You should consider whether they have enough depth to the color of the lenses when you choose sunglasses. And dark gray is better, followed by dark brown , black, blue and purple. The last two color lenses allow to enter more ultraviolet,but yellow, orange and pink as far as possible without. Apart from leisure, entertainment, if you really want to protect yourself from UV rays, you had better buy the color of gray, green, blue sunglasses. So to a certain extent, you could buy a pair of light blue tinted sunglasses, just like you say "they are in fashion and good". In addition, if you decide online shopping, be sure to choose a legal website.
It is said that light blue tinted lenses are designed to provide total UV protection, so you needn't to worry they may hurt your eyes. The only thing you should consider is whether the color is suitable for you or not. As far as i'm concerned the color is a trial to your skin. If the color is not a problem any more, light blue tinted sunglasses are a wonderful choice that will make you stand out among crowds. And I suggest you to choose light blue tinted aviator sunglasses, for aviator style has long been in trend.
Personally, i don't like blue tinted sunglasses. You can hardly see people wear blue sunglasses. I have also heard that blue sunglasses are bad for eyes because they will allow blue lights which are harmful to come into our eyes. If you are not a person like Lady Gaga who dare to try any style of dress up, you'd better not wear blue tinted sunglasses. Otherwise you will look quite strange.
They can protect your eyes from glare differently, and they also can help you see some items more clearly. Which one proper for you depend on where you will be using your sunglasses, and your own eyes. Blue tints are best for partly cloudy or even sunny situations. They allow the maximum amount of available blue light, and are often used in sunglasses for tennis, shooting in certain situations, winter sports, and even golf. While rose and pink tints give the highest contrast of all the tints, and give great low-light resolution. They are excellent for high-contrast sports like skiing. You can prepare different sunglasses for different occasion.