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What is dry eye syndrome?

Dry eye syndrome, as the name suggests, refers to the frequent dryness of the eyes, and may also include discomfort such as itching, soreness, stickiness, burning sensation, foreign body sensation, and eye fatigue. This condition has existed since ancient times ⁽¹⁾, and it can also be a symptom of other diseases, with most chronic eye diseases often accompanied by this condition.

The tears that moisturize the eyeball have three layers:

• Outermost layer: The lipid layer, derived from the sebaceous glands of the eyelid, reduces water evaporation.
• Middle layer: The aqueous layer, derived from the lacrimal gland, is the main component of tears and cleans the surface of the eyeball.
• Innermost layer: The mucin layer, derived from the goblet cells of the conjunctiva, allows tears to distribute evenly.

Each of these layers has its function, and insufficient secretion or uneven distribution of any layer can cause dry eye syndrome.

Modern medicine often conducts some tests to confirm the diagnosis, such as the most commonly performed tear secretion test ⁽²⁾, other tests include corneal and conjunctival staining tests, tear film breakup time, etc.

The causes of dry eye syndrome, according to modern medicine, are related to the following factors:

• Poor eyelid closure (due to other diseases) or reduced blinking frequency (such as staring at screens for long periods, long drives).
• Eye injuries or infections affecting tear secretion and distribution.
• Autonomic nervous system disorders.
• Long-term use of eye drops (such as certain glaucoma medications).
• Long-term use of contact lenses.
• Vitamin A deficiency (but taking vitamin A does not significantly improve symptoms).
• Long-term exposure to dry working environments (such as air-conditioned rooms, windy and dry hot places).
• Taking certain medications (such as diuretics, β-blockers, antihistamines, blood pressure medications, sleeping pills, sedatives, painkillers, alcohol, etc.).
• Aging, reduced lacrimal gland function.
• Women are more prone after menopause.
• Autoimmune diseases (such as rheumatoid arthritis, Sjogren's syndrome).

In terms of treatment, modern medicine mainly provides patients with artificial tears, but this only temporarily relieves eye discomfort and has no therapeutic effect. Most artificial tears covered by health insurance contain preservatives, to which some patients may be allergic, but preservative-free artificial tears are more expensive and must be purchased out-of-pocket. Other invasive treatments (such as conjunctival sac implants, tarsorrhaphy, lower lacrimal punctum eversion, lacrimal punctum occlusion, etc.) have poor effects and may cause further damage to the eyes. In other words, modern medicine has no cure for dry eye syndrome, and patients must frequently use artificial tears. Fortunately, besides modern medicine, patients have other better options.

This article primarily discusses the radical treatment of primary dry eye syndrome, which in modern medicine is considered to be of unknown cause and can only be managed with artificial tears. As for dry eye syndrome caused by other clear diseases or factors (i.e., secondary dry eye syndrome, such as poor eyelid closure, ocular trauma, infection, long-term contact lens wear, prolonged exposure to dry environments, etc.), curing or eliminating the main disease cause will also lead to the resolution of the dry eye syndrome.

Overall disease cause

The causes of disease formation are interconnected and complex, and can be roughly divided into local and systemic factors. Modern medicine focuses on the local insufficiency of tear secretion, while it overlooks the systemic factors, namely the close relationship between the internal organs and the eyes, and the body's regulatory disorders of energy and substances. The local aspect is the "effect" and the "symptom," while the systemic aspect is the "cause" and the "root." Our treatment of dry eye syndrome aims to restore the patient's overall physiological functions and tear secretion capabilities in the shortest possible time, permanently freeing them from the need for artificial tears.

First, consider the source and pathway of tears. Their raw materials must originate from diet, are digested and absorbed by the stomach and intestines, and then transported through the lymphatic vessels and blood circulation to the eyes. The glands in the eyes convert these raw materials into tears, which are then secreted. In other words, even a single tear requires the cooperation of various organs and tissues throughout the body to be produced. If any part of this process is disrupted, the production of tears will be affected. Therefore, treating dry eye syndrome by focusing solely on the local area of the eyes is bound to fail.

Below, we summarize the common systemic causes of dry eye syndrome from a holistic perspective of the human body.

Overuse of the eyes

Modern people often spend long periods staring at screens or books, which is a major cause of many chronic eye diseases.

Excessive use of the eyes consumes a significant amount of resources and energy. In Traditional Chinese Medicine (TCM), there is a saying that "prolonged viewing harms the blood," where "blood" refers to the essential substances that nourish and moisturize the body's tissues. Generally, when the body is deficient, the first to be sacrificed are the less critical functions or tissues that do not pose an immediate threat to life. In the case of the eyes, when they are overused, a large amount of resources and energy are consumed for vision, and the relatively less important tear gland budget is reduced. Additionally, the metabolic waste produced by excessive eye use accumulates around the eyeball, hindering the input of nutrients, leading to dry and tired eyes.

Dry eye syndrome does not develop overnight. The resources and energy within the human body are limited. Long-term overconsumption inevitably leads to depletion of the "national treasury," resulting in a constitution where even slight use of the eyes causes dryness, or even persistent dryness throughout the day. Beyond dry eyes, other tissues and organs are also affected. Patients may experience symptoms such as headaches, tinnitus, dryness of the mouth, tongue, throat, and nasal cavity, dry skin, itching, peeling, and even symptoms of "Excessive Internal Heat" (heatiness).

Modern people often use their eyes while also engaging their brains (e.g., thinking while looking at a screen). In TCM, the brain is nourished by "kidney water," which refers to a group of more fundamental nutrients that are the raw materials for development, growth, and reproduction. For example, the formation of new synapses between brain neurons relies on the nourishment of "kidney water." Excessive use of the brain depletes a significant amount of these fundamental resources.

The simultaneous overuse of the eyes and brain is like burning a candle at both ends, depleting the body and even "shaking the foundation of the nation," leading to systemic dryness and affecting the body's growth, repair capabilities, and reproductive abilities. Shouldn't we be cautious?

Poor circulation

The body's circulation includes arteries, veins, capillaries, lymphatic vessels, interstitial spaces, and the meridian system, which is often overlooked by modern medicine (see "What exactly are Meridians and Acupoints?").

The raw materials and nutrients for tears, after being digested and absorbed by the stomach and intestines, must be transported through lymphatic vessels and arteries, and diffuse through interstitial spaces to reach the glands in the eyes, where they are synthesized and secreted as tears. Blockages in blood vessels, lymphatic vessels, or interstitial spaces hinder the transport of tear raw materials and nutrients. Modern people, with their Westernized diets and lack of exercise, commonly experience poor circulation, often accompanied by many lifestyle diseases such as obesity, hypertension, and diabetes. These fall under the category of "phlegm" and "stasis" in TCM.

In those who overuse their eyes, metabolic waste tends to accumulate around the eyeball and surrounding tissues, leading to poor local circulation. The tear glands, in addition to lubricating the surface of the eyeball, also function as excretory organs. Eye discharge contains metabolic waste from the eyes, and when eye use increases, so does eye discharge. However, when tear secretion is low, eye discharge is also reduced, making it easier for metabolic waste to accumulate around the eyes, further worsening local circulation.

To determine the severity of circulatory blockages in your eyes and surrounding tissues, you can use the "Periorbital Finger Scraping Technique" invented by the author.

Zang-fu organ functional decline

As mentioned earlier, the health of all major and minor organs and tissues throughout the body is closely related to the health of the eyes. Below are just a few examples to illustrate this.

The digestive system is the source of all nutrients in the human body. If the stomach and intestines have poor digestion and absorption of food, even the best supplements will be in vain. A lack of nutrition for the lacrimal glands and the supply of raw materials for tears will easily lead to dry eyes. However, modern people often harm their stomach and intestines with bad habits such as overeating, cold foods or grilled and fried foods, and irregular eating schedules. Busy, stressful lives and high mental pressure are also key factors affecting the digestive system.

The heart, blood vessels, lymphatic vessels, and interstitial spaces are the power sources and channels for transporting nutrients (including the raw materials for tears) and expelling metabolic waste in the human body. In particular, the large veins and lymphatic vessels in the body have valves to prevent backflow. Moderate exercise can compress the veins and lymphatic vessels, aiding the return of blood and lymph, increasing fluid movement and reducing the burden on the heart. However, modern people tend to sit more and move less, which is also a reason for the deterioration of the circulatory system.

The respiratory system provides tissues with sufficient oxygen and expels carbon dioxide produced by tissue combustion. Frequent common colds or incorrect treatments can lead to a decline in the respiratory system's qi movement, and even long-term upper respiratory tract allergies, affecting the circulation around the eyes and quality of life. If the qi movement is weak, the lacrimal glands will not receive enough oxygen supply, and even with sufficient nutrition and raw materials, they cannot fully function to synthesize and secrete tears.

Autoimmune diseases

Modern medicine classifies diseases where the immune system attacks the body's own tissues as autoimmune diseases. The most well-known related to dry eye syndrome is "Sjogren's syndrome," which affects the body's exocrine glands, primarily the lacrimal and salivary glands, manifesting as dry eyes and mouth. Other tissues such as the respiratory tract, digestive tract, urinary tract, nerves, muscles, joints, and internal organs can also be damaged. Modern medicine believes the disease cause may be related to autoimmunity, genetics, viral infections, etc.

How to cure dry eye syndrome?

The principle of treating dry eye syndrome is generally to increase sources and reduce drains.

Increasing sources involves promoting and balancing the patient's zang-fu organs' functions, ensuring that the nutrition for the lacrimal glands and the raw materials for tears are not lacking; and ensuring smooth body fluid circulation, allowing nutrients to enter and metabolic waste to exit. Only TCM, Chinese medicinals, and acupuncture can achieve this.

Reducing drains involves minimizing unnecessary eye use, overwork, staying up late, sexual activity, and other depletions. Avoid staring at screens for long periods and take breaks to rest the eyes, which relies entirely on the patient's self-discipline. It is recommended to place a timer in the workplace to remind you to take a break every hour.

Acupuncture and tuina (massage) can unblock meridians, body fluid circulation, and promote or balance zang-fu organs' functions, immediately improving dry eyes with noticeable effects. However, if relying solely on acupuncture and tuina, the treatment frequency must be increased (every 1-2 days), or supplemented with Chinese medicinals; Chinese medicinals can adjust the deficiencies of zang-fu organs, replenish what is lacking, and ensure smooth circulation channels, suitable for long-term care. It is usually recommended to use both methods, and the vast majority of patients can see significant improvement in a short time.

While receiving TCM and acupuncture treatment, patients must also maintain normal routines, a light diet, relaxed mood, and moderate exercise, leading to very noticeable improvement in a short time. Good lifestyle habits must be cultivated to achieve a complete cure.

bubble_chart Footnote

1. As mentioned in Zhubing Yuanhou Lun-Dry Eyes Symptom and TCM ophthalmology books Shenshi Yaohan-White Dryness Symptom.
2. Schirmer's test: Place a test strip under the lower eyelid of the subject to absorb tears, have them close their eyes and rest for 5 minutes, then measure the length of the wet part of the test strip. Generally, > 10mm is considered normal, and those below this are at high risk for dry eye syndrome.