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In both types of PION, decreased blood flow leads to the death of optic nerve cells. Ischemic injury to the optic nerve causes inflammation and swelling. Because the posterior optic nerve passes through the optic canal, a bony tunnel leading to the brain, swelling in this rigid space causes compression of the optic nerve. This compression ...
Ocular ischemic syndrome is the constellation of ocular signs and symptoms secondary to severe, chronic arterial hypoperfusion to the eye. [1] Amaurosis fugax is a form of acute vision loss caused by reduced blood flow to the eye; it may be a warning sign of an impending stroke, as both stroke and retinal artery occlusion can be caused by thromboembolism due to atherosclerosis elsewhere in the ...
The presence of cataracts in childhood or early life can occasionally be due to a particular syndrome. Examples of chromosome abnormalities associated with cataracts include 1q21.1 deletion syndrome , cri-du-chat syndrome , Down syndrome , Patau's syndrome , trisomy 18 ( Edward's syndrome ), and Turner's syndrome , and in the case of ...
At some point—usually as you enter middle age—most people develop this eye condition, which is a clouding of the eye’s lens that can get progressively worse and impair your vision.
When considering the possible causes for spontaneous NAION, the list includes other conditions like arteritic anterior ischemic optic neuropathy (associated with inflammation of arteries), optic neuritis (inflammation of the optic nerve), infiltrative and compressive types of optic neuropathy (where the optic nerve is invaded or pressed upon by ...
Visual impairment can also be caused by problems in the brain due to stroke, premature birth, or trauma, among others. [12] These cases are known as cortical visual impairment. [12] Screening for vision problems in children may improve future vision and educational achievement. [13] Screening adults without symptoms is of uncertain benefit. [14]
It occurs when exposure to a substance – specifically, a neurotoxin or neurotoxicant– alters the normal activity of the nervous system in such a way as to cause permanent or reversible damage to nervous tissue. [1] This can eventually disrupt or even kill neurons, which are cells that transmit and process signals in the brain and other ...
A page or photograph which shows the same image twice, but slightly displaced–from a printing mishap, a camera moving during the shot, etc.–can cause eye strain due to the brain misinterpreting the image fault as diplopia and reacting by adjusting the sideways movements of the two eyeballs, in an attempt to fuse the two images into one.