When bashing around with your miniquad, your camera can get pretty beat up. A common thing that pilots use is a protective lens cover. Since the Xiaomi Yi is sized slightly differently than the GoPro, standard GoPro lens protectors won’t work. About two weeks ago I ordered one made for the Yi to try out.
The lens protector is a simple press friction fit piece of plastic. I don’t have a way to test the professionally test the optics, but I can’t see any distortions with my eye and I can’t tell any difference in the video with the lens protector on.