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The eyes possess five wheels (Wulun, the five functional zones of the eye), which correspond to the five Zang organs. The five wheels are all manifestations of the essence of the five Zang organs. They are named "wheels" because their imagery resembles the round rotation and movement of a wheel. The upper and lower eyelids correspond to Spleen Earth, aligning with the Central direction, associated with Heavenly Stems Wu and Ji, and Earthly Branches Chen, Xu, Chou, and Wei. The Spleen governs flesh, thus it is called the Flesh Wheel (Rou Lun). Spleen Earth governs movement, grinding and transforming food and drink. Externally, it corresponds to the two eyelids; their dynamic and static states respond to each other. When open, myriad functions arise, akin to Yang activation generating life; when closed, myriad things fall silent, akin to Yin stillness gathering in. This symbolizes that Earth can store myriad things and governs stillness. Thus, when the Spleen's function integrates (during sleep), myriad things become silent and one feels sleepy, reflecting the response of storing and returning to stillness. The two sharp corners of the eyes, i.e., the inner and outer canthi, correspond to Heart Fire, aligning with the Southern direction, associated with Heavenly Stems Bing and Ding, and Earthly Branches Si and Wu. The Heart governs Blood, thus it is called the Blood Wheel (Xue Lun). As there is a concept of "two hearts" (the physical heart and the spirit/mind aspect) in human viscera, the eyes also have a distinction between inner and outer wheels. The white part of the eye (Sclera/Conjunctiva) corresponds to Lung Metal, aligning with the Western direction, associated with Heavenly Stems Geng and Xin, and Earthly Branches Shen and You. Metal is the hardest among the Five Elements, thus the white part of the eye is harder than the other four wheels. The Lung governs Qi, thus it is called the Qi Wheel (Qi Lun). The greenish-black part within the white part (Cornea/Iris), known as Qing Jing, corresponds to Liver Wood, aligning with the Eastern direction, associated with Heavenly Stems Jia and Yi, and Earthly Branches Yin and Mao. Wood corresponds to Spring in the four seasons; in spring, myriad flowers grow, and its color is clear and emerald green. Since the eyes enable vision, the eyes are considered the orifice of Liver Wood. The Liver governs Wind, thus it is called the Wind Wheel (Feng Lun). The single black, lustrous point within the Qing Jing is the Pupil (Tong Shen), corresponding to Kidney Water, aligning with the Northern direction, associated with Heavenly Stems Ren and Gui, and Earthly Branches Hai and Zi. The Kidney governs Water, thus it is called the Water Wheel (Shui Lun). Among the five wheels, the four cannot see objects; only the Water Wheel (Pupil) illuminates everything without omission, being mysterious and unfathomable. It is the primordial essence fluid from pre-heaven, the original spirit at the beginning, the supreme treasure of the human body, akin to the sun and moon in the sky. Therefore, if a person's pupil is damaged, it cannot be treated.

The Eight Palaces (Baguo, the eight sectors of the eye) correspond to the Eight Trigrams. Their meridians and collaterals weave through the brain, connecting the Zang and Fu organs, reaching the blood and Qi, and circulating to nourish the eyes. "Palace" refers to city walls, implying distinct pathways for entry and exit, signifying protection and defense. Qian is located in the northwest, its collaterals connecting to the Large Intestine Fu organ, while the corresponding Zang organ is the Lung. The Lung and Large Intestine are interior-exterior paired organs. The Lung connects upwards to pure qi and transports downwards waste products, serving as the official of transmission; thus, it is called the Transmission Palace (Chuansong Guo). Kan is located due north, its collaterals connecting to the Bladder Fu organ, while the corresponding Zang organ is the Kidney. The Kidney and Bladder are interior-exterior paired organs, governing the source of water transformation and transporting body fluids; thus, it is called the Body Fluid Palace (Jinye Guo). Gen is located in the northeast, its collaterals connecting to the San Jiao (Triple Burner), with the Ming Men (Gate of Life) as the corresponding Zang aspect. The Ming Men and San Jiao are interior-exterior paired organs, converging the Yin meridians and distributing to the hundred vessels; thus, it is called the Convergence of Yin Palace (Huiyin Guo). Zhen is located due east, its collaterals connecting to the Gallbladder Fu organ, while the corresponding Zang organ is the Liver. The Liver and Gallbladder are interior-exterior paired organs, both governing purity and clarity, rejecting turbidity; thus, it is called the Purity and Clarity Palace (Qingjing Guo). Xun is located in the southeast, its collaterals connecting to the Middle Jiao Fu organ, with the Pericardium (Xin Bao) as the corresponding Zang aspect. The Pericardium and Middle Jiao are interior-exterior paired organs. The Pericardium network manages Ying (Nutrient) Blood to nourish the Middle Jiao and distributes Qi to facilitate transformation and generation; thus, it is called the Nourishment and Transformation Palace (Yanghua Guo). Li belongs to due south, its collaterals connecting to the Small Intestine Fu organ, while the corresponding Zang organ is the Heart. The Heart and Small Intestine are interior-exterior paired organs, serving as the vessel receiving and holding the Yin; thus, it is called the Vessel of Yang Palace (Baoyang Guo). Kun is located in the southwest, its collaterals connecting to the Stomach Fu organ, while the corresponding Zang organ is the Spleen. The Spleen and Stomach are interior-exterior paired organs. Earth accepts food and drink to sustain life; thus, it is called the Food and Drink Palace (Shuigu Guo). Dui is located due west, its collaterals connecting to the Lower Jiao Fu organ, with the Kidney network as the corresponding Zang aspect. The Kidney and Lower Jiao are interior-exterior paired organs, guarding the source of Yin Essence transformation; thus, it is called the Gate of Spring Palace (Guanquan Guo). The pairing of Zang and Fu organs has established methods in the ancient sage's *Nei Jing* (Inner Canon). However, the emphasis on the San Jiao and the two networks of the Liver and Kidney in this context is because the eye's configuration specifically opens into the Liver and is governed by the Kidney, hence the special dominance of these two networks. The left eye belongs to Yang, and the path of Yang proceeds clockwise; thus, the meridian and collateral patterns of the palaces also proceed clockwise. The right eye belongs to Yin, and the path of Yin proceeds counter-clockwise; thus, the meridian and collateral patterns of the palaces also proceed counter-clockwise. By observing the distinction between the two eyes and the left and right sides, the principles of Yin-Yang, clockwise, and counter-clockwise movements become clearly understandable.