Search results
Results from the WOW.Com Content Network
The optic radiation contains feedforward tracts that transmit visual information (from the retina of the eye) from the geniculate nucleus to the visual cortex, and also feedback tracts from the visual cortex to the neurons in the LGN that project to them. [2] The function of the feedback from the visual cortex back to the LGN is unknown.
This is most commonly the result of exposure to the sun at high altitude, and in areas where shorter wavelengths are readily reflected from bright surfaces, such as snow, water, and sand. UV generated by a welding arc can similarly cause damage to the cornea, known as "arc eye" or welding flash burn, a form of photokeratitis. [52]
This may cause long-term changes in the structure and function of cerebral blood vessels. The brain's mechanism for maintaining constant blood flow despite changes in systemic blood pressure, known as cerebral autoregulation, can be impaired by sleep apnea. This impairment results in periods of both reduced and excessive cerebral blood flow ...
Optical radiation is the part of the electromagnetic spectrum with wavelengths between 100 nm and 1 mm. [1] [2] This range includes visible light, infrared light, and part of the ultraviolet spectrum. [3] Optical radiation is non-ionizing, [4] and can be focused with lenses and manipulated by other optical elements.
Other factors can cause glaucoma, known as "secondary glaucoma", including prolonged use of steroids (steroid-induced glaucoma); conditions that severely restrict blood flow to the eye, such as severe diabetic retinopathy and central retinal vein occlusion (neovascular glaucoma); ocular trauma (angle-recession glaucoma); plateau iris; and ...
Brain ischemia is insufficient blood flow to the brain, and can be acute or chronic. Acute ischemic stroke is a neurological emergency typically caused by a blood clot blocking blood flow in a vessel in the brain. [15] Chronic ischemia of the brain may result in a form of dementia called vascular dementia. [16]
Despite the term posterior, this form of damage to the eye's optic nerve due to poor blood flow also includes cases where the cause of inadequate blood flow to the nerve is anterior, as the condition describes a particular mechanism of visual loss as much as the location of damage in the optic nerve.
Ischemic optic neuropathies are classified based on the location of the damage and the cause of reduced blood flow if known. [3] Anterior ischemic optic neuropathy (AION) includes diseases that affect the optic nerve head and cause swelling of the optic disc. These diseases often cause sudden rapid visual loss in one eye.