In the Chapter of Jingui Zhenyanlun in Suwen, it says: "The east is related to the green color and corresponds to the liver which opens into the eyes. The essence of the eyes is stored in the liver." This means that the eyes are the orifices for the liver to communicate with the external environment. Only when the essential substance stored in the liver is transported to the eyes can the eyes be nourished and see things.

2. Storage of Blood in the Liver Enables the Eyes 

The eyes are the outward orifices of the liver because the eyes are nourished by the blood from the liver.  That is why it is said, in the Chapter of Generation of the Five Zang-organs in Suwen, that "Storage of blood in the liver enables the eyes to see things."

The provision of blood and fluid to the eyes depends on the propelling power of qi. The normal activity of qi is related to the diffusing and dispersing function of the liver. That is why it is said in the Chapter of Measurement of Pulse in Lingshu that "The liver-qi enters the eyes and the normal function of the liver ensures normal vision of the eyes."

The liver meridian is connected with the eyes as it is mentioned in the Chapter of Meridians and Vessels in Lingshu. Among the twelve meridians, only the liver meridian is directly connected with the eyes. The liver meridian serves to connect the liver and the eyes internally and externally, associates the eyes with the liver and transports qi and blood.

The surplus of liver qi enters the gallbladder and accumulates into essence known as bile, the secretion and excretion of which is influenced by the diffusing and dispersing function of the liver. Bile is very important to the eyes. In the Chapter of Normal Span of Life in Lingshu, it says "At the age of fifty liver-qi begins to decline, the liver lobes become thin, the bile is reduced and the eyes become dim." In Zhengzhi Zhunshen, it further suggests that bile condenses into essence to nourish the eyes.