Dry eye is a disease that occurs when the cornea becomes dry due to a decrease in the amount of tears or changes in the components of tears. Tears protect the eyes from dust, soils, germs, and foreign substances and also protect the cornea by maintaining an appropriate moisturizing state. Dry eye is considered to be caused by stress, insufficient sleep, excessive use of eyes such as PC, etc. However, it may be caused by other diseases. Therefore, appropriate diagnosis is necessary.

The number of dry eye patients is estimated to be more than 8 million in Japan. In particular, one in three people who use PC at work and about 70% of the elderly are said to have dry eye. Thus, dry eye is a disease with a high frequency, but the recognition as a disease is still low.