Drinking tea can improve eyesight, which is often seen in medical books such as materia medica in past dynasties. Li Shizhen in Ming Dynasty wrote in Compendium of Materia Medica: "Tea tastes bitter and cold ... the best way to reduce fires. Fire is the source of all diseases, and fire must be clear. " In the Ming Dynasty, Qian Chunnian and Gu made a comprehensive discussion on the function of tea in Tea Spectrum, affirming that tea can "improve eyesight and benefit thinking".

There are many nutrients in tea, especially vitamin B 1, vitamin B2, vitamin C and vitamin A, which are indispensable substances to maintain the physiological function of eyes. Vitamin A is the main component to maintain the physiological function of the retina of the eye, vitamin B 1 is the nutrient to maintain the physiological function of the optic nerve, and vitamin B2 plays a redox role in human cells and is also a substance to nourish the epithelial tissue of the eye. Vitamin C is a nutrient for intraocular lens. Therefore, drinking tea often has a good effect on keeping eyesight and eye health.

In addition to oral administration, tea can also be used externally to treat eye diseases. For example, 25 grams of green tea is used to wash eyes after being clarified by decoction, which has certain curative effect on eyelid margin (commonly known as rotten eye margin) and acute infectious conjunctivitis (commonly known as pink eye).