If the patient sees the light scattered at night, it is usually caused by refractive errors, such as hyperopia, myopia, astigmatism, etc., which is mainly caused by the light not being able to focus on the retina. 1. Hyperopia: a refractive state in which parallel light is refracted by the eye and then imaged in the retina, when the refractive power of the eye is insufficient, hyperopia can occur. When the refractive power of the eye is insufficient, hyperopia can occur. Because the optical focus of the eye is behind the retina, the image formed on the retina is blurred, and the patient can see the light scattered at night. 2. Myopia: When parallel light enters the eye and focuses on the front of the retina, it can lead to the inability of the patient to form a clear image on the retina, so the patient can also have the symptom of seeing the light scattered at night. 3. Astigmatism: Astigmatism also belongs to refractive error and is related to the curvature of the cornea. Parallel light into the eye, because the refractive power of the eye in different meridian is not equal, so it is difficult to gather in one point, and will not form a clear image, this condition is called astigmatism. It is recommended that patients with poor quality of vision at night be seen promptly for evaluation of their condition and treatment as prescribed by their doctor.