Mild vitamin A deficiency usually does not present with any gross clinical signs. Yet it is very important because it is associated with loss of appetite, poor growth and severe infections (especially gastroenteritis and measles) and increased mortality.
Vitamin A deficiency results in an increased risk of severe infections.
Severe vitamin A deficiency causes eye problems and presents with photophobia (keep eyes closed in bright light), night blindness (unable to see in poor light) and xerophthalmia (dry eyes). It also causes corneal clouding, ulcers and softening (keratomalacia) which can lead to corneal scarring and blindness. Severe vitamin A deficiency is the commonest preventable cause of blindness in children in poor countries.
A patch of dry, raised conjunctiva (appears foamy) over the sclera is called a Bitot’s spot. Vitamin A deficiency causes blindness in half a million children worldwide annually.