The area between the two focal points of a spherocylindrical lens is called the Conoid of?

The area between the two focal points of a spherocylindrical lens is indeed referred to as the Conoid of Sturm. This term is named after the German optician Johann Heinrich von Sturm, who contributed significantly to the understanding of lens shapes and their optical properties. The conoid represents a geometric configuration that arises from the specific curvature of the lens, capturing how light behaves as it passes through.

Understanding the significance of the Conoid of Sturm is essential in the field of optics, especially when dealing with astigmatism corrections in vision. The phenomenon it describes allows opticians and optical engineers to create lenses that can effectively manage and manipulate light in ways that improve visual clarity for patients with different refractive errors.

In contrast to other named conoids, like those associated with the work of Gullstrand, Newton, or Fresnel, the Conoid of Sturm is specifically linked to the distinctive surface shape of cylindrical lenses and the intricacies of how they focus light. Each of these figures has its own relevance in optical theory but applies to different concepts or optical phenomena.