When the light is dim and you can’t see well, it may be caused by astigmatism, higher myopia, night blindness and so on. 1. Astigmatism: The corneal surface may be uneven due to genetic predisposition or developmental defects, resulting in abnormal astigmatism. Astigmatism itself tends to form overlapping shadows when you look at things, and becomes blurred when the light is dim. 2. Higher myopia: Higher myopia will lead to deformation of the eyeballs, so that the patient’s eyes are less sensitive to light, in poor light vision will be significantly affected, the phenomenon of the eyes can not see things. 3. Night blindness:Vitamin A deficiency due to nutritional disorders causes poor blood circulation in the eyes, and in the case of low light, the visual field perception is weakened, and the eyes can not see things. Patients appear in the dark light of the phenomenon of the eyes can not see things, it is recommended to go to the regular hospital for consultation, examination, active treatment, so as not to affect the vision.