What adapts for changing focus, particularly in varying distances?

What adapts for changing focus, particularly in varying distances?

• A. Cornea
• B. Retina
• C. Crystalline lens
• D. Pupil

Answer: (C)

The crystalline lens is responsible for adapting focus as it changes shape to accommodate varying distances. This process, known as accommodation, allows the eye to focus on objects that are close or far away. The lens is flexible and can become more convex to focus on nearby objects, increasing its refractive power, or flatten out to focus on distant objects, reducing its refractive power. While the cornea also plays a significant role in focusing light onto the retina, it has a fixed shape and does not change to adapt to different distances. Similarly, the retina is where images are projected after light has been focused by the cornea and lens, but it does not actively participate in changing focus. The pupil controls the amount of light entering the eye, but it does not contribute to changing focus itself. Therefore, the correct answer is the crystalline lens, as it is the component that dynamically adjusts to allow clear vision at varying distances.

The crystalline lens is responsible for adapting focus as it changes shape to accommodate varying distances. This process, known as accommodation, allows the eye to focus on objects that are close or far away. The lens is flexible and can become more convex to focus on nearby objects, increasing its refractive power, or flatten out to focus on distant objects, reducing its refractive power.

While the cornea also plays a significant role in focusing light onto the retina, it has a fixed shape and does not change to adapt to different distances. Similarly, the retina is where images are projected after light has been focused by the cornea and lens, but it does not actively participate in changing focus. The pupil controls the amount of light entering the eye, but it does not contribute to changing focus itself. Therefore, the correct answer is the crystalline lens, as it is the component that dynamically adjusts to allow clear vision at varying distances.