Children squinting all the time may be caused by eye fatigue, myopia, astigmatism and other reasons. 1. Eye fatigue: If children look at computers, cell phones and other electronic products for a long time, it may lead to the phenomenon of eye fatigue, causing children to squint all the time. 2. Myopia: If a child is nearsighted, it may lead to unclear vision at a distance and require squinting to see clearly, thus resulting in the child squinting all the time. 3. Astigmatism: Astigmatism is an eye condition in which the refraction is not normal. If the astigmatism is not controlled, further development will have adverse effects, it will not be able to see clearly, which may lead to the development of squinting. Parents are advised to take their children to the ophthalmology department of a regular hospital to find out the cause of frequent squinting and to take targeted measures under the guidance of a professional doctor.