For about nine years now,off and on, I have experienced this: I will lose the ability to focus on any one thing with my eyes. Like if someone has flashed a camera at me. Then I lose complete perifial view in my left eye. After about 30 minutes my full eyesight is returned but then I have a severe headache on the right side of my head which lasts about two hours. After the headache starts I become extremely fatigued and have to lay down. Should I be concerned since it only happens around once a month? Any ideas on causes?