| vascular circle of optic nerve | <anatomy, nerve> A network of branches of the short ciliary arteries on the sclera around the point of entrance of the optic nerve. Synonym: circulus vasculosus nervi optici, circulus arteriosus halleri, circulus zinnii, Haller's circle, Zinn's corona, Zinn's vascular circle. (05 Mar 2000) |
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| glioma of optic chiasm | A slow-growing tumour, usually an astrocytoma, of the optic chiasm in children. (05 Mar 2000) |
| medial root of optic tract | The smaller division of the posterior end of the optic tract that disappears under the medial geniculate body. Synonym: radix medialis tractus optici. (05 Mar 2000) |
| Graves' optic neuropathy | Visual dysfunction due to optic nerve compression in Graves' orbitopathy. (05 Mar 2000) |
| pigment epithelium of optic retina | pigmented part of retina |
| postlaminar part of optic nerve | <anatomy, nerve> The portion of the optic nerve posterior to the lamina cribrosa of the sclera. Synonym: pars postlaminaris nervi optici. (05 Mar 2000) |
| prelaminar part of optic nerve | <anatomy, nerve> The portion of the optic nerve anterior to the lamina cribrosa of the sclera. Synonym: pars prelaminaris nervi optici. (05 Mar 2000) |
| principal optic axis | A line passing through the centre of the lens of a refracting system at right angles to its surface. (05 Mar 2000) |
| septo-optic dysplasia | <radiology> Blindness, hypopituitarism, hypoplastic optic nerves, optic chiasm rotated 90 degrees, bulbous 3rd ventricle, CT findings: absent septum pellucidum, small optic nerves (12 Dec 1998) |
| neural layer of optic retina | See: retina. (05 Mar 2000) |
| neuroma, optic | A benign tumour of the optic nerve. (12 Dec 1998) |
| drusen of the optic nerve head | Basophilic, laminated, calcareous acellular masses that resemble crystals within the nerve head, anterior to the lamina cribrosa, that may simulate papilledema and/or cause visual field defects. Synonym: intrapapillary drusen. (05 Mar 2000) |
| dural sheath of optic nerve | <anatomy, nerve> The outer sheath around the optic nerve, continuous with the dura mater. Synonym: vagina externa nervi optici, dural sheath of optic nerve. (05 Mar 2000) |
| internal sheath of optic nerve | <anatomy, nerve> The innermost sheath around the optic nerve, continuous with the leptomeninges (pia-arachnoid) and including a cerebrospinal fluid-filled intervaginal space, continuous with the subarachnoid space. Synonym: vagina interna nervi optici. (05 Mar 2000) |
| intersheath spaces of optic nerve | <anatomy, nerve> The spaces within the internal sheath of the optic nerve, between the arachnoidal and pial layers, filled with cerebrospinal fluid and continuous with the subarachnoid space. Synonym: spatia intervaginalia nervi optici, intersheath spaces of optic nerve, Schwalbe's spaces. (05 Mar 2000) |