Vitamin A and Night Vision
نویسنده
چکیده
Night-blindness was attributed to scurvy by Capt. Cook, even though it failed to clear up like other scorbutic symptoms when the patient got fresh lemons. Baraffield noted in 1814 that fresh meat and vegetables,added to the diet, improved night vision, whereas antiscorbutics did not ; yet he too regarded it as a manifestation of scurvy. The full picture of vitamin A deficiency, as it affects the eyes,
منابع مشابه
Maternal Night Blindness: A New Indicator of Vitamin A Deficiency
N ight blindness—the inability to see after dusk or at night—is the most common ocular manifestation of moderate to severe vitamin A deficiency. Poor dark adaptation leading to night blindness occurs when there is decreased production of a vitamin A–dependent photosensitive pigment, rhodopsin, in the retinal receptors responsible for seeing under low levels of illumination (rods). Normally, whe...
متن کاملPrevalence of night blindness in Bashagard district in Hormozgan, Iran, in 2011
BACKGROUND Night blindness is a visual disorder associated with unusual vision during the night or in darkness. Vitamin A deficiency (VAD), which is easily preventable, is the main known etiology of night blindness. Malnutrition is a common health issue in Bashagard and some other areas in the Hormozgan province of Iran. The aim of the current study was to determine the prevalence of night blin...
متن کاملHistorical and practical uses of assessing night blindness as an indicator for vitamin A deficiency
n The assessment of vitamin A status is critical for the planning, implementation, monitoring and evaluation of vitamin A deficiency prevention and treatment programmes. Determination of night blindness is one of the traditional methods of assessing vitamin A deficiency. A variety of subjective and objective methods have been used, however, reported night blindness, the most common method to as...
متن کاملNight vision in a case of vitamin A deficiency due to malabsorption.
Night vision was tested electroretinographically and psychophysically in a vitamin A deficient patient before and after therapy. Vitamin A deficiency resulted from malabsorption due to a jeujunoileal bypass operation. Before therapy the patient had severely reduced cone and rod function. After the reversal operation, accompanied by 5 injections of a total of 500,000 units of vitamin A, complete...
متن کاملPriorities in the Assessment of VitAmin A And iron stAtus in PoPulAtions PANAMA CITY , PANAMA 15 – 17 SEPTEMBER 2010 REPORT
n The assessment of vitamin A status is critical for the planning, implementation, monitoring and evaluation of vitamin A deficiency prevention and treatment programmes. Determination of night blindness is one of the traditional methods of assessing vitamin A deficiency. A variety of subjective and objective methods have been used, however, reported night blindness, the most common method to as...
متن کامل