True or False: Not all progressives use aspheric optics.

• A. True
• B. False
• C. Not sure
• D. It depends

Answer: (B)

Progressive lenses are designed to provide a seamless change in power from distance to near while keeping vision clear across the lens. To do this well, the designer must control aberrations that occur more strongly toward the edges of the lens. Aspheric surfaces are used to shape the curvature gradually, which reduces peripheral distortion and helps maintain consistent image quality as you tilt or gaze through different parts of the lens. Because of this, modern progressive lenses almost always incorporate at least one aspheric surface (often on the back, sometimes on both surfaces) to optimize the progression and minimize unwanted distortions. Therefore, saying that not all progressives use aspheric optics isn’t accurate in today’s typical lens designs; the use of aspheric elements is the standard approach. There are older or specialized designs that may use more spherical components, but they are not representative of current practice.