Final answer:
Light enters the eye through the pupil, an opening in the iris, and is focused by the lens onto the retina, which comprises rods and cones and is responsible for sensing light and sending nerve impulses to the brain.
Step-by-step explanation:
In the process of vision, light passes through the aqueous humor and then enters the eye through an opening in the iris called the pupil before it reaches the lens, where further focusing of the light occurs. The lens plays a critical role in vision as it bends, or refracts, the light to focus it onto the retina at the back of the eye.
The retina, filled with rods and cones, is the light-sensitive layer that translates the light into nerve impulses for the brain to interpret images. The pupil's size is modulated by the iris depending on the brightness of the surrounding environment, contracting in high light conditions and dilating in low light to regulate the amount of light entering the eye.
The lens, attached to ciliary muscles, can change its shape to focus light from various distances and conditions onto the fovea, which is the area of the retina with densely packed cones that provide sharp, detailed color vision.