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 you sunglasses offer little or no UV protection, you increase your exposure to UV rays. The cheap sunglasses block some of the light, causing your iris to open allowing more light in. This lets in more UV rays as well, increasing the damage UV light can cause to the retina. UV radiation is also a contributing factor to ocular complications including cataracts, macular degeneration and tumors of the eye.