《灵枢·大惑论》岐伯曰∶五脏六腑之精气，皆上注于目，而为之精。精之窠为眼，骨之精为瞳子，筋之
精为黑眼，血之精为络，其窠气之精为白眼，肌肉之精为约束，裹撷筋骨血气之精，而与脉为系，上属于脑，
后出于项中。故邪中于项，因逢其身之虚，其入深，则随眼系以入于脑，入于脑则脑转，脑转则引目系急，
目系急则目眩以转矣。邪其精，其精所中不相比也则精散，精散则视歧，视歧见两物。目者，五脏六腑之精也，
营卫魂魄之所常营也，神气之所生也。故神劳则魂魄散，志意乱。是故瞳子、黑眼法于阴，白眼、赤脉法于阳，
阴阳合敷而精明也。目者，心使也，心者，神之舍也，故神精乱而不转，卒然见非常处，精神魂魄，散不相得，
故曰惑也。心有所喜，神有所恶，卒然相感，则精气乱，视误故惑，神移乃复。是故闻者为迷，甚者为惑。
此详言目由五脏六腑之精气聚会而成者也。其瞳子为骨之精，是根于肾，乃髓之光华，而神寓于中，故能
见物。若瞳子散
大，神光不聚，虽有黑珠，即不能见物矣。脑为髓海，故目珠之脉系上属于脑也。太阳经脉上连脑，下循项，
故邪之中项，因其体虚而脑不足。其邪入深，则随眼系以入于脑，则脑因邪气而转动，牵引目系紧急，则目
因之眩以转，故病患视物转动者，物本不动，由目光动也。目精受邪，其气血乱而不相比洽，则精华散而视歧，
见一物成两物，此言因外邪所伤者也。盖目由脏腑精华、营卫魂魄之所营聚，神气之所生者，故神劳则魂魄散，
志意乱也。瞳子黑珠在里法于阴，白眼血脉在表法于阳，阴阳之气合敷而精明也。然其所主在心，故目为心之
使，即神之用也。心者神之舍也，故神精散乱，则目光闪烁，卒然见非常境界，反动其心，使精神魂魄散不相
得，故曰惑也。如其心有所喜，神有所恶，而喜恶之事，卒然相感，则精气乱而视亦歧误，故惑；久之神定情
移，忘其喜恶，乃能复元。是故耳闻而情动不甚者为迷，目见而情动甚则为惑矣。此言皆由心志妄动，精散神
移，致目见异物，以成迷惑，如重即变痴癫痼疾，非因外邪之所致也。
《灵枢·大惑论》中，岐伯说：五脏六腑的精气，都向上灌注到眼睛，从而形成眼的精气。精气的汇聚处是眼，骨的精气表现为瞳仁，筋的精气表现为黑眼球（虹膜），血的气血精华表现为眼络（血管网），气的精气汇聚处表现为白眼珠（巩膜），肌肉的精气表现为眼睑（约束眼睑开合的组织）。这些组织包裹并汲取筋骨血气之精气，并与经脉相连作为目系，向上连接于脑，向后出于项部。
所以，邪气侵袭项部，如果恰逢人体正气虚弱，邪气深入，就会顺着目系进入脑部。邪气进入脑部会导致头脑旋转，头脑旋转会牵引目系紧张，目系紧张就会导致眼睛眩晕、视物转动。
邪气干扰了精气，使得精气与其所依附的结构不相协调，就会导致精气涣散；精气涣散就会出现视一为二（复视），看到两个物体。眼睛，是五脏六腑精气的汇聚之处，也是营气、卫气、魂、魄经常滋养的地方，更是神气产生的根源。所以，精神过度劳累会导致魂魄涣散，意志混乱。
因此，瞳仁和黑眼球效法阴，白眼珠和红色血脉效法阳，阴阳之气和谐分布，眼睛才能视力精明。眼睛，是心的使者；心，是神居住的宅舍。所以，当神与精混乱而不能正常运作时，突然看到不寻常的景象，精神、魂、魄分散而不能相互协调，这就叫做“惑”。
心中有所喜好，神有所厌恶，如果喜好与厌恶的事物突然同时触动内心，就会导致精气紊乱，视觉错误而产生迷惑；只有当神志安定、情感转移后，才能恢复常态。所以，耳朵听到声音而情动较浅的称为“迷”，眼睛看到景象而情动极深的称为“惑”。
这段文字详细说明了眼睛是由五脏六腑的精气聚会而成的。其中，瞳仁是骨之精气，根源于肾，是髓液的光华体现，神寓居其中，所以能看见事物。如果瞳仁散大，神光不能凝聚，即使有黑眼球，也不能看见事物了。脑是髓海，所以眼珠的脉络系统向上连接于脑。太阳经脉上连于脑，下循行于项部，所以邪气侵袭项部，是因为人体体质虚弱且脑髓不足。邪气深入，就顺着目系进入脑部，导致脑部因邪气而转动，牵引目系紧急，从而导致眼睛眩晕视物转动。所以病人感觉视物转动，其实物体本身并未移动，而是目光发生了动摇。
目之精气受到邪气侵犯，气血紊乱而不相协调，导致精华涣散而出现视一为二，看到一个物体变成两个，这是说明由外邪伤害所致。大概眼睛是由脏腑精华、营卫魂魄所营聚，由神气所化生的，所以精神劳倦会导致魂魄涣散、意志混乱。瞳仁和黑珠在内，效法阴；白眼珠和血脉在外，效法阳，阴阳之气和谐分布，眼睛才能视力精明。然而，眼睛的主宰在于心，所以眼睛是心的使者，即神的作用表现。心是神的宅舍，所以如果神精散乱，目光就会闪烁不定，突然看到不寻常的境界，反过来扰动内心，使精神魂魄分散而不能协调，这就叫做“惑”。如果心中有所喜好，神有所厌恶，而喜恶之事突然触动内心，就会导致精气紊乱，视觉也会错乱，因而产生迷惑；久而久之，神志安定，情感转移，忘记了喜恶，才能恢复元气。所以，耳闻而情动不深的是“迷”，眼见而情动极深的是“惑”。
以上论述都是由于心志妄动，精气涣散，神志移易，导致眼睛看见异物，从而形成迷惑。如果病情严重，就会转变为痴呆、癫狂等顽固性疾病，这并不是由外邪引起的。
In the *Ling Shu: Da Huo Lun* (Great Confusion Chapter of the Spirit Pivot), Qibo stated: The essence and qi of the five zang organs and six fu organs all ascend to pour into the eyes, thereby forming the essence of the eyes. The gathering place of this essence is the eye; the essence of bone manifests as the pupil (Tongzi); the essence of sinews manifests as the black eye (Heiyan, referring to the iris/cornea area); the essence of blood manifests as the collaterals (Luo, referring to conjunctival vessels); the gathering place of the essence of qi manifests as the white eye (Baiyan, referring to the sclera); and the essence of muscles manifests as the constraints (Yueshu, referring to the eyelids). These structures envelop and extract the essence of sinews, bones, blood, and qi, connecting with the meridians to form the optic nerve system (Mu Xi), which ascends to connect with the brain and emerges posteriorly from the nape of the neck.
Therefore, when pathogenic factors invade the nape, coinciding with a deficiency in the body's healthy qi, if the invasion is deep, it follows the optic nerve system into the brain. Once entering the brain, it causes dizziness or rotation of the head; this rotation pulls on the optic nerve system, causing tension; such tension leads to vertigo and visual spinning.
When pathogenic factors interfere with the essence, causing the essence to lose its proper coordination with its supporting structures, the essence scatters. When the essence scatters, diplopia (Shi Qi, seeing double) occurs, resulting in the perception of two objects. The eyes are the gathering place of the essence of the five zang and six fu organs; they are constantly nourished by Ying-Wei (Nutritive and Defensive Qi), Hun, and Po; and they are the source where Shen (Spirit) arises. Therefore, mental fatigue causes Hun and Po to scatter and Zhi (Will) to become chaotic.
Thus, the pupils and black eyes follow Yin, while the white eyes and red vessels follow Yang. When the qi of Yin and Yang harmoniously distributes, clear vision (Ming Jing) is achieved. The eyes are the messengers of the Heart; the Heart is the residence of Shen. Therefore, when Shen and Jing (Essence) are chaotic and fail to function normally, suddenly seeing unusual scenes causes Shen, Hun, and Po to scatter and lose coordination; this state is called "Huo" (Confusion/Delusion).
If the heart harbors likes and the spirit harbors dislikes, and these opposing stimuli suddenly affect the interior, it leads to chaos in essence and qi, erroneous vision, and thus confusion. Only when the Shen stabilizes and emotions shift can normalcy be restored. Hence, auditory stimulation causing mild emotional disturbance is termed "Mi" (Lost/Confused), while visual stimulation causing intense emotional disturbance is termed "Huo" (Confused/Deluded).
This passage details that the eyes are formed by the gathering of essence from the five zang and six fu organs. The pupil, being the essence of bone, is rooted in the Kidney; it is the brilliance of Marrow and houses Shen, enabling sight. If the pupil dilates and Shen Guang (Spirit Light) fails to gather, even with intact black eyes, vision is lost. The Brain is the Sea of Marrow; hence, the vascular system of the eyeball connects upward to the brain. The Taiyang Meridian connects to the brain above and descends along the nape below. Thus, pathogenic factors invade the nape due to constitutional weakness and insufficient brain marrow. Deep invasion follows the optic nerve into the brain, causing the brain to rotate due to pathogenic influence, pulling the optic nerve tight, leading to vertigo and visual spinning. Consequently, patients perceive rotating objects, although the objects themselves are stationary; this is due to the instability of visual perception.
When the essence of the eye is affected by pathogens, chaotic qi and blood fail to coordinate, causing the essence to scatter and resulting in diplopia (seeing one object as two). This describes damage caused by external pathogens. Generally, the eyes are gathered from the essence of zang-fu, nourished by Ying-Wei, Hun, and Po, and generated by Shen. Mental fatigue causes Hun and Po to scatter and Zhi to become chaotic. The pupils and black eyes are internal and follow Yin; the white eyes and vessels are external and follow Yang. Harmonious distribution of Yin and Yang qi ensures clear vision. However, the eyes are governed by the Heart; thus, the eyes are the messengers of the Heart, representing the function of Shen. Since the Heart is the residence of Shen, if Shen and Jing scatter chaotically, the gaze becomes flickering. Suddenly seeing unusual realms agitates the Heart, causing Shen, Hun, and Po to scatter and lose coordination, hence termed "Huo." If the heart has likes and dislikes, and these are suddenly triggered, essence and qi become chaotic, vision becomes erroneous, and confusion ensues. Over time, with stabilized Shen and shifted emotions, forgetting likes and dislikes allows recovery. Thus, hearing causing mild emotion is "Mi"; seeing causing intense emotion is "Huo."
These discussions attribute confusion to erratic mind-will, scattering of essence, and shifting of Shen, leading to the perception of abnormal objects and resulting in delusion. Severe cases may transform into dementia, mania, or chronic diseases, not caused by external pathogens.