Accommodation is the process by which the eye adjusts to focus on objects at various distances. This involves changes in the shape of the lens, allowing it to refract light rays appropriately so that they converge on the retina for clear vision.
The ciliary body plays a crucial role in this process. It contains smooth muscle fibers that can contract and relax. When we look at nearby objects, the ciliary body contracts, which reduces the tension on the suspensory ligaments (also known as zonules) that hold the lens in place. As the tension decreases, the lens becomes more rounded due to its natural elasticity, increasing its curvature. This increased curvature allows the lens to bend light rays more sharply, facilitating the focus of those rays onto the retina.
Conversely, when we look at distant objects, the ciliary body relaxes, which increases the tension on the suspensory ligaments. This causes the lens to flatten. A flatter lens is less curved and is better suited for focusing light rays coming from far away onto the retina.
In summary, accommodation involves the ciliary body contracting or relaxing to change the shape of the lens—from round for close objects to flat for distant ones—allowing for precise focus of light rays on the retina.