What Are Trivex Lenses?
What is Trivex? Trivex lenses were first produced in 2001. Trivex lenses come with several features such as light, impact-resistance, and high-performance strength. Recently, the use of Trivex as ophthalmic lens material has grown in popularity. Lenses made from Trivex material fulfill the same safety standards as those made from polycarbonate.
In addition, because of Trivex’s manufacturing process, plastic lenses sporting Trivex material do not distort vision as much. Trivex lenses offer 100 percent protection from UAV and UAB rays, sharper central vision, and sharper peripheral vision. Trivex was developed for military applications, so it is good for outdoor use. Other benefits include resistance to chemicals and better light refraction.
So, in the following section, we will show you the advantages and disadvantages of the Trivex lenses.
The design evolution of progressive lenses
Spherical and aspheric designs
The design of the front surface of the far-use area of the early progressive lens is similar to that of the ordinary spherical single vision lenses, so it is called a spherical progressive lens. Since 1974, the front surface of the far-use region of the lens is designed to be aspheric by designers, which not only reduces the peripheral aberration but makes the lens thinner, lighter, and less powerful.
Hard and soft design
For hard design, the channel is short, and the gradient is large. The near-use area position is high. The effective visual area of remote and near-use areas was larger. Peripheral astigmatism is relatively concentrated. Because surrounding astigmatism increases rapidly and the distribution is dense, the curve effect is more obvious. The gradient area is narrow. It is more difficult and takes longer for wearers to adapt.
Lenses with soft designs have slower gradients, longer gradients, and wider gradients. The angle of rotation of the eye from the far area to the near area is greater. It's easier to get used to. Compared with the hard design, the effective visual area of the far and near use areas is smaller, and the location of the near use area is lower.
Single, diverse, and individualized design
Initially, the progressive lenses used a single design, in which each basic curve was scaled equally and a luminosity combination was added within the range of its semi-finished lens blanks. The steepest base curve uses the same lens design as the flattest base curve. Lenses designers quickly realized that the overall performance of the lens could be improved by microcustomizing the lens design, leading to progressive lenses with multiple designs. This kind of design is called diverse design. By the mid-1990s, there was the emergence of individualized lens designs. In addition to using different gradients, these first individualized lens designs used steeper baseline curves with a slightly larger approach area to compensate for increased magnification and reduced field of view.
Symmetrical and asymmetric design
There is no difference between the left and right eyes in the symmetrical design of progressive lenses. As the eyes turn inward when they see near objects, the gradual gradient area gradually tilts to the nasal side from top to bottom, so the left/right progressive lenses should be rotated clockwise/counterclockwise respectively during processing. An asymptotic lens with left and right eye divisions is called an asymmetric design. The gradient is gradually and moderately inclined to the nasal side from top to bottom. The refractive force, astigmatism, and vertical prism of the two sides of the left and right gradient of the asymmetric design lenses are basically similar. At the same time, considering the characteristics of eye movement parameters in binocular vision, the peripheral aberrations of the corresponding positions of the left and right lenses were appropriately balanced to improve the visual effect of the wearer.
Disadvantages of glasses
They can distort vision, especially at the edges of lenses if you have strong prescriptions or astigmatism. Some people have trouble adjusting to progressive lenses. These lenses fog up and splash in the rain. Due to the limitation of the frame itself and the effect of the prism effect in the peripheral part of the glasses, the wearer can see a relatively narrow field of vision.
This kind of glasses does not have a frame to wrap the eyeglass ring, only the metal nose pad, and temples, and the lens is fixed after being punched, which is relatively lighter. This kind of glasses is lighter and more fashionable and is the first choice for ladies in the workplace.
Does a long-face suit wear transparent glasses?
A long face gives people a sense of being relatively thin, so it is best not to wear a transparent, thin frame, or it will show a longer face. It is best to wear glasses with wider rims and darker colors. Compared with women and men, because the overall image of the difference is relatively large, in the selection of glasses, it is best to foil the characteristics of the face and highlight the overall contour of the face. At the same time, the man with a lighter skin color can choose a lighter color frame like the tortoiseshell gold silver frame. People with dark skin color can choose a heavier color frame, like red, black, and so on.
The disadvantages of progressive lenses
- The field of view in the near and middle distances is relatively narrow.
- The adaptation time is longer and patients with greater astigmatism are not suitable for wearing.
- The peripheral aberration is large, and there will be large astigmatism in the periphery.
What are the advantages and disadvantages of bifocal reading glasses?
The advantage of bifocal reading glasses is a large field of vision, and they can be used with the same pair of glasses to see far, near. The cost is lower. But different areas have obvious intervals, and the appearance is not beautiful. The middle distance is fuzzy. They need to adapt to the period. Bifocal reading glasses lens is divided into two parts, and the degree of the two parts is not the same. The upper part is the mother of the flat area to see far, and the next part is the child of the reading area to see near. There is an obvious interval. The appearance is not beautiful. There is no transition area between two different areas, so its vision is fuzzy, easy to produce a 'jump image'. Long-term wearing will make people dizzy or fall down when climbing stairs.