1, teenagers can be used to slow down visual fatigue and control the development speed of myopia.

2, adult belt can be used for anti-fatigue, for teachers, doctors, people who use computers at close range and too much.

3. Progressive multifocal glasses are characterized by continuous diopters from far to near, so that objects at different distances can achieve high definition.

4. It can coordinate the adjustment of human eyes and reduce visual fatigue. Progressive multifocal glasses can be adjusted by applying different diopters to objects at different distances through continuous illumination, so as to make them conform to the normal physiology of human eyes, reduce the development of myopia caused by accommodation obstacles and reduce the occurrence of visual fatigue.

Second, the disadvantages of multifocal lenses:

1, the adaptation period is relatively slow, which usually takes about one month, but the length of the adaptation period varies from person to person, and walking is slow when you are dizzy.

2. Because both sides of the lens are astigmatism obstacle areas, the objects on both sides cannot be seen clearly when the light turns to the eyeball, and it is necessary to rotate the neck and eyeball at the same time to see clearly.

When you go downstairs, put your glasses down and try to look out from the far area above, otherwise it will be difficult to see clearly.

4, the design problem is not very good, the field of vision is small (blind spots on both sides).

Third, pay attention to:

Our most common lenses are monofocal lenses with only one luminosity; Bifocal lenses are bifocal lenses, which are used by many elderly people to solve the problem of seeing far and near at the same time. However, because of their main shortcomings and the popularity of progressive multifocal lenses, bifocal lenses have been basically eliminated. As a milestone in the history of lens development, multifocal lenses will also be the main direction of research and development and marketing for scientists in the future.

Extended data:

1, multifocal lens The design of this special lens is inspired by the shape similar to the nose. People make the curvature of the front surface of the lens increase from top to bottom, which can make its refractive power change accordingly, that is, from the far area above the lens, the refractive power gradually increases continuously until the near area at the bottom of the lens reaches the required near refractive power.

2. French Methner designed the first progressive lens with modern ideas in 195 1 year, which can be used for clinical wear. After many improvements, it was first put into the French market on 1959. Its innovation in the concept of visual correction won the world's attention and soon spread to continental Europe and North America.

3. With the development of computer, advanced design software and instruments have been applied to the design and development of spectacle lenses, which has made great progress in the design of progressive lenses. The general trend is: from single, rigid, symmetrical and spherical far-field design to diverse, flexible, asymmetric and aspherical far-field design.

4. In the initial design of progressive addition lenses, people mainly consider the problems of mathematics, mechanics and optics. With a more comprehensive understanding of the visual system, modern and future progressive lens design will pay more and more attention to the relationship between progressive lenses and physiological optics, ergonomics, aesthetics and psychophysics.

After several major innovations, there are more and more kinds of lenses, and more and more people wear progressive lenses. In France, Germany and other western European developed countries, progressive lenses have become the first choice for vision correction. In Japan and the United States, the wearing of progressive lenses shows an obvious increasing trend every year; In the Asia-Pacific region and Eastern Europe.

6. With the popularization of optometry education courses with the fitting of progressive lenses as the core, more and more optometrists and optometrists regard progressive lenses as an important choice for vision correction.

References:

Baidu encyclopedia-multifocal lens