The extraction of titanium
Nowadays, the commonly used extraction method is the reduction method of titanium tetrachloride. Compared to copper and zinc, although high in content, much more expensive. On the other hand, China is the country with the largest reserves of titanium, and a large number of steel mills with perennial overcapacity began to produce titanium, so the price of titanium fell year after year.
Understand the impact of frame selection on the lens
Frame size is an important consideration when using progressive lenses because some progressive lenses work better in frames of different sizes. Since progressive lenses allow you to see at all distances, it's important that the whole range of vision fits within the frame. Therefore, very short lenses and larger lenses are not suitable for progressive lenses.
Where to Buy Anti Glare Glasses?
From the above part, you have learned the benefits of the anti reflective coating glasses. So, you may wonder where to buy them. To do that, you can buy them from the local optical store and online. If you want to buy anti reflective glasses online, you can try Koalaeye Optical, which provides all kinds of glasses, sunglasses, and frames. In addition, Koalaeye glasses are stylish and come at a cheap price. So, if you need to a pair of anti glare coating glasses, try Koalaeye glasses.
Editor's Pick: Polarspex Polarized Night Driving Glasses
The most popular product on Amazon is Polarspex's line of polarized sunglasses. A wide variety of finishes are available. You'll want to select Night Driving Yellow lenses for your night driving glasses. Affordable and stylish, these glasses feature a plastic frame, metal-reinforced hinges, and plastic polarized lenses designed to block BOTH UVA and UVB rays.
Silhouette Dynamics Colorwave 5500 BJ 6660
The Contoured Dynamic Colorwave 5500 BJ glasses come with a solid metal frame. Prescription lenses for SmartBuyGlasses are a great option so that your glasses are ready to wear. The lenses are coated with a special premium coating that makes them anti-glare and scratch-resistant. The contour dynamic color wave 5500 BJ glasses feature a gray frame and standard lens. The simplicity of rimless glasses is not that easy to create. Innovation plays a role in every rimless style. A focus on craftsmanship excellence and self-imposed high standards are part of this enduring manufacturer's legacy.
Eyeglass pinches your nose.
Not only can a pair of glasses that pinch your nose be uncomfortable, but chronic stress can also lead to headaches or migraines. How you solve this problem depends on your frame material. If you're wearing a metal frame, just use your thumb to widen the plastic nose pad until the frame fits comfortably. If wearing plastic frames, after soaking the glasses arm in warm water for 30 to 60 seconds, gently press the glasses arm outward to make the glasses more comfortable. If your glasses continue to clamp your nose after adjustment, seek help from a professional optician.
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.
