The development history and global popularity of progressive lenses
In 1907, Owen Aves first proposed progressive multifocal lenses, marking a new vision correction concept. The progressive lens design is inspired by the shape of an elephant's nose. People increase the curvature of the front surface of the lens continuously from the top to the bottom so that it can change the refractive power accordingly. The refractive power increases gradually and continuously from the far zone located on the upper part of the lens until the near zone at the bottom of the lens reaches the desired diopters of the near zone.
Based on predecessors' ideas, with the help of new results of design and development provided by modern technology. In 1951, Frenchman Bernard Maitenaz designed the first progressive lens with a modern concept, which can be used for clinical wear. After many improvements, they first put it on the French market in 1959. Its innovation in vision correction made it win the world's attention and soon promoted it to the European continent and North America.
With the development of computers, advanced design software and instruments have been applied to the design and development of spectacle lenses, which has enabled the design of progressive lenses to achieve tremendous development. With a more comprehensive understanding of the visual system, the modern and future progressive lens designs will increasingly focus on connecting progressive lenses and physiological optics, ergonomics, aesthetics, and psychophysics.
After several significant innovations, progressive lenses got huge improvements. Except the types of lenses are increasing, and the number of wearing progressive lenses is growing. In developed countries in Western Europe such as France and Germany, progressive lenses have become the first choice for vision correction; in Japan and the United States, progressive lenses are increasing in recent years; in the Asia-Pacific region and Eastern Europe, with the promotion of optometry education courses centered on progressive lens fitting, more and more optometrists and ophthalmologists regard progressive lens as a vital part of vision correction choose.
What are progressive lens?
For photographers, ensuring the sharpness of photos is one of the crucial factors for taking good photos, and the first prerequisite for clear photos is accurate focus. When shooting simple scenes, the lens can directly focus on a specific area with a single point to take clear pictures.
When the shooting area is more complicated (multi-target or a strong sense of layering), the lens often does not choose the focus point. If you want to take a good photo, you need to choose the proper focus to ensure the overall clarity of the photo.
Like the camera, we also need to choose the proper focus to see objects clearly with our eyes. When you look close, the distance becomes a blurry background; when you look far away, you can't see objects in the vicinity even if you are close at hand. Thanks to the magical eyes, we can freely switch the focus in the near and far scenes and see everything we want.
However, because myopic friends need to wear glasses, the lenses are generally single-focal. When looking far or near for a long time, there will be a lag in eyeball adjustment resulting in a temporary loss of focus, so they lose the magical experience of far and near real-time vision. Progressive multifocal lenses are indispensable for overall clear vision.
Progressive multifocal lenses are also called progressive glass lenses. As the name implies, a lens has multiple focal points.
Progressive lens meaning
The progressive lens realizes the addition of the near-use positive lens power through the change of the lens power on the central line of sight channel of the lens, thereby solving the problem of using different lens power for viewing distant objects, middle-distance objects, and near-distance objects, reducing or compensating the use of adjustment power. It enables the wearer to realize the vision of continuous images in the far, middle, and short distances without paying too much adjustment force.
For whom are progressive glass lenses suitable?
In recent years, progressive multifocal lenses have shown rapid development and popularization in China. Nowadays, scientists have researched multifocal lenses according to the eye use methods and physiological characteristics of people of different ages. Finally, they are divided into three types of progressive lenses:
1. Juvenile myopia control lenses-used to relieve visual fatigue and control the development speed of myopia.
2. Adult anti-fatigue lenses-used for teachers, doctors, people who use too much computer at close range to reduce visual fatigue caused by work.
3. Progressive lenses for middle-aged and elderly people-a pair of glasses for middle-aged and older people to easily see near and farsightedness.
1. Student reading and writing multifocal lenses
Recommended crowd: student crowd
Advantages: Students need to frequently switch from looking at the blackboard from a distance to reading a book at a close distance. The single-lens lens has a single power, and it is easy to overcorrect when looking close, which causes the imaging focus to be outside the retina, causing a temporary out of focus; students reading and writing multifocal lens add a specific positive power in the immediate area under the lens so that the imaging focus is always on the retina when the distance is switched, which reduces the burden on the eyes, thereby reducing the probability of eye fatigue and rapid growth of myopia.
2. Anti-fatigue lenses
Recommended crowd: white-collar workers, IT, and other people who work with computers and mobile phones for a long time
Advantages: White-collar workers are prone to visual fatigue, dry eyes, and sore eyes due to long-term exposure to computers, mobile phones, and other electronic products in the near and middle places. Anti-fatigue lenses are a type of progressive multifocal lenses. Anti-fatigue lenses can reduce the blind area of your visual field, allowing you to efficiently cope with work and adapt to the switching of far, medium, and near vision.
3. Middle-aged and elderly progressive multifocal lenses
Recommended crowd: people over 40 years old
Advantages: The essence of presbyopia is the decline of the adjustment ability of the eyes, and age is the most critical factor affecting the adjustment ability. Generally, the adjustment ability of the eyes gradually decreases at the age of 40. Free-form surface design, according to factors such as presbyopia strength and frame selection, practical design of parameters such as light addition, gradual focus rate, channel length, can not only meet the needs of long-distance and short-distance clear vision for people with presbyopia but also make the eyes different. The transition is more natural and comfortable when switching between distance and vision, and a pair of glasses can meet the needs of wearing in various scenes.
Precautions for wearing progressive multifocal lenses
①When matching glasses, try to choose a large frame. Because the progressive glass lenses have to be divided into far, middle, and near areas, only a large frame can ensure a sufficiently wide near area. It is best to use a full-frame frame because the more extensive the lens, the thicker the edge of the lens, and the full-frame groove can cover the thickness of the edge of the lens.
② Generally, it takes about a week to adapt, but the adaptation period varies from person to person, and walking slower when dizzy.
③Since the two sides of the lens are astigmatism disorder areas, it is difficult to see objects on both sides by turning the eyeballs with light, and you need to rotate the neck and eyeballs simultaneously to see clearly.
④When going downstairs, bring your glasses lower and try to see from the upper far area.