The origin of the eye is the origin of the central nervous system and is vital in explaining the operation of the latter and its effect on immunology.

Although the current live animals eyes and nervous systems are very different they all have their common origin in Ciona intestinalis and marine annelids.

Ciona intestinalis has a single isolated ganglion with two extensions, one on each side, and in annelids the ganglion has been doubled so that each ring has two ganglions. The ganglions of the first ring are connected to each other, transversely, and the next ring ganglia, lengthwise, forming a structure called "chain or rope ladder strung"

In Disclosure 7 entitled: Rhodopsin: proteins of receipt, we noted that the receptor molecules are able to detect extracellular signals from outside or other bodies, to transmit into the cell, and trigger the appropriate response.

Drs Tessmar-Raible and Snyman in 2004 isolated light-sensitive opsins in the ganglion cells of the marine annelid Platynereis dumerilii (living fossil with a history of 600 million years), with a very similar structure to the opsins that exist in the rods and cones of the vertebrate eye.

In this way has been established a direct biochemical connection between the first cranial nerve ganglia of the nervous system of marine annelids, and the first cranial nerve ganglia of the nervous system of vertebrates (your eyes). From this primitive model of annelids, insects and vertebrates have evolved independently resulting in different eyes and nervous systems. However, the model is identical to a chain of nervous ganglion that have specialized but maintain the primitive connection between them (chain or rope ladder strung)

Although the current annelids such as earthworms (Lumbricus terrestris), maintain the structure of double node connected to each other and with the next couple of lymph nodes at the next ring, the first eye, in its current concept, seen in fossils Trilobites with an age 540 million years.

More complex is the origin of the central nervous system although the phylogeny indicates that pituitary lobes arise from the specialization of the second pair of ganglia, stay connected with their eyes, that the origin of the brain and cerebellum correspond to the following node (it stay connected to the pituitary gland) and so on including possibly lumboaortic lymph node chain in mammals.