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However, the anterior end of the optic nerve stops abruptly at the eye. Hence the pressure is asymmetrical and this causes a pinching and protrusion of the optic nerve at its head. The fibers of the retinal ganglion cells of the optic disc become engorged and bulge anteriorly. Persistent and extensive optic nerve head swelling, or optic disc ...
Retrobulbar neuritis, an inflamed optic nerve, but with a normal-appearing nerve head, is associated with pain and the other findings of papillitis. Pseudopapilledema is a normal variant of the optic disk , in which the disk appears elevated, with indistinct margins and a normal vascular pattern.
The term "disc-at-risk" refers to an optic nerve head characterized by a small cup-to-disc ratio and a crowding of optic nerve fibers. This anatomical feature is a significant factor in the development of NAION. [4] [5] Individuals predisposed to this condition typically have smaller optic discs with minimal or no cupping. This anatomical ...
Unilateral or bilateral optic disc edema may occur. The exact etiology, pathogenesis and mechanism of the disc edema is unknown. [ 1 ] [ 2 ] Theories suggest that the dis edema is due to retinal vascular leakage into and surrounding the optic nerve and disruption of axoplasmic flow resulting from microvascular disease of the optic nerve head. [ 2 ]
The optic nerve can be damaged when exposed to direct or indirect injury. Direct optic nerve injuries are caused by trauma to the head or orbit that crosses normal tissue planes and disrupts the anatomy and function of the optic nerve; e.g., a bullet or forceps that physically injures the optic nerve.
NAION is believed to be caused by reduced blood flow to the optic nerve head. It can lead to permanent visual loss in one eye that may develop painlessly and suddenly or over several days before ...
Advanced imaging using optical coherence tomography (OCT) is very sensitive reveal damage to the optic nerve. The OCT shows corresponding optic disc swelling acutely or an inter-eye difference in the thickness of the neurons and their nerves connecting the eye with the brain in above 4-5% within ≥ 3 months after onset. [1]
The optic nerve is the bundle of axons that carry the visual signals from the eye to the brain. This optic nerve must penetrate through the wall of the eye, and the hole to accommodate this is usually 20-30% larger than the nerve diameter. In some patients the optic nerve is nearly as large as the opening in the back of the eye, and the optic ...