Nerve fiber layer
Encyclopedia
The retina
l nerve fiber layer (nerve fiber layer, stratum opticum, RNFL) is formed by the expansion of the fibers of the optic nerve
; it is thickest near the porus opticus, gradually diminishing toward the ora serrata
.
As the nerve fibers pass through the lamina cribrosa
sclerae they lose their medullary sheaths and are continued onward through the choroid
and retina
as simple axis-cylinders.
When they reach the internal surface of the retina they radiate from their point of entrance over this surface grouped in bundles, and in many places arranged in plexuses.
Most of the fibers are centripetal, and are the direct continuations of the axis-cylinder processes of the cells of the ganglionic layer, but a few of them are centrifugal and ramify in the inner plexiform and inner nuclear layer
s, where they end in enlarged extremities.
Patients with retinitis pigmentosa
have abnormal thinning of the RNFL which correlates with the severity of the disease. However the thickness of the RNFL also decreases with age and not visual acuity. The sparing of this layer is important in the treatment of the disease as it is the basis for connecting retinal prostheses to the optic nerve, or implanting stem cells that could regenerate the lost photoreceptors.
RNFL is a sensitive structure. Some process can excites its natural apoptosis. Harmful situation can make some damage on RNFL such as high intraocular pressure, high fluctuation on phase of intraocular pressure, inflammation, vascular disease and any kind of hypoxia. Gede Pardianto (2009) reported 6 cases of RNFL thickness change after the procedures of phacoemulsification.
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
l nerve fiber layer (nerve fiber layer, stratum opticum, RNFL) is formed by the expansion of the fibers of the optic nerve
Optic nerve
The optic nerve, also called cranial nerve 2, transmits visual information from the retina to the brain. Derived from the embryonic retinal ganglion cell, a diverticulum located in the diencephalon, the optic nerve doesn't regenerate after transection.-Anatomy:The optic nerve is the second of...
; it is thickest near the porus opticus, gradually diminishing toward the ora serrata
Ora serrata
The ora serrata is the serrated junction between the retina and the ciliary body. This junction marks the transition from the simple non-photosensitive area of the retina to the complex, multi-layered photosensitive region. In animals in which the region does not have a serrated appearance, it is...
.
As the nerve fibers pass through the lamina cribrosa
Lamina cribrosa
Lamina cribrosa may refer to:*Cribriform plate of the ethmoid bone *Lamina cribrosa sclerae, a mesh-like structures which allows nerve fibres of the optic nerve to pass through the sclera...
sclerae they lose their medullary sheaths and are continued onward through the choroid
Choroid
The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye, containing connective tissue, and lying between the retina and the sclera. The human choroid is thickest at the far extreme rear of the eye , while in the outlying areas it narrows to 0.1 mm...
and retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
as simple axis-cylinders.
When they reach the internal surface of the retina they radiate from their point of entrance over this surface grouped in bundles, and in many places arranged in plexuses.
Most of the fibers are centripetal, and are the direct continuations of the axis-cylinder processes of the cells of the ganglionic layer, but a few of them are centrifugal and ramify in the inner plexiform and inner nuclear layer
Inner nuclear layer
The inner nuclear layer or layer of inner granules is made up of a number of closely packed cells, of which there are three varieties, viz.: bipolar cells, horizontal cells, and amacrine cells.-Bipolar cells:...
s, where they end in enlarged extremities.
Patients with retinitis pigmentosa
Retinitis pigmentosa
Retinitis pigmentosa is a group of genetic eye conditions that leads to incurable blindness. In the progression of symptoms for RP, night blindness generally precedes tunnel vision by years or even decades. Many people with RP do not become legally blind until their 40s or 50s and retain some...
have abnormal thinning of the RNFL which correlates with the severity of the disease. However the thickness of the RNFL also decreases with age and not visual acuity. The sparing of this layer is important in the treatment of the disease as it is the basis for connecting retinal prostheses to the optic nerve, or implanting stem cells that could regenerate the lost photoreceptors.
RNFL is a sensitive structure. Some process can excites its natural apoptosis. Harmful situation can make some damage on RNFL such as high intraocular pressure, high fluctuation on phase of intraocular pressure, inflammation, vascular disease and any kind of hypoxia. Gede Pardianto (2009) reported 6 cases of RNFL thickness change after the procedures of phacoemulsification.