Glasses, also known as eyeglasses or spectacles, are
vision
Vision, Visions, or The Vision may refer to:
Perception Optical perception
* Visual perception, the sense of sight
* Visual system, the physical mechanism of eyesight
* Computer vision, a field dealing with how computers can be made to gain un ...
eyewear
Eyewear consists of items and accessories worn on or over the eyes, for fashion or adornment, protection against the environment, and to improve or enhance visual acuity.
Common forms of eyewear include glasses (also called ''eyeglasses'' or ''s ...
, with
lenses
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
(clear or tinted) mounted in a frame that holds them in front of a person's
eyes
Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conve ...
, typically utilizing a bridge over the nose and hinged arms (known as temples or temple pieces) that rest over the ears.
Glasses are typically used for
vision correction, such as with reading glasses and glasses used for
nearsightedness
Near-sightedness, also known as myopia and short-sightedness, is an eye disease where light focuses in front of, instead of on, the retina. As a result, distant objects appear blurry while close objects appear normal. Other symptoms may include ...
; however, without the specialized lenses, they are sometimes used for cosmetic purposes.
Safety glasses provide
eye protection
Eye protection is protective gear for the eyes, and sometimes face, designed to reduce the risk of injury. Examples of risks requiring eye protection can include: impact from particles or debris, light or radiation, wind blast, heat, sea spray ...
against flying debris for construction workers or lab technicians; these glasses may have protection for 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 or
radiation
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes:
* ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...
. Glasses are worn for eye protection in some sports, such as
squash
Squash may refer to:
Sports
* Squash (sport), the high-speed racquet sport also known as squash racquets
* Squash (professional wrestling), an extremely one-sided match in professional wrestling
* Squash tennis, a game similar to squash but pla ...
.
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 of the glasses and breaking. The loss of glasses would be detrimental to those working in these conditions.
Sunglasses
Sunglasses or sun glasses (informally called shades or sunnies; more names below) are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes. They can s ...
allow for better vision in bright daylight, and may protect one's eyes against damage from excessive levels of
ultraviolet light
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
. Typical sunglasses lenses are tinted for protection against bright light or polarized to remove glare;
photochromic glasses
A photochromic lens is an optical lens that darkens on exposure to light of sufficiently high frequency, most commonly ultraviolet (UV) radiation. In the absence of activating light, the lenses return to their clear state. Photochromic lenses may ...
are blacked out or lightly tinted in dark or indoor conditions, but turn into sunglasses when they come in 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 have
photophobia
Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of ...
as a primary symptom (like certain
migraine
Migraine (, ) is a common neurological disorder characterized by recurrent headaches. Typically, the associated headache affects one side of the head, is pulsating in nature, may be moderate to severe in intensity, and could last from a few hou ...
disorders or
Irlen syndrome
Irlen syndrome, occasionally referred to as scotopic sensitivity syndrome (SSS) or Meares–Irlen syndrome, is a postulated disorder of vision or image-processing in the brain. Irlen syndrome is also sometimes referred to as asfedia or visual ...
) 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
Stereoscopy (also called stereoscopics, or stereo imaging) is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. The word ''stereoscopy'' derives . Any stereoscopic image is ...
for
3D films
3-D, 3D, or 3d may refer to:
Science, technology, and mathematics Relating to three-dimensionality
* Three-dimensional space
** 3D computer graphics, computer graphics that use a three-dimensional representation of geometric data
** 3D film, a ...
(
stereoscopy
Stereoscopy (also called stereoscopics, or stereo imaging) is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. The word ''stereoscopy'' derives . Any stereoscopic image is ...
). 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.
Types
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.
Corrective
![Microfiber cloth](https://upload.wikimedia.org/wikipedia/commons/c/cd/Microfiber_cloth.jpg)
Corrective lenses are used to correct
refractive error
Refractive error, also known as refraction error, is a problem with focus (optics), focusing light accurately on the retina due to the shape of the human eye, eye and or cornea. The most common types of refractive error are myopia, near-sightedne ...
s by bending the light entering the eye in order to alleviate the effects of conditions such as
nearsightedness (myopia),
farsightedness (hypermetropia) or
astigmatism
Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. This results in distorted or blurred vision at any distance. Other symptoms can include eyestrain, headaches, and trouble driving at nig ...
. 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 is
presbyopia
Presbyopia is physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. Also known as age-related farsightedness (or age-related long si ...
, which is caused by the eye's
crystalline lens
The lens, or crystalline lens, is a transparent biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. By changing shape, it functions to change the focal length of the eye so that it can ...
losing elasticity, progressively reducing the ability of the lens to
accommodate (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 the
prescription of an
ophthalmologist
Ophthalmology ( ) is a surgery, surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders.
An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Followin ...
or
optometrist
Optometry is a specialized health care profession that involves examining the eyes and related structures for defects or abnormalities. Optometrists are health care professionals who typically provide comprehensive primary eye care.
In the Uni ...
. A
lensmeter
A lensmeter or lensometer (sometimes even known as focimeter or vertometer), is an ophthalmic instrument. It is mainly used by optometrists and opticians to measure the back or front vertex power of a spectacle lens and verify the correct presc ...
can be used to verify the specifications of an existing pair of glasses. Corrective eyeglasses can significantly improve the
life quality
Quality of life (QOL) is defined by the World Health Organization as "an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards ...
of the wearer. Not only do they enhance the wearer's visual experience, but can also reduce problems that result from eye strain, such as
headaches
Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches.
Headaches can occur as a result of m ...
or squinting.
The most common type of corrective lens is "single vision", which has a uniform
refractive index
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.
The refractive index determines how much the path of light is bent, or ...
. For people with
presbyopia
Presbyopia is physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. Also known as age-related farsightedness (or age-related long si ...
and
hyperopia
Far-sightedness, also known as long-sightedness, hypermetropia, or hyperopia, is a condition of the eye where distant objects are seen clearly but near objects appear blurred. This blurred effect is due to incoming light being focused behind, i ...
,
bifocal and
trifocal
Trifocals are eyeglasses with lenses that have three regions which correct for distance, intermediate (arm's length), and near vision. John Isaac Hawkins developed the trifocal lens in 1827.
Trifocals are mostly used by people with advanced pres ...
glasses provide two or three different refractive indices, respectively, and
progressive lenses
Progressive lenses, also called multifocal lenses, progressive addition lenses (PAL), varifocal lenses, progressive power lenses, graduated prescription lenses, or progressive spectacle lenses are corrective lenses used in eyeglasses to correct pr ...
have a continuous gradient. 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
A corrective lens is a lens (i.e. a transmissive optical device) that is typically worn in front of the eye to improve daily vision. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia. Glasse ...
provide a separate set of glasses for focusing on close by objects. Reading glasses are available without prescription from
drugstore
A pharmacy (also called "drugstore" in American English or "community pharmacy" or "chemist" in Commonwealth English, or rarely, apothecary) is a retail shop which provides pharmaceutical drugs, among other products. At the pharmacy, a pharmacis ...
s, and offer a cheap, practical solution, though these have a pair of simple lenses of equal power, and so will not correct refraction problems like
astigmatism
Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. This results in distorted or blurred vision at any distance. Other symptoms can include eyestrain, headaches, and trouble driving at nig ...
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 their
driver's licenses
A driver's license is a legal authorization, or the official document confirming such an authorization, for a specific individual to operate one or more types of motorized vehicles—such as motorcycles, cars, trucks, or buses—on a public r ...
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 typically
GI glasses
GI glasses are eyeglasses issued by the American military to its service members. Dysphemisms for them include the most common "birth control glasses" (BCGs) and other variants. At one time, they were officially designated as regulation prescri ...
. Many state prisons in the United States issue glasses to inmates, often in the form of clear plastic aviators.
Adjustable-focus eyeglasses
Adjustable focus eyeglasses are eyeglasses with an adjustable focal length. They compensate for refractive errors (such as presbyopia) by providing variable focusing, allowing users to adjust them for desired distance or prescription, or both.
Cu ...
might be used to replace bifocals or trifocals, or might be used to produce cheaper single-vision glasses (since they don't have to be custom-manufactured for every person).
Pinhole glasses
Pinhole glasses, also known as stenopeic glasses, are eyeglasses with a series of pinhole-sized perforations filling an opaque sheet of plastic in place of each lens. Similar to the workings of a pinhole camera, each perforation allows only a very ...
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 a
diffraction
Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a s ...
limited system, which has an increased depth of field, similar to using a small
aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane.
An opt ...
in photography. This form of correction has many limitations that prevent it from gaining popularity in everyday use. Pinhole glasses can be made in a
DIY
"Do it yourself" ("DIY") is the method of building, modifying, or repairing things by oneself without the direct aid of professionals or certified experts. Academic research has described DIY as behaviors where "individuals use raw and semi ...
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.
Safety
![SafetyGlassesShield](https://upload.wikimedia.org/wikipedia/commons/8/8e/SafetyGlassesShield.jpg)
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. 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. 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 for
welding
Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing Fusion welding, fusion. Welding is distinct from lower ...
, which are styled like wraparound sunglasses, but with much darker lenses, for use in welding where a full-sized
welding helmet A welding helmet is a type of personal protective equipment used in performing certain types of welding to protect the eyes, face, and neck from flash burn, sparks, infrared and ultraviolet light, and intense heat. The modern welding helmet used tod ...
is inconvenient or uncomfortable. These are often called "flash goggles" because they provide protection from welding flash.
Nylon
Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic.
Nylon is a silk-like thermoplastic, generally made from petro ...
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
![Woman wearing sunglasses](https://upload.wikimedia.org/wikipedia/commons/d/df/Woman_wearing_sunglasses.jpg)
Sunglasses provide more comfort and protection against bright
light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 tera ...
and often against
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
(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.
Light
polarization 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 display
A liquid-crystal display (LCD) is a flat-panel display
A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipmen ...
s 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 and
mirrorshades
''Mirrorshades: The Cyberpunk Anthology'' (1986) is a cyberpunk short story collection, edited by American writer Bruce Sterling.
Contents
* "The Gernsback Continuum" by William Gibson
* "Snake-Eyes" by Tom Maddox
* "Rock On" by Pat Cadigan
* "T ...
. Many
blind 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 wear
contact lens
Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic ...
es to correct their vision so that standard sunglasses can be used.
Mixed doubleframe
![Doubleframe uplifting eyewear - Nella](https://upload.wikimedia.org/wikipedia/commons/7/76/Doubleframe_uplifting_eyewear_-_Nella.gif)
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 by
four-bar linkage
In the study of mechanisms, a four-bar linkage, also called a four-bar, is the simplest closed- chain movable linkage. It consists of four bodies, called ''bars'' or ''links'', connected in a loop by four joints. Generally, the joints are configu ...
. For example, sun lenses could be easily lifted up and down while mixed with
myopia
Near-sightedness, also known as myopia and short-sightedness, is an eye disease where light focuses in front of, instead of on, the retina. As a result, distant objects appear blurry while close objects appear normal. Other symptoms may include ...
lenses that always stay on.
Presbyopia
Presbyopia is physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. Also known as age-related farsightedness (or age-related long si ...
lenses could be also combined and easily removed from the field of view if needed without taking off glasses.
3D glasses
The
illusion 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
Anaglyph 3D is the stereoscopic 3D effect achieved by means of encoding each eye's image using filters of different (usually chromatically opposite) colors, typically red and cyan. Anaglyph 3D images contain two differently filtered colored ...
glasses have a different colored filter for each eye, typically red and blue or red and green. A
polarized 3D system
A polarized 3D system uses polarization glasses to create the illusion of three-dimensional images by restricting the light that reaches each eye (an example of stereoscopy).
To present stereoscopic images and films, two images are projected s ...
on the other hand uses
polarized filters. Polarized 3D glasses allow for color 3D, while the red-blue lenses produce an image with distorted coloration. An
active shutter 3D system
An active shutter 3D system (a.k.a. alternate frame sequencing, alternate image, AI, alternating field, field sequential or eclipse method) is a technique of displaying stereoscopic 3D images. It works by only presenting the image intended for t ...
uses electronic
shutters.
Head-mounted display
A head-mounted display (HMD) is a display device, worn on the head or as part of a helmet (see Helmet-mounted display for aviation applications), that has a small display optic in front of one (monocular HMD) or each eye ( binocular HMD). An H ...
s can filter the signal electronically and then transmit light directly into the viewer's eyes.
Anaglyph and polarized glasses are distributed to audiences at
3D movies
3D films are motion pictures made to give an illusion of three-dimensional solidity, usually with the help of special glasses worn by viewers. They have existed in some form since 1915, but had been largely relegated to a niche in the motion pict ...
. 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.
Magnification (bioptics)
Glasses can also provide magnification that is useful for people with vision impairments or specific occupational demands. An example would be ''
bioptics'' or ''bioptic telescopes'' which have small
telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...
s 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 resemble
goggles
Goggles, or safety glasses, are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in chemistry laboratories and ...
or
binoculars
Binoculars or field glasses are two refracting telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most binoculars are sized to be held ...
, or may be attached to existing glasses.
Yellow-tinted computer/gaming glasses
Yellow-tinted glasses are a type of glasses with a minor yellow tint. They perform minor color correction, on top of reducing eyestrain from lack of blinking. They may also be considered minor corrective non-prescription glasses. Depending on the company, these computer or gaming glasses can also filter out
high energy blue and ultra-violet light from LCD screens,
fluorescent lighting
A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet ligh ...
, and other sources of light. This allows for reduced eye-strain. These glasses can be ordered as standard or prescription lenses that fit into standard optical frames.
Blue-light blocking glasses
Eyeglasses that filter out blue light from
computers
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs ...
,
smartphones
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, which ...
and
tablets are becoming increasingly popular in response to concerns about problems caused by blue light overexposure.
The problems claimed range from
dry eyes
Dry eye syndrome (DES), also known as keratoconjunctivitis sicca (KCS), is the condition of having dry eyes. Other associated symptoms include irritation, redness, discharge, and easily fatigued eyes. Blurred vision may also occur. Symptoms range ...
to
eye strain
Eye strain, also known as asthenopia (from Greek ''a-sthen-opia'', grc, ἀσθενωπία, ), is a common eye condition that manifests through non-specific symptoms such as fatigue, pain in or around the eyes, blurred vision, headache, and ...
,
sleep cycle
The sleep cycle is an oscillation between the slow-wave and REM (paradoxical) phases of sleep. It is sometimes called the ultradian sleep cycle, sleep–dream cycle, or REM-NREM cycle, to distinguish it from the circadian alternation between s ...
disruption, up to
macular degeneration
Macular degeneration, also known as age-related macular degeneration (AMD or ARMD), is a medical condition which may result in blurred or no vision in the center of the visual field. Early on there are often no symptoms. Over time, however, som ...
which can cause partial blindness.
However, there is no measurable ultraviolet radiation from computer monitors.
Long hours of computer use may cause eye strain, not blue light.
Many eye symptoms caused by computer use will lessen after the usage of the computer is stopped.
Decreasing evening screen time and setting devices to night mode will improve sleep.
Several studies have shown that blue light from computers does not lead to eye diseases, including macular degeneration.
The
American Academy of Ophthalmology
The American Academy of Ophthalmology (Academy) is a professional medical association of ophthalmologists. It is headquartered in San Francisco, California. Its membership of 32,000 medical doctors includes more than 90 percent of practicing ...
(AAO) does not recommend special eyewear for computer use,
although it recommends using prescription 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.
The position of the
College of Optometrists
The College of Optometrists is the professional, scientific and examining body for optometry in the United Kingdom, working for the public benefit. Their headquarters is at 41-42 Craven Street, London WC2, of which no 41 is a Grade II listed bu ...
(UK) is "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."
Frames
![Szemüveg - 1920-as évek](https://upload.wikimedia.org/wikipedia/commons/c/ca/Szem%C3%BCveg_-_1920-as_%C3%A9vek.JPG)
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.
Parts
* 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 glasses
aviator 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 glasses
browline glasses
Browline glasses are a style of eyeglass frames where the "bold" upper part holding the lenses resembles eyebrows framing the eyes. They were very popular during the 1950s and 1960s, especially in the United States of America. The glasses were ...
* 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.
Temple types
* 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 a
springy 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). See the image of 1920s frames above.
Materials
Plastic and polymer
*
Cellulose acetate
In biochemistry, cellulose acetate refers to any acetate ester of cellulose, usually cellulose diacetate. It was first prepared in 1865. A bioplastic, cellulose acetate is used as a film base in photography, as a component in some coatings, and ...
* Optyl, a type of
hypoallergenic
Hypoallergenic, meaning "below average" or "slightly" allergenic, is a term meaning that something (usually cosmetics, pets, textiles, food, etc.) causes fewer allergic reactions. The term was first used in 1953 in an advertising campaign for cosm ...
material made especially for eyeglass frames. It features a type of elasticity that returns the material to its original shape.
*
Cellulose propionate, a molded, durable plastic
*
3D-printed
3D printing or additive manufacturing is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer co ...
plastic using super-fine
polyamide
A polyamide is a polymer with repeating units linked by amide bonds.
Polyamides occur both naturally and artificially. Examples of naturally occurring polyamides are proteins, such as wool and silk. Artificially made polyamides can be made through ...
powder and
Selective laser sintering
Selective laser sintering (SLS) is an additive manufacturing (AM) technique that uses a laser as the power and heat source to sinter powdered material (typically nylon or polyamide), aiming the laser automatically at points in space defined b ...
processes – see
Mykita
MYKITA GmbH is a high-end eyewear design manufacturer based in Berlin, Germany known internationally for its handcrafted eyeglasses and sunglasses.
Company
The company was founded by Harald Gottschling, Daniel Haffmans, Philipp Haffmans and Mori ...
Mylon (The frames can be 3-D printed by
Fused Filament Fabrication
Fused filament fabrication (FFF), also known as fused deposition modeling (with the trademarked acronym FDM), or called ''filament freeform fabrication'', is a 3D printing process that uses a continuous filament of a thermoplastic material. Filam ...
for pennies of
ABS,
PLA
PLA may refer to:
Organizations Politics and military
* People's Liberation Army, the armed forces of China and of the ruling Chinese Communist Party
* People's Liberation Army (disambiguation)
** Irish National Liberation Army, formerly called ...
or nylon)
*
Nylon
Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic.
Nylon is a silk-like thermoplastic, generally made from petro ...
Metal
Various metals and
alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...
s may be used to make glasses, such as gold, silver, aluminum,
beryllium
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form mi ...
,
stainless steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
,
titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
,
monel
Monel is a group of alloys of nickel (from 52 to 67%) and copper, with small amounts of iron, manganese, carbon, and silicon. Monel is not a cupronickel alloy because it has less than 60% copper.
Stronger than pure nickel, Monel alloys are res ...
and
nickel titanium
Nickel titanium, also known as Nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages. Different alloys are named according to the weight percentage of nickel; e.g., Nitinol 55 and ...
.
Natural material
Natural materials such as wood, bone, ivory, leather and semi-precious or precious stones may also be used.
Corrective lens shape
![Brille eingeklappt fcm](https://upload.wikimedia.org/wikipedia/commons/0/02/Brille_eingeklappt_fcm.jpg)
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 distort
peripheral vision
Peripheral vision, or ''indirect vision'', is vision as it occurs outside the point of fixation, i.e. away from the center of gaze or, when viewed at large angles, in (or out of) the "corner of one's eye". The vast majority of the area in the ...
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
Trifocals are eyeglasses with lenses that have three regions which correct for distance, intermediate (arm's length), and near vision. John Isaac Hawkins developed the trifocal lens in 1827.
Trifocals are mostly used by people with advanced pres ...
, and
progressive lens
Progressive lenses, also called multifocal lenses, progressive addition lenses (PAL), varifocal lenses, progressive power lenses, graduated prescription lenses, or progressive spectacle lenses are corrective lenses used in eyeglasses to correct pr ...
es 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 correcting
myopic
Near-sightedness, also known as myopia and short-sightedness, is an eye disease where light focuses in front of, instead of on, the retina. As a result, distant objects appear blurry while close objects appear normal. Other symptoms may include ...
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 either round,
oval
An oval () is a closed curve in a plane which resembles the outline of an egg. The term is not very specific, but in some areas (projective geometry, technical drawing, etc.) it is given a more precise definition, which may include either one or ...
,
rectangular
In Euclidean geometry, Euclidean plane geometry, a rectangle is a quadrilateral with four right angles. It can also be defined as: an equiangular quadrilateral, since equiangular means that all of its angles are equal (360°/4 = 90°); or a par ...
or curved
octagon
In geometry, an octagon (from the Greek ὀκτάγωνον ''oktágōnon'', "eight angles") is an eight-sided polygon or 8-gon.
A '' regular octagon'' has Schläfli symbol and can also be constructed as a quasiregular truncated square, t, whi ...
s. It was not until glasses began to be seen as an accessory that different shapes were introduced to be more aesthetically pleasing than functional.
History
Precursors
![Portrait of a Cardinal by El Greco](https://upload.wikimedia.org/wikipedia/commons/b/bf/Portrait_of_a_Cardinal_by_El_Greco.jpg)
Scattered evidence exists for use of visual aid devices in Greek and Roman times, most prominently the use of an emerald by
Emperor Nero
Nero Claudius Caesar Augustus Germanicus ( ; born Lucius Domitius Ahenobarbus; 15 December AD 37 – 9 June AD 68), was the fifth Roman emperor and final emperor of the Julio-Claudian dynasty, reigning from AD 54 unti ...
as mentioned by
Pliny the Elder
Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic '' ...
.
The use of a
convex lens
A lens is a transmissive optics, optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a #Compound lenses, compound lens consists of several simp ...
to form an enlarged/magnified image was most likely described in
Ptolemy
Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...
's ''
Optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
'' (which survives only in a poor Arabic translation). Ptolemy's description of lenses was commented upon and improved by
Ibn Sahl (10th century) and most notably by
Alhazen
Ḥasan Ibn al-Haytham, Latinized as Alhazen (; full name ; ), was a medieval mathematician, astronomer, and physicist of the Islamic Golden Age from present-day Iraq.For the description of his main fields, see e.g. ("He is one of the prin ...
(''
Book of Optics
The ''Book of Optics'' ( ar, كتاب المناظر, Kitāb al-Manāẓir; la, De Aspectibus or ''Perspectiva''; it, Deli Aspecti) is a seven-volume treatise on optics and other fields of study composed by the medieval Arab scholar Ibn al- ...
'', c. 1021).
Latin translations of Ptolemy's ''Optics'' and of Alhazen became available in Europe in the 12th century, coinciding with the development of "
reading stone
A reading stone is an approximately hemispherical lens that can be placed on top of text to magnify the letters so that people with presbyopia can read it more easily. Reading stones were among the earliest common uses of lenses.
The invention o ...
s".
Robert Grosseteste
Robert Grosseteste, ', ', or ') or the gallicised Robert Grosstête ( ; la, Robertus Grossetesta or '). Also known as Robert of Lincoln ( la, Robertus Lincolniensis, ', &c.) or Rupert of Lincoln ( la, Rubertus Lincolniensis, &c.). ( ; la, Rob ...
's treatise ''De iride'' (''On the Rainbow''), written between 1220 and 1235, mentions using optics to "read the smallest letters at incredible distances". A few years later in 1262,
Roger Bacon
Roger Bacon (; la, Rogerus or ', also '' Rogerus''; ), also known by the scholastic accolade ''Doctor Mirabilis'', was a medieval English philosopher and Franciscan friar who placed considerable emphasis on the study of nature through empiri ...
is also known to have written on the magnifying properties of lenses.
The development of the first eyeglasses took place in northern
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...
in the second half of the 13th century.
Independently of the development of optical lenses, some cultures developed "
sunglasses
Sunglasses or sun glasses (informally called shades or sunnies; more names below) are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes. They can s ...
" for eye protection, without any corrective properties.
For example, flat panes of
smoky quartz
Smoky quartz is a brownish grey, translucent variety of quartz that ranges in clarity from almost complete transparency to an almost-opaque brownish-gray or black crystals. The smoky color results from free silicon formed from the silicon dioxide ...
were used in 12th-century
China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, and the
Inuit
Inuit (; iu, ᐃᓄᐃᑦ 'the people', singular: Inuk, , dual: Inuuk, ) are a group of culturally similar indigenous peoples inhabiting the Arctic and subarctic regions of Greenland, Labrador, Quebec, Nunavut, the Northwest Territories ...
have used
snow goggles
Snow goggles (Inuktitut: or , syllabics: or ; esu, nigaugek, ) are a type of eyewear traditionally used by the Inuit and the Yupik peoples of the Arctic to prevent snow blindness. The goggles fit tightly against the face so that the only li ...
for eye protection.
Invention
![Conrad von Soest, 'Brillenapostel' (1403)](https://upload.wikimedia.org/wikipedia/commons/c/cf/Conrad_von_Soest%2C_%27Brillenapostel%27_%281403%29.jpg)
The earliest recorded comment on the use of lenses for optical purposes was made in 1268 by
Roger Bacon
Roger Bacon (; la, Rogerus or ', also '' Rogerus''; ), also known by the scholastic accolade ''Doctor Mirabilis'', was a medieval English philosopher and Franciscan friar who placed considerable emphasis on the study of nature through empiri ...
.
The first eyeglasses were estimated to have been made in
central Italy
Central Italy ( it, Italia centrale or just ) is one of the five official statistical regions of Italy used by the National Institute of Statistics (ISTAT), a first-level NUTS region, and a European Parliament constituency.
Regions
Central It ...
, most likely in
Pisa
Pisa ( , or ) is a city and ''comune'' in Tuscany, central Italy, straddling the Arno just before it empties into the Ligurian Sea. It is the capital city of the Province of Pisa. Although Pisa is known worldwide for its leaning tower, the cit ...
, by about 1290: In a sermon delivered on 23 February 1306, the
Dominican friar
Giordano da Pisa (–1311) wrote "It is not yet twenty years since there was found the art of making eyeglasses, which make for good vision ... And it is so short a time that this new art, never before extant, was discovered. ... I saw the one who first discovered and practiced it, and I talked to him."
Giordano's colleague Friar Alessandro della Spina of Pisa (d. 1313) was soon making eyeglasses. The ''Ancient 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
pina Pina may refer to:
People
* Pina (name), a list of people with the given name, nickname, surname or stage name
Places
* Pina, Nepal, a village development committee
* Pina, Mallorca, Spain, a town
* Pina de Ebro, a municipality of the province o ...
made them and shared them with everyone with a cheerful and willing heart."
Venice
Venice ( ; it, Venezia ; vec, Venesia or ) is a city in northeastern Italy and the capital of the Veneto Regions of Italy, region. It is built on a group of 118 small islands that are separated by canals and linked by over 400 ...
quickly became an important center of manufacture, especially due to using the high-quality glass made at
Murano
Murano is a series of islands linked by bridges in the Venetian Lagoon, northern Italy. It lies about north of Venice and measures about across with a population of just over 5,000 (2004 figures). It is famous for its glass making. It was on ...
.
By 1301, there were
guild
A guild ( ) is an association of artisans and merchants who oversee the practice of their craft/trade in a particular area. The earliest types of guild formed as organizations of tradesmen belonging to a professional association. They sometimes ...
regulations in Venice governing the sale of eyeglasses. and a separate guild of Venetian spectacle makers was formed in 1320.
In the fourteenth century they were very common objects:
Francesco Petrarca
Francesco Petrarca (; 20 July 1304 – 18/19 July 1374), commonly anglicized as Petrarch (), was a scholar and poet of early Renaissance Italy, and one of the earliest humanists.
Petrarch's rediscovery of Cicero's letters is often credited w ...
says in one of his
letters
Letter, letters, or literature may refer to:
Characters typeface
* Letter (alphabet), a character representing one or more of the sounds used in speech; any of the symbols of an alphabet.
* Letterform, the graphic form of a letter of the alphabe ...
that, until he was 60, he didn't need glasses, and
Franco Sacchetti
Franco Sacchetti (; c. 1335 – c. 1400), was an Italian poet and novelist.
Biography
Born in Florence or in Ragusa (Croatia), Ragusa (modern Dubrovnik), he was the son of Benci di Uguccione, surnamed ''"Buono"'', a Florentine merchant of ...
mentions them often in his
Trecentonovelle.
![Medieval Spectacles](https://upload.wikimedia.org/wikipedia/commons/4/47/Medieval_Spectacles.jpg)
The earliest pictorial evidence for the use of eyeglasses is
Tommaso da Modena
Tomaso Barisini, better known as Tommaso da Modena and sometimes called Tomaso Baffini (1326 – 1379) was an Italian painter of the mid-14th century.
Biography
Tommaso trained in Venice and worked mostly in Northern Italy, but also worked for ...
's 1352 portrait of the cardinal Hugh de Provence reading in a
scriptorium
Scriptorium (), literally "a place for writing", is commonly used to refer to a room in medieval European monasteries devoted to the writing, copying and illuminating of manuscripts commonly handled by monastic scribes.
However, lay scribes and ...
. Another early example would be a depiction of eyeglasses found north of the
Alps
The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...
in an altarpiece of the church of
Bad Wildungen
Bad Wildungen is a state-run spa and a small town in Waldeck-Frankenberg district in Hesse, Germany. It is located on the German Timber-Frame Road.
Geography
Location
Bad Wildungen lies in the eastern foothills of the Kellerwald range in the so ...
, Germany, in 1403. These early glasses had
convex lenses
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
that could correct both
hyperopia
Far-sightedness, also known as long-sightedness, hypermetropia, or hyperopia, is a condition of the eye where distant objects are seen clearly but near objects appear blurred. This blurred effect is due to incoming light being focused behind, i ...
(farsightedness), and the
presbyopia
Presbyopia is physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. Also known as age-related farsightedness (or age-related long si ...
that commonly develops as a symptom of
aging
Ageing ( BE) or aging ( AE) is the process of becoming older. The term refers mainly to humans, many other animals, and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal. In ...
. Although concave lenses for
myopia
Near-sightedness, also known as myopia and short-sightedness, is an eye disease where light focuses in front of, instead of on, the retina. As a result, distant objects appear blurry while close objects appear normal. Other symptoms may include ...
(near-sightedness) had made their first appearance in the mid-15th century,
it was not until 1604 that
Johannes Kepler
Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws ...
published the first correct explanation as to why convex and concave lenses could correct presbyopia and myopia.
Early frames for glasses consisted of two magnifying glasses
rivet
A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite to the head is called the ''tail''. On installation, the rivet is placed in a punched ...
ed 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 at
Kloster Wienhausen, a
convent
A convent is a community of monks, nuns, religious brothers or, sisters or priests. Alternatively, ''convent'' means the building used by the community. The word is particularly used in the Catholic Church, Lutheran churches, and the Anglican ...
near
Celle
Celle () is a town and capital of the district of Celle, in Lower Saxony, Germany. The town is situated on the banks of the river Aller, a tributary of the Weser, and has a population of about 71,000. Celle is the southern gateway to the Lü ...
in Germany; they have been dated to ''circa'' 1400.
The world's first
spectacle specialist shop opened in
Strasbourg
Strasbourg (, , ; german: Straßburg ; gsw, label=Bas Rhin Alsatian, Strossburi , gsw, label=Haut Rhin Alsatian, Strossburig ) is the prefecture and largest city of the Grand Est region of eastern France and the official seat of the Eu ...
(then
Holy Roman Empire
The Holy Roman Empire was a Polity, political entity in Western Europe, Western, Central Europe, Central, and Southern Europe that developed during the Early Middle Ages and continued until its Dissolution of the Holy Roman Empire, dissolution i ...
, now France) in 1466.
Other claims
The 17th century claim by
Francesco Redi
Francesco Redi (18 February 1626 – 1 March 1697) was an Italian physician, naturalist, biologist, and poet. He is referred to as the "founder of experimental biology", and as the "father of modern parasitology". He was the first person to cha ...
that
Salvino degli Armati
Salvino D'Armato degli Armati of Florence is sometimes credited with the invention of eyeglasses in the 13th century, however it has been shown that this claim was a hoax, and that there was no member of the Armati family with that name at the time ...
of Florence invented eyeglasses in the 13th century has been exposed as erroneous.
Marco Polo
Marco Polo (, , ; 8 January 1324) was a Venetian merchant, explorer and writer who travelled through Asia along the Silk Road between 1271 and 1295. His travels are recorded in ''The Travels of Marco Polo'' (also known as ''Book of the Marv ...
is mistakenly claimed to have encountered eyeglasses during his travels in China in the 13th century. However, no such evidence appears in his accounts.
[ Section (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 ]hat book
A hat is a head covering which is worn for various reasons, including protection against weather conditions, ceremonial reasons such as university graduation, religious reasons, safety, or as a fashion accessory. Hats which incorporate mecha ...
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." Indeed, the earliest mentions of eyeglasses in China occur in the 15th century and those Chinese sources state that eyeglasses were imported.
In 1907 Professor
Berthold Laufer
Berthold Laufer (October 11, 1874 – September 13, 1934) was a German anthropologist and Historical geography, historical geographer with an expertise in East Asian languages. The American Museum of Natural History calls him, "one of the most dis ...
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. However,
Joseph Needham
Noel Joseph Terence Montgomery Needham (; 9 December 1900 – 24 March 1995) was a British biochemist, historian of science and sinologist known for his scientific research and writing on the history of Chinese science and technology, in ...
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 the
Ming dynasty
The Ming dynasty (), officially the Great Ming, was an Dynasties in Chinese history, imperial dynasty of China, ruling from 1368 to 1644 following the collapse of the Mongol Empire, Mongol-led Yuan dynasty. The Ming dynasty was the last ort ...
.
In 1971 Rishi Agarwal, in an article in the ''
British Journal of Ophthalmology
The ''British Journal of Ophthalmology'' is a peer-reviewed medical journal covering all aspects of ophthalmology. The journal was established in 1917 by the amalgamation of the ''Royal London (Moorfields) Ophthalmic Hospital Reports'' with the ''O ...
'', states that
Vyasatirtha
Vyāsatīrtha (. 1460 – 1539), also called ''Vyasaraja'' or ''Chandrikacharya'', was a Hindu philosopher, scholar, polemicist, commentator and poet belonging to the Madhwacharya's Dvaita order of Vedanta. As the patron saint of the Vijay ...
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 did
Hindu mathematics
Indian mathematics emerged in the Indian subcontinent from 1200 BCE until the end of the 18th century. In the classical period of Indian mathematics (400 CE to 1200 CE), important contributions were made by scholars like Aryabhata, Brahmagupta ...
and the ophthalmological works of the ancient Hindu surgeon
Sushruta
Sushruta, or ''Suśruta'' (Sanskrit: सुश्रुत, IAST: , ) was an ancient Indian physician. The ''Sushruta Samhita'' (''Sushruta's Compendium''), a treatise ascribed to him, is one of the most important surviving ancient treatises on ...
", but all dates are given well after the existence of eyeglasses in Italy was established, and there had been significant shipments of eyeglasses from Italy to the Middle East, with one shipment as large as 24,000 glasses.
Later developments
![Harry S](https://upload.wikimedia.org/wikipedia/commons/c/cf/Harry_S._Truman.jpg)
The American scientist
Benjamin Franklin
Benjamin Franklin ( April 17, 1790) was an American polymath who was active as a writer, scientist, inventor, statesman, diplomat, printer, publisher, and political philosopher. Encyclopædia Britannica, Wood, 2021 Among the leading inte ...
, who had both
myopia
Near-sightedness, also known as myopia and short-sightedness, is an eye disease where light focuses in front of, instead of on, the retina. As a result, distant objects appear blurry while close objects appear normal. Other symptoms may include ...
and
presbyopia
Presbyopia is physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. Also known as age-related farsightedness (or age-related long si ...
, invented
bifocals
Bifocals are eyeglasses with two distinct optical powers. Bifocals are commonly prescribed to people with presbyopia who also require a correction for myopia, hyperopia, and/or astigmatism.
History
Benjamin Franklin is generally credited with t ...
. Historians have from time to time produced evidence to suggest that others may have preceded him in the invention; however, a correspondence between
George Whatley
George Whatley (died 1791) was an English lawyer, a friend and correspondent of Benjamin Franklin. He was also Vice President (1772–1779) and Treasurer (1779–1791) of the Foundling Hospital in London.
Whatley was the author of '' Principles ...
and
John Fenno
John Fenno (Aug. 12, 1751 ( O.S.) – Sept. 14, 1798.) was a Federalist Party editor among early American publishers and major figure in the history of American newspapers. His ''Gazette of the United States'' played a major role in shaping the b ...
, editor of ''
The Gazette of the United States
The ''Gazette of the United States'' was an early American newspaper, first issued semiweekly in New York on April 15, 1789, but moving the next year to Philadelphia when the nation's capital moved there the next year. It was friendly to the Fe ...
'', suggested that Franklin had indeed invented bifocals, and perhaps 50 years earlier than had been originally thought. The first lenses for correcting
astigmatism
Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. This results in distorted or blurred vision at any distance. Other symptoms can include eyestrain, headaches, and trouble driving at nig ...
were designed by the British astronomer
George Airy
Sir George Biddell Airy (; 27 July 18012 January 1892) was an English mathematician and astronomer, and the seventh Astronomer Royal from 1835 to 1881. His many achievements include work on planetary orbits, measuring the mean density of the E ...
in 1825.
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
Pince-nez ( or , plural form same as singular; ) is a style of glasses, popular in the late 19th and early 20th centuries, that are supported without earpieces, by pinching the bridge of the nose. The name comes from French ''pincer'', "to pinch ...
'').
Girolamo Savonarola
Girolamo Savonarola, OP (, , ; 21 September 1452 – 23 May 1498) or Jerome Savonarola was an Italian Dominican friar from Ferrara and preacher active in Renaissance Florence. He was known for his prophecies of civic glory, the destruction of ...
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 optician
Edward Scarlett
Edward Scarlett (1688 – 1743 in London) was an English optician and instrument maker, who first invented an eyeglass frame with earhooks in 1727. This frame is held by the nose and ears, at times the glasses were called in contrast to the nasal ...
. These designs were not immediately successful, however, and various styles with attached handles such as "
scissors-glasses
Scissors-glasses (or binocles-ciseaux) are eyeglasses, normally used to correct distance vision, mounted on scissoring stems rather than on temple stems as modern eyeglasses are.
The invention of scissors-glasses solved the problem of the single ...
" and
lorgnette
A lorgnette () is a pair of spectacles with a handle, used to hold them in place, rather than fitting over the ears or nose. The word ''lorgnette'' is derived from the French ''lorgner'', to take a sidelong look at, and Middle French, from ''lor ...
s 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
Moritz von Rohr (4 April 1868 – 20 June 1940) was an optical scientist at Carl Zeiss in Jena, Germany.
A street in Jena is named after him: Moritz-von-Rohr-Straße, near Carl-Zeiss-Promenade and Otto-Schott-Straße.
Life
Moritz von Ro ...
and
Zeiss Zeiss or Zeiß may refer to:
People
*Carl Zeiss (1816–1888), German optician and entrepreneur
*Emil Zeiß (1833–1910), German Protestant minister and painter
Companies
*Carl Zeiss AG, German manufacturer of optics, industrial measurem ...
(with the assistance of H. Boegehold and A. Sonnefeld) developed the Zeiss Punktal spherical point-focus lenses that dominated the eyeglass lens field for many years. In 2008,
Joshua Silver
Joshua D. Silver is a British physicist whose discoveries have included a new way to change the curvature of lenses, with a significant application for the low-cost manufacture of corrective lenses and adjustable spectacles, especially in low- ...
designed eyewear with adjustable corrective glasses. They work by using a built-in syringe to pump a
silicone
A silicone or polysiloxane is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cooking ...
solution into a flexible lens.
Despite the increasing popularity of
contact lenses
Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic ...
and
laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
corrective eye surgery
Refractive eye surgery is optional eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea (keratomileusi ...
, glasses remain very common, as their technology has improved. For instance, it is now possible to purchase frames made of special
memory metal
In metallurgy, a shape-memory alloy (SMA) is an alloy that can be deformed when cold but returns to its pre-deformed ("remembered") shape when heated. It may also be called memory metal, memory alloy, smart metal, smart alloy, or muscle wire.
P ...
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 as
titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
alloys, which were not available in earlier times.
In fashion
250px, Woman wearing eyewear with non-prescription lenses in a fashion .">photo shoot.
In the 1930s, "spectacles" were described as "medical appliances".
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.
Graham Pullin describes how devices for disability, like glasses, have traditionally been designed to camouflage against the skin and restore ability without being visible.
In the past, design for disability has "been less about projecting a positive image as about trying not to project an image at all".
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.
Much like other fashion designs and accessories, eyewear is created by designers, has reputable labels, and comes in collections, by season and designer.
In recent years it has become more common for consumers to purchase eyewear with non-prescription lenses as a fashion accessory.
Society and culture
Market
The market for spectacles has been characterized as having highly
inelastic demand
A good's price elasticity of demand (E_d, PED) is a measure of how sensitive the quantity demanded is to its price. When the price rises, quantity demanded falls for almost any good, but it falls more for some than for others. The price elastici ...
. Advertising restrictions in the United States, for example, have correlated with higher prices, suggesting that adverts make the spectacles market more
price-competitive. It has also been claimed to be
monopolistically competitive, as in the case of
Luxottica
Luxottica Group S.p.A. is an Italian eyewear conglomerate and the world's largest company in the eyewear industry. It is based in Milan, Italy.
Luxottica is a vertically integrated company, which has been described as a monopoly—it designs, m ...
.
There are claims that insufficiently free
market competition
In economics, competition is a scenario where different Economic agent, economic firmsThis article follows the general economic convention of referring to all actors as firms; examples in include individuals and brands or divisions within the sa ...
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.
Redistribution
Some organizations like
Lions Clubs International
The International Association of Lions Clubs, more commonly known as Lions Clubs International, is an international non-political service organization established originally in 1916 in Chicago, Illinois, by Melvin Jones. It is now headquartere ...
,
Unite For Sight
Unite for Sight is a 501(c)(3) non-profit organization founded in 2000 by Jennifer Staple-Clark specializing in healthcare delivery to communities around the world. The organization invests human and financial resources in local eye clinics in ...
, ReSpectacle, and
New Eyes for the Needy
New Eyes for the Needy is a non-profit organization started in 1932 as New Eyes (incorporated 1948) and based in Short Hills, New Jersey, which provides people in the United States with eyeglasses and sends recycled eyeglasses to needy people overs ...
provide a way to donate glasses and sunglasses to people on low incomes or no income. Unite For Sight has redistributed more than 200,000 pairs.
Fashion
![Demo Day 2016 - Design Center (19)](https://upload.wikimedia.org/wikipedia/commons/c/c7/Demo_Day_2016_-_Design_Center_%2819%29.jpg)
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.
Personal image
![BarryGoldwater](https://upload.wikimedia.org/wikipedia/commons/b/b7/BarryGoldwater.jpg)
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.
The
stigma began to fall away in the U.S. in the early 1900s when the popular
Theodore Roosevelt
Theodore Roosevelt Jr. ( ; October 27, 1858 – January 6, 1919), often referred to as Teddy or by his initials, T. R., was an American politician, statesman, soldier, conservationist, naturalist, historian, and writer who served as the 26t ...
was regularly photographed wearing eyeglasses, and in the 1910s when popular comedian
Harold Lloyd
Harold Clayton Lloyd, Sr. (April 20, 1893 – March 8, 1971) was an American actor, comedian, and stunt performer who appeared in many silent comedy films.Obituary ''Variety'', March 10, 1971, page 55.
One of the most influential film co ...
wore a pair of
horn-rimmed glasses
Horn-rimmed glasses are a type of eyeglasses. Originally made out of either horn or tortoise shell, for most of their history they have actually been constructed out of thick plastics designed to imitate those materials. They are characterized by ...
as the "Glasses" character in his films.
In the United Kingdom, wearing glasses was characterised in the nineteenth century as "a sure sign of the weakling and the mollycoddle", according to
Neville Cardus
Sir John Frederick Neville Cardus, CBE (2 April 188828 February 1975) was an English writer and critic. From an impoverished home background, and mainly self-educated, he became ''The Manchester Guardian''s cricket correspondent in 1919 and it ...
, writing in 1928.
"Tim" Killick was the first professional
cricketer
Cricket is a bat-and-ball game played between two teams of eleven players on a field at the centre of which is a pitch with a wicket at each end, each comprising two bails balanced on three stumps. The batting side scores runs by striki ...
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."
Since eyeglasses have become an acceptable fashion item and often act as a key component in individuals' personal image. Musicians
Buddy Holly
Charles Hardin Holley (September 7, 1936 – February 3, 1959), known as Buddy Holly, was an American singer and songwriter who was a central and pioneering figure of mid-1950s rock and roll. He was born to a musical family in Lubbock, Texas ...
and
John Lennon
John Winston Ono Lennon (born John Winston Lennon; 9 October 19408 December 1980) was an English singer, songwriter, musician and peace activist who achieved worldwide fame as founder, co-songwriter, co-lead vocalist and rhythm guitarist of ...
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
''Harry Potter'' is a series of seven fantasy literature, fantasy novels written by British author J. K. Rowling. The novels chronicle the lives of a young Magician (fantasy), wizard, Harry Potter (character), Harry Potter, and his friends ...
glasses"). British comedic actor
Eric Sykes
Eric Sykes (4 May 1923 – 4 July 2012) was an English radio, stage, television and film writer, comedian, actor, and director whose performing career spanned more than 50 years. He frequently wrote for and performed with many other leading com ...
was known in the United Kingdom for wearing thick, square, horn-rimmed glasses, which were in fact a sophisticated
hearing aid
A hearing aid is a device designed to improve hearing by making sound audible to a person with hearing loss. Hearing aids are classified as medical devices in most countries, and regulated by the respective regulations. Small audio amplifiers su ...
that alleviated his
deafness
Deafness has varying definitions in cultural and medical contexts. In medical contexts, the meaning of deafness is hearing loss that precludes a person from understanding spoken language, an audiological condition. In this context it is written ...
by allowing him to "hear" vibrations.
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. Senator
Barry Goldwater
Barry Morris Goldwater (January 2, 1909 – May 29, 1998) was an American politician and United States Air Force officer who was a five-term U.S. Senator from Arizona (1953–1965, 1969–1987) and the Republican Party nominee for presiden ...
and comedian
Drew Carey
Drew Allison Carey (born May 23, 1958) is an American comedian, actor and game show host. After serving in the U.S. Marine Corps and making a name for himself in stand-up comedy, he gained stardom in his own sitcom, ''The Drew Carey Show'', an ...
continued to wear non-prescription glasses after being fitted for
contacts
Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic ...
and getting
laser eye surgery
Eye surgery, also known as ophthalmic or ocular surgery, is surgery performed on the eye or its adnexa, by an ophthalmologist or sometimes, an optometrist. Eye surgery is synonymous with ophthalmology. The eye is a very fragile organ, and requ ...
, respectively.
Other celebrities have used glasses to differentiate themselves from the characters they play, such as
Anne Kirkbride
Anne Kirkbride (21 June 1954 – 19 January 2015) was an English actress, best known for her long-running role as Deirdre Barlow in the ITV (TV network), ITV soap ''Coronation Street'', which she played for 42 years from 1972 to 2014. For this ...
, who wore oversized 1980s-style round horn-rimmed glasses as
Deirdre Barlow
Deirdre Anne Barlow (also Hunt, Langton and Rachid) is a fictional character from the British ITV soap opera ''Coronation Street'', played by Anne Kirkbride. She made her first screen appearance during the episode broadcast on 20 November 1972 ...
in the soap opera ''
Coronation Street
''Coronation Street'' is an English soap opera created by Granada Television and shown on ITV since 9 December 1960. The programme centres around a cobbled, terraced street in Weatherfield, a fictional town based on inner-city Salford.
Origi ...
''; and
Masaharu Morimoto
is a Japanese chef, best known as an Iron Chef on the Japanese TV cooking show ''Iron Chef'' and its spinoff '' Iron Chef America''. He is also known for his unique style of presenting food.
Career
Morimoto received practical training in sush ...
, who wears glasses to separate his professional persona as a chef from his stage persona as
Iron Chef
is a Japanese television cooking show produced by Fuji Television. The series, which premiered on October 10, 1993, was a stylized cook-off featuring guest chefs challenging one of the show's resident "Iron Chefs" in a timed cooking battle bui ...
Japanese. In 2012, some
NBA
The National Basketball Association (NBA) is a professional basketball league in North America. The league is composed of 30 teams (29 in the United States and 1 in Canada) and is one of the major professional sports leagues in the United St ...
players wore
lensless glasses
Lensless glasses are glasses that lack lenses. They are worn solely for aesthetic or fashion purposes, having no function in vision correction or eye protection. The frames are usually oversized, and commonly all black in color. They may be worn ...
with thick plastic frames like
horn-rimmed glasses
Horn-rimmed glasses are a type of eyeglasses. Originally made out of either horn or tortoise shell, for most of their history they have actually been constructed out of thick plastics designed to imitate those materials. They are characterized by ...
during
post-game interviews -
geek chic
The word ''geek'' is a slang term originally used to describe eccentric or non-mainstream people; in current use, the word typically connotes an expert or enthusiast obsessed with a hobby or intellectual pursuit. In the past, it had a generall ...
that draws comparisons to actor
Jaleel White
Jaleel Ahmad White (born November 27, 1976) is an American actor. He is best known for his role as Steve Urkel on the sitcom ''Family Matters''.
The character was originally intended to be a one-time guest appearance on the show; however, he wa ...
's infamous styling as TV character
Steve Urkel
Steven Quincy Urkel is a fictional character on the American ABC/CBS sitcom ''Family Matters'', portrayed by Jaleel White. Originally slated to be a one-time-only character on the show, he broke out to be its most popular character and gradually ...
.
In
superhero
A superhero or superheroine is a stock character that typically possesses ''superpowers'', abilities beyond those of ordinary people, and fits the role of the hero, typically using his or her powers to help the world become a better place, ...
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
Superman is a superhero who appears in American comic books published by DC Comics. The character was created by writer Jerry Siegel and artist Joe Shuster, and debuted in the comic book ''Action Comics'' #1 (cover-dated June 1938 and publi ...
is well known for wearing 1950s-style horn-rimmed glasses as
Clark Kent
Superman is a superhero who appears in American comic books published by DC Comics. The character was created by writer Jerry Siegel and artist Joe Shuster, and debuted in the comic book ''Action Comics'' #1 (cover-dated June 1938 and publish ...
, while
Wonder Woman
Wonder Woman is a superhero created by the American psychologist and writer William Moulton Marston (pen name: Charles Moulton), and artist Harry G. Peter. Marston's wife, Elizabeth Holloway Marston, Elizabeth, and their life partner, Olive Byr ...
wears either round, Harold Lloyd-style glasses or 1970s-style
bug-eye glasses
Bug-eye glasses are a form of Glasses, eyewear. They were popular in the 1970s, 1980s and 1990s, and were used for regular glasses and sunglasses. They first became popular in the mid-1970s, and succeeded the cat eye glasses of the 1950s and 1960s ...
as
Diana Prince
Diana Prince is a fictional character appearing regularly in stories published by DC Comics, as the secret identity of the Amazonian superhero Wonder Woman, who bought the credentials and identity from a United States Army nurse named Diana Pri ...
. An example of the
halo effect
The halo effect (sometimes called the halo error) is the tendency for positive impressions of a person, company, brand, or product in one area to positively influence one's opinion or feelings in other areas. Halo effect is “the name given to t ...
is seen in the
stereotype
In social psychology, a stereotype is a generalized belief about a particular category of people. It is an expectation that people might have about every person of a particular group. The type of expectation can vary; it can be, for example ...
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 in
Western culture
Leonardo da Vinci's ''Vitruvian Man''. Based on the correlations of ideal Body proportions">human proportions with geometry described by the ancient Roman architect Vitruvius in Book III of his treatise ''De architectura''.
image:Plato Pio-Cle ...
s.
Styles
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.
*
Aviator sunglasses
Aviator sunglasses are a style of sunglasses that were developed by a group of American firms. The original Bausch & Lomb design is now commercially marketed as Ray-Ban Aviators, although other manufacturers also produce aviator-style sunglass ...
*
Browline glasses
Browline glasses are a style of eyeglass frames where the "bold" upper part holding the lenses resembles eyebrows framing the eyes. They were very popular during the 1950s and 1960s, especially in the United States of America. The glasses were ...
*
Bug-eye glasses
Bug-eye glasses are a form of Glasses, eyewear. They were popular in the 1970s, 1980s and 1990s, and were used for regular glasses and sunglasses. They first became popular in the mid-1970s, and succeeded the cat eye glasses of the 1950s and 1960s ...
*
Cat eye glasses
Cat eye glasses (sometimes called "cat eyes" or "cat glasses") are a shape of eyewear. The form is closely related to the browline style, differentiated by having an upsweep at the outer edges where the temples or arms join the frame front. ...
*
GI glasses
GI glasses are eyeglasses issued by the American military to its service members. Dysphemisms for them include the most common "birth control glasses" (BCGs) and other variants. At one time, they were officially designated as regulation prescri ...
*
Goggles
Goggles, or safety glasses, are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in chemistry laboratories and ...
*
Horn-rimmed glasses
Horn-rimmed glasses are a type of eyeglasses. Originally made out of either horn or tortoise shell, for most of their history they have actually been constructed out of thick plastics designed to imitate those materials. They are characterized by ...
*
Lensless glasses
Lensless glasses are glasses that lack lenses. They are worn solely for aesthetic or fashion purposes, having no function in vision correction or eye protection. The frames are usually oversized, and commonly all black in color. They may be worn ...
*
Monocle
A monocle is a type of corrective lens used to correct or enhance the visual perception in only one eye. It consists of a circular lens, generally with a wire ring around the circumference that can be attached to a string or wire. The other ...
*
Pince-nez
Pince-nez ( or , plural form same as singular; ) is a style of glasses, popular in the late 19th and early 20th centuries, that are supported without earpieces, by pinching the bridge of the nose. The name comes from French ''pincer'', "to pinch ...
*
Rimless glasses
Rimless eyeglasses are a type of eyeglasses in which the lenses are mounted directly to the bridge and/or temples. The style is divided into two subtypes: three-piece glasses are composed of lenses mounted to a bridge and two separate temple arms ...
*
Sunglasses
Sunglasses or sun glasses (informally called shades or sunnies; more names below) are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes. They can s ...
*
Wayfarer sunglasses
*
Windsor glasses
Windsor glasses are a type of eyeglasses characterised by circular or nearly circular eyerims and a thin metal frame. The style emerged in the 19th century and first became popular in the 1880s. Traditionally the bridge of Windsor glasses is a "s ...
See also
*
Adjustable-focus eyeglasses
Adjustable focus eyeglasses are eyeglasses with an adjustable focal length. They compensate for refractive errors (such as presbyopia) by providing variable focusing, allowing users to adjust them for desired distance or prescription, or both.
Cu ...
*
Baden-Powell's unilens
The unilens monocular is a simple refracting telescope for field use, designed by Robert Baden-Powell, 1st Baron Baden-Powell, Robert Baden-Powell. Consisting of only one Lens (optics), lens, it is the simplest of all telescopes, and while occupyin ...
*
Eye examination
An eye examination is a series of tests performed to assess vision and ability to focus on and discern objects. It also includes other tests and examinations pertaining to the eyes. Eye examinations are primarily performed by an optometrist, op ...
*
Eyeglass prescription
An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist, that specifies the value of all parameters the prescriber has deemed necessary to construct and/or dispense corrective lenses appropriate for a patie ...
*
History of optics
Optics began with the development of lenses by the ancient Egyptians and Mesopotamians, followed by theories on light and vision developed by ancient Greek philosophers, and the development of geometrical optics in the Greco-Roman world. The wo ...
*
X-ray vision
In science fiction stories or superhero comics, X-ray vision is the supernatural ability to see through normally opaque physical objects at the discretion of the holder of this superpower. The most famous possessor of this ability is DC Comics' i ...
*
Plurale tantum
A ''plurale tantum'' (Latin for "plural only"; ) is a noun that appears only in the plural form and does not have a singular variant for referring to a single object. In a less strict usage of the term, it can also refer to nouns whose singular fo ...
Notes
References
General bibliography
* .
* .
External links
Spectacles Galleryat the British Optical Association Museum
* .
* , on eyes and how eyeglasses correct vision (page 120).
"Common Spectacles Styles before, during and after the Civil War"(2012 article) via the
Internet Archive
The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including websites, software applications/games, music, ...
; Antique Eyeglasses in America.
{{Authority control
Corrective lenses
Eyewear
Italian inventions
Ophthalmology
Protective gear
Sports equipment