What is the black layer on the plastic of imported glasses?

Hello; There are two common reasons for this situation. The first is that the glasses may fall off due to the hot weather, and the second reason is that there is a problem with the quality of the lenses! If the lens peels off, there is no way to remedy it! I don’t know how long you have been wearing glasses, but you can go to your glasses store and ask for a free replacement! I hope my answer will be helpful to you. Thank you!