Synonyms
The name Brille comes from the late Middle High German word “berille”, which in turn is derived from the word “beryl”. These are the 1300 used cut semi-precious stones; rock crystals usually called beryl. As colloquial synonyms names like “nose bicycle” or “eyeglasses” are circulating.
Definition
Glasses are an aid for the correction of ametropia. They are also used to protect the eye against injuries (welding goggles, motorcycle goggles, bicycle goggles), over-stimulation (diving goggles, sunglasses, snow and ski goggles) and also in the diagnostic and experimental field (Frenzel goggles, polarisation goggles, red-green goggles/red-green weakness, binocular functions, shutter goggles). It usually consists of a fixed frame or rack and two lenses, which are grinded and processed especially for the intended purpose and are called lenses if they have refractive properties.
According to a survey of 3,600 people aged 16 and over, 40 percent of those questioned said that glasses “emphasize one’s own personality” or “make many people more interesting”. Glasses were invented in Italy around the end of the 13th century. However, the roots of glasses can be traced back to antiquity.
One of the pioneers was the mathematician and physicist Archimedes (287-212 BC). He invented the burning mirror with which, according to legend, he set Roman ships on fire. But even the ancient Greeks produced polished hemispheres of quartz or glass around 2000 BC, which could be used to enlarge writing, but were only used as jewellery for swords, sceptres and clothing.
The great moment of optics first came around 1240 when the work of the Arab mathematician and astronomer Ibn al-Haitam (965-1039) was translated into Latin. His “Treasure of Optics”, which dealt with the teachings of vision, refraction and reflection, was now available in monastery libraries. His groundbreaking idea was to support the eye with an optical, polished lens.
In a monastery the first “reading stone” was then probably cut by monks and used to correct presbyopia. Only around the second half of the 13th century did reading glasses and spectacles follow. The oldest representation of glasses is on a portrait by Tomasco di Modena.
It was made around 1352 and shows Cardinal Hugo de Province with his rivet spectacles (spectacles made of iron, wood or horn, which did not yet have a fastening for the head and were simply held in front of the eyes). Around the second half of the 14th century, the spectacles underwent the first technical innovation and the spectacles with temples were created. For this purpose, two set glasses were connected by a bow or bow made of wood, iron, bronze, leather, bone, horn or whalebone and provided with an eyelet in the middle, which gave room for a chain that was supposed to prevent the glasses from falling off.
The slits made the bridge more elastic and the glasses sat better on the nose. In the following centuries, newer and more comfortable ideas came to the fore. Thus, especially women from the 15th to 18th century used a particularly unique type of visual aid – the so-called cap glasses (also called forehead glasses).
An auxiliary construction made it easy to attach them to a deep-seated cap. Around the same time, the monocle experienced an upswing. Already in the 14th century its practical use was recognized, but especially in the 18th century the fashionable trend followed, which continued into the bourgeoisie.
The round single reading glass was clamped between cheek and upper eyelid in front of the eye and could be quickly stowed away in the vest pocket when attached to a chain. About inventions such as the forehead glasses, in which the lenses hung down from a metal hoop attached to the forehead, the hinged glasses, a further development of the rivet glasses with a hinged joint, the pince-nez, in which two lenses were connected to each other by a spring bow made of iron or copper and clamped onto the nose contributed to better vision, the thread goggles, in which the extreme pressure of the pince-nez on the nose was reduced by tying a thread around the ears and thus obtaining a secure hold without painful bridge of the nose, were finally introduced at the beginning of the 18th century. Century to the invention of the ear glasses.
Laterally attached rods also gave it the name “temporal spectacles”. These achieved a more optimal fit by means of a metal ring attached to the end. All in all, it took 500 years to develop a pair of spectacles that were attached behind the ears.
Even today, ever newer innovations still increase the wearing comfort. New materials (plastics in the frame industry, light metals such as titanium) minimized the weight of the glasses to less than 15 grams. The most common use for glasses is the correction of ametropia due to a refractive error (refractive anomaly) of the eye.
The cause is either the abnormal length of the eyeball (so-called axial ametropia) in the case of short- or long-sightedness, as well as presbyopia or, more rarely, abnormal refractive values of the cornea or lens (so-called refractive ametropia). In the case of myopia, the eyeball is too long compared to the refractive power of the lens. Parallel incoming light rays are bundled in front of the retina and a blurred image is created.
Those affected can only see objects at a distance to a limited extent or in a blur (“blurred”). In contrast, in hyperopia the eyeball is too short compared to the refractive power of the lens and the image of incoming light rays is projected behind the retina. Close objects, e.g. the letters of a newspaper, are perceived blurred.
Presbyopia is a special form of presbyopia. With increasing age, the lens of the eye loses its elasticity. This also results in blurred vision of close objects. In addition to the defective vision of the eye, various incidents leading to the loss of the lens (e.g. due to accidents) can also be an indication for glasses.