The Beneficial Effects of Tea on Eye Health: A Historical Perspective and Scientific Evidence

The belief that tea can improve eyesight has been seen in various medical texts throughout history. Li Shizhen, a Ming Dynasty scholar, wrote in his book "Compendium of Materia Medica" that tea has a bitter taste and a cooling effect, making it highly effective in reducing internal heat which is the root cause of many diseases. Qian Chun Nian and Gu Yuanqing, also from the Ming Dynasty, discussed the functions of tea in their book "Tea Universal", affirming that tea can "brighten the eyes and enhance thinking".

Tea leaves contain numerous nutrients, especially vitamins B1, B2, C, and A, which are essential for maintaining the physiological functions of the eyes. Vitamin A is a major component for maintaining the function of the retina. A deficiency in vitamin A can lead to night blindness. Vitamin B1 is a nutrient that supports the physiological function of the optic nerve. A deficiency can cause optic neuritis, resulting in blurred vision and dry eyes. Vitamin B2 plays a role in the oxidation-reduction process of human cells and is crucial for the nourishment of eye epithelial tissue. A deficiency in vitamin B2 can lead to corneal opacity, dry eyes, and decreased vision. Vitamin C is a nutrient for the lens in the eye, and inadequate intake of vitamin C is one of the factors contributing to cataracts. Therefore, drinking tea regularly has a positive effect on maintaining visual acuity and eye health.

Researchers have conducted a study on 200 patients with cataracts to investigate the relationship between cataracts and tea consumption. It was found that the incidence of cataracts was about twice as high in non-tea drinkers compared to those who regularly consumed tea, and the severity of the condition was also greater. Tea leaves contain a rich amount of vitamins necessary for maintaining eye health. Therefore, regular consumption of tea ensures timely supplementation of nutrients for the eyes, leading to normal vision and reduced eye fatigue.

In addition, drinking tea can promote urination and clear heat from the body, which has a beneficial effect on the visual function of the eyes. Traditional Chinese medicine believes that the function of the eyes is closely related to the liver, blood, and other organs. During the process of metabolism, the body produces toxins that are mainly eliminated through urine. Drinking tea can promote urination and effectively remove toxins from the body, purifying the blood and the essence of the organs. This purification process is closely related to the health of the liver, blood, and organs, resulting in improved eye health and clarity. Clinical practice has also proven this principle. There are many prescriptions in traditional Chinese ophthalmology literature that use tea for the treatment of eye diseases. For example, the book "Yin Shi Yao Han" contains 36 prescriptions. These prescriptions have shown good therapeutic effects on many eye diseases.

In addition to internal consumption, tea can also be used externally for the treatment of eye diseases. For example, boiling 25 grams of green tea in water, clarifying the solution, and using it to wash the eyes can have a certain effect on conditions such as blepharitis (commonly known as "sore eyelids") and acute infectious conjunctivitis (commonly known as "pink eye").