History
The precursors of today’s sunglasses have been around for a very long time. Already in ancient Rome, there are said to have been ways of protecting the eyes from too much light. In those days, very thinly cut stone slabs were used, which were held in front of the eye and thus guaranteed the view to the outside but let less light pass through to the inside.
In the 15th century, manufactured lenses were gradually introduced. In the 17th century smoked glass was used. 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 tinted lenses could be folded. In the early 19th century, the problem of UV radiation was addressed. This was followed by the development of thin amber slices which were to take over these tasks.
At the beginning of the 20th century special UV filter glasses were developed. Also other ethnic groups knew how to help themselves against the high solar radiation. The ethnic group of the Inuits living in the ice made leather templates from seal fur and put them in front of their eyes.
Here, too, numerous holes were speared in order to allow a view, albeit restricted. Prices for sunglasses are very variable and range from 2 EUR to several thousand euros for custom-made products. One can say that the more medical the tasks for sunglasses are, the higher the price increases.
Thus, sunglasses that filter only the light are often particularly cheap. Glasses with good UV filters, on the other hand, are sometimes enough for about 100 EUR. For special sunglasses for high mountains or snowy areas you have to pay several hundred EUR.
And medical sunglasses used for certain eye diseases cost almost ten times as much. Another price factor is the quality of the lenses. It is possible to have the lenses ground in according to your defective vision, so that you can also use the sunglasses as normal glasses.
Depending on the manufacturer, you have to calculate with 150-300 EUR per lens.On the other hand, so-called sun clips, tinted lenses that can be attached to the temples of the eyeglasses and folded in front of the lenses if necessary, are a good idea. Self-tinted sunglasses can be purchased in the price range from 60 EUR. There are no upper limits.
In the field of fashionable sunglasses, prices vary even more. Sunglasses of certain fashion labels are prohibitively expensive and correspond to the price ranges of the textile market. After surgical operations in ophthalmology, it can be advantageous to protect the eyes from light for a certain period of time after the operation.
Intensive light protection is indispensable after photodynamic therapy, in which a light-sensitive substance is first injected into the patient and accumulates in the body. The aim is to protect the visual cells of the back of the eye, but the surrounding cells are also enriched with the substance. After the procedure, in which diseased cells are irradiated and thereby killed, sunlight can also damage healthy cells when exposed to it.
Therefore, it is essential to avoid sunlight and use sunglasses with a high UV filter and low light transmission. Even if patients have the fundus of the eye examined by an ophthalmoscopy and the pupil has to be dilated for this reason, sunglasses should be worn afterwards or the sunlight should be avoided completely for a few hours. In case of melanoma of the eye, sunlight should also be filtered by wearing good sunglasses.
In the USA special medical glasses are used in age-related macular degeneration to stop the progression of the disease. There is no evidence whether sunlight accelerates macular degeneration. In Germany these medical sunglasses are rarely used.
