Normal people wake up in the morning, there is a very small amount of secretion in the corners of the eyes, which is related to the reduction of eyelid movement, tear secretion and slow discharge during sleep at night. Normal eye secretions mainly come from lacrimal gland, tarsal gland, mucus secreted by ocular surface cells and exfoliated ocular surface epithelial cells. Most of them are transparent or white and are usually not easily detected. Because the amount of secretion is small and can be discharged from the lacrimal passage in time, it will not cause eye discomfort. When certain diseases occur in the eyes, changes in the quantity or character of eye secretions occur. Once the secretion of the eye increases, it is necessary to pay special attention to the time when the secretion increases, the characteristics of the secretion (color, volume, odor), whether the eye has foreign body sensation, whether the vision is impaired?