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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 main symptom is loss of vision, with colors appearing subtly washed out ...
Ophthalmology. Toxic and nutritional optic neuropathy is a group of medical disorders defined by visual impairment due to optic nerve damage secondary to a toxic substance and/or nutritional deficiency. The causes of these disorders are various, but they are linked by shared signs and symptoms, which this article will describe.
[86] [87] Another effect is known as cosmic ray visual phenomena. [a] NASA survey of 300 male and female astronauts, about 23 percent of short-flight and 49 percent of long-flight astronauts said they had experienced problems with both near and distance vision during their missions. Again, for some people vision problems persisted for years ...
Deathbed phenomena refers to a range of experiences reported by people who are dying. [1] [2] There are many examples of deathbed phenomena in both non-fiction and fictional literature, which suggests that these occurrences have been noted by cultures around the world for centuries, although scientific study of them is relatively recent.
Posterior ischemic optic neuropathy ( PION) is a medical condition characterized by damage to the retrobulbar portion of the optic nerve due to inadequate blood flow (ischemia) to the optic nerve. 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 ...
Photic retinopathy is damage to the eye 's retina, particularly the macula, from prolonged exposure to solar radiation or other bright light, e.g., lasers or arc welders. The term includes solar, laser, and welder's retinopathy and is synonymous with retinal phototoxicity. [1] It usually occurs due to staring at the Sun, watching a solar ...
Visual or vision impairment ( VI or VIP) is the partial or total inability of visual perception. In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment – visual impairment may cause the individual difficulties with normal daily tasks including reading and walking. [6]
Acute radiation syndrome ( ARS ), also known as radiation sickness or radiation poisoning, is a collection of health effects that are caused by being exposed to high amounts of ionizing radiation in a short period of time. [1] Symptoms can start within an hour of exposure, and can last for several months.