The blurred vision of the eyes in the dark may be caused by the following diseases: First, there may be refractive error, especially the more serious astigmatism. Astigmatism itself tends to overlap, double vision, vignetting, and blurring when looking at things, so in dim light conditions, that is, after dark, the eyes will look blurry. Second, highly myopic eyes, which also have weaker retinal function, will have blurred vision after dark when the light is dimmer. Third, night blindness, night blindness will be in a dimly lit environment, where you cannot see clearly after dark and cannot see objects around you. Night blindness may be a result of retinal lesions, especially retinal pigment degeneration in the fundus, damage to the optic rod cells, and pigment disorders, so that the dark adaptation function is poor, resulting in blurred vision when the light is dim. Fundus exclusion is required to rule out retinal pigment degeneration. Night blindness has a genetic correlation, and when the patient already feels it, it means the disease has progressed to a certain stage and is tricky to treat.