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Ischemic optic neuropathy (ION) is the loss of structure and function of a portion of the optic nerve due to obstruction of blood flow to the nerve (i.e. ischemia).Ischemic forms of optic neuropathy are typically classified as either anterior ischemic optic neuropathy or posterior ischemic optic neuropathy according to the part of the optic nerve that is affected.
The repetition of an idiopathic optic neuritis is considered a distinct clinical condition, and when it shows demyelination, it has been found to be associated to anti-MOG and AQP4-negative neuromyelitis optica. [20] When an inflammatory recurrent optic neuritis is not demyelinating, it is called chronic relapsing inflammatory optic neuropathy ...
The exact mechanism of optic nerve ischemia in these cases remains unclear, but contributing factors may include hypotension, anemia, hypoxia, and changes in the autoregulation of optic nerve arterial blood flow. The incidence of ischemic optic neuropathy leading to vision loss following general surgeries ranges between 0.1% and 0.002%. [15] [16]
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 disc appears "crowded" when seen by ophthalmoscopy. A crowded disc is also referred to as a "disc ...
Optic neuritis, when combined with the presence of multiple demyelinating white matter brain lesions on MRI, is suspicious for multiple sclerosis. Several causes and clinical courses are possible for the optic neuritis. It can be classified in: Single isolated optic neuritis (SION) relapsing isolated optic neuritis (RION)
Chart 1 is the basic version, which is the most familiar and widely used chart among all the charts. In this chart the grid consists of 0.5 cm squares (each for 1° visual field), which totally measures 10 cm X 10 cm size. Most commonly grid is in white color with black background. [3]
The second most common initial manifestation of the disease is inflammation of the optic nerve and/or optic chiasm (optic neuritis, ON). [4] ON may lead to varying degrees of visual impairment with decreased visual acuity , although visual field defects, or loss of color vision , may occur in isolation or prior to formal loss of visual acuity.
Autoimmune optic neuropathy (AON), sometimes called autoimmune optic neuritis, may be a forme fruste of systemic lupus erythematosus (SLE) associated optic neuropathy. AON is more than the presence of any optic neuritis in a patient with an autoimmune process, as it describes a relatively specific clinical syndrome.