polarized sunglasses with good quality won't cause cancer because they will block the harmful rays or glare that would damage our eyes. If your eyes are exposed to the sun directly, then it will cause cancer.However, polarized sunglasses is the strongest defense against cancer of the eye.
Polarized Michael Kors sunglasses come with the warning. Material used to make them can cause cancer and birth defects, so yes there is some potential danger in using them.