There are several possible causes for the condition of seeing as if there is a fog in front of the eye after being hit. The most common cause may be blurred vision due to a reflex dilatation of the pupil following trauma. Some people can return to normal after a period of time, but some people may always have a large pupil and see things in a blurred manner. There is also the case of trauma-induced retinal concussion or damage to the optic nerve, which can also lead to blurred vision. In more serious cases, retinal detachment or dislocation of the lens caused by trauma can also cause blurred vision, but this often requires emergency surgery to prevent further vision loss. If blurred vision occurs after trauma, it is recommended to go to the hospital for a lens and fundus examination, and if there are certain dangerous lesions, such as optic nerve damage or retinal detachment, active treatment is needed to restore vision.