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The *Neijing* (Yellow Emperor's Inner Classic) states: "The eyes can see when they receive blood." This sentence is the Sage's discussion on the normal state of Qi and blood in human beings. Physicians of later generations, failing to comprehend its purport, developed the notion that "cherishing blood is as precious as gold." From this premise, eye diseases and various headache conditions could not be cured. Why is this so? Although the Sage stated that the eyes can see when nourished by blood, blood also has conditions of excess and deficiency. Excess leads to obstruction in the eyes causing pain; deficiency leads to exhaustion of the eyes resulting in loss of vision. Therefore, young people mostly suffer from excess, while old people mostly suffer from deficiency. Young people do not have deficiency, but among old people, there are still cases of excess, which must not be overlooked.

The inner canthus of the eye is where the Foot-Taiyang Bladder Channel begins; here, blood is abundant and Qi is scarce. The outer canthus belongs to the Foot-Shaoyang Gallbladder Channel; here, blood is scarce and Qi is abundant. The upper eyelid (upper net) belongs to the Foot-Taiyang Bladder Channel, also having abundant blood and scarce Qi. The lower eyelid (lower net) belongs to the Foot-Yangming Stomach Channel, where both blood and Qi are abundant. However, the Foot-Yangming Stomach Channel originates at both sides of the eyes, intersects at the root of the nose, and meets with the Taiyang and Shaoyang channels at the eyes. Only the Foot-Jueyin Liver Channel connects to the eye system. Thus, blood excess pertains to the excess patterns of the Taiyang and Yangming channels; blood deficiency pertains to the deficiency pattern of the Jueyin channel. Therefore, bloodletting is suitable for the Taiyang and Yangming channels because these two channels have abundant blood. The Shaoyang channel alone is not suitable for bloodletting because its blood is scarce. Bloodletting from the Taiyang and Yangming channels will make the eyes clearer; bloodletting from the Shaoyang channel will make the eyes dimmer. One must understand that one should avoid both excess and deficiency, simply using blood to nourish the eyes. This is what the *Neijing* means by "the eyes can see when they receive blood."

Generally speaking, too much blood causes stagnation, while too little causes withering. When the body is hot, blood circulates rapidly and abundantly; when cold, it circulates slowly and sparingly; this is a general principle. As for the eyes, they are the external manifestation of the Liver. The Liver governs the eyes and corresponds to Wood in the Five Elements. Wood, as a substance, if too lush becomes dense and obstructive; if too weak, it becomes withered. If dense, wind cannot circulate freely, leading to breakage; if withered, fluids cannot moisten, leading to lack of luster. Furthermore, human eyes are like the sun and moon in the sky; eye opacities are like clouds and mist around the sun and moon. Clouds arise from evaporation and rising vapor; even in midwinter this occurs, let alone in midsummer.

Therefore, sudden redness and swelling of the eyes, photophobia with a gritty sensation, continuous tearing, and squinting due to sudden cold exposure are all caused by occupational strain or environmental factors. The Five Wheels of the eye represent the essence of the Zang-Fu organs and the gathering point of the Mai (vessels). The Qi Wheel belongs to Lung Metal; the Flesh Wheel to Spleen Earth; the Red Vessels to Heart Fire; the Black Water and Divine Light to Kidney Water, and also relate to Liver Wood. This is known to the common people. Yet when eye diseases occur, people often fail to understand the pathology, not realizing that eyes do not become diseased without Fire. Why? Redness of the Qi Wheel indicates Fire invading the Lung; redness and swelling of the Flesh Wheel indicate Fire invading the Spleen; opacity obscuring the Black Water and Divine Light indicates Fire invading the Liver and Kidney; red vessels penetrating the eye indicate Fire flourishing itself. Treating Fire resolves the issue in one phrase. Hence, the *Neijing* states: "When heat prevails, swelling occurs."

To treat Fire, pharmacologically use salty-cold herbs, employing emesis and purgation methods; acupuncturally, bleeding the Shenting (GV24), Shangxing (GV23), Xinhui (GV22), Qian Ding (GV20), and Baihui (GV20) points can immediately clear opacities, stop pain, restore clarity, and reduce swelling. However, the Xinhui point should not be needled in children due to thin tissue and risk of bone injury. Children have Water above and Fire below, hence clear vision; the elderly have Fire above and insufficient Water, hence dim vision. The *Neijing* states: "For blood excess, release it." It also states: "Deficiency is tonified, excess is drained." Conditions such as night blindness (Que Mu) and internal cataracts result from sudden anger or great sorrow, involving Liver deficiency of blood; bleeding is contraindicated, and tonifying the Liver and nourishing the Kidney is appropriate. For sudden redness, swelling, and pain, bleeding the aforementioned five points is indicated, followed by applying salted oil to the hair roots; severe cases may require repetition until the condition stabilizes. Hair turning black and regrowth are miraculous effects, not to be lightly shared. For individuals aged 40-50, regardless of gender, suffering from sudden eye redness, swelling, and difficulty opening, pricking Qian Ding and Baihui with a three-edged needle to bleed is highly effective. For young people with premature white hair, hair loss, or dandruff, this is due to excessive Heat in the blood. Common knowledge holds that hair is the surplus of blood and thus reflects blood deficiency. They do not realize that extreme Blood Heat prevents hair luxuriance. The Liver is Wood; with excessive Fire and deficient Water, Wood fails to flourish. Fire flaring up to the vertex is intense upward movement. After high fever with sweating, or following consumptive diseases, hair falls out; this is not due to Cold. Therefore, those with declining years and prevailing Fire benefit most from bloodletting. People dislike seeing bloodletting, not knowing that bloodletting actually nourishes blood. Avoid rabbit, chicken, pork, dog meat, alcohol, vinegar, damp dough, wind-aggravating/cold-producing foods, and emotional labor/stress; violation leads to non-recovery. The Hou Ding, Jiang Jian, Naohu, and Fengfu points should not be easily needled due to numerous taboos; error may cause aphonia, so caution is required. The first five points treat not only eye diseases but also headaches, stiff neck/back, and scrotal dryness/itching via bleeding. Do not needle deeply to avoid bone injury. Tang Zhenqiang was particularly skilled in bloodletting.

The secular saying "washing eyes with hot water clears vision in ten days" is long erroneous. If Fire invades the eyes, adding hot water creates a clash of heats, akin to arming a thief. Cool water temporarily constricts but eventually lubricates; hot water temporarily lubricates but eventually constricts. Otherwise, why do eye patients avoid bathing? Some claim cool water stops blood circulation. I laugh at this. Eye drops containing Coptis Rhizome (Huanglian), Borax (Pengsha), Mirabilite (Puxiao), Borneol (Longnao), and Bear Bile (Xiongdan) all inhibit blood circulation? How absurd! Severe headwind disorders lead to dim vision over time; lateral headwind involves Shaoyang Ministerial Fire, leading to pupil constriction over time. Intestinal constipation leads to dim vision. Conversely, chronic diarrhea often improves vision, except in children where chronic diarrhea leads to malnutrition-related eye dimness (Gan eye). Extremes reverse, differing slightly here; otherwise, bloodletting and strong purgation are indicated. I once suffered from red eyes, alternating swelling and opacity, lasting over 100 days with photophobia and pain. Dr. Jiang Zhongan advised pricking from Shangxing to Baihui 40-50 times, plus 10 pricks at Zanzhu and Sizhuzhu near the eyebrows, stimulating bleeding with a straw. About 2 liters of blood were released from three sites. By the next day, half recovered; within three days, fully restored. I sighed: a hundred days of suffering resolved in one morning. Having studied medicine for half a lifetime, I lacked this method; how could I neglect learning it? Only pediatric eruptions entering the eyes are due to lingering residual heat, treated by clearing Heart Fire, draining Liver Wind, and benefiting Kidney Water. Adult acute eye diseases require diaphoresis, purgation, and emesis. Because blood is in the exterior, diaphoresis is used; because Fire is superior, emesis is used; because Heat is central, purgation is used. Bloodletting and diaphoresis differ in name but share substance. Thus, the five points from the *Tongren* text are recorded for reference.