Often itchy eyes can be caused by dry eye, conjunctivitis, and eyelid eczema. At the same time, itchy eyes may also be caused by physiological factors such as visual fatigue. 1. Dry eye: refers to any cause of abnormal tear quality, or abnormal kinetics resulting in decreased tear film stability. Symptoms of itchy eyes can be caused by over-drying of the eyes. 2. Conjunctivitis: It is an inflammatory disease that occurs in the conjunctiva, mostly caused by microbial infection, external irritation, or secondary to other diseases. Due to the stimulation of inflammation, symptoms such as increased secretion, itchy eyes and photophobia can occur. 3. Eyelid eczema: also known as eyelid eczema dermatitis, is a common skin disease related to allergy. The cause of the disease is complex, and the cause of sensitization is often not easy to identify. As a result of allergic reaction, the eye can appear erythema, papules, conscious itching and other symptoms. 4. Physiological factors: if the use of electronic products for a long time, reading and writing posture is not correct, it is easy to cause visual fatigue, may also trigger the symptoms of itchy eyes, can be relieved after rest, it is important to develop good eye habits. In addition, itchy eyes can also be seen in other diseases, it is recommended that patients go to the hospital as soon as possible to do the relevant examination, clear causes, and active treatment.