Spectacle lens material | acīm.lv
Today, optics is a very broad range of eyeglass lenses offered. Sometimes the client to hear as much information about the lenses get confused because they can not assess that he would be better. Therefore, it is eye specialists or consultants, which explains the differences in the lens.
Choosing spectacle lenses, attention should be paid to the quality, practicality, aesthetic appearance and price. There is a lens that provides higher image quality, but also lenses that downward. It is the lens that can cause discomfort, fatigue and damage the aesthetic appearance, such as Latvian often have a tendency to choose the expensive brand frames, but put in the cheapest lenses which this aesthetic appearance perished because they are not as good quality.
Several years ago, the optic sphere was not so advanced. Very rarely was able to get the necessary spectacle lenses in a timely manner, so that people had to make do with what is. Many people even months waiting for his spectacle lenses from abroad. The available material was glass. Today, this material is no longer offered as primary. Choosing spectacle lenses must take into account a number cambridge of the properties of materials
Spectacle lens material is fundamentally characterized by the following parameters: refractive or refractive index (index) - the higher the refractive index, because the lens thinner and less distortion. The difference is best seen large diopter cases, as well as when there is a big difference between the eyes. It is possible to buy as much as possible, similar cambridge to the thickness of the lens. Glass refractive index ranges from 1.5- 1.9, while the optical plastic 1.5- 1.7. Lentils with an index greater than 1.6, is called a high index lenses. Abbes number (indicating the degree of distortion or aberration of the lens edge, as seen through the lens optical center of the distortion is not, but looking at the edges of the visible color distortion, called chromatic aberration; the lower figure Abbes, the greater distortion) Weight. Usually specified lens catalog and depends on the lens thickness and material selection. The glass is half heavier than plastic.
Spherical lenses - both surfaces can be considered as part of the surface of the sphere, or one of the parties to the surface may be flat. Glasses are usually placed so that more or less curved concave surface is closer to the eye. With this lens is usually adjusted in simpler cases.) Spherical spectacle lenses and a little thicker than liektākas aspheric lens design, as well as to incline eye view is greater than the strength of error asfersikām lenses.
Aspherical lens - around 1990 rapidly cambridge appeared on the market this lens, which is much more complex than the spherical lens. These lenses have several advantages compared to the spherical lens design: they are flatter, thinner cambridge and hence lighter, reduces distortion (which has a high refractive index, ending with a thinner edge) visual eye a smaller increase or decrease cambridge (placed close to the eye), even lighter and 43% less strength mistake, looking to the side.
Spectacle lens material types: Glass is based on mineral lenses, but they can also be a variety of impurities, which changes the properties of the lens, such as Crohn's glass is a big heavy metal impurity, the result is expressed in terms of hardness, increase the refractive index decreases Abbes figure to it will increase the amount of distortion.
The oldest of the material is glass. It is heavy, breakable, traumatic, but it is scraping as fast as plastic. The main advantages of the glass has a higher refractive index than the limits of plastic and mechanical strength (with the exception of shocks). cambridge This material is usually chosen more often by people cambridge who used glasses for many years and have become accustomed to this material that they are elderly people, as well as certain professions, such as welders (fine metal particles can be much easier to damage the plastic lenses over glasses) and cases if the work is at very high temperatures, because glass has a higher temperature resistance.
Choice of glass: older people who for years used glass lenses; particular profession; high diopter, when a client is unable to pay for plastic lenses, because glass is usually thinned cheaper; Customers who want the thinnest lenses (available in thinner glass than plastic).
As previously mentioned, the glass is no longer common in the community, because good quality glass lenses, like Zeiss branded glass hameljona outgoing clear lens coverage, paid very expensive. Polymer or plastic: Polikarbonāts- hard, unbreakable plastic, used in the manufacture of skrūvbriļļu CR39- flimsy against scraping, burst into pieces; Polimetilakrilāts (plastics) - 50% less weight, less dangerous than glass, less sweat, the lower heating cambridge value.
There have been opinions that plastic eyeglass lenses scratch easily, it is less clear and lower quality. cambridge However, like to say that this fact is insidious because nowadays technology in highly developed. Plastic lenses
Today, optics is a very broad range of eyeglass lenses offered. Sometimes the client to hear as much information about the lenses get confused because they can not assess that he would be better. Therefore, it is eye specialists or consultants, which explains the differences in the lens.
Choosing spectacle lenses, attention should be paid to the quality, practicality, aesthetic appearance and price. There is a lens that provides higher image quality, but also lenses that downward. It is the lens that can cause discomfort, fatigue and damage the aesthetic appearance, such as Latvian often have a tendency to choose the expensive brand frames, but put in the cheapest lenses which this aesthetic appearance perished because they are not as good quality.
Several years ago, the optic sphere was not so advanced. Very rarely was able to get the necessary spectacle lenses in a timely manner, so that people had to make do with what is. Many people even months waiting for his spectacle lenses from abroad. The available material was glass. Today, this material is no longer offered as primary. Choosing spectacle lenses must take into account a number cambridge of the properties of materials
Spectacle lens material is fundamentally characterized by the following parameters: refractive or refractive index (index) - the higher the refractive index, because the lens thinner and less distortion. The difference is best seen large diopter cases, as well as when there is a big difference between the eyes. It is possible to buy as much as possible, similar cambridge to the thickness of the lens. Glass refractive index ranges from 1.5- 1.9, while the optical plastic 1.5- 1.7. Lentils with an index greater than 1.6, is called a high index lenses. Abbes number (indicating the degree of distortion or aberration of the lens edge, as seen through the lens optical center of the distortion is not, but looking at the edges of the visible color distortion, called chromatic aberration; the lower figure Abbes, the greater distortion) Weight. Usually specified lens catalog and depends on the lens thickness and material selection. The glass is half heavier than plastic.
Spherical lenses - both surfaces can be considered as part of the surface of the sphere, or one of the parties to the surface may be flat. Glasses are usually placed so that more or less curved concave surface is closer to the eye. With this lens is usually adjusted in simpler cases.) Spherical spectacle lenses and a little thicker than liektākas aspheric lens design, as well as to incline eye view is greater than the strength of error asfersikām lenses.
Aspherical lens - around 1990 rapidly cambridge appeared on the market this lens, which is much more complex than the spherical lens. These lenses have several advantages compared to the spherical lens design: they are flatter, thinner cambridge and hence lighter, reduces distortion (which has a high refractive index, ending with a thinner edge) visual eye a smaller increase or decrease cambridge (placed close to the eye), even lighter and 43% less strength mistake, looking to the side.
Spectacle lens material types: Glass is based on mineral lenses, but they can also be a variety of impurities, which changes the properties of the lens, such as Crohn's glass is a big heavy metal impurity, the result is expressed in terms of hardness, increase the refractive index decreases Abbes figure to it will increase the amount of distortion.
The oldest of the material is glass. It is heavy, breakable, traumatic, but it is scraping as fast as plastic. The main advantages of the glass has a higher refractive index than the limits of plastic and mechanical strength (with the exception of shocks). cambridge This material is usually chosen more often by people cambridge who used glasses for many years and have become accustomed to this material that they are elderly people, as well as certain professions, such as welders (fine metal particles can be much easier to damage the plastic lenses over glasses) and cases if the work is at very high temperatures, because glass has a higher temperature resistance.
Choice of glass: older people who for years used glass lenses; particular profession; high diopter, when a client is unable to pay for plastic lenses, because glass is usually thinned cheaper; Customers who want the thinnest lenses (available in thinner glass than plastic).
As previously mentioned, the glass is no longer common in the community, because good quality glass lenses, like Zeiss branded glass hameljona outgoing clear lens coverage, paid very expensive. Polymer or plastic: Polikarbonāts- hard, unbreakable plastic, used in the manufacture of skrūvbriļļu CR39- flimsy against scraping, burst into pieces; Polimetilakrilāts (plastics) - 50% less weight, less dangerous than glass, less sweat, the lower heating cambridge value.
There have been opinions that plastic eyeglass lenses scratch easily, it is less clear and lower quality. cambridge However, like to say that this fact is insidious because nowadays technology in highly developed. Plastic lenses
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