The causes of the disease which are complicated include, besides some local inflammatory infections, not only demyelinating  disease, poisoning,  denutrition, heredity,  dysbolism but other unidentified factors as well. The clinical manifestations of the disease show that the case should pertain to"Baomang" (sudden blindness) or"Shizhan Hunmiao" (blurring of vision) in traditional Chinese medicine. Usually, the disease is caused by the fact that exogenous pathogenic heat attacks the viscera and gives rise to hyperactivity of liver fire that affects upwards the eye, or that fire hyperactivity due to yin deficiency disturbs the orifices in head, or that disorder of liver qi by emotional depression leads to qi and blood stagnation. And the deficiency of qi and blood in breast feeding period can also cause the disease.