Progressive multifocal is the French Bernard Maitenaz first applied the principle of progressive multifocal lens to glasses in 1959 after eight years of research. Between the high beam area and the near use area of the same lens, the far use area and the near use area can be organically connected from the far use area to the near use area in the way of gradual change of diopter. Therefore, on one lens, the far, medium and short-range stations can be set up at the same time Different luminosity required. The original intention of progressive multifocal lens design is to provide a natural, convenient and comfortable correction method for presbyopia patients. Wearing progressive lenses is like using a camera to take pictures. A pair of glasses can not only see the distance, but also see the near. So we describe progressive lens as "zoom lens". After wearing one pair of glasses, it is equivalent to multiple glasses.
Progressive multifocal lens
The difference between progressive multifocal lens and bifocal lens: grind two different refractive forces on the same lens to become two area lens, which is called bifocal lens or bifocal lens. Although the binocular glasses can see far and near, there are obvious gaps in different areas, unsightly appearance, fuzzy middle distance, need to adapt period, prism jumping phenomenon, going up and down the stairs will be dizzy. The progressive multifocal lens has no obvious spacing, and its appearance is more beautiful and comfortable as the common myopia lens.
bifocal lens
1. Look far:
The upper part of the progressive multifocal mirror is the remote central area, which can let the presbyopic friends see the long-distance vision.
2. Look far and look close middle distance:
There is a distance between the far center and the near center, which is a gradual process from seeing far to seeing near. It changes gradually with the degree of hyperopia and myopia. The longer the middle distance is, the smaller the range of the center area and the near center area is. The shorter the middle distance is, the larger the range of the far center area and the near center area is.
3. Look close:
The lower part of the progressive multifocal mirror is the near center area, which can let the presbyopic friends see the close field of vision.
4. Astigmatic area:
There are astigmatic areas on both sides of the progressive multifocal mirror, and the astigmatic areas are fuzzy areas. The larger the fuzzy area is, the longer and narrower the near middle distance is, the smaller the fuzzy area is, and the wider and shorter the near middle distance is.
5. Add value:
In the process of optometry, the diopter needed to see far should be determined first, that is, the diopter of far use. Again, the diopter needed to see the near is the number of near uses. The absolute value of the difference between the two degrees is the down add light, also known as add. Add is the main parameter of progressive multifocal lens, which must be measured and written clearly. The principle of optometry prescription should be composed of far use degree and add degree, because its value affects the choice of lens. The lower light is the light added on the basis of looking far.
Wearing presbyopia glasses is also very learned. You must have accurate optometry before matching glasses. Otherwise, wearing inappropriate glasses will only backfire and even cover up some eye diseases, such as cataract and diabetes in the eye. Progressive multi focus glasses are customized glasses, which can be customized according to your optometry results, face shape, skin color, hair style, etc. It is easy to wear (only one pair is needed to look far and near, and only one pair is needed to look far, nearsighted, presbyopia and astigmatism); it can control the growth of presbyopia degree (it is not necessary to take it back and forth, and it is comfortable to wear it for a long time); it can not see the age limit (the appearance is the same as the myopia mirror, light and beautiful); it has many functions (discoloration, UV / blue light resistance).
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