Glaucoma Week Series 2011- episode 5 ( The Optic nerve head)

Optom
The Optic nerve, the cranial nerve II, is the anterior extension of the white matter of the brain. It arises from the ganglion cells of the neural retina to the lateral geniculate body. It is made up of approximately 1 million axons, mainly myelinated except those of the retina. These axons relay with the visual cortex of the brain via the optic radiation.  The Optic nerve head is covered by a thin strip of flexible sclera known as the lamina cribrosa.It separates the myelinated part of the Optic nerve from the unmyelinated retina. This strip of sclera is susceptible to damage & injury. The optic nerve does not possess Schwann cell and hence do not regenerate when injured or damaged.
The Optic nerve is is covered by three layers of meninges and it is surrounded by an extension of the subarachnoid space. The Optic nerve head is supplied by the arterial branches of the long and short posterior ciliary arteries, the central retinal artery and from the partial arterial circle of Haller-Zinn. The blood supply of Optic nerve drains into the central retinal vein.
To be continued...

Dr Ezebuiroh Okwudiri Victor.