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Cataracts can arise as an effect of exposure to various types of radiation. X-rays, one form of ionizing radiation, may damage the DNA of lens cells. [21] Ultraviolet light, specifically UVB, has also been shown to cause cataracts, and some evidence indicates sunglasses worn at an early age can slow its development in later life. [22]
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]
In an effort to understand the cause of cataracts—beyond the normal wear-and-tear of aging, smoking, and exposure to UV rays, all of which can damage a lens’ fiber cells—researchers are ...
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 ...
Closed-head injuries can range from mild injuries to debilitating traumatic brain injuries and can lead to severe brain damage or death. Common closed-head injuries include: [5] concussion – a head injury resulting in temporary dysfunction of normal brain function. Almost half of the total concussions reported each year are sports-related [5]
A-PION is caused by an inflammatory disease called giant cell arteritis (GCA). GCA is an inflammatory disease of blood vessels. It is believed to be an autoimmune disease caused by inappropriate T-cell activity. [4] [17] When T-cells damage arteries supplying the optic nerve, a blood clot forms and stops blood flow. When blood flow stops ...
This may occur in the event of posterior capsule rupture, zonular dehiscence, [Note 8] a dropped nucleus [Note 9] with a nuclear fragment more than half the size of the cataract, [14] problematic capsulorhexis with a hard cataract, [14] or a very dense cataract where the heat developed by phacoemulsification is likely to cause permanent damage ...
Cortical blindness-Cortical blindness is the total or partial loss of vision in a normal-appearing eye caused by damage to the brain's occipital cortex. [7] Retrobulbar neuritis- Retrobulbar neuritis cause of visual loss with normal fundus but there will be relative afferent pupillary defect (RAPD) and abnormal visually evoked responses. [8]