”Dry eye” refers to any cause of reduced tear secretion, change in tear quality or reduction in the number of blinks, etc., so that the eyes do not get enough moisture and lubrication from tears, resulting in clinical symptoms such as dry eyes, burning, and foreign body sensation. In some patients, the eyes are so dry that the lack of basic tears stimulates reflex tear secretion and causes the symptoms of frequent tearing. In 1995, the American Dry Eye Research Group proposed that “dry eye” be divided into two categories: the type with partially insufficient tear production and the type with excessive evaporation. The common clinical examination methods include tear secretion test (ink absorption test) to understand the change of tear secretion and tear film rupture time to reflect the stability of tear film. Timely detection of the cause and treatment for the cause is the key to treating dry eye. Patients with blepharitis and chronic conjunctivitis, for example, are promptly treated for local inflammation. Patients with life and environment-related conditions, such as those who spend a lot of time in air-conditioned rooms or work in front of computers for a long time, can be relieved by reducing eye time, increasing environmental humidity, and blinking more often (most people blink about 20 times per minute). Local treatment of dry eye is focused on relieving dry eye symptoms and reducing complications. In the case of partial deficiency of tear production, supplementation of artificial tears and reduction of tear loss (e.g., tear puncta embolism) are the mainstays, while in the case of excessive evaporation, in addition to appropriate supplementation of lipid-containing artificial tears, the mainstays are maintaining eyelid hygiene, treating lid margin inflammation, and improving lid gland function. It should be noted that the use of artificial tears is not the better. For severe dry eyes, one should ask if they are accompanied by dry mouth and arthralgia in order to exclude Sjogrens syndrome.