Many times when people buy a pair of sunglasses they think about style and not so much about the eye protection.  The most important thing when wearing sunglasses is the UV protection.  Make sure you look at the sunglasses and see if they have a sticker on them or marked somewhere that say UV400, this is the maximum protection a pair can have.  UV 400 will block UVA and UVB sun rays.  Many times manufactures on cheap sunglasses will cut costs and don't care about the UV protection they offer.

Read more on Did you know not all sunglass have UV protection…