The correct option for the question is C. ciliary muscles. Explanation of the Correct Answer Ciliary Muscles and Long-Sightedness: - Long-sightedness, or hyperopia, occurs when the eye is unable to focus on nearby objects clearly. This condition is often associated with aging due to changes in the eye's structure and function. - The ciliary muscles are responsible for controlling the shape of the lens in the eye. When these muscles contract, they allow the lens to become more rounded, which is necessary for focusing on close objects. As people age, the ciliary muscles can weaken, making it more difficult to change the shape of the lens effectively. This leads to difficulty in focusing on nearby objects, resulting in long-sightedness. Why the Other Options Are Incorrect A. Optic Nerves: - The optic nerves are responsible for transmitting visual information from the retina to the brain. While they are crucial for vision, they do not directly affect the ability to focus on objects. Changes in the optic nerves are not typically associated with long-sightedness. B. Retina: - The retina is the light-sensitive layer at the back of the eye that converts light into neural signals. While age-related changes can affect the retina (such as macular degeneration), these changes do not directly cause long-sightedness. Long-sightedness is primarily related to the focusing mechanism of the eye, which involves the lens and ciliary muscles. D. Cornea: - The cornea is the clear front surface of the eye that helps to focus light. While the shape and curvature of the cornea can affect vision, long-sightedness is not primarily caused by changes in the cornea. Instead, it is more about the lens and the ability of the ciliary muscles to adjust the lens shape. Summary of Key Points

• Long-sightedness (hyperopia) is often due to weakened ciliary muscles with age, affecting the ability to focus on close objects.
• The optic nerves, retina, and cornea do not directly cause long-sightedness, as they are involved in different aspects of vision.
• Understanding the role of ciliary muscles is crucial for grasping how age-related changes can impact vision.

Revision Summary

• Long-sightedness is primarily caused by weakened ciliary muscles in older adults.
• The ciliary muscles control the lens shape for focusing on nearby objects.
• The optic nerves, retina, and cornea do not directly contribute to long-sightedness.
• Age-related changes in the eye can lead to various vision problems, but ciliary muscle function is key for hyperopia.