optic nerve

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Related to Optic nerves: Cranial nerves, Olfactory nerves

optic nerve:

see visionvision,
physiological sense of sight by which the form, color, size, movements, and distance of objects are perceived. Vision in Humans

The human eye functions somewhat like a camera; that is, it receives and focuses light upon a photosensitive receiver, the retina.
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Optic Nerve

 

(nervus opticus), the second pair of cranial nerves, along which visual stimuli received by the sensory cells of the retina are transmitted to the brain.

The optic nerve is not a typical cranial nerve in structure, but is like brain matter transported to the periphery and connected with the nuclei of the diencephalon, and through them also with the cortex of the large hemispheres. The optic nerve originates in the ganglial cells of the retina. Processes of these cells gather into the optic disk (or papilla), which is located 3 mm closer to the middle from the posterior pole of the eye. Farther on, the bundles of nerve fibers penetrate the sclera in the region of the lamina cribrosa and are surrounded by meningeal structures, forming a compact nerve trunk. Located among the bundles of fibers of the optic nerve are the central artery of the retina and the analogous vein. Together with the ophthalmic artery, the optic nerve passes into the cranial cavity through the optic canal, which is formed by a small wing of the sphenoid bone. Within the cranial cavity, the optic nerve goes from each eye toward the posterior and closer to the middle for about 1 cm, and then approaches the optic nerve of the opposite side over the sella turcica of the sphenoid bone; anterior to the hypophysis the optic chiasma is formed, where there is a crossover only of the axons of the cells of the nasal half of the retina. After the chiasma, the optic nerve continues into the optic tracts.

V. V. KUPRIIANOV

optic nerve

[′äp·tik ‚nərv]
(neuroscience)
The second cranial nerve; a paired sensory nerve technically consisting of three layers of special nerve cells in the retina of the eye; fibers converge to form the optic tracts.
References in periodicals archive ?
We can see the endsurface of the optic nerve as it exits from the eye to connect the brain inside the skull with the same instrument we use for examining the inside of the eye.
Approaches that stimulate JAK-STAT and mTOR signaling, such as inflammatory stimuli or genetic deletions of PTEN and/or SOCS3, promoted pronounced regeneration within the optic nerve [9-11], and when these approaches were combined, there was a partial restoration of the visual function [12].
Ischemic infarction of the retrolaminar optic nerve with variable involvement of laminar and prelaminar regions characterizes both arteritic and nonarteritic anterior ION.
The left eye initially had normal optic nerve function tests and visual field, but the colour vision deteriorated two days after his initial presentation.
Neurofilament staining was used to evaluate axonal loss in sections of optic nerves isolated at day 42 postimmunization.
The optic nerve head (ONH) size is not consistent among individuals and shows an interindividual variability in the area ranging from about 0.80 [mm.sup.2] to almost 6.00 [mm.sup.2] in a normal Caucasian population [5].
of Patients Percentage 16-20 7 6.93 21-40 62 61.38 41-60 26 25.75 >60 6 5.94 Total 101 100 Table 3: Type I Optic Nerves Involvement No.
Semithin cross sections of rat optic nerves. Ai and Aii, Normal optic nerve having several bundles of nerve fibers among septa within astrocytic processes (arrows).
Magnetic Resonance Imaging (MR) (Figure 1, B) revealed mild left proptosis with diffuse inflammatory enhancement of the intraconal fat and optic nerve sheath spanning mid orbit to apex.
In response to this situation, pediatric neuroophthalmologist Mark Borchert, director of both the Eye Birth Defects and Eye Technology Institutes in the Vision Center at Children's Hospital Los Angeles, realized that a controlled trial of sufficient size was needed to evaluate whether stem cell therapy is effective at improving optic nerve function in children with ONH.
Optic disc drusen (ODD) are congenital and developmental anomalies characterized by calcific degeneration of the optic nerve head.
Justyna said: "Only stem cells can help her optic nerves grow and give her sight.