You might think you've found a bargain when you picked up those $3 sunglasses but your eyes might end up paying a bigger price.
Those bargain sunglasses can actually do great damage to your vision by allowing harmful UV light to penetrate rather than blocking it.
Wearing tinted lenses causes your eyes to dilate, which lets in more light and that includes more UV light if the sunglasses do not have a built-in UV filter. UV exposure may increase the likelihood of cataracts, macular degeneration and even possibly certain types of skin cancer.
When shopping for sunglasses, choose those that include UVA/UVB protection of 99-100%.*