can also reduce problems that result from eye strain, such asheadaches or squinting.
The most common type of corrective lens is "single vision", which has a uniformrefractive index. For people withpresbyopia andhyperopia,bifocal andtrifocal glasses provide two or three different refractive indices, respectively, andprogressive lenses have a continuous gradient.[1] Lenses can also be manufactured with high refractive indices, which allow them to be more lightweight and thinner than their counterparts with "low" refractive indices.
Reading glasses provide a separate set of glasses for focusing on close by objects. Reading glasses are available without prescription fromdrugstores, and offer a cheap, practical solution, though these have a pair of simple lenses of equal power, and so will not correct refraction problems likeastigmatism or refractive or prismatic variations between the left and right eye. For the total correction of the individual's sight, glasses complying to a recent ophthalmic prescription are required.
People who need glasses to see often have corrective lens restrictions on theirdriver's licenses that require them to wear their glasses every time they drive or risk fines or jail time.
Some militaries issue prescription glasses to servicemen and women. These are typicallyGI glasses. Many state prisons in the United States issue glasses to inmates, often in the form of clear plastic aviators.
Adjustable-focus eyeglasses might be used to replace bifocals or trifocals, or might be used to produce cheaper single-vision glasses (since they do not have to be custom-manufactured for every person).
Pinhole glasses are a type of corrective glasses that do not use a lens. Pinhole glasses do not actually refract the light or change focal length. Instead, they create adiffraction limited system, which has an increased depth of field, similar to using a smallaperture in photography. This form of correction has many limitations that prevent it from gaining popularity in everyday use. Pinhole glasses can be made in aDIY fashion by making small holes in a piece of card which is then held in front of the eyes with a strap or cardboard arms.
Glasses may also house other corrective or assistive devices. After the development of thetransistor in the 1940s, combined eyeglass-hearing aids became popular. With thick-rimmed glasses the fashion at the time, ahearing aid could be concealed in the temple part of the frame. These fell out of fashion after the 1970s, but there are still occasions when combined eyeglass-hearing aids may be useful.[3]
Safety glasses are worn to protect the eyes in various situations. They are made with break-proof plastic lenses to protect the eye from flying debris or other matter.[4] Construction workers, factory workers, machinists and lab technicians are often required to wear safety glasses to shield the eyes from flying debris or hazardous splatters such as blood or chemicals.[5] As of 2017, dentists and surgeons in Canada and other countries are required to wear safety glasses to protect against infection from patients' blood or other body fluids. There are also safety glasses forwelding, which are styled like wraparound sunglasses, but with much darker lenses, for use in welding where a full-sizedwelding helmet is inconvenient or uncomfortable. These are often called "flash goggles" because they provide protection from welding flash.[6]Nylon frames are usually used for protective eyewear for sports because of their lightweight and flexible properties. Unlike most regular glasses, safety glasses often include protection beside the eyes as well as in front of the eyes.
Sunglasses provide more comfort and protection against brightlight and often againstultraviolet (UV) light. To properly protect the eyes from the dangers of UV light, sunglasses should have UV-400 blocker to provide good coverage against the entire light spectrum that poses a danger.[7]
Lightpolarization is an added feature that can be applied to sunglass lenses. Polarization filters are positioned to remove horizontally polarized rays of light, which eliminates glare from horizontal surfaces (allowing wearers to see into water when reflected light would otherwise overwhelm the scene). Polarized sunglasses may present some difficulties for pilots since reflections from water and other structures often used to gauge altitude may be removed.Liquid-crystal displays emit polarized light, making them sometimes difficult to view with polarized sunglasses. Sunglasses may be worn for aesthetic purposes, or simply to hide the eyes. Examples of sunglasses that were popular for these reasons include tea shades andmirrorshades. Manyblind people wear nearly opaque glasses to hide their eyes for cosmetic reasons. Many people with light sensitivity conditions wear sunglasses or other tinted glasses to make the light more tolerable.
Sunglasses may also have corrective lenses, which requires a prescription. Clip-on sunglasses or sunglass clips can be attached to another pair of glasses. Some wrap-around sunglasses are large enough to be worn over another pair of glasses. Otherwise, many people opt to wearcontact lenses to correct their vision so that standard sunglasses can be used.
Double-frame eyewear with one set of lenses on the moving frame and another pair of lenses on a fixed frame (optional).
The double frame uplifting glasses have one moving frame with one pair of lenses and the basic fixed frame with another pair of lenses (optional), that are connected byfour-bar linkage. For example, sun lenses could be easily lifted up and down while mixed withmyopia lenses that always stay on.Presbyopia lenses could be also combined and easily removed from the field of view if needed without taking off glasses. These glasses are often used for drivers going through tunnels, with the upper frame serving as sunglasses and the second frame as transparent lenses.
Theillusion of three dimensions on a two-dimensional surface can be created by providing each eye with different visual information. 3D glasses create the illusion of three dimensions by filtering a signal containing information for both eyes. The signal, often light reflected off a movie screen or emitted from an electronic display, is filtered so that each eye receives a slightly different image. The filters only work for the type of signal they were designed for.
Anaglyph 3D glasses have a different colored filter for each eye, typically red and blue or red and green. Apolarized 3D system on the other hand usespolarized filters. Polarized 3D glasses allow for color 3D, while the red-blue lenses produce an image with distorted coloration. Anactive shutter 3D system uses electronicshutters.Head-mounted displays can filter the signal electronically and then transmit light directly into the viewer's eyes.
Anaglyph and polarized glasses are distributed to audiences at3D movies. Polarized and active shutter glasses are used with many home theaters. Head-mounted displays are used by a single person, but the input signal can be shared between multiple units.
Glasses can also provide magnification that is useful for people with vision impairments or specific occupational demands. An example would bebioptics orbioptic telescopes which have smalltelescopes mounted on, in, or behind their regular lenses. Newer designs use smaller lightweight telescopes, which can be embedded into the corrective glass and improve aesthetic appearance (mini telescopic spectacles). They may take the form of self-contained glasses that resemblegoggles orbinoculars, or may be attached to existing glasses.
Recumbent orprism glasses are glasses that use a prism with a 90°refraction to allow the wearer to read or view a screen while lying on their back. Developed byLiverpudlian ophthalmologist Andrew McKie Reid in the 1930s to assist people bedbound by chronic illness or spinal injury, recumbent glasses have more recently been marketed not simply as an assistive device but also as 'lazy glasses'.[9] They do not assist with vision, although they can be worn over regular corrective glasses.
Yellow-tinted glasses are a type of glasses with a minor yellow tint. They perform a slight color correction, on top of reducing eyestrain from lack of blinking. They may also be considered minor corrective non-prescription glasses.[10] Depending on the company, these computer or gaming glasses can also filter outhigh energy blue and ultra-violet light from LCD screens,fluorescent lighting, and other sources of light. This allows for reduced eye-strain.[11] These glasses can be ordered as standard or prescription lenses that fit into standard optical frames.[12]
By the end of the 2010s, eyeglasses that filter outblue light fromcomputers,smartphones andtablets are becoming increasingly popular in response to concerns about problems caused by blue light overexposure.[13][14]The problems claimed range fromdry eyes toeye strain,sleep cycle disruption, up tomacular degeneration which can cause partial blindness.[13] They may also block outultraviolet (UV) radiation. However, there is no measurable UV light from computer monitors.[13][15][contradictory] The problem ofcomputer vision syndrome (CVS) can result from focusing the eyes on a screen for long, continuous periods. Many times the glasses do not appear to have much of a tint, or, if any, a slight yellow tint, but they may be more heavily tinted.
Long hours of computer use (not blue light) may cause eye strain.[13][16][14][17]Many eye symptoms caused by computer use will lessen after the usage of the computer is stopped.[13]Decreasing evening screen time and setting devices to night mode will improve sleep.[16][18]Several studies have shown that blue light from computers does not lead to eye diseases, including macular degeneration.[16][19][20] The total amount of light entering the eyes can be adjusted without glasses using the screen brightness settings. Similarly, the blue light can often specifically be adjusted using the "night mode" of different operating systems, which can usually be activated outside of nighttime hours.
TheAmerican Academy of Ophthalmology (AAO) does not recommend special eyewear for computer use,[13][14]although it recommends usingprescription glasses measured specifically for computer screen distance (depending on individuals, but possibly 20–26 inches from the face), which are not the same as "blue-light blocking" glasses.[21]The position of theCollege of Optometrists (UK) is that "the best scientific evidence currently available does not support the use of blue-blocking spectacle lenses in the general population to improve visual performance, alleviate the symptoms of eye fatigue or visual discomfort, improve sleep quality or conserve macula health."[22]
The ophthalmic frame is the part of a pair of glasses that is designed to hold the lenses in the proper position.Ophthalmic frames come in a variety of styles, sizes, materials, shapes, and colors.[23]
pair of eye wires or rims surrounding and holding the lenses in place
bridge which connects the two eye wires
chassis, the combination of the eye wires and the bridge
top bar or brow bar, a bar just above the bridge providing structural support and/or style enhancement (country/Grandpa style). The addition of a top bar makes a pair of glassesaviator eyeglasses
pair of brows or caps, plastic or metal caps which fit over the top of the eye wires for style enhancement and to provide additional support for the lenses. The addition of brows makes a pair of glassesbrowline glasses
pair of nose pads that allows a comfortable resting of the eye wires on the nose
pair of pad arms connect the nose pads to the eye wires
pair of temples (earpieces) on either side of the skull
pair of temple tips at the ends of the temples
pair of end pieces connect the eye wires via the hinges to the temples
pair of frame-front end pieces
pair of hinges connect the end pieces to the temples, allowing a swivel movement. Spring-loaded flex hinges are a variant that is equipped with a small spring that affords the temples a greater range of movement and does not limit them to the traditional, 90-degree angle.
Skull temples: bend down behind the ears, follow the contour of the skull and rest evenly against the skull
Library temples: generally straight and do not bend down behind the ears. Hold the glasses primarily through light pressure against the side of the skull
Convertible temples: used either as library or skull temples depending on the bent
Riding bow temples: curve around the ear and extend down to the level of the ear lobe. Used mostly on athletic, children's, and industrial safety frames
Comfort cable temples: similar to the riding bow, but made from aspringy cable of coiled metal, sometimes inside a plastic or silicone sleeve. The tightness of the curl can be adjusted along its whole length, allowing the back to fit the wearer's ear curve perfectly. Used for physically active wearers, children, and people with high prescriptions (heavy lenses).[24][25] See the image of 1920s frames above.
Optyl, a type ofhypoallergenic material made especially for eyeglass frames. It features a type of elasticity that returns the material to its original shape.
Corrective lenses can be produced in many different shapes from a circular lens called a lens blank. Lens blanks are cut to fit the shape of the frame that will hold them. Frame styles vary and fashion trends change over time, resulting in a multitude of lens shapes. For lower power lenses, there are few restrictions, allowing for many trendy and fashionable shapes. Higher power lenses can distortperipheral vision and may become thick and heavy if a large lens shape is used. However, if the lens is too small, it can drastically reduce the field of view.
Bifocal,trifocal, andprogressive lenses generally require a taller lens shape to leave room for the different segments while preserving an adequate field of view through each segment. Frames with rounded edges are the most efficient for correctingmyopic prescriptions, with perfectly round frames being the most efficient. Before the advent of eyeglasses as a fashion item, when frames were constructed with only functionality in mind, virtually all eyeglasses were eitherround,oval, panto,rectangular,octagonal, orsquare. It was not until glasses began to be seen as an accessory that different shapes were introduced to be more aesthetically pleasing than functional.
Scattered evidence exists for use of visual aid devices in Greek and Roman times, most prominently the use of an emerald byEmperor Nero as mentioned byPliny the Elder.[27]
The use of aconvex lens to form an enlarged/magnified image was most likely described inPtolemy'sOptics (which survives only in a poor Arabic translation). Ptolemy's description of lenses was commented upon and improved byIbn Sahl (10th century) and most notably byAlhazen (Book of Optics,c. 1021).Latin translations of Ptolemy'sOptics and of Alhazen became available in Europe in the 12th century, coinciding with the development of "reading stones".
There are claims that single lens magnifying glasses were being used in China during theNorthern Song dynasty (960–1127).[28][29]
Robert Grosseteste's treatiseDe iride (On the Rainbow), written between 1220 and 1235, mentions using optics to "read the smallest letters at incredible distances".[30] A few years later in 1262,Roger Bacon is also known to have written on the magnifying properties of lenses.[31][32] The development of the first eyeglasses took place in northernItaly in the second half of the 13th century.[33]
Independently of the development of optical lenses, some cultures developed "sunglasses" for eye protection, without any corrective properties.[34] For example, flat panes ofsmoky quartz were used in 12th-centuryChina, and theInuit have usedsnow goggles for eye protection.[a]
Giordano's colleague FriarAlessandro della Spina of Pisa (d. 1313) was soon making eyeglasses. TheAncient Chronicle of the Dominican Monastery of St. Catherine in Pisa records: "Eyeglasses, having first been made by someone else, who was unwilling to share them, he [Spina] made them and shared them with everyone with a cheerful and willing heart."[38]Venice quickly became an important center of manufacture, especially due to using the high-quality glass made atMurano.[39] By 1301, there wereguild regulations in Venice governing the sale of eyeglasses[40] and a separate guild of Venetian spectacle makers was formed in 1320.[39] In the fourteenth century, they were very common objects:Francesco Petrarca says in one of hisletters that, until he was 60, he did not need glasses,[41][42] andFranco Sacchetti mentions them often in hisTrecentonovelle.
The earliest pictorial evidence for the use of eyeglasses isTommaso da Modena's 1352 portrait of the cardinalHugh de Saint-Cher reading in ascriptorium. Another early example would be a depiction of eyeglasses found north of theAlps in an altarpiece of the church ofBad Wildungen, Germany, in 1403. These early glasses hadconvex lenses that could correct bothhyperopia (farsightedness), and thepresbyopia that commonly develops as a symptom ofaging. Although concave lenses formyopia (near-sightedness) had made their first appearance in the mid-15th century,[39] it was not until 1604 thatJohannes Kepler published the first correct explanation as to why convex and concave lenses could correct presbyopia and myopia.[b]
Early frames for glasses consisted of two magnifying glassesriveted together by the handles so that they could grip the nose. These are referred to as "rivet spectacles". The earliest surviving examples were found under the floorboards atKloster Wienhausen, aconvent nearCelle in Germany; they have been dated tocirca 1400.[45]
The world's first specialist shop for spectacles—what we might regard today as anoptician—opened inStrasbourg (thenHoly Roman Empire, now France) in 1466.[46]
Marco Polo is mistakenly claimed to have encountered eyeglasses during his travels in China in the 13th century. However, no such evidence appears in his accounts.[49][50] Indeed, the earliest mentions of eyeglasses in China occur in the 15th century and those Chinese sources state that eyeglasses were imported.[51]
In 1907, ProfessorBerthold Laufer speculated, in his history of glasses, that for glasses to be mentioned in the literature of China and Europe at approximately the same time it was probable that they were not invented independently, and after ruling out the Turks, proposed India as a location.[52][c] However,Joseph Needham speculated that the mention of glasses in the Chinese manuscript Laufer used "in part" to credit the prior invention of them in Asia did not exist in older versions of that manuscript, and the reference to them in later versions was added during theMing dynasty.[53]
In 1971, Rishi Agarwal, in an article in theBritish Journal of Ophthalmology, states thatVyasatirtha was observed in possession of a pair of glasses in the 1520s, he argues that it "is, therefore, most likely that the use of lenses reached Europe via the Arabs, as didHindu mathematics and the ophthalmological works of the ancient Hindu surgeonSushruta",[54] but all dates are given well after the existence of eyeglasses in Italy was established, including significant shipments of eyeglasses from Italy to the Middle East, with one shipment as large as 24,000 glasses,[55] as well as a spectacles dispensary in Strasbourg in 1466.[46]
The American scientistBenjamin Franklin, who had bothmyopia andpresbyopia, inventedbifocals. Historians have from time to time produced evidence to suggest that others may have preceded him in the invention; however, a correspondence betweenGeorge Whatley andJohn Fenno, editor ofThe Gazette of the United States, suggested that Franklin had indeed invented bifocals, and perhaps 50 years earlier than had been originally thought.[56] The first lenses for correctingastigmatism were designed by the British astronomerGeorge Airy in 1825.[57]
Over time, the construction of frames for glasses also evolved. Early eyepieces were designed to be either held in place by hand or by exerting pressure on the nose (pince-nez).Girolamo Savonarola suggested that eyepieces could be held in place by a ribbon passed over the wearer's head, this in turn secured by the weight of a hat. The modern style of glasses, held by temples passing over the ears, was developed sometime before 1727, possibly by the British opticianEdward Scarlett. These designs were not immediately successful, however, and various styles with attached handles such as "scissors-glasses" andlorgnettes were also fashionable from the second half of the 18th century and into the early 19th century.
In the early 20th century,Moritz von Rohr andZeiss (with the assistance of H. Boegehold and A. Sonnefeld[58]) developed the Zeiss Punktal spherical point-focus lenses that dominated the eyeglass lens field for many years. In 2008,Joshua Silver designed eyewear with adjustable corrective glasses. They work by using a built-in syringe to pump asilicone solution into a flexible lens.[59]
Despite the popularity ofcontact lenses andlasercorrective eye surgery, glasses remain very common, as their technology has improved. For instance, it is now possible to purchase frames made of specialmemory metal alloys that return to their correct shape after being bent. Other frames have spring-loaded hinges. Either of these designs offer dramatically better ability to withstand the stresses of daily wear and the occasional accident. Modern frames are also often made from strong, lightweight materials such astitanium alloys, which were not available in earlier times.
In the 1930s, "spectacles" were described as "medical appliances".[60] Wearing spectacles was sometimes considered socially humiliating. In the 1970s, fashionable glasses started to become available through manufacturers, and governments also recognized the demand for stylized eyewear.[60]
Graham Pullin describes how devices for disability, like glasses, have traditionally been designed to camouflage against the skin and restore ability without being visible.[60] In the past, design for disability has "been less about projecting a positive image as about trying not to project an image at all".[60] Pullin uses the example of spectacles, traditionally categorized as a medical device for "patients", and outlines how they are now described as eyewear: a fashionable accessory.[60] Much like other fashion designs and accessories, eyewear is created by designers, has reputable labels, and comes in collections, by season and designer.[60] In recent years, it has become more common for consumers to purchase eyewear with non-prescription lenses as a fashion accessory.[60]
The market for spectacles has been characterized as having highlyinelastic demand. Advertising restrictions in the United States, for example, have correlated with higher prices, suggesting that adverts make the spectacles market moreprice-competitive.[61] It has also been claimed to bemonopolistically competitive, as in the case ofLuxottica.[62][63][64]
There are claims that insufficiently freemarket competition inflates the prices of frames, which cost an average of $25–$50 U.S. to make, to an average retail price of $300 in the United States. This claim is disputed by some in the industry.[65][66][67]
The United States also prohibits the sale of glasses unless the user has a recent prescription from an optometrist or ophthalmologist, whereas in most of the world, glasses and contact lenses can be bought without needing to get a neweye exam first.[68] This means that Americans who lose or break their glasses may be unable to see well until they can get, and pay for, an appointment with an optometrist.[68] In most of the world, someone who has lost their glasses merely goes to the nearest store selling glasses and buys a replacement over the counter.[68]
Many people require glasses for the reasons listed above. There are many shapes, colors, and materials that can be used when designing frames and lenses that can be utilized in various combinations. Oftentimes, the selection of a frame is made based on how it will affect the appearance of the wearer. Some people with good natural eyesight like to wear eyeglasses as a style accessory. In Japan, some companies ban women from wearing glasses.[73]
For most of their history, eyeglasses were seen as unfashionable, and carried several potentially negative connotations: wearing glasses caused individuals to be stigmatized and stereotyped as pious clergymen, as those in religious vocation were the most likely to be literate and therefore the most likely to need reading glasses, elderly, or physically weak and passive.[74][75] Thestigma began to fall away in the U.S. in the early 1900s when the popularTheodore Roosevelt was regularly photographed wearing eyeglasses, and in the 1910s when popular comedianHarold Lloyd wore a pair ofhorn-rimmed glasses as the "Glasses" character in his films.[74][75]
In the United Kingdom, wearing glasses was characterized in the nineteenth century as "a sure sign of the weakling and the mollycoddle", according toNeville Cardus, writing in 1928.[76]"Tim" Killick was the first professionalcricketer to play while wearing glasses "continuously", after his vision deteriorated in 1897. "With their aid he placed himself in the forefront among English professionals of all-round abilities."[76] The American tenorJan Peerce, plagued with poor eyesight, credited comedianSteve Allen for normalizing and even popularizing the wearing of eyeglasses in front of live television and stage audiences; prior to this, performers who read on early television were expected to squint or use contact lenses.[77]
Since then, eyeglasses have become an acceptable fashion item and often act as a key component in individuals' personal image. MusiciansBuddy Holly andJohn Lennon became synonymous with the styles of eye-glasses they wore to the point that thick, black horn-rimmed glasses are often called "Buddy Holly glasses" and perfectly round metal eyeglass frames called "John Lennon glasses" (or, more recently, "Harry Potter glasses"). British comedic actorEric Sykes was known in the United Kingdom for wearing thick, square, horn-rimmed glasses, which were in fact a sophisticatedhearing aid that alleviated hisdeafness by allowing him to "hear" vibrations.[78] Some celebrities have become so associated with their eyeglasses that they continued to wear them even after taking other measures against vision problems: U.S. SenatorBarry Goldwater and comedianDrew Carey continued to wear non-prescription glasses after being fitted forcontacts and gettinglaser eye surgery, respectively.
Insuperhero fiction, eyeglasses have become a standard component of various heroes' disguises as masks, allowing them to adopt a nondescript demeanor when they are not in their superhero personae:Superman is well known for wearing 1950s-style horn-rimmed glasses asClark Kent, whileWonder Woman wears either round, Harold Lloyd-style glasses or 1970s-stylebug-eye glasses asDiana Prince. An example of thehalo effect is seen in thestereotype that those who wear glasses are intelligent. This belief can have positive consequences for people who wear glasses, for example in elections. Studies show that wearing glasses increases politicians' electoral success, at least inWestern cultures.[81]
In the 20th century, eyeglasses came to be considered a component of fashion; as such, various different styles have come in and out of popularity. Most are still in regular use, albeit with varying degrees of frequency.
^ Chinese judges wore dark glasses to hide their facial expressions during court proceedings.[35]
^ In his treatiseAd Vitellionem paralipomena [Emendations (or Supplement) to Witelo] (1604), Kepler explained how eyeglass lenses compensate for the distortions that are caused by presbyopia or myopia, so that the image is once again properly focused on theretina.[43][44]
^Laufer, Berthold (1907),Geschichte der Brille(PDF), vol. 6, p. 26, retrieved29 May 2019 Translation:
I am interested in the remarks of Prof. J. HIRSCHBERG on the "History of the Invention of Glasses" published in the last issue of this journal (Volume VI, pp. 221–223) and the subsequent discussion by Prof. GÜPPERT. The book by HIRSCHBERG mentioned therein, in which his theory should be presented in detail, has not yet become accessible to me. I, therefore, limit my criticism of it as far as possible and prefer to prove, by means of new material from Chinese literature, that the view of the original invention of spectacles in India is the greatest probability. HIRSCHBERG theory is highly unlikely, as all previous experience has shown and contradicts analogies in cultural history and in the history of inventions in particular; Crystal spectacles appear in the European Middle Ages, in India, and in China, and from the historical point of view one can suppose from the outset that these inventions did not occur independently in each of these three cultural groups, but that a historical connection is here present.
^Duarte, IA; Mde F, Hafner; Malvestiti, AA (2015), "Ultraviolet radiation emitted by lamps, TVs, tablets and computers: are there risks for the population?",An Bras Dermatol, vol. 90, no. 4, pp. 595–7,doi:10.1590/abd1806-4841.20153616,PMC4560556,PMID26375236
^Grant, Edward, ed. (1974),A Source Book in Medieval Science, Cambridge, Massachusetts: Harvard University Press, p. 389,ISBN9780674823600 From Grant's English translation of Robert Grosseteste'sDe Iride (On the rainbow) in Latin, p. 389: "This part [viz, from Aristotle's supposed treatise on optics] of perspective, if perfectly understood, shows us how to make nearby objects appear very small, and how to make a small object placed at a distance appear as large as we wish, so that it would be possible to read minute letters from incredible distances or count sand, seeds, blades of grass, or any minute objects."
^Bacon, Roger; Burke, Robert Belle, trans. (1962)The Opus Majus of Roger Bacon (New York: Russell & Russell, Inc.) vol. 2. Part 5, Ch. IV, p. 582. From p. 582: "For we can so shape transparent bodies, and arrange them in such a way with respect to our sight and objects of vision, that the rays will be refracted and bent in any direction we desire, and under any angle, we wish we shall see the object near or at a distance. Thus from an incredible distance we might read the smallest letters and number grains of dust and sand ..."
^Kriss, Timothy C; Kriss, Vesna Martich (April 1998), "History of the Operating Microscope: From Magnifying Glass to Microneurosurgery",Neurosurgery,42 (4):899–907,doi:10.1097/00006123-199804000-00116,PMID9574655
^Petrarch (Franciscus Petrarca) mentions eyeglasses in hisEpistola ad Posteros (Letter to Posterity):Petrarca, Francisci (1859), Fracassetti, Joseph (ed.),Epistolae de Rebus Familiaribus et Variae ... (in Latin), vol. 1, Florence, Italy: Felice Le Monnier, pp. 1–2,... colore vivido inter candidum et subnigrum, vivacibus oculis et visu per longum tempus acerrimo, qui preter spem supra sexagesimum etatis annum me destituit, ut indignanti michi ad ocularium confugiendum esset auxilium.
^English translation:Petrarch (1914), Robinson, James Harvey; Rolfe, Henry Winchester (eds.),Petrarch: The First Modern Scholar and Man of Letters (2nd ed.), New York: G. P. Putnam's Sons, p. 60,I was possessed of a clear complexion, between light and dark, lively eyes, and for long years a keen vision, which however deserted me, contrary to my hopes, after I reached my sixtieth birthday, and forced me, to my great annoyance, to resort to glasses.
^Rosen, Edward (1956), "The invention of eyeglasses",Journal of the History of Medicine and Allied Sciences,11 (2): 13–46 (part 1), 183–218 (part 2),doi:10.1093/jhmas/xi.2.183,PMID13306950
^Hirschberg, Julius (1911), "Geschichte der Augenheilkunde" [History of Ophthalmology], in Graef, Alfred K; Saemisch, Theodor (eds.),Handbuch der gesamten Augenheilkunde [Handbook of all ophthalmology], Handbuch der Augenheilkunde, vol. 13, Leipzig, Germany: Wilhelm Engelmann, pp. 265 ff SectionGeschichte der Brillen (History of Eyeglasses) From pp. 266–267 (translated): "3. Do the Europeans have the Chinese to thank for eyeglasses? ... Messrs. Scrini and Fortin in Paris have asserted this recently with the words: 'One knows, on the other hand, that when Marco Polo went to China, he learned that for a very long time already, the inhabitants had been using eyeglasses.' This assertion lacked any substantiation. So I have closely perused the German translation of 'the books of Marco Polo' (2nd ed., Leipzig 1855) once again as well as carefully compared [that book] to the original text (the book of Marco Polo by Pauthier, Paris 1865, 2 volumes): not a syllable about eyeglasses in China is found therein. Our highly esteemed Sinologist, Prof. Graube, had the kindness to peruse also the English edition (by Yule, London 1875), with the same negative result. Thus the sentence of Messrs. Scrini and Fortin is to be crossed out; this error may not be the only one to have infiltrated the literature."
^Laufer, Berthold (1907)."Geschichte der Brille" [History of eyeglasses].Mitteilungen zur Geschichte der Medizin und der Naturwissenschaften [Communications on the History of Medicine and the Sciences],6 (4) : 379–385.
^Bruen, Robert,"Sir George Biddell Airy",The Lucasian Chair of Mathematics at Cambridge University, Robert Bruen, archived fromthe original on 25 January 2021, retrieved1 January 2014
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