Question

Regarding the eye. What is accommodation? Explain how the ciliary body and the lens adjust to focus light on the retina include the following key terms: accommodation, ciliary body, lens, suspensory ligament, retina, light rays, contract, relax, round, flat

Answer 1

Accommodation is the process by which the eye adjusts its focus to see objects clearly at different distances. This vital function involves the ciliary body, the lens, and the interactions with suspensory ligaments.

When we look at a nearby object, the ciliary body contracts. This contraction releases tension on the suspensory ligaments (also known as zonules) that connect the ciliary body to the lens. As the tension decreases, the lens becomes rounder due to its natural elasticity. A rounder lens has a greater curvature, which allows it to bend light rays more strongly, increasing the refractive power necessary to focus those rays onto the retina.

Conversely, when we focus on distant objects, the ciliary body relaxes, which increases tension on the suspensory ligaments. This pulls the lens into a flatter shape. A flatter lens has a reduced curvature and refracts light rays less, allowing them to focus correctly on the retina.

In summary, during accommodation, the ciliary body contracts for nearby objects, making the lens round, while it relaxes for distant objects, making the lens flat. This dynamic adjustment ensures that light rays are properly focused on the retina, enabling clear vision at varying distances.