TVT is a contrast enhacing technology for variable weather conditions. TVT lenses are also highly catch resistant.
UV400 & Anti Fog refers to the intense UV protective qualities of HEAD lenses and their ability to minimise fogging. The light on the mountain is intense so you need the best protection possible as well as anti-fogging qualities to maintain the best visibility.
The Cylindrical Lens is a flat lens with a single lateral curve that provides a superior field of vision. It also looks great!