Aspherical lenses are lenses with complex curved surfaces, such as where the radius of curvature changes according to the distance from the optical axis. In other words, it is a lens whose surface profiles is not a portion of a sphere or cylinder. The most notable benefit of aspherical lenses is their ability to correct for spherical aberration. Spherical lenses are subject to aberration and therefore cannot concentrate all the light into one point. Aspheric elements are commonly used in ophthalmic applications for vision correction or in camera lenses.