Certified Paraoptometric (CPO) Exam – Practice Test & Study Guide 2025

The ability of the eye to focus objects at varying distances is known as accommodation. This term specifically refers to the ability of the lens in the eye to change shape and adjust its focal length in order to focus on objects at different distances. This process is controlled by the muscles in the eye and allows us to see clearly both up-close and far away. Convergence, on the other hand, refers to the inward movement of the eyes when focusing on a near object. Weber's Law is a principle that states the just noticeable difference in a sensory stimulus is a constant fraction of the original stimulus. Refraction is the bending of light as it passes through different mediums, including the different parts of the eye, but it is not specifically related to the eye's ability to focus objects at varying distances. Therefore, the most accurate answer to this question is A, accommodation.