原病式曰目昧不明目赤肿痛翳膜皆疡皆为热也及目膜俗谓之眼黑亦为热也或平白目无所
见者
热气郁之甚也或言目昧为肝肾虚冷者误也是以妄谓肝生于目肾主瞳子故妄言目昧为虚而冷也
然肾水冬阴也虚则当热肝木春阳也虚则当冷肾阴肝阳岂能同虚而为冷者欤或通言肝肾之中阴
实阳虚而无由目昧也俗妄谓肝肾之气衰少而不能至于目也不知经言热甚目瞑眼黑也岂由寒乎
又如仲景言伤寒病热极则不识人乃目盲也正理论曰由热甚怫郁于目而致之然也若目无所见耳
无所闻悉由热气怫郁玄府闭密而致气液血脉荣卫精神不能升降出入故也各随郁结微甚而有病
之轻重也故知热郁于目无所见也故目微昏者至近则转难辨物由目之玄府闭小也隔缣视物之象
也
或视如绳翼者玄府有所闭合者也或目昏而见黑花者由热气甚而发之于目亢则害承乃制而反出
其泣气液昧之以其至近故虽微而亦见如黑花也及冲风泣而目暗者由热甚而水化制之也故经言
厥则目无所见夫人厥则阳气并于上阴气并于下阳并于上则火独光也阴气并于下则足阴足阴则
胀也夫一水不能胜五火故目 而盲是以冲风泣下而不止夫风之中于目也阳气内守于睛是火气
燔目故见风泣下
按此论热甚怫郁阴阳并厥玄府闭密致目病之由为详盖一主于火热之化也若由饮食辛热七
情所
动六气淫郁气血虚实则东垣子和陈无择辈论亦已详然亦有痰热湿热与夫服食金石燥热之药致
者或久病后荣卫虚弱肝气肾阴不足或元气精气虚衰及脱营为病皆有虚热实热之殊并宜分治
《原病式》说：眼睛昏暗不明、红赤肿痛、有翳膜，这些都属于疮疡类病变，都是由热邪引起的。至于眼黑（俗称为“眼黑”），也是由热邪引起的。有的人平素视力正常却突然看不见东西，这是因为热气郁结非常严重的缘故。有人说眼睛昏暗是肝肾虚冷造成的，这是错误的。人们胡乱认为肝气生于目，肾气主宰瞳孔，所以妄言眼睛昏暗是由于虚寒所致。
然而，肾水属于冬季的阴气，肾虚时应当表现为热；肝木属于春季的阳气，肝虚时应当表现为冷。肾阴和肝阳怎么可能同时虚弱而表现为寒冷呢？有人笼统地说肝肾之中是阴实阳虚，从而没有理由解释眼睛昏暗。世俗之人胡乱认为肝肾之气衰少，不能上达于目。却不知道经典中说，热邪极盛会导致眼睛闭合、视物不清（眼黑），这难道是由寒邪引起的吗？
又如张仲景说，伤寒病热邪极盛时会使人神志不清，进而导致目盲。《正理论》说，这是由于热邪极盛，怫郁（郁结不通）于眼部所致。如果眼睛看不见、耳朵听不见，都是因为热气怫郁，导致玄府（汗孔及气液出入之微观通道）闭塞紧密，使得气、液、血脉、营卫、精神不能升降出入的缘故。根据郁结程度的轻重不同，疾病的严重程度也不同。因此知道，热邪郁结于目会导致失明。所以，眼睛轻微昏花的人，在距离很近时也难以分辨物体，这是因为眼的玄府闭塞变小了，就像隔着细绢看东西一样。
有的人视物如见丝线或翅膀晃动，这是因为玄府有所闭合。有的人眼睛昏花并看见黑花飞舞，是因为热气极盛发散于眼部。当亢盛的热邪受到制约时，反而会出现流泪、气液浑浊的现象，因为距离眼睛太近，所以即使是微小的现象也能看见，如同黑花一般。还有迎风流泪且视力昏暗的情况，是因为热邪极盛，被水气所制约（水克火）。所以经典中说，“厥证”会导致眼睛看不见。人发生厥逆时，阳气并聚于上部，阴气并聚于下部。阳气并于上，则火独显光芒；阴气并于下，则足部阴盛，足部阴盛则胀满。由于一水不能胜五火，所以眼睛昏暗甚至失明。因此迎风流泪不止。风邪侵袭眼睛时，阳气内守于睛明穴所在之处，这是火气燔灼眼部，所以见到风就流泪。
按照这一论述，热邪极盛、怫郁、阴阳并逆、玄府闭塞是导致眼病的详细原因，其根本主要在于火热之化。如果是由于饮食辛辣燥热、七情触动、六淫之气淫溢郁结、气血虚实等原因导致的，李东垣、刘完素（子和）、陈无择等人的论述也已经很详尽了。然而，也有因痰热、湿热，以及服用金石类燥热药物导致的；或者有久病后营卫虚弱、肝气肾阴不足，或者元气精气虚衰，以及脱营等病症，这些都存在虚热和实热的区别，应当分别进行治疗。
The *Yuan Bing Shi* (Treatise on the Causes of Disease) states: Dimness of vision, redness and swelling of the eyes, and the presence of nebulae (membranous opacities) are all considered ulcerative lesions caused by Heat. Even "eye blackness" (a colloquial term for sudden visual loss or darkening), is also caused by Heat. In cases where a person who was previously seeing clearly suddenly loses vision, it is due to severe stagnation of Heat Qi. Some claim that dimness of vision is caused by deficiency-cold of the Liver and Kidney; this is an error. They erroneously assert that the Liver manifests in the eyes and the Kidney governs the pupils, thus falsely attributing dimness to deficiency-cold.
However, Kidney Water belongs to Yin of Winter; when deficient, it should manifest as Heat. Liver Wood belongs to Yang of Spring; when deficient, it should manifest as Cold. How can Kidney Yin and Liver Yang both be deficient and manifest as Cold? Some generally state that within the Liver and Kidney there is Excess-Yin and Deficiency-Yang, providing no explanation for dimness of vision. Laypeople erroneously believe that the Qi of the Liver and Kidney is depleted and cannot reach the eyes. Yet they do not know that the Classics state: "When Heat is extreme, one closes the eyes and experiences 'eye blackness'." Is this caused by Cold?
Furthermore, Zhang Zhongjing stated that in Shanghan (Cold Damage) disease, when Heat reaches its extreme, one becomes delirious and blind. The *Zheng Li Lun* (Correct Principles Discourse) explains that this results from extreme Heat causing Fu Yu (stagnation/oppression) in the eyes. If one cannot see with the eyes nor hear with the ears, it is because Heat Qi is stagnant, causing the Xuan Fu (mysterious pores/micro-channels for fluid and Qi exchange) to close tightly. Consequently, Qi, fluids, blood vessels, Ying (Nutritive) and Wei (Defensive) Qi, and Spirit cannot ascend, descend, enter, or exit. Depending on the severity of the stagnation, the severity of the disease varies. Thus, we know that Heat stagnation in the eyes causes blindness. Therefore, those with slight dimness of vision find it difficult to distinguish objects even at close range because the eye's Xuan Fu have become small and closed, similar to viewing objects through fine silk.
Those who see visions like threads or wings moving have some closure of their Xuan Fu. Those whose vision is dim and who see floating black spots do so because extreme Heat disperses into the eyes. When Hyperactive [Heat] causes harm, it is controlled by the subsequent element, leading to the reverse emergence of tears and turbid fluids. Because these phenomena are close to the eye, even minute ones are visible, appearing like black flowers. Regarding dimness and tearing upon exposure to wind, this occurs because extreme Heat is controlled by Water transformation. Hence, the Classics state: "Jue (Reversal) leads to inability to see." In Jue syndrome, Yang Qi aggregates above and Yin Qi aggregates below. Yang aggregating above means Fire shines alone; Yin aggregating below means Foot-Yin is excessive, leading to distension. Since one portion of Water cannot overcome five portions of Fire, the eyes become dim and blind. Thus, tearing continues unabated upon exposure to wind. When Wind attacks the eyes, Yang Qi remains internally guarded within the Jingming region; this is Fire Qi blazing the eyes, hence tearing occurs upon seeing wind.
According to this discourse, extreme Heat, Fu Yu (stagnation), simultaneous reversal of Yin and Yang, and closure of the Xuan Fu are detailed causes of eye diseases, primarily governed by the transformation of Fire-Heat. If caused by spicy/hot diet, emotional disturbances, or excessive influence of Six Evils leading to Qi-Blood stagnation or deficiency/excess, the theories of Dong Yuan (Li Dongyuan), Hezi (Liu Wansu), and Chen Wuyue are already detailed. However, there are also cases caused by Phlegm-Heat, Damp-Heat, or ingestion of metallic/mineral hot drugs. Additionally, after prolonged illness, weakness of Ying and Wei, insufficiency of Liver Qi and Kidney Yin, decline of Yuan Qi and Essence, or conditions like Tuo Ying (Depletion of Camp) present distinct differences between Deficiency-Heat and Excess-Heat, requiring differentiated treatment.