Children’s constant blinking may be related to refractive error, ADHD, dry eye, allergic conjunctivitis, etc. 1. Refractive error: it is the most common eye disease in childhood. If a child has refractive error, he or she may pursue better visual quality by blinking frequently. 2. ADHD: one of the more common chronic brain development and behavioral disorders in childhood. If the patient suffers from ADHD, he or she may have habitual movements, such as blinking, as well as symptoms of inattention. 3. Dry eye: These patients will have fewer tears, foreign body sensation, burning sensation and other discomforts in the eyes, which will be relieved by frequent blinking. 4. Allergic conjunctivitis: Inflammation of the eye will make children feel uncomfortable and blink frequently. It can be accompanied by congestion, redness, pain, itching, photophobia, increased secretion, tearing and other symptoms. Children always blinking, need to go to the hospital for examination to clarify the cause and treatment.