A number of patients come in for a foreign body sensation in their eyes. Patients often say, “I don’t know if I have sand in my eyes. There is always a foreign body sensation.” In fact, there are many causes of foreign body sensation in the eyes: Foreign body sensation is constant and significant 1. Conjunctival foreign bodies: common foreign bodies include dust, coal dust, insect hair, grain shells, and dynamite powder. With the location of the foreign body is different, located in the subglottic groove, the transient eye can rub damage to the cornea, foreign body feeling is obvious, if the foreign body in the dome, half moon fold or subconjunctiva, can be asymptomatic. Treatment: Foreign bodies affixed to the conjunctival surface can be flushed out with saline, and if you have antibiotic eye drops at home, you can flush out a few drops of eye drops, and small foreign bodies will be flushed out or dipped in wet cotton swabs. General foreign body removed will foreign body feeling immediately eliminated, if there is still a foreign body feeling, to the hospital for examination and treatment. 2, corneal foreign body: common foreign bodies are ash particles, coal dust, stone chips, animal and plant thorns, knocking splashes of tiny foreign bodies, debris from explosions such as dynamite powder. After the foreign body is embedded in the cornea, the eye will suddenly experience irritation symptoms, such as foreign body sensation, photophobia, tearing, conjunctival congestion, and eyelid spasm. 3. Inverted eyelashes: common symptoms are foreign body sensation, tearing, eye redness or slight photophobia. The eyelashes are disorganized and tilted inward to rub the eyeball, and may be accompanied by superficial punctate keratitis and conjunctival congestion. Treatment: For a small amount of eyelashes, the eyelashes can be removed at home, but after a while they will grow again and need to be removed repeatedly. If you have ingrown eyelashes, surgery is required to correct them. 4. Conjunctival calculi: Most often seen in adults or the elderly, they are often accompanied by chronic inflammation of the conjunctiva. It is a product of cellular degeneration located in the epithelial recesses of the lid conjunctiva or in the deep crypt. Small, hard yellow dots, either dense or scattered, are visible on the surface of the lid conjunctiva. There are usually no obvious symptoms, but if the stone is above the conjunctival surface, there is a distinct foreign body sensation. Chronic cicatricial conjunctivitis can be caused by untreated or incomplete treatment of acute cicatricial conjunctivitis, or by the stimulation of foul air, sand, noxious gases or dust, or lack of sleep. It can also be caused by chronic dacryocystitis, blepharitis, canthal blepharitis, and refractive error. Common symptoms are foreign body sensation or dryness, eye itching, and visual fatigue, which is more pronounced at night. The lid conjunctiva is mildly congested, or there is papillary hyperplasia with a small amount of mucus or milky foamy discharge. 2. Acute Catarrhal Conjunctivitis: Commonly known as fire eye, it is caused by bacterial infection and has an acute onset, with simultaneous or sequential onset in both eyes, often with a history of contact with patients with eye diseases. It is epidemic and occurs in spring and autumn, with a feeling of foreign body, burning, itching, discharge, and marked conjunctival congestion and edema. The disease occurs almost every year. Treatment: (i) rinse with RI saline or 3% boric acid water when there is a lot of discharge, and apply cold compresses locally. Antibiotic eye drops. 3, trachoma: Chlamydia trachomatis as the causative agent, mostly due to the sharing of towels, handkerchiefs infections. Acute onset, foreign body sensation, photophobia and tearing, mucous or purulent discharge. The eyelids are red and swollen. The conjunctiva has papillae and follicles. Before liberation, it was the main blinding eye disease in China, but now the incidence is very low in large and medium-sized cities. 4. Spring conjunctivitis; itching is the most prominent conscious symptom of the disease, with foreign body sensation, burning sensation, and sometimes mild photophobia, lacrimation and other irritating symptoms. The disease is usually considered to be related to pollen sensitivity. Protein components of various microorganisms, animal dander, dust, feathers, food, etc. may also cause sensitization. It is a variant of interstitial conjunctival inflammation that often affects both eyes and is recurrent. It often develops in the spring, resolves or disappears in the fall and winter, and then recurs the following spring, and can recur for years, gradually decreasing or disappearing. Very few patients have symptoms year-round, but they peak in the spring and summer, with milder symptoms in other seasons. The disease is mostly seen in children and young people and can last for 5 to 10 years, with a higher incidence in men than in women, and is especially common in Xinjiang in the northwest of China. 5, dry eye: often bilateral onset, foreign body sensation, burning sensation, eye redness, dryness, visual fatigue, encountering smoke, wind, heat, low humidity environment, or after a long time reading, reading computer, cell phone aggravated. 6, superficial punctate keratitis: foreign body sensation, photophobia, pain, eye redness. This disease corneal epithelial punctate defects, corneal fluorescein staining positive. The etiology is also complex, such as ocular dryness syndrome, blepharitis, exposure keratitis, eye drop toxicity, ultraviolet radiation, corneal contact lens-related diseases, eyelid relaxation syndrome, etc. can cause superficial punctate keratitis. 7, filiform keratitis: foreign body sensation, eye redness, eye pain, photophobia. The corneal epithelium has filiform exfoliation with one end attached to the anterior surface of the cornea and fluorescein staining staining. In conclusion, the perception of the cornea is very sensitive. If the lid or conjunctival lesion irritates the cornea, or if the trigeminal nerve endings are stimulated when there is inflammation in the cornea, the patient will feel a foreign body sensation in the eye, accompanied by irritation symptoms such as photophobia, tearing and eyelid spasm. If it is a foreign body in the conjunctiva, you can first take antibiotic drops by yourself, and if you still have a foreign body sensation go to the hospital for examination and treatment.