UltraFlex II Aspheric lens design effectively controls spherical aberration in the lens and human eye. Spherical aberration is the inability of a lens to focus light on a common point. That means UltraFlex II Aspheric contact lenses are able to focus light, providing clearer, crisper, sharper vision regardless of the amount of correction required. At the same time, a thinner, patented edge design provides excellent comfort. UltraFlex II Aspheric provides better vision, comfort, and proven performance.