Vitamin A And Night Blindness
Vitamin a plays an important role in your vision.
Vitamin a and night blindness. Night vision was tested electroretinographically and psychophysically in a vitamin a deficient patient before and after therapy. Severe vitamin a deficiency can lead to night blindness several observational studies have reported a high prevalence of night blindness in developing nations 12 13 14 15 due to the extent. Vitamin a deficiency vad or hypovitaminosis a is a lack of vitamin a in blood and tissues.
It is one of the major causes of night blindness in pregnant women. Nyctalopia night blindness is one of the first signs of vad. Your eye also needs vitamin a to nourish other parts of your eye including the cornea.
Corrective lenses such as eyeglasses or contacts can improve nearsighted vision both during the day. Vitamin a helps form a light sensitive pigment that receives and sends images to the brain. Therefore doses above the ul should be avoided because vitamin a has been associated with an increase risk for hip fracture in postmenopausal women lung cancer cardiovascular mortality and total mortality.
Without vitamin a night blindness occurs. Night blindness is often regarded as a vitamin a deficiency disease. It is common in poorer countries especially among children and women of reproductive age but is rarely seen in more developed countries.
Vitamin a deficiency is the major cause of severe diseases infections and preventable blindness in children. Xerophthalmia keratomalacia and complete blindness can also occur since vitamin a has a major role. As with any medication or supplement excessive doses or unnecessary exposure can be harmful.
Vitamin a deficiency stops the production of these pigments leading to night blindness. Vitamin a deficiency resulted from malabsorption due to a jeujunoileal bypass operation. Night blindness caused by nearsightedness cataracts or vitamin a deficiency is treatable.
It also affects the immune system and results in deaths from malaria diarrhoea and measles.
