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These diverticula make their appearance before the closure of the anterior end of the neural tube; [1] [2] after the closure of the tube around the 4th week of development, they are known as the optic vesicles. Previous studies of optic vesicles suggest that the surrounding extraocular tissues – the surface ectoderm and extraocular mesenchyme ...
Non-arteritic anterior ischemic optic neuropathy (NAION) is a medical condition characterized by loss of vision caused by damage to the optic nerve as a result of ischemia, or insufficient blood supply. The key symptom of NAION is optic disc swelling, which typically resolves within 2 months, but often leads to optic atrophy. The likelihood of ...
Arteritic anterior ischemic optic neuropathy (arteritic AION, A-AION or AAION) is vision loss that occurs in giant cell arteritis (also known as temporal arteritis). Temporal arteritis is an inflammatory disease of medium-sized blood vessels that happens especially with advancing age.
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.
Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain. Damage and death of these nerve cells, or neurons, leads to characteristic features of optic neuropathy.
The optic vesicles project toward the sides of the head, and the peripheral part of each expands to form a hollow bulb, while the proximal part remains narrow and constitutes the optic stalk. [1] [2] Closure of the choroidal fissure in the optic stalk occurs during the seventh week of development. The former optic stalk is then called the optic ...
The optic vesicles then develop into the optic cup with the inner layer forming the retina and the outer portion forming the retinal pigment epithelium. The middle portion of the optic cup develops into the ciliary body and iris. [7] During the invagination of the optic cup, the ectoderm begins to thicken and form the lens placode, which ...
Failure of closure of the anterior neuropore during embryogenesis will lead to anencephaly, the failure of the brain and skull to develop.In less severe situations it may lead to different forms of encephalocele (i.e. cranium bifidum).