The breakdown of the molecules triggers an impulse. The Rod and Cone cells are attached to nerve cells. The light of the ray has triggered a chemical change that initiates an electrical signal within a nerve cell attached to the photoreceptor. The nerve cell transmits information from the Retina throughout the visual system. All the nerve cells of the retina converge to form a single nerve, the Optic Nerve.
All visual impulses travel through the optic nerve in a highly organized fashion towards the brain.
At some point along the voyage, the nerve from the right eye joins the nerve from the left eye. The point where the nerve fibers from the 2 eyes mesh together is called the Optic Chiasm. The nerve fibers traveling posterior to the Chiasm carry images from the retina of both eyes. The visual signals collated in the Chiasm are sent posteriorly through structures called Optic Radiations. Some visual information from both eyes travels to structures in the brainstem called Nuclei.