optic chiasm

Also found in: Thesaurus, Medical, Encyclopedia, Wikipedia.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.optic chiasm - the crossing of the optic nerves from the two eyes at the base of the brain
chiasm, chiasma, decussation - an intersection or crossing of two tracts in the form of the letter X
References in periodicals archive ?
Twelve-year-old Poppy, from Tamworth, was diagnosed at 14 months old with Optic Chiasm Glioma, a brain tumour behind the eye, a condition which gave her a 50 per cent chance of survival.
Results showed equivalent plan quality, with dynamic jaws mode providing a more efficient delivery and better sparing of the optic chiasm, pituitary and parotid glands when compared to fixed jaw delivery mode.
The binasal field defects could be due to a defect in the normal sorting and segregation of retinal ganglion axon populations that decussate and those that remain ipsilateral upon entering the optic chiasm from the optic nerves.
The entire cyst was dissected carefully from the optic chiasm and cavenous sinus after Sylvian fissure dissection, but the calcified capsule of the cyst was removed subtotally.
The coalescence of multiple granulomas in the brain parenchyma can produce space-occupying lesions, most commonly in the optic chiasm, floor of the third ventricle, and pituitary stalk, but can occur anywhere in the CNS.
When abnormalities of the pituitary gland are visible, CT may reveal expansion and hyperdensity of the gland, which may be accompanied by mass effect on the suprasellar structures, including the optic chiasm (Figure 5).
Initial imaging revealed a space-occupying, non-enhancing lesion in the optic chiasm.
Surgery may be considered for patients who have pituitary incidentalomas if there is clinically significant growth of the lesion, loss of endocrino-logic function, or an "unremitting headache," or if a patient is planning a pregnancy and has a lesion close to the optic chiasm.
The SCN, located in the hypothalamus just above the optic chiasm, controls a person's circadian rhythm.
Visual defects occurred in some, secondary to pressure in the area of the optic chiasm from associated hydrocephalus.