What eye adjustment is required when an object is moved closer to it to maintain a sharp focus on the image?

• The ciliary muscles in the eye contract as an object is brought closer to it. When the ciliary muscles contract, the suspensory ligaments that are connected to them loosen, which prevents the eye lens from being pulled. As a result, the eye lens becomes thick, and its converging power increases.
• When an object is moved closer to the eye, the eye needs to adjust its focus in order to keep the image sharp on the retina. This process is known as accommodation, and it involves changes in the shape of the eye's lens.
• The ciliary muscles in the eye play a crucial role in accommodation. When the ciliary muscles contract, they reduce the tension on the suspensory ligaments that are attached to the lens. This allows the lens to become more rounded and thicker. The increased curvature and thickness of the lens increase its refractive power, enabling it to bend light more strongly.

           This adjustment in the shape of the lens allows the eye to focus light from the near object accurately onto the retina, resulting in a sharp and clear image.

• Conversely, when the eye is focused on a distant object, the ciliary muscles relax, and the suspensory ligaments become more taut. This flattens the lens, reducing its refractive power and allowing the eye to focus on faraway objects.

Therefore, the correct answer is ciliary muscles.