Make sure the sunglasses are really non-prescription, or it will make your vision worse. It is safe for you to wear Non-prescription sunglasses with contact lenses. In addition, your eyes will get a dual protection, by doing this may unintentionally add UV protection to the lenses which most optical shops will do for a small fee.
No,it won't damage your vision. There are so many people who wear contacts wearing sunglasses over the contacts when they go outdoors.The contact lenses help you see clearly and the sunglasses can protect your eyes through blocking harmful rays.Wearing sunglasses is also a fashion trend. The only thing you should remember is to make sure the sunglasses have 100% UV protection.