QS Study

The fibers of the optic nerve are the axons of the cells in the ganglionic layer of the retina. They converge on the optic disc and exit from the eye, about 3 or 4 mm to the nasal side of its center, as the optic nerve. It is the second cranial nerve, responsible for transmitting the special sensory information for vision.

The fibers of the optic nerve are myelinated but the sheaths are formed from oligodendrocytes.


The anatomical course of the optic nerve describes the transmission of special sensory information from the retina of the eye to the primary visual cortex of the brain. It is ensheathed in all three meningeal layers (dura, arachnoid, and pia mater) rather than the epineurium, perineurium, and endoneurium found in peripheral nerves. Each human optic nerve contains between 770,000 and 1.7 million nerve fibers, which are axons of the retinal ganglion cells of one retina.

Optic Nerve 1

Fig: Formation of Optic Nerve

It is developed from the optic vesicle, an outpocketing of the forebrain. The optic nerve can, therefore, be considered part of the central nervous system, and examination of the nerve enables an assessment of intracranial health. The job of the optic nerve is to transfer visual information from the retina to the vision centers of the brain via electrical impulses. Aside from the optic nerve, the eye has a number of other components. These include the cornea, iris, pupil, lens, retina, macula, and vitreous.

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