• The acuity of central vision (at the optic disc) was explained by the concentration of visual spirit where the optic nerve met the retina. (nature.com)
  • The job of the optic nerve is to transfer visual information from the retina to the vision centers of the brain via electrical impulses. (healthline.com)
  • Our blind spot is caused by the absence of specialized photosensitive (light-sensitive) cells, or photoreceptors, in the part of the retina where the optic nerve exits the eye. (healthline.com)
  • In the case of such partial decussation, the optic nerve fibres on the medial sides of each retina (which correspond to the lateral side of each visual hemifield, because the image is inverted) cross over to the opposite side of the body midline. (wikipedia.org)
  • The inferonasal retina are related to the anterior portion of the optic chiasm whereas superonasal retinal fibers are related to the posterior portion of the optic chiasm. (wikipedia.org)
  • Ephrin-B2 is expressed at the chiasm midline by radial glia and acts as a repulsive signal to axons originating from the ventrotemporal retina expressing EphB1 receptor protein, giving rise to the ipsilateral, or uncrossed, projection. (wikipedia.org)
  • The optic chiasm is a key structure in the visual system, where the fate of axons from the retina is decided, such that axons carrying information from the right visual hemifield are guided to the left hemisphere and vice versa. (frontiersin.org)
  • The optic pathway includes the retina, optic nerve, optic chiasm, optic radiations, and occipital cortex (see figure Higher visual pathways). (merckmanuals.com)
  • The crossed and uncrossed fibres of the optic chiasma differ not only anatomically in the areas of retina in which they arise but also physically. (bmj.com)
  • Direct ophthalmoscopy revealed diffuse hyperemia and edema of the optic disc in both the eyes with a normal macula and retina, suggestive of bilateral papillitis. (pediatriconcall.com)
  • As a consequence, a great number of fibers from the temporal retina cross the midline at the optic chiasm and project contralaterally. (arvojournals.org)
  • Beyond the optic chiasm, with crossed and uncrossed fibers, the optic nerves are called optic tracts. (wikipedia.org)
  • additionally reporting thinner optic nerves and wider angles between optic tracts. (frontiersin.org)
  • Brain tumor and its treatment can affect the visual system at different levels, from the optic nerves (through compression or infiltration), to subcortical structures like the superior colliculus (SC) and lateral geniculate nuclei (LGN) to optic tracts, optic radiations, and visual cortices ( 1 - 4 ). (frontiersin.org)
  • Any tumor that grows out of the pituitary can compress optic nerve tracts, including the chiasm. (merckmanuals.com)
  • This patient does have NF-I, but only about one fourth of patients with optic gliomas have NF-I. They commonly involve the optic chiasm and extend posteriorly to involve optic tracts and radiations, as in this case. (uab.edu)
  • In such a merged optic chiasm, part of the nerve fibres do not cross the midline, but continue towards the optic tract of the ipsilateral side. (wikipedia.org)
  • The optic tract inserts on the optic tectum (in mammals known as superior colliculus) of the midbrain. (wikipedia.org)
  • Contralateral axons cross the chiasm midline as they progress from the optic nerve to the optic tract. (umontreal.ca)
  • In contrast, ipsilateral axons deviate from the chiasm and continue in the ipsilateral optic tract. (umontreal.ca)
  • What does disruption of the right optic tract cause? (freezingblue.com)
  • A midline crossing of nerves inside the brain is called a decussation (see Definition of types of crossings). (wikipedia.org)
  • In all vertebrates, the optic nerves of the left and the right eye meet in the body midline, ventral to the brain. (wikipedia.org)
  • Ssh expressed at the central nervous system midline inhibits crossing prior to the chiasm, where it is downregulated. (wikipedia.org)
  • RGC axons that do cross at the optic chiasm are guided by the vascular endothelial growth factor, VEGF-A, expressed at the midline, which signals through the receptor Neuropilin-1 (NRP1) expressed on RGC axons. (wikipedia.org)
  • Chiasm crossing is also promoted by Nr-CAM (Ng-CAM-related cell adhesion molecule) and Semaphorin6D (Sema6D) expressed at the midline, which form a complex that signals to Nr-CAM/Plexin-A1 receptors on crossing RGC axons. (wikipedia.org)
  • Together with the presence of Shh at the midline, this complementary expression pattern led us to hypothesize that Shh might repel ipsilateral RGC axons at the chiasm. (umontreal.ca)
  • The disorder is ophthalmoscopically distinct from optic nerve hypoplasia. (molvis.org)
  • Septo-optic dysplasia (SOD) , also known as de Morsier syndrome , is a condition characterized by optic nerve hypoplasia and absence of the septum pellucidum and, in two-thirds of patients hypothalamic-pituitary dysfunction . (radiopaedia.org)
  • Rudimentary optic nerve on neuroimaging in one case suggests that ONA is on the continuum of optic nerve hypoplasia. (bvsalud.org)
  • Sometimes a pituitary tumor affects the optic nerve on just one side. (xshotpix.com)
  • When a pituitary tumor pushes the optic chiasm, it causes visual loss in both eyes. (xshotpix.com)
  • If a pituitary tumor is strongly suspected, your doctor may refer you to an eye doctor to check your vision, as pituitary tumors can damage nerves leading to the eyes. (xshotpix.com)
  • Eyeglasses do not correct visual loss that occurs when a pituitary tumor has affected the optic nerves or optic chiasm. (xshotpix.com)
  • If a pituitary tumor pushes one of these nerves, it causes weakness of some of the muscles that move the eye. (xshotpix.com)
  • The two optic nerves meet at the optic chiasm, which is an area behind the eyes immediately in front of the pituitary gland and just below the front portion of the brain (cerebrum). (msdmanuals.com)
  • The optic chiasm lies in close proximity to the pituitary gland and can be compressed by tumors leading to visual disturbances (bitemporal hemianopsia) [6]. (bvsalud.org)
  • Diamox, Lasix, corticosteroids), and disc swelling with visual field loss progresses, direct fenestration of the optic nerve sheaths via medial or lateral orbitotomy has been shown to be an effective and relatively simple procedure for relief of papilledema. (aetna.com)
  • The anterior and posterior attachments of the medial and lateral fibres of the nerves have been studied. (bmj.com)
  • 1. The adenohypophysis caudal to the optic chiasma and medial to the internal carotid artery and trigeminal ganglion. (ehd.org)
  • There is a main split at the optical chiasma , with roughly half of each nerve, possibly corresponding to blanking the medial nasal hemispheres of vision. (wdv.com)
  • T1 weighted axial MRI after gadolinium reveals an enhancing mass at the base of the brain extending into the orbital optic nerves, midbrain, and medial left temporal lobe. (uab.edu)
  • The researchers found significant abnormalities within the visual system brain structures of Parkinson's disease patients, including alterations of optic radiations, a reduction of white matter concentration and a reduction of optic chiasm volume. (eurekalert.org)
  • The gross anatomy of the optic nerves and chiasma has been studied, and differences in the tension in the crossed and uncrossed fibres after chiasmal displacement have been investigated. (bmj.com)
  • Optic nerve aplasia (ONA, OMIM 165550) is a very rare unilateral or bilateral condition that leads to blindness in the affected eye, and is usually associated with other ocular abnormalities. (molvis.org)
  • Optic nerve aplasia (ONA, OMIM #165550 ) is a very rare congenital anomaly that can be unilateral or bilateral. (molvis.org)
  • Fig. 1) Visual Evoked Potential (VEP) showed bilateral demyelination of the optic nerves. (pediatriconcall.com)
  • bilateral optic nerve involvement and optic chiasm compression further add to the complexity of the surgical decision-making process. (medscape.com)
  • Retinal ganglion cell (RGC) axons leaving the eye through the optic nerve are blocked from exiting the developing pathway by Slit2 and Sema5A inhibition, expressed bordering the optic nerve pathway. (wikipedia.org)
  • Damage along the optic pathway causes a variety of visual field defects. (merckmanuals.com)
  • Damage to the optic pathway or visual cortex in the left brain-perhaps from a stroke-can cause complete loss of the right visual field. (jrank.org)
  • Methods The authors performed a retrospective analysis of 45 patients with anterior and middle fossa meningiomas with involvement of the optic pathway in whom surgery was performed by the senior author (O.A.M.) during the period from 1993 to 2007. (medscape.com)
  • The growth of anatomy and influence of mechanical philosophy from the 17th century led to visual spirit being replaced with the concept of nerve force, which later became associated with electricity travelling along nerve fibres. (nature.com)
  • The partial crossing over of optic nerve fibres at the optic chiasm allows the visual cortex to receive the same hemispheric visual field from both eyes. (wikipedia.org)
  • Bitemporal hemianopia, as well as associated or independent hemianopic scotomata, results from stretching of the crossing fibres in the chiasma. (bmj.com)
  • Binasal hemianopia results from compression of the uncrossed fibres in the optic nerve or chiasma by the anterior cerebral or internal carotid arteries. (bmj.com)
  • The rest of the story of visualization is much more complex because it involves bundles of nerves whose interactions are not fully understood. (allaboutvision.com)
  • The mass in combination with retinal detachment obscured clear visualization of optic nerve disc and macula. (ajnr.org)
  • Optic neuritis is an inflammatory injury of the optic nerve that causes vision loss, which is common in MS and other CNS inflammatory disorders. (medscape.com)
  • Over the past few years, there has been remarkable development in the area of optic neuritis. (lww.com)
  • Antiaquaporin4 antibodies and antimyelin oligodendrocytes antibodies are now considered as distinct entities of optic neuritis with their specific clinical presentation, neuroimaging characteristics, treatment options, and course of the disease. (lww.com)
  • Similarly, there has been a substantial change in the treatment of optic neuritis which was earlier limited to steroids and interferons. (lww.com)
  • The development of new immunosuppressant drugs and monoclonal antibodies has reduced the relapses and improved the prognosis of optic neuritis as well as an associated systemic disease. (lww.com)
  • This review article tends to provide an update on the approach and management of optic neuritis. (lww.com)
  • The landscape of optic neuritis (ON) is rapidly changing with the discovery of new antibodies, advent of latest investigations, and revised diagnostic criteria. (lww.com)
  • We searched PubMed and Medline for studies published during the last 10 years with the general term "optic neuritis" and specific terms like "typical optic neuritis," "atypical optic neuritis," "multiple sclerosis," "neuromyelitis optic neuritis," and "myelin oligodendrocyte glycoprotein antibody. (lww.com)
  • Mitra S, Samanta M, Sarkar M, Chatterjee S. Isolated Demyelinating Optic Neuritis in Neurotuberculosis. (pediatriconcall.com)
  • Isolated demyelinating optic neuritis is a rare presenting feature of neurotuberculosis in the pediatric population. (pediatriconcall.com)
  • Most of the optic neuritis cases that are reported in pediatric tuberculosis are usually associated with other focal neurodeficits or follow anti-tubercular therapy, especially ethambutol . (pediatriconcall.com)
  • He was diagnosed with demyelinating optic neuritis with evidence of neurotuberculosis and was managed successfully with anti-tubercular drug therapy and corticosteroids. (pediatriconcall.com)
  • Being an endemic country, neurotuberculosis should be considered as a potential cause of demyelinating optic neuritis in the pediatric population. (pediatriconcall.com)
  • MRI brain revealed bilaterally swollen optic nerves and diffuse high signal intensities in the region of the optic nerves and optic chiasma on T2 weighted images suggestive of optic neuritis. (pediatriconcall.com)
  • Non-arteritic anterior ischemic optic neuropathy (NAION) is a common cause of sudden loss of vision, especially in the elderly. (aetna.com)
  • It is caused by infarction of the short posterior ciliary arteries supplying the anterior optic nerve. (aetna.com)
  • The brain is the anterior part of the central nervous system, which is based on a nerve cell. (abchealthonline.com)
  • Visual disturbance due to optic nerve compression is the initial presentation for many patients with anterior and middle fossa meningiomas. (medscape.com)
  • The fact that the CNN recognition of the optic chiasm fails for chiasm abnormalities in PWA underlines the fundamental differences in their spatial features. (frontiersin.org)
  • Total aplasia of the left optic nerve was not combined with other congenital central nervous system (CNS) abnormalities. (ajnr.org)
  • We report a 6-month-old boy who presented with unilateral leukocoria, retinal detachment, and a retrolental mass in a microphthalmic eye based on retinal dysplasia with concurrent optic nerve aplasia. (ajnr.org)
  • We report MR imaging findings of unilateral retinal dysplasia with concurrent optic nerve aplasia. (ajnr.org)
  • OBJECTIVE: Optic nerve aplasia (ONA) is a rare ocular anomaly. (bvsalud.org)
  • They are the most common astrocytic tumors in children, accounting for 80-85% of cerebellar astrocytomas and 60% of optic gliomas. (medscape.com)
  • Decompression of the optic canal and removal of the tumor inside is a crucial step in the surgical management of these tumors to optimize visual recovery and prevent tumor recurrence. (medscape.com)
  • Optic nerve decompression surgery (also known as optic nerve sheath decompression surgery) involves cutting slits or a window in the optic nerve sheath to allow cerebrospinal fluid to escape, thereby reducing the pressure around the optic nerve. (aetna.com)
  • Initial results of uncontrolled studies suggested that optic nerve sheath decompression was a promising treatment of progressive visual loss in patients with NAION. (aetna.com)
  • The optic nerve and sheath complex were not visible within the left orbit or anywhere along the usual course of the nerve ( Fig 2 ). (ajnr.org)
  • The first step of this integration is possible anatomically with the segregation of contralateral and ipsilateral axons at the optic chiasm. (umontreal.ca)
  • In vivo, we show that Boc is required for the normal segregation of ipsilateral axons at the optic chiasm and, conversely, that Boc expression in contralateral RGCs prevents their axons from crossing the optic chiasm. (umontreal.ca)
  • We will trace the history of ideas about optic nerve anatomy and function in the Western world from the ancient Greeks to the early 20th century and show how these influenced causal theories of optic nerve diseases. (nature.com)
  • According to the Greek physician,Galen (CE 129-c.216), whose influence on anatomy prevailed in the Western world until the 16th century, nerve 'channels' were described by Herophilus (c.330-260 BCE) 3 and Erasistratus (c.330-255 BCE), 4 the first documented human anatomists who taught in Hellenistic Alexandria. (nature.com)
  • Additional complications include cranial nerve palsies, hydrocephalus, and apoplexy (from hemorrhage/infarction into the tumor). (medscape.com)
  • There was no evidence of any other cranial nerve involvement. (pediatriconcall.com)
  • The neurological symptoms are due to compression or invasion of adjacent structures, such as the optic nerve, causing visual involvement [10]. (bvsalud.org)
  • Juvenile pilocytic astrocytomas usually arise in the cerebellum, brainstem, hypothalamic region, or optic pathways, but they may occur in any area where astrocytes are present, including the cerebral hemispheres and the spinal cord. (medscape.com)
  • Optic gliomas are usually pilocytic astrocytomas. (uab.edu)
  • Clinical presentation of septo-optic dysplasia is varied and mostly dependent on whether or not it is associated with schizencephaly (~50% of cases). (radiopaedia.org)
  • To resolve the controversy over the effectiveness of optic nerve decompression for NAION, the National Eye Institute sponsored the Ischemic Optic Neuropathy Decompression Trial, a multicenter, randomized controlled clinical trial of optic nerve decompression surgery for patients with NAION. (aetna.com)
  • In vertebrates with a large overlap of the visual fields of the two eyes, i.e., most mammals and birds, but also amphibians, reptiles such as chameleons, the two optic nerves merge in the optic chiasm. (wikipedia.org)
  • In other cases, it affects a structure known as the "optic chiasm," where the optic nerves from each eye merge together. (xshotpix.com)
  • The investigators concluded that optic nerve decompression surgery is not an effective treatment for NAION, and in fact, may increase the risk of progressive visual loss in NAION patients. (aetna.com)
  • A structured evidence review (Dickersin and Manheimer, 2002) concluded that "[r]esults from the Ischemic Optic Neuropathy Decompression Trial indicate that optic nerve decompression surgery for nonarteritic ischemic optic neuropathy is not effective. (aetna.com)
  • A Cochrane review (Dickersin et al, 2012) concluded that results from the single trial indicate no evidence of a beneficial effect of optic nerve decompression surgery for NAION. (aetna.com)
  • In this study we review 45 patients with meningiomas extending into the optic canal, and we discuss the pattern of involvement of the canal and implications for method of decompression as well as the outcome. (medscape.com)
  • Glaucoma is one of the most common illnesses affecting the optic nerve. (healthline.com)
  • The optic chiasm volume differed significantly between the control and advanced NTG groups ( p = 0.0003) and between early and advanced glaucoma patients ( p = 0.004). (mdpi.com)
  • Juxtasellar meningiomas frequently extend into the optic canal. (medscape.com)
  • Removing these meningiomas from the optic canal is crucial for favorable visual outcome. (medscape.com)
  • Involvement of the optic canal in meningiomas is frequent. (medscape.com)
  • Cite this: Meningiomas Involving the Optic Canal - Medscape - May 01, 2011. (medscape.com)
  • In his physiology of the nervous system, psychic pneuma was collected in the ventricles of the brain and distributed through the nerves to all parts of the body to provide them with sensation and motion. (nature.com)
  • from Greek χίασμα 'crossing', from Ancient Greek χιάζω 'to mark with an X'), is the part of the brain where the optic nerves cross. (wikipedia.org)
  • The optic chiasm is found in all vertebrates, although in cyclostomes (lampreys and hagfishes), it is located within the brain. (wikipedia.org)
  • Located along the nerves connecting the nose to the brain. (aans.org)
  • The optic chiasm is the part of the brain where the left and right optic nerves intersect. (eurekalert.org)
  • Before we talk about the nerves and the brain, however, we have to talk about the optic mechanisms in the eyes that help send photons where they need to go to produce eyesight. (allaboutvision.com)
  • An MRI of the brain was performed and showed cavum septum pellucidum and verge as well as small optic nerves and chiasma. (hindawi.com)
  • Thus, the right side of the brain receives information through both optic nerves for the left field of vision, and the left side of the brain receives information through both optic nerves for the right field of vision. (msdmanuals.com)
  • it is the point at which many of the nerves from the left part of the body cross to the right side of the brain and vice versa. (medscape.com)
  • image: Left and right optic radiation (OR) image in a representative subject overlaid onto a T1-weighted axial volume image of the same subject. (eurekalert.org)
  • What does complete capsular destruction of R optic radiation cause? (freezingblue.com)
  • There is no direct treatment for NAION, although corticosteroids are sometimes used to reduce optic nerve edema. (aetna.com)
  • In many vertebrates the left optic nerve crosses over the right one without fusing with it. (wikipedia.org)
  • At 24 months, he had an ophthalmologic exam which showed left eye esotropia and amblyopia and anomalous optic nerves with the left being smaller than the right. (hindawi.com)
  • 3 He admitted that cobweb-thin nerves might not possess a lumen but those in the optic nerves ( poroi optikoi -optic channels) were large enough to be visible and to be probed with a hog bristle. (nature.com)
  • Since all vertebrates, even the earliest fossils and modern jawless ones, possess an optic chiasm, it is not known how it evolved. (wikipedia.org)