Explain Night Blindness - micronutrient deficiencies?

Night blindness is the earliest symptom of Vitamin 'A' deficiency. The reduction in the supply of vitamin A aldehyde i.e. retinal to the rod cells of the retina results in the impairment of dark adaptation. Under such situations, the affected child cannot see properly in sunlight particularly after the sunset. Often, an attentive mother can recognize the child's inability to see the plate of food or toys in ill-lit room. Pregnant women often experience deficiency symptoms, such as night blindness, that continues into the early period of lactation. In most part of the country, there is a local term for the condition, example in Hindi, it is called as "Rathaundi".