It is generally believed that sunglasses which can keep off sunshine protect eyes. However, things are more complicated than expected. A pair of unqualified sunglasses would hurt your eyes, which is worse than not wearing one. Therefore, more caution is needed when we are going to buy sunglasses.
The first and foremost step when buying sunglasses is to check whether the lenses are smooth or not, for warping ones lead to the deviation of sight line while those mixed with air bubbles make one dizzy. In the meantime, do not buy sunglasses with too thin lenses, because they are inclined to deform in heat.
What comes next when buying sunglasses is to make sure the lens materials applied are capable to cut off UV rays. In fact as we can not discern this function with naked eyes, they only reference is the information—labels reading “100% UV-cut” or “UV400” marked by manufacturers.
Moreover, try not to buy sunglasses that are blue and purple. Because the deeper the color is, the more capable they tend to cut off UV. Therefore, buy sunglasses that are dark grey, chocolate and black should be wise choices.
The last step is to try them on. It’s best to buy sunglass in a sunny day when the light is strong. Walk out the store and look around. If you feel dizzy or uncomfortable, this pair may be unqualified or not suitable to you.
Different people buy different sunglasses for different uses, but the basic principle for buying sunglasses is to choose one that guarantees security and eye protection.