Nerve fiber layer

Nerve fiber layer
Section of retina. (Stratum opticum labeled at right, second from the top.)
Plan of retinal neurons. (Stratum opticum labeled at left, second from the top.)
Latin	stratum neurofibrarum retinae
Gray's	subject #225 1015

The retinal 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 layers, where they end in enlarged extremities.

Patients with retinitis pigmentosa have abnormal thinning of the RNFL which correlates with the severity of the disease.^[1] However the thickness of the RNFL also decreases with age and not visual acuity.^[2] 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.^[3]

References

1. ↑ Walia S, Fishman GA, Edward DP, Lindeman M. Retinal nerve fiber layer defects in RP patients. Invest Ophthalmol Vis Sci. 2007 Oct;48(10):4748-52. PMID 17898300
2. ↑ Oishi A, Otani A, Sasahara M, Kurimoto M, Nakamura H, Kojima H, Yoshimura N. Retinal nerve fiber layer thickness in patients with retinitis pigmentosa. Eye. 2008 Mar 14, online advance publication. PMID 18344951
3. ↑ Pardianto G, Mastering phacoemulsification in Mimbar Ilmiah Oftalmologi Indonesia.2009;10:26.

External links

• BU Histology Learning System: 07902loa

This article incorporates text from a public domain edition of Gray's Anatomy.

v t e Sensory system – visual system – globe of eye (TA A15.2.1–6, TH 3.11.08.0-5, GA 10.1005) Fibrous tunic (outer) Sclera Episcleral layer Schlemm's canal Trabecular meshwork Cornea Limbus layers Epithelium Bowman's Stroma Descemet's Endothelium Uvea/vascular tunic (middle) Choroid Capillary lamina of choroid Bruch's membrane Sattler's layer Ciliary body Ciliary processes Ciliary muscle Iris Stroma Pupil Iris dilator muscle Iris sphincter muscle Retina (inner) Layers Inner limiting membrane Nerve fiber layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer External limiting membrane Layer of rods and cones Retinal pigment epithelium Cells Photoreceptor cells (Cone cell, Rod cell) → (Horizontal cell) → Bipolar cell → (Amacrine cell) → Retina ganglion cell (Midget cell, Parasol cell, Bistratified cell, Giant retina ganglion cells, Photosensitive ganglion cell) → Diencephalon: P cell, M cell, K cell Muller glia Other Macula Foveola Fovea centralis Parafovea Perifovea Optic disc Optic cup Anterior segment Anterior chamber Aqueous humour Posterior chamber Lens Capsule of lens Zonule of Zinn Posterior segment Vitreous humour Other Asthenopia Keratocytes Ocular immune system Tapetum lucidum M: EYE anat (g/a/p)/phys/devp/prot noco/cong/tumr, epon proc, drug (S1A/1E/1F/1L)