Visual or vision impairment is the partial or total inability of visual perception. For the former and latter case, the terms low vision and blindness respectively are often used. In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment – visual impairment may cause the individual difficulties with normal daily tasks including reading and walking. In addition to the various permanent conditions, fleeting temporary vision impairment, amaurosis fugax, may occur, and may indicate serious medical problems.