The formation of tears is divided into two forms: basic tear secretion and reflex tear secretion. 1. Basic tear secretion: It is produced by the secretion of the cup cells of the conjunctiva, and its main components include mucin, water, and lipids, etc. It prevents the cornea and conjunctival epithelium from drying out, and serves as a lubricant between the eyeballs and eyelids, which makes the eyeball’s movement smoother. 2. Reflex tear secretion: After the eye is stimulated by foreign bodies, irritating gases, etc., the lacrimal gland located above the outer orbital area starts to secrete a large amount of tears, the main component of which is water, which plays a role in discharging foreign bodies or irritating objects out of the eye to minimize the damage to the eye. If the tear formation is impaired, dry eye can occur and symptoms of dryness and discomfort in the eyes can occur. Clinicians should be consulted if eye discomfort occurs.