Woodcut illustrating the 17th century Chinese medical text Yangyi daquan (Great Compendium of The Medicine of Sores) Gu Shicheng, from an edition published in 1901 (27th year of the Guangxu reign period of the Qing dynasty). This is a schematic drawing of the eye, showing the 'five spheres' (wu lun), i.e. diagnostic sectors, marked with the words heart (xin), kidney (shen), liver (gan), spleen (pi ) and lung (fei). In early Chinese medicine, a close connection was believed to exist between pathological changes in these five sectors and the physiology and pathology of the corresponding viscera.
The five spheres comprise the flesh sphere (rou lun), the blood sphere (xue lun), the Qi sphere (qi lun), the wind sphere (feng lun) and the water sphere (shui lun). The flesh sphere consists of the upper and lower eyelids, and corresponds to the spleen. Since the spleen, which governs the muscles, stands in an external-internal relationship to the stomach, pathologies of this sector are related to both the spleen and the stomach. On the same principle, pathologies of the blood sphere, which consists of the inner and outer canthus (the corners of the eyes), are related to the heart and small intestine. The Qi sphere is the white of the eye, and its pathologies are related to the lung and large intestine. The wind sphere is the cornea, and its pathologies are related to the liver and gall bladder. Water sphere refers to the pupil, and its pathologies are related to the kidney and bladder.
