People were able to film through the lenses for standard VR glasses. I can't find anyone that tried it for Hololens but given that they also cost several thousand dollars it's probably not that surprising. I have used the Hololens quite a bit and I can't see any reason why you couldn't film from the eye's point of view.
CastAR/Tilt5 all demos. We also allowed the press to film through our hardware.