Different tone of lens in glasses for bicycle I bought yellow glasses for bicycle, and one lens has little bit less tone (more lighter). Is this defect?
It probably just means that the quality standards aren't too exacting. Kind of like how display panels with a few dead pixels aren't considered defective.

You could contact the manufacturer to ask whether the problem is covered by warranty, or you could just return them and buy a different brand. There's no point in keeping glasses you dislike.