An example of MS-DOS's command-line interface, this one showing that the current directory is the root of drive C. MS-DOS (/ËÉmÉsËdÉs/ EM-es-DOSS; acronym for Microsoft Disk Operating System) is a discontinued operating system for x86-based personal computers mostly developed by Microsoft.
Written by: Kierstan Boyd. Nov. 08, 2012. The main symptom of vitamin A deficiency is vision loss and blindness. Vision loss often begins as a problem adjusting to seeing in the dark, or night blindness. People with night blindness do not see well in the dark, but are able to see normally if enough light is present.
1 Vitamin A deficiency: Night blindness is one of the first signs of vitamin A deficiency, which is commonly associated with malnutrition. 2  The vitamin deficiency often develops in malnourished children who are too young to recognize a problem with their night vision or report a vision problem. Vitamin A deficiency: Night blindness is one of the first signs of vitamin A deficiency, which is commonly associated with malnutrition. 2  The vitamin deficiency often develops in malnourished children who are too young to recognize a problem with their night vision or report a vision problem.