Best Men'S Sunglasses 2022
Thu, May 05, 22 By : Koalaeye
What Are High-Index Lenses? High index lenses are eyeglasses lenses that are designed to be thinner and lighter than regular lenses. High-index lenses have a high refractive index than their conventional counterparts. So, they are generally recommended for people who have significantly high refractive errors and strong prescriptions for nearsightedness, farsightedness or astigmatism. High-index lenses correct all types of refractive errors. And they are also available as single vision lenses, or a reading prescription that corrects presbyopia, such as in...

What Are High-Index Lenses?

High index lenses are eyeglasses lenses that are designed to be thinner and lighter than regular lenses. High-index lenses have a high refractive index than their conventional counterparts. So, they are generally recommended for people who have significantly high refractive errors and strong prescriptions for nearsightedness, farsightedness or astigmatism.

High-index lenses correct all types of refractive errors. And they are also available as single vision lenses, or a reading prescription that corrects presbyopia, such as in a bifocal or progressive lens.

High-index lens has a higher refractive index and which is ranging from 1.53 to 1.74. A lens with an index of 1.74 could be up to 50 percent thinner than a regular plastic lens with an index of 1.50.


How to Know If You Need Bifocal Glasses?

As you get older, you will find that is more and more difficult to read or focus on things that are really close up. This is called presbyopia and it is a common eye condition among older people.

How to know if you need bifocal glasses? If you find yourself squinting at the text that once was easy to read or your vision is blurry, you may need to see an eye doctor. In this situation, you may need bifocal glasses to correct your eyes.

If you currently wear glasses but see print more clearly when you remove them, it is a sign that you may need bifocal glasses in the future.

To know if you need bifocal glasses exactly, check your eyes by an optometrist or ophthalmologist.



How much should a pair of prescription glasses cost?

Speaking of glasses, everyone's first feeling may be that it is not cheap to have a pair of prescription glasses. Just such a small pair of glasses, ranging from a few hundred dollars to a few thousand dollars. Why is the difference so big? So some people go online to buy glasses for dozens of dollars as if they look the same. But is it actually the same? There are a lot of differences between the glasses for dozens of dollars and for thousands of dollars, apart from the price. Also, you should be responsible for your own eyes.

Better glasses brands will adopt better designs to ensure beautiful appearance and structural safety, and have stricter quality standards. At first, these glasses are not cheap because the cost has increased a lot. In addition to the brand, different materials, process requirements, and mass production scale will also affect the cost and thus the final selling price. As for the question of what price glasses to choose, my suggestion is to choose the high-priced one within your budget. So, to choose a suitable pair of glasses, what aspects need to be considered?


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 are titanium glasses so expensive?

Light Weight. The term 'pure titanium' means a titanium metal material with a purity of more than 99%. A mineral containing titanium was found in 1791, but pure titanium was not produced until 19. Pure titanium glasses are lighter than titanium alloy glasses. For frames of the same design or appearance, titanium frames weigh only half as much as other ordinary metal frames, reducing the load on the bridge of the nose.


Contact lenses or glasses, which is better?

The choice between glasses and contact lenses is a matter of personal preference. Lifestyle, comfort, convenience, budget, and beauty should be all the factors in your decision. Each approach has its pros and cons in terms of vision, ease of use, and eye health. So deciding that if you wear contacts or glasses, and when, is often a matter of personal preference. But Keep in mind that if you wear contacts all day, you should have up-to-date glasses in case you need to stop because of an eye infection or irritation.



Types of Bifocal Lenses

Executive: in this type of bifocal lens, the lens is separated completely from each other and the upper part of the lens and the lower part of the lens are divided into two equal halves. There is a distinction line and it is visible.

Progressive lens: these types of lenses are more popular than the other kind of lenses. There is no line in the progressive lens. There is a slow transition of the power from the upper part of the lens to the lower part of the lens.

Progressive multifocal lenses: a progressive multifocal lens gradually changes power from the upper part of the lens to the lower part of the lens and gives a smooth transition between the two different types of bifocal lenses. There is no distinction line in the lens. They are popular because they provide better adaption, comfort, and clarity than the other lenses.

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