A “feeling of something in the eye but not there” is a sign of foreign body sensation in the eye. Foreign body sensation can be divided into two categories: one is when something really comes into the eye (e.g. dust, debris) or the eye’s own structure scratches the cornea (e.g. eyelid stones, eyelid ingrown eyelashes); the other is when nothing enters the eye, but the eye feels itchy, causing the illusion of foreign body invasion, mostly due to inflammatory infections or allergies that cause congestion, follicles and papillae growth. Do not rub your eyes because foreign bodies are usually hard or carry pathogens. Rubbing your eyes will cause the foreign bodies to bruise the cornea and conjunctiva, giving the pathogens a chance to take advantage of the situation. Eyelash impingement is caused by the eyelashes growing toward the cornea, causing damage to the corneal epithelium and causing irritation; eyelid stones are caused by poor drainage from the eyelid lid gland mouth and the secretions that accumulate in the lid gland for a long time deteriorate into hard solid particles, similar to small sand in the eye. If the eyelid impingement or eyelid stones are causing the problem, you can have the stones picked and treated or have surgery to treat the impingement after a hospital examination. If you feel something in your eye, but it is difficult to tell where it is, and it is accompanied by redness and photophobia and increased secretion, it is often caused by conjunctivitis keratitis, so you should go to the hospital and get the right treatment for the cause. In addition, eye fatigue caused by excessive use of the eyes, dry eye syndrome will also appear in the eye seems to have something and no discomfort, you can pay attention to rest, often hot compress both eyes or point artificial tear solution treatment. To sum up, feeling something in the eye but not there is a common complaint of patients. First of all, we need to check in the hospital to rule out whether there is really no tiny hidden foreign body, and at the same time, the doctor will diagnose and treat the related diseases that cause this symptom.