Hi James,
Welcome to Neuro Talk! The colors that you saw are do to the optical lobe
in the back of your head where your eye sight is. My advice to you is to get a MRI done or a CT scan to be sure there's no damage in the area of your head
where you fell. Also take note if certain lighting doesn't bother you if it does that means you may be photosensitive. I found I was photosensitive after having a e.e.g. (brainwave) test done and they flashed different color strobe lights one at a time. I wish you the best of luck and May God Bless You!

Sue