Which term describes the ability to adjust the crystalline lens to focus near or far objects?

Which term describes the ability to adjust the crystalline lens to focus near or far objects?

• A. Refraction
• B. Focal Vision
• C. Convergence
• D. Accommodation

Answer: (D)

Accommodation is the ability to adjust the crystalline lens to focus near or far objects. When you shift your gaze to something close, the ciliary muscle contracts, releasing tension on the zonular fibers and letting the lens become thicker and more curved. This increases the lens’s optical power so light from the near object focuses on the retina. For distant objects, the ciliary muscle relaxes, the lens flattens, and its power decreases, allowing distant light to focus correctly. This lens-shape change happens mainly through parasympathetic control and tends to decline with age (presbyopia). Other terms don’t describe this lens-sculpting process: refraction is about bending light overall, while convergence refers to the eyes turning inward to maintain single vision, not changing the lens shape.

Accommodation is the ability to adjust the crystalline lens to focus near or far objects. When you shift your gaze to something close, the ciliary muscle contracts, releasing tension on the zonular fibers and letting the lens become thicker and more curved. This increases the lens’s optical power so light from the near object focuses on the retina. For distant objects, the ciliary muscle relaxes, the lens flattens, and its power decreases, allowing distant light to focus correctly. This lens-shape change happens mainly through parasympathetic control and tends to decline with age (presbyopia). Other terms don’t describe this lens-sculpting process: refraction is about bending light overall, while convergence refers to the eyes turning inward to maintain single vision, not changing the lens shape.