Astigmatism may be related to congenital factors, or it may be caused by poor eye habits or eye diseases. 1. Congenital factors: usually due to the embryonic development period, affected by various adverse factors, resulting in the development of the lens and cornea did not develop into a regular shape, thus causing astigmatism. 2. Bad eye habits: it is common to use eyes improperly for a long period of time, such as often lying down to read, often rubbing the eyes, squinting, etc., which is easy to cause pressure on the cornea, resulting in changes in the shape of the cornea, which may cause astigmatism. 3. Eye diseases: Corneal ulcers, conical cornea and other eye diseases, such as conical cornea, can lead to corneal thinning in the center, and project forward to form a cone, which is easy to form astigmatism. When symptoms of astigmatism appear, you should go to the hospital in time, and make a clear diagnosis and then make corrections.