Cheap sunglasses worth several bucks can also block the UV. As a matter of fact, it’s not technically difficult to add an anti-UV function to the lens, and the cost is not that high, so qualified cheap sunglasses also have the function to block the harmful sunlight.
People may wonder why the prices of sunglasses vary so distinctly from several hundred dollars to several bucks with similar functions. Actually, the prices of sunglasses are closely related to the material of lens, frames, techniques and other factors. And other famous brands like Bolon are attached with the brand value which is much higher than the materials themselves. And sunglasses exported from foreign countries are added with the tariff and exportation fees. The materials used in cheap sunglasses will definitely be inferior to those adopted in those expensive ones.
According to eye experts, the pupil of human eyes become smaller to prevent light from entering in normal sunlight, while the pupil becomes relatively bigger when people wear sunglasses. If people wear sunglasses of poor quality for a long time, it can not perform its function fully to block the UV. What’s worse, it even can hurt the cornea or ocular surface caused by retinal burns, which will lead to keratitis, cataracts and other eye diseases.
Therefore, eye experts advised that sunglasses should be taken off when you come into the room. And do not wear it all the time. The children still in the developing stage of visual growth need normal sunlight to stimulate the development of optic nerve. Long-time wearing the wrong sunglasses is likely to cause myopia, amblyopia and other eye diseases. People have a history of glaucoma are suggested not to wear sunglasses.
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