If your eyes keep blacking out, you should pay attention to it because it indicates that there is something wrong with your health. There may be irregularities in your blood pressure, so you should have your blood pressure tested and do something about it. Aneamic and diabetes are also the cause of blacking out. When there is problem in the content of Sodium or Potasium in your blood, you will experience the blacking out. A rare form of migraine which is called basilar migraine can also cause blacking out, for it will shut down the basilar artery temporarily. If you suffer from the blacking out continually, you should see your doctor as soon as possible to get timely treatment.