The Disadvantages of Polycarbonate Lens
In this section, we will show you the disadvantages of polycarbonate glasses.
First, the polycarbonate lens is expensive than other regular lenses. It can cost up to double the price of regular eyeglasses.
Second, compared with high-index lenses, polycarbonate glasses have a lower abbe value, which is used to measure the dispersion of light for different eyeglasses lens materials. Polycarbonate lens rates lower mean they have the potential to cause slight chromatic aberrations in your peripheral vision.
Third, compared with Trivex lens, polycarbonate lens has bad durability since they are thinner and lighter.
Optometry for prescription glasses
The key prerequisite for proper glasses is accurate optometry. In foreign countries, professional optometrists are generally required to be qualified to issue prescriptions for optometry. However, this is not very standardized in China. Many optometrists have only been trained for a short period of time and do not have the basic knowledge of ophthalmology. For some complex situations, they may not give a proper prescription for glasses. Therefore, optometry should choose a qualified institution. If you are adolescents, people with high myopia, people with anisometropia, etc., you may need to dilate your pupils for optometry. It is best to go to the optometry center of the hospital for optometry
How to choose progressive lenses
The progressive lens can effectively control the deepening of myopia, but there is no reliable empirical evidence. At present, the height of the lens frame is only about 30mm. The distance from the design of the transition interval is not enough, and the comfort of the eye is difficult to adjust the short distance. From the quality and technology, the foreign brand design process is stable and mature, but the price is too high, there are still a lot of people who are not easy to adapt. The parameters of progressive lenses need to be determined by strict optometry.
PRiSMA blue light blocking glasses
PRiSMA is a functional anti-blue light glasses brand introduced by Germany to the world. Since its establishment in 1993, PRiSMA has been selling well in 33 countries and regions around the world. They use OAR double-layer coating technology to reduce reflection and increase penetration index. Ensuring a high blue light barrier at the same time, they increase the color contrast, so you can see more clearly, and effectively relieve eye fatigue. The product can protect the retina and relieve visual fatigue. They regulate melatonin secretion or reduces visual stress.
Contact Lens Materials - Non-HEMA materials
The non-HEMA materials are hydrophilic soft lens material, which does not contain HEMA components. They are stronger and more oxygen permeable than most HEMA polymers.
The water content of regular hydrogel lenses varies from 30% to 58%. When oxygen passes through the hydrogel, it needs to be carried by water molecules in the material. Therefore, the higher the water content of the lens, the higher the oxygen permeability value. The softer the lens, the more comfortable it is to wear, which is conducive to the metabolism of the cornea. However, at the same time, the higher the water content of the lens, the faster the water evaporation, easy to dehydration, and easy to cause dry eyes. A lens with high water content has low material density, poor durability, and easy breakage, so they are suitable for making lenses that are frequently changed or discarded. On the contrary, the lens with low water content has good formability, easy operation, durability, and is not easy to dehydrate and cause dry eyes.
Pure Titanium Glasses Frame Brand - MARCWALKS
So far, the industrial structure of the company has been very perfect, and all the single products are very good in the overall quality. Among them, the single product of the pure titanium spectacle frame series has been recognized by the industry and consumers in terms of material and workmanship. The company enjoys a high status among consumers.The variety is complete and the price is reasonable.They ensure product quality. With a variety of operating characteristics and the principle of small profits, they won the trust of most customers.
The development of glasses
In 1451, Nicholas of Cusa of Germany invented a lens that was thinner in the middle and thicker at the end to help short-sighted people. In 1727, Edward Scarlett, an English optician, invented modern frames that could be worn over ears and noses. Benjamin Franklin, an American scientist, and philosopher invented bifocals, which divide the lenses into far and near parts. The two lenses are held together by a metal frame. Frame construction has improved over the centuries, and today frames have come in different kinds of styles and designs. Unbreakable lenses were invented in 1955, and in 1971 a new type of lens combining plastic and glass properties was invented.
