Visual or vision impairment is the partial or total inability of visual perception. 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. The terms low vision and blindness are often used for levels of impairment which are difficult or impossible to correct and significantly impact daily life. In addition to the various permanent conditions, fleeting temporary vision impairment, amaurosis fugax, may occur, and may indicate serious medical problems.