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Optic nerve melanocytoma does not usually produce symptoms or grow. If they slowly grow, optic nerve melanocytoma can produce afferent pupillary defects (30%), subretinal fluid (10%), and an enlarged blind spot (75%). On fundoscopic exam, the optic disc may be swollen, atrophic, or even normal. [1] Central retinal vein occlusion may occur.
Optic neuritis involving external fibers of the optic nerve causes tunnel vision. [4] Optic neuritis involving internal fibers of the optic nerve causes central scotoma. [4] lf unilateral central scotoma is detected, careful observation of the temporal visual field of other eye is essential to rule out the possibility of compressive lesions at ...
NMO is more common in women than men, with women comprising over two-thirds of patients and more than 80% of those with the relapsing form of the disease. [ 18 ] A retrospective study found that prevalence of neuromyelitis optica spectrum disorders was 1.5% among a random sample of neurological patients , with a MS:NMOSD ratio of 42:7.
Leber hereditary optic neuropathy is a condition related to changes in mitochondrial DNA. Although most DNA is packaged in chromosomes within the nucleus, mitochondria have a distinct mitochondrial genome composed of mtDNA. Mutations in the MT-ND1, MT-ND4, MT-ND4L, and MT-ND6 genes cause Leber hereditary optic neuropathy. [6]
Optic gliomas are usually pilocytic tumors, and can involve the optic nerve or optic chiasm. [3] Optic gliomas are usually associated with neurofibromatosis type 1 in 30% of people with the condition. [3] Optic nerve gliomas have low mortality but extremely high prevalence of vision loss and eye-bulging exophthalmos) in children. [4]
In-flight ultrasound shows proximal kinking and increased optic nerve sheath diameter (ONSD) of approximately 12 mm that is consistent with raised ICPs. Optic nerve shown in purple and the ONSD in green. Figure 10: MRI (R+30 days) of the fourth case of visual changes from long-duration spaceflight. There is prominence of central T2 ...
The most common cause is multiple sclerosis (MS) or ischemic optic neuropathy due to thrombosis or embolism of the vessel that supplies the optic nerve. [ 13 ] [ 14 ] Up to 50% of patients with MS will develop an episode of optic neuritis, and 20–30% of the time optic neuritis is the presenting sign of MS .
Visual acuity is reduced in half, and over 60% have a visual field defect. [2] [4] The visual loss depends on which part of the nerve is affected. If the part of the nerve between the eye and the chiasm is compressed, the result is vision loss in one eye. If the part after the chiasm is affected, visual loss on one side of the visual field ...