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Clinical Anatomy (New York, N.Y.) Nov 2014The optic chiasm is formed when the optic nerves come together in order to allow for the crossing of fibers from the nasal retina to the optic tract on the other side.... (Review)
Review
The optic chiasm is formed when the optic nerves come together in order to allow for the crossing of fibers from the nasal retina to the optic tract on the other side. This enables vision from one side of both the eyes to be appreciated by the occipital cortex of the opposite side. This review makes note of the embryology, anatomy and vascular supply of the optic chiasm, then discusses the clinical syndromes associated with chiasmal disease, and the diseases which commonly influence its function.
Topics: Adenoma; Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis; Arachnoid Cysts; Central Nervous System Cysts; Craniopharyngioma; Glioma; Humans; Optic Chiasm; Optic Nerve Diseases; Optic Nerve Neoplasms; Pituitary Neoplasms; Sarcoidosis; Tuberculosis; Visual Fields; Visual Pathways
PubMed: 24824063
DOI: 10.1002/ca.22385 -
Asian Journal of Surgery Mar 2023
Topics: Humans; Optic Chiasm; Hand; Foot; Upper Extremity; Lower Extremity
PubMed: 36253264
DOI: 10.1016/j.asjsur.2022.08.121 -
Ophthalmic Plastic and Reconstructive... 2019
Topics: Anatomic Landmarks; Humans; Natural Orifice Endoscopic Surgery; Nose; Ophthalmologic Surgical Procedures; Optic Chiasm; Sphenoid Bone; Terminology as Topic
PubMed: 31283690
DOI: 10.1097/IOP.0000000000001394 -
Journal of the Neurological Sciences Apr 2017Vision loss is a disabling complication of tuberculous meningitis. Approximately, 15% of survivors are either completely or partially blind. All structures of the visual... (Review)
Review
Vision loss is a disabling complication of tuberculous meningitis. Approximately, 15% of survivors are either completely or partially blind. All structures of the visual pathway may be affected in tuberculous meningitis. Optic nerve and optic chiasma are most frequently and dominantly affected. Thick-gelatinous exudates lying over the base of brain, are the pathological hallmark of tuberculous meningitis and are responsible for almost all of its major complications, including vision loss. Strangulation of optic nerves and optic chiasma by the exudates, compression over optic chiasma by the dilated third ventricle, raised intracranial pressure, endarteritis, shunt failure, bacterial invasion of optic nerves and drug-induced optic nerve damage are important reasons that are considered responsible for vision loss. Prompt antituberculosis treatment is the best management option available. Immunomodulatory drugs and cerebrospinal fluid diversion procedures are of limited help. Early recognition and treatment of tuberculous meningitis is the only way forward to tackle this problem.
Topics: Blindness; Humans; Optic Chiasm; Optic Nerve; Tuberculosis, Meningeal
PubMed: 28320145
DOI: 10.1016/j.jns.2017.01.031 -
Acta Neurochirurgica 1995Two cases of cavernous malformation of the optic chiasm are reported, and 12 previously reported cases are reviewed. The first patient presented with gradually... (Review)
Review
Two cases of cavernous malformation of the optic chiasm are reported, and 12 previously reported cases are reviewed. The first patient presented with gradually progressive and the second patient with a subacute chiasmal syndrome. Total excision was performed in both cases. Visual function improved slightly after surgery in the first patient while the other showed marked improvement. Although cavernous malformations are angiographically occult, pre-operative diagnosis has become possible based on the characteristic features such as repeated haemorrhages in multiple sinusoidal structures as revealed by magnetic resonance imaging (MRI). A gliotic interspace between the malformation and normal neural tissue provides a plane of cleavage for dissection which permits total excision without causing new deficits. Review of previously reported cases revealed that chiasmal cavernous malformations haemorrhage more frequently than those in the brain. Early diagnosis with total excision is the treatment of choice for cavernous malformations of the optic chiasma.
Topics: Adolescent; Cranial Nerve Neoplasms; Diagnosis, Differential; Female; Hemangioma, Cavernous; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Optic Chiasm; Optic Nerve Diseases; Postoperative Complications; Treatment Outcome; Visual Fields
PubMed: 8748824
DOI: 10.1007/BF01411432 -
Asian Journal of Surgery Feb 2024
Topics: Humans; Optic Chiasm; Optic Nerve; Foot; Lower Extremity
PubMed: 37945403
DOI: 10.1016/j.asjsur.2023.10.090 -
Journal Francais D'ophtalmologie Jan 2021The optic chiasm is an essential anatomical structure in neuro-ophthalmology. The systematization of the visual pathways results from the arrangement of the retinal... (Review)
Review
The optic chiasm is an essential anatomical structure in neuro-ophthalmology. The systematization of the visual pathways results from the arrangement of the retinal ganglion cell fibers. It explains the signs of chiasmal syndrome. A good knowledge of the anatomy permits to correlate visual field defects with imaging results. It is now possible to map the organization of the ganglion cell fibers within the chiasm. Their hemidecussation allows for stereoscopic vision in humans. The causes of chiasmal syndrome are multiple, but tumors and compressive causes predominate. The proximity of the pituitary region to the chiasm accounts for the frequency of chiasmal syndrome, which involves ophthalmologists not only through dysfunction of the visual pathway, which may be the presenting sign, but also through possible complications throughout the course of the disease. This review aims to synthesize the embryology, anatomy and principles of work-up for chiasmal syndrome as well as its many possible causes.
Topics: Cranial Nerve Diseases; Humans; Magnetic Resonance Imaging; Neoplasms; Optic Chiasm; Vision Disorders; Visual Field Tests
PubMed: 33183775
DOI: 10.1016/j.jfo.2020.07.004 -
Handbook of Clinical Neurology 2011In the first part of this chapter the anatomy and vascular supply of the chiasm are recounted, and the visual symptoms that may arise in chiasmal disease are noted. The... (Review)
Review
In the first part of this chapter the anatomy and vascular supply of the chiasm are recounted, and the visual symptoms that may arise in chiasmal disease are noted. The neuro-ophthalmic signs, including the pattern of visual field defects, appearance of the optic disc, and various uncommon clinical accompaniments, are described. The second part deals with a comprehensive list of disease processes that may directly or indirectly affect the chiasm. These are divided into inflammatory disorders, including sarcoidosis, multiple sclerosis, and idiopathic chiasmitis; infective disorders, including tuberculosis; and a large section on tumors, including pituitary adenomas, cysts, and choristomas, malignant disorders, including germ cell tumors and glioma, and meningioma; and finally vascular disorders and compression due to hydrocephalus. In each case the clinical features and management of the disorder are noted, as well as the prognosis for visual improvement following treatment.
Topics: Humans; Magnetic Resonance Imaging; Optic Chiasm; Optic Nerve Diseases; Vision Disorders; Visual Fields
PubMed: 21601067
DOI: 10.1016/B978-0-444-52903-9.00013-3 -
Journal of Neuro-ophthalmology : the... Sep 2018In evaluating a 3-month-old boy with horizontal nystagmus, brain MRI revealed absence of the optic chiasm. The remainder of the brain was normal in appearance. Achiasma...
In evaluating a 3-month-old boy with horizontal nystagmus, brain MRI revealed absence of the optic chiasm. The remainder of the brain was normal in appearance. Achiasma was confirmed with diffusion tensor imaging and best visualized with optimized probabilistic-based tractography.
Topics: Diffusion Magnetic Resonance Imaging; Follow-Up Studies; Humans; Infant; Male; Optic Chiasm; Optic Nerve Diseases; Visual Acuity
PubMed: 29561327
DOI: 10.1097/WNO.0000000000000650 -
Neurologia Medico-chirurgica Sep 2019Optic nerve avulsion is an exceedingly rare condition. Here, we describe a case of optic nerve avulsion in a 74-year-old man with temporal hemianopia in the...
Optic nerve avulsion is an exceedingly rare condition. Here, we describe a case of optic nerve avulsion in a 74-year-old man with temporal hemianopia in the contralateral eye after a bear attack. Magnetic resonance imaging (MRI) revealed separation of the optic nerve distal to the optic chiasma, whereas the high signal in diffusion-weighted imaging suggested nerve injury from the left side of the optic chiasma to the left optic tract. MRI slices parallel to the optic chiasma were obtained and used for evaluating the site of optic nerve avulsion and nerve injury, which were responsible for temporal hemianopia in the contralateral eye.
Topics: Aged; Animals; Animals, Wild; Crush Injuries; Diagnosis, Differential; Diffusion Magnetic Resonance Imaging; Facial Injuries; Hemianopsia; Humans; Magnetic Resonance Imaging; Male; Optic Chiasm; Optic Nerve Injuries; Ursidae
PubMed: 31231085
DOI: 10.2176/nmc.cr.2019-0035