What is the type of bifocal lens that features a gradual change in power from the center to the periphery?

The correct choice reflects a lens design that provides a gradual transition in optical power, enhancing visual acuity at varying distances without abrupt changes. An aspheric lens does precisely this by employing a gradual change in curvature, which allows for a smooth transition between different focal points. This characteristic makes aspheric lenses particularly beneficial for individuals who require both near and distance vision correction, as they can seamlessly shift focus without the visual jumps that traditional bifocal lenses can create.

In contrast, traditional bifocal lenses typically feature a distinct line separating the two power sections, leading to a sudden change in vision quality. Multifocal lenses, while they do offer multiple fields of vision, do not specifically denote the gradual power change characteristic described in the question. Cylindrical lenses are primarily used for astigmatism correction and do not serve the purpose of providing bridge changes in focal power across the lens. Thus, the uniqueness of the aspheric design contributes to its appropriateness for the given context of gradual change in power.