What kind of glasses are bifocals?
Bifocals are mainly used in presbyopia correction, providing presbyopic opticians with a clear vision for both near and far use in one pair of glasses. The bifocal lens can be divided into two separate areas, with the upper part of the lens providing clear distance vision and the lower part providing clear near vision. The two regions of the bifocal lens provide different refractive forces, and the difference between these two refractive forces is the reading proximal addition, which compensates for adjustment during presbyopic reading.
Production technology of progressive lenses
In addition to the evolution in design, the production technology of progressive lenses is also constantly improving: the most representative one is the free-form technology. The emergence of free-form surface technology makes the production more flexible and rapid and can realize a more personalized design. For now, progressive lens design is done on the inside surface of the lens by a computer-controlled lathe, as if a master engraver could carve a piece of stone into a work of art.
Be sure to wear qualified glasses.
Many people are eager to buy glasses online without the necessary checks at a proper optical center for glasses. But, in reality, these tests are not only to replace glasses but to take responsibility for the safety of their own eyes. These cheap and inferior glasses will do a lot of harm to most myopic friends. If you wear unqualified glasses, it will cause visual fatigue, headache, dizziness, nausea, and other symptoms, vision loss. Severe cases can lead to amblyopia, strabismus, or other functional impairments.
What Are Progressive Lenses?
Progressive lenses are designed for people who are over 40 years old. It is a blended multi-focal lens with distance correction at the top, intermediate in the middle, and reading at the bottom. The goal is for the lens to work how your eye naturally works to let you see things both close up and far away.
Progressive lenses are made with an hourglass shape so there is some blurriness on the outer edges, but since it gives you your full range of vision, it is generally better than a bifocal despite being similar.
The Advantages of Polycarbonate Glasses
In fact, polycarbonate glasses come with several benefits and this section will show some of them.
First, polycarbonate glasses are safe and are virtually unbreakable. A study found that polycarbonate glasses were more impact-resistance than glasses or other types of plastic lenses.
Second, polycarbonate glasses are thinner than other types of lenses. This feature makes them ideal for people who have strong prescriptions. Lighter and thinner eyeglasses are less likely to slip off your nose and are more comfortable for everyday wear.
Third, extended exposure to UV radiation from the sun can cause damage to your eyes and lead to some eye conditions such as cataracts or macular degeneration. Of course, polycarbonate glasses can block out harmful UV rays from the sun and provide good protection for your eyes.
However, there are some negative voices of polycarbonate lenses.
How to adapt to progressive lenses?
People who are prone to motion sickness or have inner ear diseases may suffer dizziness, nausea, vomiting, and other symptoms due to their inability to tolerate the slight deformation of the visual objects, so they need to pay more attention when wearing them. For people who have not worn reading glasses before, it is not recommended to wear graded multi-focus glasses directly because their eyes will not be able to adapt quickly.
Ray-ban clear frames are of high quality.
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