Describe the function of each part of the eye, limited to: (a) cornea – refracts light (b) iris – controls how much light enters the pupil (c) lens – focuses light on to the retina (d) retina – contains light receptors, some sensitive to light of different colours (e) optic nerve – carries impulses to the brain

The eye is a complex organ composed of various parts, each with specific functions that contribute to the process of vision. Here’s a detailed description of the function of each specified part:

1. Cornea

• Function: The cornea is responsible for refracting light. It is the clear, dome-shaped surface at the front of the eye that bends incoming light rays as they enter. This initial refraction helps focus light onto the lens, which further fine-tunes the focus before it reaches the retina.

2. Iris

• Function: The iris controls how much light enters the eye by regulating the size of the pupil. It is the colored part surrounding the pupil and consists of muscles that contract or relax to adjust the pupil’s diameter. In bright light, the iris constricts to reduce light entry, while in dim light, it dilates to allow more light in.

3. Lens

• Function: The lens focuses light onto the retina. It is a flexible, transparent structure located behind the iris and pupil. The lens can change shape—becoming thicker to focus on nearby objects and thinner for distant objects—ensuring that light rays are precisely focused on the retina for clear vision.

4. Retina

• Function: The retina contains light receptors, specifically rods and cones, which are sensitive to different wavelengths of light. Rods are responsible for vision in low-light conditions, while cones enable color vision and detailed sight in brighter conditions. The retina converts incoming light into electrical signals that are sent to the brain via the optic nerve.

5. Optic Nerve

• Function: The optic nerve carries electrical impulses from the retina to the brain. This nerve transmits visual information that has been processed by photoreceptors in the retina, allowing the brain to interpret these signals as images