Woodcut from the Chinese medical text Yanke zhuan yao (Compiled Essentials of Ophthalmology), published in 1914 (3rd year of the Chinese Republic). It shows the names and relative positions of the five diagnostic spheres (wu lun) of the eye. These comprise the wind sphere (feng lun), the blood sphere (xue lun), the Qi sphere (qi lun), the flesh sphere (rou lun) and the water sphere (shui lun). In general, they are thought to correlate with the physiology and pathologies of the five zang viscera. The wind sphere is the cornea: it is associated with the liver and wood. Since the liver, which is the organ of wind and wood, stands in an internal-external relationship with the gall bladder, it relates to diseases of both the liver and the gall bladder. The blood sphere consists of the network of blood vessels at both canthuses of the eye. It is associated with the heart and fire. Since the heart, which governs fire, stands in an internal-external relationship with the small intestine, it relates to diseases of the heart and the small intestine. The Qi sphere is the white of the eye. It is associated with the lung and metal. The lung, which governs Qi, stands in an internal-external relationship with the large intestine; thus this sector relates to pathologies of the lung and the large intestine. The flesh sphere consists of the upper and lower eyelids, and is associated with the spleen and earth. Since the spleen, which governs the muscles and limbs, stands in an external-internal relationship to the stomach, this sector relates to pathologies of the spleen and the stomach. The water sphere is the pupil of the eye. It is associated with the kidney, which governs water and stands in an external-internal relationship to the bladder. Thus, this sector relates to diseases of the kidney and bladder.
