One of the most important vitamins for our bodys general wellness is vitamin A. It is also known as retinol, and it is crucial for the development of rhodopsin, a pigment that serves as a photoreceptor in the retina of the eye. Additionally, it aids in maintaining the epithelial tissues that cover the majority of the bodys internal organs, glands, and surfaces. Since our livers store 80 to 90 % of the vitamin A we consume, a liver disorder may be the cause of a vitamin A deficit. Therefore, the doctor advises the vitamin A test to check for a deficiency that could possibly result in a childs death.