Which structure is the focusing lens of the eye?

Which structure is the focusing lens of the eye?

• A. Lens
• B. Pupil
• C. Iris
• D. Retina

Answer: (A)

Light is focused onto the retina by a transparent, flexible structure located behind the pupil that can change its shape. This is the lens. It sits after the cornea and, while the cornea provides most of the eye’s refractive power, the lens fine-tunes the focus by changing curvature through the action of the ciliary muscles. When you look at something far away, the lens becomes flatter; for close objects, it becomes thicker to bend light more. The pupil, controlled by the iris, mainly regulates how much light enters, and the retina is the light-sensitive layer that detects the focused image. So the focusing element is the lens.

Light is focused onto the retina by a transparent, flexible structure located behind the pupil that can change its shape. This is the lens. It sits after the cornea and, while the cornea provides most of the eye’s refractive power, the lens fine-tunes the focus by changing curvature through the action of the ciliary muscles. When you look at something far away, the lens becomes flatter; for close objects, it becomes thicker to bend light more. The pupil, controlled by the iris, mainly regulates how much light enters, and the retina is the light-sensitive layer that detects the focused image. So the focusing element is the lens.