Certified Paraoptometric (CPO) Practice Exam 2025

The correct choice is cylindrical lenses. These lenses are specifically designed to correct astigmatism, which is a common refractive error caused by an irregular shape of the cornea or lens. The cylindrical lens has different powers in different meridians, allowing it to compensate for the unequal curvature of the eye that contributes to blurred vision associated with astigmatism.

Spherical lenses, on the other hand, have the same power across all meridians and are typically used to correct myopia or hyperopia, but not astigmatism. Planar refers to surfaces that are flat and wouldn't be used for vision correction. Concave lenses, while useful for correcting nearsightedness, do not provide the specific correction needed for astigmatism, which requires the unique properties of cylindrical lenses.