What Are Category 4 Sunglasses? | KOALAEYE OPTICAL

What Are Category 4 Sunglasses?

Polarized Sunglasses Cheap Leiendo What Are Category 4 Sunglasses? 5 minutos Siguiente Bolle Prescription Sunglasses

Men's clear glasses are a fashion item.

Although glasses are the tool that corrects myopia, a lot of people like to dress up fashion with it now. Men's fashion frames allow you to express your taste and fashion sense and can increase your appearance and image. An eyeglass frame is an important part of a pair of glasses, mainly playing the role of supporting the lens. While the beautiful appearance of the eyeglass frame can play a certain role in aesthetics. Handsome frames add points for appearance.

A clear glasses frame is not only for a schoolgirl. Clear and transparent design more feel cool and refreshing in scorching summer. At the same time, it will not cover the facial features too much, making the face more delicate and clean. Small pure and fresh picture frames tie in some of the clothes of literature and art naturally. Therefore, the scope of use of clear glasses is very limited, only suitable for fashionable men.


Why is a prescription for glasses different from a prescription for contact lenses?

The frame glasses degrees are the optometric degrees of the eye, and the difference between the frame glasses degrees and the contact lens degrees is mainly due to the different contact distances between the two lenses and the eye. Usually, degrees of contact lenses and glasses need to be converted by a professional through vertex diopter. The conversion formula is Fc=Fs/(1-d×Fs). In the formula, Fc is the diopter of contact lens, Fs is the diopter of glasses frame lens, and D is the distance between frame glasses lens and cornea. Assuming that the prescription of frame glasses is -4.00d and the distance between lens apex is 12mm, the prescription of contact lenses is -4.00/ [1-0.012×(-4.00)] = -3.82d.



Titanium alloys have low thermal elasticity

The thermal conductivity of titanium is about 1/4 of nickel, 1/5 of iron, 1/14 of aluminum, and the thermal conductivity of different titanium alloys is about 50% lower than that of titanium.

The elastic modulus of titanium alloy is about 1/2 that of steel, so its rigidity is poor and is easy to deform, and it is not suitable to make slender rods and thin wall parts. When cutting, the spring back of the processing surface is very large, about 2 ~ 3 times of stainless steel, resulting in severe friction, adhesion, and bonding wear of the knife surface.


Why do you need rimless glasses?

Traditional full-frame glasses can sometimes make your face look heavy, especially if the lenses are thicker. Rimless glasses can replace heavy frames without weight from the rims. This reduces the pressure on the nose pad, making your face feel lighter and more comfortable.



Pay attention to the wearing of myopia sunglasses when driving.

Some drivers are slightly myopic, usually driving without wearing a myopic mirror. There is no problem. But once you wear sunglasses, the problem comes: your eyes are more likely to tire and your vision will decline, just as your driving vision will be affected at night. Therefore, for the driver of slight myopia, there is no problem in usually driving, but if you want to wear sunglasses, you must be equipped with the lens of myopia degrees.


Progressive Lens

Standard progressive lenses are multifocal lenses with three observation areas, farsightedness, intermediate vision, and nearsightedness. Unlike bifocals, there are no visible lines between each viewing area. They have a seamless, invisible design, where the optical power changes 'gradually' throughout the lens. Many people confuse 'bifocal' or 'trifocal' with 'progressive' but remember that bifocals and trifocals have visible lines in the lens, while progressive lenses do not. Because progressive lenses have no lines in the lens, they are more popular multifocal lenses than bifocal lenses.

The main observation area of the progressive lens is a far distance, the smaller area at the bottom of the lens is used for myopia, and the middle area in the middle is smaller. Standard progressive glasses are very suitable for general purpose glasses, focusing on hyperopia activities (such as driving and walking) and sufficient area in the lenses for nearsighted activities (such as reading and computer use). The left and right sides or 'convex corners' of the lens are deliberately blurred to achieve an invisible design. The clearest line of sight in the gradual process is from the center to the top of the lens.


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Which face types are suitable for rimless glasses?

Rimless glasses are mainly suitable for round faces, heart-shaped faces, square faces, and other most face shapes. Rimless frames are designed to be light, hence, they ease the wearer's stress, increasing comfort, and providing a wide view. Rimless glasses suit most face types, suitable for people who are short-sighted within 600 degrees. If the degrees are too high, you should not wear rimless glasses. When the degrees are too high, the lens will be suitable for thickening, so rimless glasses will show bloated.

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