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Results for “Optic Chiasm”

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At least 19 recordsLinked to original sources
PubMed1979

Cavernous hemangioma of optic chiasm, optic nerves and right optic tract. Case report and review of literature.

Diminishing right ocular visual acuity for three weeks in a 30 year old man was confirmed by examination. Bilateral scotomata and bitemporal hemiachromatopsia indicated a chiasmal lesion; reduced visual acuity and Marcus Gunn pupil of the right eye and left relative temporal hemianopia indicated asymmetric involvement. Erythrocytes in the CSF verified a suspected subarachnoid bleed; contrast-enhanced CAT scan demonstrated a suprasellar mass. A cystic, multiloculated, bluish mass distorted the right optic nerve, tract, and chiasm. A hematoma was evacuated and biopsy revealed a cavernous hemangioma of the right optic nerve. Post-operatively, visual acuity has recovered in the right eye but a left homonymous temporal hemianopia has developed.

Adult↗
PubMed1979

Surgical lesions of the intracranial optic nerves and optic chiasm.

Compressive tumors and vascular lesions affecting the intracranial optic nerves and optic chiasm are of interest to both the neurosurgeon and the neuro-ophthalmologist. Common types of tumors that occur in the chiasmal and parasellar regions are discussed in terms of their course, neuro-ophthalmologic implications, and surgical treatment by the transsphenoidal approach as opposed to the standard subfrontal approach. Vascular lesions that cause visual distrubances, including intracranial aneurysms and arteries acting as compressive lesions of the chiasm and nerves or in conjunction with tumors, are discussed.

Aneurysm↗
PubMed1977

Pathological changes in the optic chiasm of the cat following local injection of diphtheria toxin.

The optic chiasm in 14 cats was injected stereotactically with small amounts of diphtheria toxin and the morphological changes were examined by light and electron microscopy. Phagocytosis was already well-marked at 3 hr after injection and massive at 1 week. Intercellular oedema was extensive in the first week and, though diminished, was still present after 1 month. The oedema was most marked in the subendothelial regions in the early stages but was found among the nerve fibres and glial processes in those animals which survived for longer periods. Demyelination and Wallerian-type degeneration were established at 3 hr after injection and both processes continued up to 2 months and beyond. Scarring and an absolute loss of nerve fibres were present in the longer-surviving animals. Unequivocal evidence of remyelination was not obtained.

Animals↗
PubMed1978

Venous angioma of the optic chiasm.

A 30-year-old man presented with decreased vision in the right eye of three weeks' duration. Examination indicated a chiasmal syndrome and evidence of subarachnoid hemorrhage. CAT scan showed a large suprasellar mass. Surgical intervention confirmed the presence of a globular lesion filled with blood clots involving mainly the right side of the optic chiasm. Following removal of the clots, the chiasm regained its shape and anatomical landmarks. Biopsy of the mass demonstrated a venous angioma located within the optic chiasm as well as recent and old bleeding. Following surgery the patient did well and recovered vision in the right eye, though a left homonymous hemianopia persisted.

Adult↗
PubMed1975

Polytomoencephalography of the optic chiasm and adjacent structures.

The addition of polytomography considerably increases the sensitivity of pneumoencephalography. The chiasmatic area lends itself particularly well to investigation by polytomoencephalography. In a series of 28 patients, the transverse dimension of the optic chiasm ranged from 4 to 20 mm, with a mean of 18 mm. The posterior portion of the chiasm tended to be U-shaped; its anterior portion's shape was that of a dumbbell. Intrachiasmatic tumors distort and enlarge the chiasm. The diaphragma sella is also particularly well evaluated by this technique. The study is safe, reliable, and can be repeated as needed.

Adolescent↗
PubMed1979

A route for direct retinal input to the preoptic hypothalamus: dendritic projections into the optic chiasm.

With the use of Golgi, horseradish peroxidase, and electron microscopic techniques, neurons within a broad region of the preoptic hypothalamus of the mouse were shown to have dendrites that projected well into the depths of the optic chiasm. Further experimental and ultrastructural investigation demonstrated synapses between these dendrites and retinal axonal boutons within the chiasm. All synapses located in the chiasm were classified as Gray's type I. The possible function of these dendritic projections is discussed.

Animals↗
PubMed1979

Convergence of sensory input from tooth pulp, optic chiasm and sciatic nerve onto locus coeruleus neurons in the rat.

Electrophysiological studies using rats were performed to determine whether or not neurons in the locus coeruleus (LC), subcoeruleus and parabrachial areas receive convergence of sensory input from tooth pulp (TP), optic chiasm (OC) and sciatic nerve (SN). Convergence of input from these nerves was observed in 23% and 33% of LC and subcoeruleus neurons, respectively, and from two nerves in 31% and 20% of LC and subcoeruleus neurons, respectively, while convergence was rarely detected in parabranchial neurons. These results suggest that there is a convergence of peripheral sensory input onto more than half the noradrenergic coerulear neurons.

Animals↗
PubMed1977

Anatomic considerations for computed tomography of the optic chiasm.

When the clinical distinction between lesions of the optic nerves or the chiasm is not apparent, computed tomographic scans should be performed at both 0 degrees and 25 degrees or 35 degrees to the orbital-meatal line (Reid's baseline). The former plane is preferable for the demonstration of the optic nerves or orbital structures, while the latter allows superior visualization of perichiasmatic structures.

Female↗