《机要》曰∶在腑则为表，当除风散热；在脏则为里，宜养血安神。暴发者，为表而易
治；久病者，在里而难愈。
子和曰∶圣人虽言目得血而能视，然血亦有太过不及也。太过则目壅塞而发痛，不及则
目耗竭而失明。故年少之人多太过，年老之人多不及。但年少之人，则无不及；年老之人，
其间犹有太过者，不可不察也。夫目之内 ，太阳经之所起，血多气少；目之锐 ，少阳经
也，血少气多；目之上纲，太阳经也，亦血多气少；目之下纲，阳明经也，血气俱多。然阳
明经起于目两旁交 之中，与太阳少阳俱会于目。惟足厥阴经连于目系而已。故血太过
者，太阳阳明之实也；血不及者，厥阴之虚也。故出血者，宜太阳阳明。盖此二经，血多故
也。少阳一经，不宜出血，血少故也。刺太阳阳明出血，则目愈明；刺少阳出血，则目愈昏
。要知无使太过不及，以养血目而已。凡血之为物，太多则滥，太少则枯。人热则血行疾而
多，寒则血行迟而少，此常理也。目者，肝之外候也。肝主目，在五行属木，虽木之为物，
太茂则蔽密，太衰则枯瘁矣。夫目之五轮，乃五脏六腑之精华，宗脉之所聚。其白轮属肺金
，肉轮属脾土，赤脉属心火，黑水神光属肾水，兼属肝木，此世俗皆知之矣。及有目疾，则
不知病之理，岂知目不因火则不病，何以言之？白轮变赤，火乘肺也；肉轮赤肿，火乘脾也
；黑水神光被翳，火乘肝与肾也；赤脉贯目，火自甚也。能治火者，一句可了。故《内经》
曰∶热胜则肿。凡目暴赤肿起，羞明隐涩，泪出不止，暴寒目瞒，皆太热之所为也。治火之
法，在药则咸寒，吐之下之；在针则神廷、上星、囟会、前顶、百会，血之翳者可使立退，
痛者可使立已，昧者可使立明，肿者可使立消。惟小儿不可刺囟会，为肉分浅薄，恐伤其骨
。然小儿水在上，火在下，故目明；老人火在上，水不足，故目昏。《内经》曰∶血实者宜
决之。又经曰∶虚者补之，实者泻之。如雀目不能夜视，及内障暴怒，大忧之所致也。皆肝
主目，血少禁出血，止宜补肝养肾。至于暴赤肿痛，皆宜以 针刺前五穴出血而已，次
调盐油以涂发根。甚者，虽至于再，至于三，可也。量其病势，以平为期。
按∶此谓目疾出血最急，于初起热痛暴发，或久病郁甚，非三棱针宣泄不可。然年高之
人，及久病虚损，并气郁者，宜从毫针补泻之则可。故知子和亦大略言尔。于少阳一经，不
宜出血，无使太过不及，以养血目而已。斯意可见。
《机要》说：病在腑属于表证，应当祛除风邪、清散热邪；病在脏属于里证，适宜养血安神。发病急骤的，属于表证，容易治疗；病程长久的，病位在里，难以痊愈。
张子和说：圣人虽然说过眼睛得到血液滋养才能视物，但是血液也有过多和不足的情况。血液过多会导致眼部气血壅塞而引发疼痛，血液不足则导致眼部耗竭而失明。所以年轻人多表现为血液太过，老年人多表现为血液不及。不过，年轻人通常没有血液不足的情况；老年人中，其中仍有部分人表现为血液太过，这一点不可不仔细辨别。眼内眦（眼角内侧），是足太阳膀胱经起始的地方，这里血多气少；外眦（眼角外侧），是足少阳胆经所在，这里血少气多；眼睑上部（上睑），属足太阳膀胱经，也是血多气少；眼睑下部（下睑），属足阳明胃经，这里气血都多。然而足阳明胃经起于目旁两颧交会的部位，与足太阳、足少阳经脉都在眼部交会。只有足厥阴肝经连接着眼系。所以血液太过的情况，是足太阳和足阳明经的实证；血液不足的情况，是足厥阴经的虚证。因此，放血疗法适宜用于足太阳和足阳明经。因为这两条经脉血液较多。唯独足少阳胆经不宜放血，因为其血液较少。针刺足太阳和足阳明经使其出血，眼睛会更加明亮；针刺足少阳胆经使其出血，眼睛会更加昏暗。要知道不要让血液出现太过或不及的情况，以滋养眼睛为目的罢了。大凡血液这种东西，太多就会泛滥，太少就会干枯。人体受热则血液运行快且多，受寒则血液运行慢且少，这是常理。眼睛是肝脏的外候。肝脏主管眼睛，在五行中属木，虽然树木这种事物，长得过于茂盛就会遮蔽视线，过于衰败就会枯死。眼的五轮，是五脏六腑精华汇聚之处，也是众多经脉聚集的地方。白轮（巩膜）属肺金，肉轮（眼睑）属脾土，赤脉（血管）属心火，黑水神光（瞳孔及视力）属肾水，同时也兼属肝木，这是世俗之人都知道的。等到发生眼疾时，却不知道疾病的原理，怎么知道眼睛不因火邪就不会生病呢？为什么这么说？白轮变红，是火邪侵犯肺脏；肉轮红肿，是火邪侵犯脾脏；黑水神光被翳障遮蔽，是火邪侵犯肝脏和肾脏；赤脉贯穿眼球，是火邪自身亢盛。能治好火邪，一句话就能解决。所以《内经》说：热邪胜则肿胀。凡是眼睛突然发红肿胀，怕光隐痛涩滞，流泪不止，突然受寒导致的视物模糊，都是由于太热造成的。治疗火邪的方法，用药方面用咸寒性质的药物，通过催吐或泻下的方法；用针灸方面，选取神庭、上星、囟会、前顶、百会穴，有翳障的可以使之立即消退，疼痛的可以使之立即停止，昏蒙的可以使之立即明亮，肿胀的可以使之立即消除。只有小儿不宜针刺囟会穴，因为小儿头骨部位的肌肉较浅薄，恐怕损伤骨骼。然而小儿水火分布是水在上、火在下，所以眼睛明亮；老人则是火在上、水不足，所以眼睛昏花。《内经》说：血实者适宜决破泄血。又经书说：虚证用补法，实证用泻法。如雀目（夜盲症）不能夜间视物，以及内障因暴怒、极大忧愁所致，都是因为肝脏主管眼睛，血液少禁止放血，只适宜补肝养肾。至于突然发红肿痛，都适宜用针刺上述五个穴位放血，其次调配盐油涂抹发根。严重的，即使进行两次、三次也可以。根据病情轻重，以平衡为准则。
按语：这里说的是眼疾放血最为紧急，适用于初起热痛暴发，或者久病郁结严重的情况，非用三棱针宣泄不可。然而年高之人，以及久病虚损，还有气郁的人，适宜采用毫针进行补泻治疗就可以了。所以知道张子和的话也是大概而言罢了。对于足少阳这一条经脉，不宜放血，不要使血液出现太过或不及，以滋养眼睛为目的罢了。这个意思可以看出来。
The *Jiyao* (Essential Principles) states: When the disease is in the Fu organs, it belongs to the Exterior level; one should dispel Wind and dissipate Heat. When the disease is in the Zang organs, it belongs to the Interior level; one should nourish Blood and calm the Spirit. Acute onset indicates an Exterior condition, which is easy to treat; chronic duration indicates an Interior condition, which is difficult to cure.
Zihe (Zhang Congzheng) said: Although the Sages stated that "the eyes can see when they receive Blood," there are also conditions of Blood excess and deficiency. Excess leads to obstruction in the eyes causing pain; deficiency leads to exhaustion of the eyes causing blindness. Therefore, young people mostly exhibit Blood excess, while old people mostly exhibit Blood deficiency. However, young people generally do not have Blood deficiency; among old people, some still exhibit Blood excess, which must be carefully observed. The inner canthus (Neican) is where the Foot-Taiyang Bladder Meridian begins; here, Blood is abundant and Qi is scarce. The outer canthus (Waican) is where the Foot-Shaoyang Gallbladder Meridian resides; here, Blood is scarce and Qi is abundant. The upper eyelid (Shanggan) belongs to the Foot-Taiyang Bladder Meridian, where Blood is abundant and Qi is scarce. The lower eyelid (Xiagan) belongs to the Foot-Yangming Stomach Meridian, where both Blood and Qi are abundant. However, the Foot-Yangming Stomach Meridian originates at the intersection beside the eyes and converges with the Taiyang and Shaoyang meridians at the eyes. Only the Foot-Jueyin Liver Meridian connects to the eye system. Thus, Blood excess is a Fullness syndrome of the Foot-Taiyang and Foot-Yangming meridians; Blood deficiency is a Deficiency syndrome of the Foot-Jueyin meridian. Therefore, bloodletting is suitable for the Foot-Taiyang and Foot-Yangming meridians because these two meridians have abundant Blood. The Foot-Shaoyang meridian alone is unsuitable for bloodletting because its Blood is scarce. Pricking the Foot-Taiyang and Foot-Yangming meridians to bleed will make the vision clearer; pricking the Foot-Shaoyang meridian to bleed will make the vision dimmer. One must know not to cause excess or deficiency, but rather to nourish the eyes with Blood. Generally speaking, if Blood is too much, it overflows; if too little, it dries up. When the body is hot, Blood circulates rapidly and abundantly; when cold, it circulates slowly and sparingly; this is the general principle. The eyes are the external manifestation of the Liver. The Liver governs the eyes and belongs to Wood in the Five Elements. Although trees, as objects, if too lush become obstructive, if too withered become dry. The Five Wheels of the eyes are the essence of the Zang and Fu organs and the gathering place of the collaterals. The White Wheel (Sclera) belongs to Lung Metal; the Flesh Wheel (Eyelids) belongs to Spleen Earth; the Red Vessels belong to Heart Fire; the Black Water and Divine Light (Pupil and Vision) belong to Kidney Water, and also jointly belong to Liver Wood. This is known by common people. When eye diseases occur, however, people often do not understand the pathology. How can one say that eyes do not get sick without Fire? Why? If the White Wheel turns red, it is Fire invading the Lung; if the Flesh Wheel becomes red and swollen, it is Fire invading the Spleen; if the Black Water and Divine Light are obscured, it is Fire invading the Liver and Kidney; if red vessels penetrate the eye, it is Fire being excessive itself. To treat Fire, one sentence suffices. Thus, the *Neijing* says: "When Heat prevails, swelling occurs." All cases of sudden redness and swelling of the eyes, photophobia, heaviness, tearing, and sudden blurriness due to cold are caused by excessive Heat. The method to treat Fire involves using salty-cold herbs, employing emesis or purgation methods; in acupuncture, points such as Shenting (GV24), Shangxing (GV23), Xinhui (GV16), Qian Ding (GV20), and Baihui (GV20) are selected. For opacities, they can be cleared immediately; for pain, it can cease immediately; for dimness, clarity can return immediately; for swelling, it can subside immediately. However, children should not be needled at Xinhui (GV16) because the flesh is thin and bone is superficial, risking injury to the skull. Children have Water above and Fire below, so their vision is clear; old people have Fire above and insufficient Water, so their vision is dim. The *Neijing* says: "For Blood excess, one should drain it." Another classic states: "Deficiency is tonified, Fullness is reduced." Conditions like night blindness (Que Mu) inability to see at night, and internal cataracts caused by violent anger or great sorrow, result from the Liver governing the eyes and having deficient Blood; bloodletting is prohibited, and one should only tonify the Liver and nourish the Kidney. As for sudden redness and swelling, one should prick the aforementioned five points to bleed, then apply salt-oil to the hair roots. In severe cases, this may be repeated twice or three times. Measure the severity of the disease and aim for balance.
Commentary: This refers to the urgency of bloodletting for eye diseases, applicable to acute onset with heat and pain, or chronic conditions with severe stagnation, requiring venting via a three-edged needle. However, for elderly individuals, those with chronic deficiency, and those with Qi stagnation, using fine needles for tonification and reduction is appropriate. Thus, Zihe's words are a general guideline. For the Foot-Shaoyang meridian alone, bloodletting is unsuitable; one must avoid excess or deficiency, aiming only to nourish the eyes with Blood. This intent is evident.