Causes of Night Blindness
If you have ever walked into a room and were blinded by the light when you turned on the switch or found yourself suddenly sightless in a dark room, you have suffered temporary night blindness. While this is easily cured by waiting for your eyes to adjust, there are other causes for the more permanent forms of night blindness. Many causes are genetic; almost all are treatable.
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Identification
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Nyctalopia, nyctanopia or night blindness is a medical condition which affects the vision, causing the most impact in areas with little or no light. A person suffering from night blindness also has trouble moving from bright areas to dim areas quickly, because their sight does not adjust to the dim light like others' does.
Cataracts
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One cause of night blindness is cataracts, which are cloudy areas that develop over the eyes and are more common in persons over the age of 50. A genetic cousin of this is retinitis pigmentosa, which occurs in younger people, a disorder that causes eyes to deteriorate over time and, if left untreated, can eventually lead to blindness.
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Myopia
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Myopia, also known as nearsightedness, is marked by difficulty focusing, and objects that are far away can appear blurry. This condition also reduces the eyes' ability to adapt to darkness or very dimly lit areas, thereby causing a form of night blindness.
Vitamin Deficiency
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Vitamin deficiency and poor nutrition have been linked to many health issues, including night blindness. It is believed that insufficient levels of vitamin A can cause reduced vision in dark areas and thus cause night blindness.
Other Causes
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Medications that block vitamin A absorption into the bloodstream can contribute to night blindness, as can any damage to the retina. Birth defects that distort the retina also cause night blindness, though these are all treatable.
Treatment
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Treatments for night blindness usually involve fixing or correcting the cause. In the case of cataracts, this includes surgery or medication that dissolves the cloudy area. Myopia is usually reversed with corrective eyewear. Nutrition bolsters vitamin deficiencies, as does reducing the dosage of medications that block Vitamin A absorption. Birth defects can also be corrected with reparative surgery.
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