Frequent blinking of a 4-year-old child may be caused by eye overstrain, inverted eyelashes, allergic conjunctivitis and so on, which can be treated by general treatment, physical therapy, surgery and other methods. 1. Eye overstrain: If 4-year-old children watch electronic products for a long time, such as watching TV, cell phones, etc., they are prone to eye overstrain, which may lead to frequent blinking of the child. Generally there is no need for special treatment, parents need to control the child’s time to watch cell phones, watching TV, and with eye exercises to massage the eyes. 2. Inverted eyelashes: If a 4-year-old child has inverted eyelashes, it will be easy to constantly irritate the cornea, resulting in frequent blinking symptoms. It can be treated by physical therapy, such as electrolysis to destroy the hair follicles at the root of the inverted eyelashes, so that the eyelashes will no longer grow. 3. Allergic conjunctivitis: If a 4-year-old child is exposed to allergic factors such as airborne pollen and irritating foods, it may lead to allergic conjunctivitis and frequent blinking. Relief can be provided by medications such as azelastine hydrochloride eye drops and olopatadine eye drops under the guidance of a doctor. When a 4-year-old child has frequent blinking, he should go to the hospital immediately for relevant examinations, and the doctor will give appropriate treatment according to the examination results.