Search results
Results from the WOW.Com Content Network
Prevalence of vitamin A deficiency, 1995-2005. Vitamin A deficiency (VAD) or hypovitaminosis A is a lack of vitamin A in blood and tissues. [1] It is common in poorer countries, especially among children and women of reproductive age, but is rarely seen in more developed countries. [1]
Nyctalopia (/ ˌ n ɪ k t ə ˈ l oʊ p i ə /; from Ancient Greek νύκτ-(núkt-) 'night' ἀλαός (alaós) 'blind, invisible' and ὄψ (óps) 'eye'), [1] also called night-blindness, is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases.
Vitamin A status involves eye health via two separate functions. Retinal is an essential factor in rod cells and cone cells in the retina responding to light exposure by sending nerve signals to the brain. An early sign of vitamin A deficiency is night blindness. [6] Vitamin A in the form of retinoic acid is essential to normal epithelial cell ...
The causes are vitamin A deficiency during pregnancy, followed by low transfer of vitamin A during lactation and infant/child diets low in vitamin A or beta-carotene. [ 4 ] [ 5 ] The prevalence of pre-school age children who are blind due to vitamin A deficiency is lower than expected from incidence of new cases only because childhood vitamin A ...
If detected early enough nyctalopia can be reversed and visual function can be regained; however; prolonged vitamin A deficiency can lead to permanent visual loss if left untreated. [55] Night blindness is especially prominent in developing countries due to malnutrition and therefore a lack of vitamin A in the diet. [55]
Since paroxysmal nocturnal dyspnea occurs mainly because of heart or lung problems, common risk factors include those that affect the function of the heart and lungs. Risk factors for cardiac diseases include high blood pressure, high cholesterol, diabetes, obesity, and a lifestyle lacking exercise and a healthy diet.
Without blood flow, the affected areas swell up, stop working correctly and start to die, resulting in severe vision loss or blindness, according to the Cleveland Clinic.
Vitamin A deficiency is a leading cause of preventable childhood blindness, particularly in developing countries. Vitamin A deficiency is defined as a serum (blood) concentration of less than 0.70 μmol/L while a severe deficiency is defined as less than 0.35 μmol/L, per the Centers of Disease Control National Health and Nutrition Examination ...