Looking from the outside，progressive lenses is almost the same as the ordinary lens, but the reality is completely different. Ordinary glasses only has one degree requirement, while for the progressive lenses, there are a number of different brightness. Of course, it is a regular. Designers make use of the width of the lens’ up and down, the upper portion of the lens is designed to use for the luminosity far, the second part of the lens is designed to near reading, between the upper and lower parts were designed as a continuous increase in optical section, so you will get a clear vision from distance through the middle of the transition until the recent use of a continuous range of viewpoints.
According to the function, we usually divide the area of Progressive lenses into three parts, far zone, middle zone and the surrounding area. Seeing distant and close objects from the far and near part when people wearing progressive glasses; From the middle zone, we can see all the way glasses are almost in the middle distance of objects; On both sides of the lenses’ surrounding area, there is a certain photometric changes, as a result, the degree of the clear, seeing objects through the definition of the region will decline. Progressive multifocal lens, which the top area used to see far, and to see near from the bottom, the degree is different on up and down part. From the fixed of the top part of the lenses to the near bottom one, Far from the lens at the top of a fixed lens part to a fixed near in the bottom, the degree is not a sudden change, but between the two through a gradual change in refractive power gradually transition. Comparing to the normal lens, there are many advantages. Lens appearance as a single optical lens, you will can not see the changes in the boundary degrees. Not only the beautiful appreance, but also can protect the the privacy of the wearer’s age (for those who wear reading glasses ) , they do not have to worry about the age for wearing glasses and the secret leaked out. As the lenses change is gradual and will not produce as jump. Wearing comfortable make it easy to adapt. So the progressive glasses are easy to be accepted. Due to the degree of regulation as an alternative, it is also close under the progressive shortening of the increase, there is no regulation of the fluctuations, so it is hard to cause visual fatigue. All distances in the visual range of clear vision are available. Reading and full time wear are all combinated in one pair of glasses. It is brought the gospel for teachers, doctors, musicians, computer operators, because for theses people, most of the time, they not only need to see far and near objects, but also can see the the middle distance，such as blackboard, sheet music, computer screens and other objects.