Humans possess two eyes, akin to Heaven having the Sun and Moon; they are the supreme treasures of the body, gathering the essence of the Five Zang Organs (Zang-Fu Organs). The Five Wheels of the eye correspond to the Five Elements (Wu Xing); the Eight Palaces (Ba Kuo) symbolize numerical patterns. Frequently gazing at the Sun and Moon, staring intently at sparks, reading small print by night, viewing books under moonlight, copying for many years, carving fine details, playing games without rest, dwelling long in smoke and fire, weeping excessively, or pricking the head causing much bleeding—such conditions are all roots leading to blindness. Furthermore, galloping in hunting fields, rushing through dust and sand day and night, also serves as a medium for injuring the eyes. If one does not cherish and protect oneself during youth and strength, by the age of forty, vision will gradually become dim and blurred. Therefore, those who are skilled in nurturing life should, upon reaching middle age, often close their eyes when idle, avoid letting their gaze wander elsewhere, and not open them unless there is an urgent matter; thus, even in old age, vision will not decline. Generally, when Ying and Wei Qi (Defensive and Nutritive Qi) flow smoothly, such diseases cannot arise; when Ying and Wei Qi decline, diseases multiply. Moreover, contracting wind-cold causes tearing; deficiency leads to blurriness; overwork causes redness; swelling of the eyelids indicates the Spleen has been affected by toxicity; sores indicate Wind-Heat invading the Lungs; yellowing indicates alcohol damaging the Spleen; blood flooding the pupil and redness both indicate Heat in the Heart. Photophobia with seeing red flowers suggests Cold in the Liver; seeing black flowers indicates Kidney Deficiency; seeing blue flowers indicates Cold in the Gallbladder; seeing flowers of five colors indicates Kidney Deficiency combined with Heat; treatment cannot be uniform. If deficiency is not tonified and excess is not purged, efficacy is hard to achieve. Upper deficiency refers to Liver Deficiency, lower deficiency refers to Kidney Deficiency. Liver Deficiency causes dizziness, deafness, and vertigo; Kidney Deficiency causes virtual stagnation generating visual spots and cicada-like tinnitus in the ears; it is especially appropriate to tonify the Liver and benefit the Kidney. Profuse hot tears and red, painful eyelids indicate extreme Heat in the Liver; tearing in the wind indicates Kidney Deficiency with exogenous Heat; cooling the Liver and purging the Kidney is most suitable. As for the other Zang Organs, similar reasoning applies. Deficiency generates Cold, Excess generates Heat; the use of tonification and purgation must be carefully considered, for a difference of a hair's breadth can lead to an error of a thousand miles. Other cases are merely triggered by various stimuli or occur after severe illnesses, presenting diverse symptoms. For instance, sudden acute redness (Acute Conjunctivitis) is mostly due to floating Heat rushing upward, or irregular sleep and diet, eating full meals near fire, compounded by overwork and lack of care, or consuming toxic foods, turning into malignant syndromes. Physicians who do not investigate the origin, but simply know that acute redness belongs to Yang, may use blood-dispersing agents or Heart-cooling medicines. Even if symptoms subside, this may cause Cold in the Spleen Meridian, loss of appetite, and floating edema of the head and eyes. With the Five Zang Organs now deficient, internal cataracts (Internal Obstruction) may form. Some, seeing the patient cannot eat, administer hot medicines, leading to sudden dryness of the San Jiao (Triple Burner), with Heat Qi attacking upward, causing blurry vision, sticky discharge, and tearing. Or, provoked by extreme anger and heavy labor, fleshy growths (Pterygium) may appear. Restless Heart Qi combined with Wind-Heat transforms into Pterygium; these varied symptoms constitute External Obstructions. Similarly, diseases caused by excessive reading or gaming are named Liver Fatigue (Liver Labor). One should not merely administer Liver-treating formulas or treat it as other syndromes, as this yields no effect; rather, one must keep the eyes closed and protected, avoiding extreme distance viewing, so that recovery might be possible. Those suffering from Wind-Rashes often have dim vision; first attack the Wind, then the dimness will clear. Women before pregnancy and after childbirth must observe medication taboos. Pediatric eye conditions require careful treatment; only mild washing should be applied. Incision with blades or acupuncture must absolutely not be used. It is also necessary to forbid children from frequently rubbing their eyes, lest the eyeball rupture, leading to incurable damage. These various syndromes should be noted by specialists in ophthalmology.