A bicycle helmet is a helmet intened to be worn while riding a bicycle. They are designed to attenuate impacts to the cranium of a cyclist in falls while minimizing side effects such as interference with peripheral vision. There is intense academic debate on whether helmet use offers any reduction of the chance of head injury. The debate on whether helmet use should be compulsory is even more intense and occasionally bitter, often based not only on differing interpretations of the academic literature, but also on differing assumptions and interests on the two sides.