Light must pass through several structures in the eye before it reaches the rods and cones in the retina, which are the receptor cells responsible for initiating a nerve impulse that informs the brain about visual stimuli. The journey of light begins at the cornea, the clear outer layer of the eye that first refracts incoming light. After passing through the cornea, light travels into the aqueous humor, a clear fluid that fills the space between the cornea and the lens.

Next, light encounters the lens, which further focuses the light onto the retina. Following the lens, light moves through the vitreous humor, a gel-like substance that occupies the majority of the eyeball's interior. Finally, light reaches the retina, but it must pass through several layers of cells before reaching the rods and cones.

The first layer encountered is the ganglion cells, which have long axons that transmit visual information to the brain via the optic nerve. After the ganglion cells, light passes through the bipolar cells, which serve as intermediaries, relaying signals from the rods and cones to the ganglion cells. Once light reaches the rods and cones, it triggers a nerve impulse, allowing the brain to process the visual information received.

This sequence of structures—cornea, aqueous humor, lens, vitreous humor, ganglion cells, bipolar cells, and finally rods and cones—illustrates the pathway light takes to facilitate vision, highlighting the intricate design of the eye in processing visual stimuli.