The health of ocular surface is maintained by the ocular surface(cornea and conjunctiva, accessory lacrimal gland and meibomian gland), the main lacrimal gland and the lachrymal function units between them, any damage in which can lead to the failure of integrity and normal function of tear film. With the development of medical science, more and more eye surgeries are operated to treat eye diseases. However, preoperative anesthetic applications, operation process, preservatives in the eye drops may lead to tear film instability and/or abnormal manifestation on eye surface which may cause dry eyes.