There are different types of lenses available in the market, which one is the best?
There are three types of spectacles that are used to work at different distances:
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Bifocal
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Trifocal
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Progressive or multi-focal
The image below shows the bifocal lenses. These are the lenses that have two parts, one part is used for normal activities while the other part is used for near work. Many people like these lenses, although many others are not satisfied with them.
The image below shows a trifocal spectacle. These are lenses that have three parts. One part is used for performing normal activities. The other part is used for working on a computer or similar medium distance work. With the third part near work is done. Most people do not like these lenses because they are very difficult to use and require a lot of practice to become comfortable
Progressive glasses of spectacles
These are lenses have many parts. The top part is used for general activities. The middle part is used for computer work or similar distance work. The lowest part is for near work. In this type of lenses, the number changes gradually and different numbers become available for viewing at different distances. There are some areas on either side of thecenter that have no numbers. These parts cause a nuisance to most people.
The image below shows the distribution of the different parts of the progressive lens
The pictures below show what the progressive lenses look like or how the different parts of them work.
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