True or False: Atorics technically have to be spherocylinders by definition, and don't include spherical lenses.

• A. False
• B. They can be spherical lenses in some designs
• C. They are only used for high index lenses
• D. True

Answer: (D)

Atorics are designed to correct astigmatism, which means the lens must provide different refractive powers along two perpendicular meridians. A purely spherical lens has the same power in every direction, so it cannot correct astigmatism. Therefore, an atoric must combine a spherical component with a cylindrical component, i.e., be a spherocylinder. In other words, its prescription is a sphere plus a cylinder at a given axis, delivering two principal powers. Some designs might realize this with different surface shapes, but the end effect is still two distinct powers—not a single spherical power. That’s why the statement is true.