Astigmatism, myopia, and hyperopia are all refractive errors. But myopia and astigmatism are still different. First of all, the imaging principles of the two are different. If there is no refractive error in the eye, it is orthophoria. When the eye is not adjusted, parallel light enters the eye and becomes a clear image on the retina through the refractive system of the eye. In myopic eyes, the image is in front of the retina; in hyperopic eyes, the image is behind the retina; in astigmatic eyes, the image is on the retina, but instead of a focal point, a focal line is formed, and the distance between the two focal lines determines the degree of astigmatism. In addition, the clinical manifestations and the methods of correction are also different. Patients with myopia show a decrease in distance vision, while near vision is normal; patients with myopia may also sometimes experience mild visual fatigue, and at the same time may be prone to exotropia, or exotropia, due to insufficient adjustment and a corresponding weakening of the pooling effect; they need concave lens correction. Whereas in the case of low astigmatism, the vision is generally not affected, in the case of moderate to high astigmatism, it may affect both distance vision and near vision; patients with astigmatism often experience visual fatigue, which is more pronounced than myopic symptoms, manifesting as eye pain, headache, especially forehead pain, double vision, unsustainable close work, etc.; requiring column lens correction.