1. Lung Controls qi and Qi Ensures Vision
The lung is associated with all vessels and controls qi. Qi can promote blood circulation to nourish and warm the whole body. With the normal function of lung-qi and smooth flow of qi and blood, the visceral essence flows into the eyes to enable the eyes to see things. If lung-qi is deficient, the eyes will lose sufficient nourishment and become dim.
2. Dispersing and Descending functions of Lung
The normal functions of the lung make the blood vessels smooth. With the warming and nourishment of the defensive qi and body fluids, the eyes will maintain normal in functions because turbid substances descend and will not affect the eyes.
3. Relationship Between Eyes and Large Intestine
The small intestine transfers turbid materials into the large intestine which transforms them into waste. Such a tranference and transformation depends on lung-qi to depurate, descend and discharge waste from the body. If heat is accumulated in the large intestine, it will affect the functions of the lung, leading to disorders of the eyes due to stagnation of qi, blood and body fluids.