怎样选择太阳镜
如果室外阳光刺眼，你可能会不假思索地带副太阳镜出门。但如果你要买副新的，那就得考虑很多因素了——是去折扣店还是商场专柜?到了店里以后，你又会被众多的选择弄的眼花缭乱。这篇文章就将带你揭开太阳镜的谜底，教你如何挑选太阳镜。A pair of sunglasses seems so simple -- it's two pieces of tinted glass or
plastic in some sort of plastic or metal frame. How much more straightforward
can something get? It turns out that there are many different things you can do
with two pieces of glass, and these things can have a big effect on you when you
use the lenses. As you will see in this article, there really is a difference
between the various sunglasses you'll find out there.
There are four things that a good pair of sunglasses should do for you:
• Sunglasses provide protection from ultraviolet rays(紫外线) in sunlight.
Ultraviolet (UV) light damages the cornea(角膜)and the retina(视网膜). Good
sunglasses can eliminate UV rays completely.
• Sunglasses provide protection from intense light.
When the eye receives too much light, it naturally closes the iris. Once it
has closed the iris as far as it can, the next step is squinting(斜视). If there
is still too much light, as there can be when sunlight is reflecting off of
snow, the result is damage to the retina. Good sunglasses can block light
entering the eyes by as much as 97 percent to avoid damage.
• Sunglasses provide protection from glare(强光).
Certain surfaces, such as water, can reflect a great deal of light, and the
bright spots can be distracting or can hide objects. Good sunglasses can
completely eliminate this kind of glare using polarization (分化).
• Sunglasses eliminate specific frequencies of light.
Certain frequencies of light can blur vision, and others can enhance
contrast. Choosing the right color for your sunglasses lets them work better in
specific situations.
When you buy a pair of cheap sunglasses, you often give up all of these
benefits and can even make things worse. For example, if your sunglasses offer
no UV protection, you increase your exposure to UV rays. The cheap sunglasses
block some of the light, causing your iris to open to allow more light in. This
lets in more of the UV light as well, increasing the damage UV light can cause
to the retina. So there is a difference. Buying the right pair of good
sunglasses for the conditions in which you use them gives you maximum protection
and performance.
页:
[1]