Historical and practical uses of assessing night blindness as an indicator for vitamin A deficiency
نویسنده
چکیده
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 assess poor dark adaptation, does not correlate strongly with biochemical indicators of vitamin A deficiency. Recently, more standardized field-based methods that utilize a standard stimulus to the eye have been developed, specifically the pupillary response test and the night vision threshold test. These low-cost, non-invasive methods have the potential to provide rapid assessment to determine whether the prevalence of vitamin A deficiency within a population is of public health significance or changes with an intervention. A2.1 ASSESSING NIGHT BLINDNESS AS AN INDICATOR FOR VITAMIN A DEFICIENCY
منابع مشابه
Priorities 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 کاملMaternal 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 کاملSevere vitamin A deficiency in India during pulse polio immunization.
Although this assessment of children monitored during the pulse polio rounds does not serve as a formal vitamin A deficiency survey, the number of children assessed and the large number of sites sampled exceeded the minimum numbers of children and clusters required for the most basic vitamin A deficiency survey using night blindness as the main indicator (3,042 children and 30 cluster). The WHO...
متن کاملAnterior Segment Findings in Vitamin A Deficiency: A Case Series
Vitamin A deficiency is a rare but vision threatening disorder in the developed world, which can lead to blindness for severe keratomalacia with cornea scarring and perforation or night blindness due to impaired dark adaptation. Conversely, the disease is quite common in developing countries, as a consequence of chronic malnutrition. The correct diagnosis and therapy with prompt vitamin A suppl...
متن کاملVitamin A and Night Vision
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 th...
متن کامل