Last one I know for sure was a mTBI. Chair hit the back of my head and I saw the flash of light. Within that month or two a piece of plywood also slammed down on my head althought I dont remember that one being too bad at all. I have been a lucky dog not to have it worse I must say, however. My vision is def the most finicky. strange thing was after two days of being outdoors/biking it improved greatly.