sunglasses

Synonyms in the broader sense

Glasses, spectacle lenses, sunglass lenses

English: sunglasses

definition

Sunglasses are glasses with darkened, tinted or alternating lenses that adapt to the external light conditions.

Manufacturing

The production of the actual spectacle frame does not differ from that of a normal one Sight glasses. There are only differences in the manufacture of the glasses.
As a rule, no ground material is used for the glasses, but rather unpolished material, usually made of plastic. The plastic is colored with small color particles. Depending on how close together these molecules are, the sounding effect also occurs.
There are also self-tinting lenses that are used both indoors and outdoors with different light levels and adapt their tint to the light conditions. Here the lens reacts with the UV-Share of light. The reason is deposits in the glass of silver and fluorine, chlorine, bromine or iodine.
The silver is the controlling factor here. In the dark, it is in a certain charged form. If rays of light hit the silver, the silver molecules absorb electrons and are thereby neutralized. Neutralized silver molecules are less opaque and the lens turns dark.
If the wearer is short-sighted at the same time, the lens can also have a sunglasses be ground in, i.e. the Ametropia (Farsightedness or Brief moisture) is corrected automatically and you can also use the sunglasses as a glasses use for the distance.
Spectacle lenses can be made of real glass or plastic. The coloring is done either directly during manufacture (Real glass) or later (for plastic).

It is possible to color the sunglasses with different colors instead of the classic brown / black coloring, which in addition to the different filtering properties can convey other color impressions. A lens that has been colored with light colors (e.g. yellow or orange) more light through than glasses colored with green, brown or black. If you put on an orange or yellow colored spectacle lens on cloudy days with little light, you feel the light even more intense, the darker image of the outside world appears brighter.

history

The forerunners of today's sunglasses have been around for a very long time. Already in ancient Rome there were supposed to have been ways in which the eyes could be protected from too much light.
At that time, very thinly ground stone slabs were used, which were held in front of the eye and thus ensured the view outside but let less light through to the inside. In the 15th century, manufactured glasses were gradually introduced.

Smoked glass was used in the 17th century. At the same time, people protected themselves with leather templates that were provided with numerous holes and thus shielded a large part of the bright light. In the 18th century, sunglasses were developed in front of which greenish colored lenses could be folded. In the early 19th century, the problem of UV radiation was turned to. This was followed by the development of thin amber discs that were supposed to take on these tasks.
At the beginning of the 20th century, special UV filter glasses were developed. Other ethnic groups also knew how to counteract the high levels of sunlight. The ethnic group of the Inuits who live in the ice made themselves from sealskin leather templates and put them in front of their eyes. Here, too, numerous holes were speared so that a view, albeit limited, was possible.

Prices

prices for Sunglasses are very variable and range from 2 EUR to several thousand euros for custom-made products.
It can be said that the more medical the tasks for sunglasses, the higher the price. Sunglasses that only filter the light are often particularly cheap. Glasses with good UV filters, on the other hand, are sometimes enough 100 EUR. You have to pay several hundred euros for special sunglasses for high mountains or snowy areas.

And medical sunglasses for certain Eye diseases are used, then cost almost ten times as much. Another price factor is that Glass texture. It is possible to have the lenses grinded in according to your ametropia so that you can use the sunglasses as normal glasses. Depending on the manufacturer, you have to go with it 150-300 EUR per glass calculate. In contrast, so-called sun clips, tinted panes that can be attached to the temple of the glasses and, if necessary, can be folded in front of the glasses, are favorable. Self-tinting sunglasses are available in the price range from 60 EUR. There are no upper limits.
In the area of ​​fashionable sunglasses, prices vary even more. Sunglasses by certain fashion labels are prohibitively expensive and correspond to the price ranges of the textile market.

Medical indications

After surgery in the Ophthalmology it can be an advantage to protect your eyes from light for a certain time after the procedure. Intensive light protection after one is indispensable photodynamic therapy, in which a light-sensitive substance is first injected into the patient and accumulates in the body.

The target are the visual cells of the fundus but also surrounding cells are enriched with the substance. After the procedure, in which diseased cells are irradiated and thereby killed, exposure to sunlight can also damage healthy cells. It is therefore essential to avoid sunlight and to use sunglasses with a high UV filter and low light transmission.
Even if patients are affected by a Fundoscopy If the fundus of the eye is examined and the pupil has to be dripped wide for this reason, sunglasses should be worn afterwards or sunlight should be avoided completely for a few hours. In the clinical picture of Melanoma In the eye, sunlight should also be filtered through appropriately good sunglasses. In the US, special medical glasses are used for age-related Macular degeneration related to stopping the disease from progressing. There is no evidence that sunlight accelerates macular degeneration. These medical sunglasses are rarely used in Germany.