A foreign body sensation inside the upper eyelid of the eye may be caused by dry eye, impingement, conjunctival stones and other diseases. 1. Dry eye: this disease is mainly caused by insufficient tear secretion, abnormal tear composition, excessive evaporation of tears, etc. It can be induced by improper diet, air pollution, eye drops abuse and other factors, resulting in eye fatigue, foreign body sensation and dryness, as well as photophobia, eye pain, redness of the eyes and other symptoms. 2. Inverted eyelashes: The occurrence of this disease may be related to congenital entropion, lower eyelid redundancy, trauma, degenerative changes and other reasons. Because the patient has several eyelashes will grow toward the eyeball, contacting the conjunctiva and cornea, which will then cause photophobia, pain, foreign body sensation and other symptoms. 3. Conjunctival stones: Conjunctival stones are mostly composed of degenerated conjunctival epithelial cells and secretions. When the stones are small, there may be no obvious symptoms, and when the stones are large, there may be eye discomforts such as foreign body sensation, which need to be removed by a doctor. There are many causes of foreign body sensation in the upper eyelid of the eye, when the discomfort is obvious, you need to go to the hospital for examination to clarify the cause of the disease.