Traditional lenses are made from the curved surface of a glass or plastic sphere. Aspherical lenses, on the other hand, are made by using special molded glass, and although they still have a curved surface, they are not entirely spherical.
Definition and How They’re Made
Aspherical lenses are lenses made by heating optical glass until it can be placed into heat-resistant molds. Manufacturers then create individual variations of aspherical lenses.
Shape Of The Lens
Although aspherical lenses have curved surfaces, they do not share the same shape as traditional lenses. This difference in shape makes an aspherical lens more precise, and with fewer visual aberrations, than a spherical lens.