Dry eye is a multifactorial disease, many external or internal causes can lead to dry eye, so there are many factors that cause dry eye, and finding the “root cause” can be better treated. In terms of environmental factors, environmental pollution such as smoke, dust, sand, air conditioning, long hours of computer TV and reading and writing can lead to excessive tear evaporation and dry eyes. Some people think that dry eyes will be better in summer when the air is humid, but in summer people often stay in air-conditioned rooms and cars, but dry eye symptoms are aggravated, and this should not be ignored. In terms of age and gender, the elderly and women are the most prevalent groups, and the incidence of children is also increasing due to computer and television, etc. Many children often blink and are examined for dry eye, which will be relieved by using artificial tears. Wearing contact realm, blepharitis, etc., can lead to chronic inflammation of the ocular surface causing dry eye. In addition, the use of drugs that inhibit lacrimal secretion, such as atropine, antidepressants and the long-term use of preservative-containing eye medications is also a factor in the development of dry eye, especially dry eye caused by the long-term use of preservative-containing eye medications, which is gradually attracting the attention of ophthalmologists. Computer-induced dry eye is a symptom of computer terminal-related ophthalmology syndrome. A survey of 1025 cases of video terminal users in Japan found that 23% of those who used computers for an average of 5 hours a day were diagnosed with dry eye and 42% were suspected of having dry eye, which requires more attention. In addition, various traumas, including chemical injuries and various eye surgeries, including myopic laser surgery, are the causes of dry eye.