As we know,knockoff sunglasses have poor quality such as poor materials and workmanship.So,in my opinion,knockoff sunglasses are bad for your eyes.There are some reasons to support this point.Firstly,the lens of sunglasses may not be shatterproof and could damage your eyes in accidents because it couldn't provide adequate UV protection.Secondly,your eyes may decrease the accommodation to the light because of the long time cover under the gray lenses. What's more,lens of knockoff sunglasses would be distorted and will cause headache.Therefore,put knockoff sunglasses away!