Inside the eye like into the sand, mainly foreign body feeling, the reasons are as follows: a. Foreign body into the conjunctival sac: including dust particle-like foreign body, in the clinical more common is dry eye, that is, the conjunctiva and cornea on the surface of the eye lose tear moisten, epithelial with become dry, so it will feel grinding abnormal feeling. Second, impingement or blockage of the lid ducts: greasy particle-like secretions gather on the edge of the lid margin, which can lead to an abnormal sensation of grinding as the eyelid closes. III. Stones or follicles: Conjunctival stones or larger follicles can form on the conjunctival surface of the lid, mostly related to inflammatory stimulation, etc. Allergic factors: After exposure to allergens, this can lead to a high degree of edema of the bulbar conjunctiva, which can be particularly pronounced after rubbing, and can lead to a grinding foreign body sensation.