In tropical countries, International and missionary organizations work/ have worked “overtime” to reduce blindness of children by giving them regular extra large doses of vitamin A, especially after measles “epidemics”. May these people be blessed!

One may get enough vitamin A by consuming enough beta-carotene [yellow and orange fruits and vegetables]

In the body, beta-carotene is converted into vitamin A (retinol) to do its work, but this does not always happen or the conversion may not always be optimal and in certain diseases this conversion may also be sub-optimal

The most known symptoms of a lack of vitamin A are eye symptoms: night blindness! , dry eyes, conjunctivitis.

Below I will write some conditions where one should think about a vitamin A deficiency, but there can be many other reasons for these conditions of course
Acne vulgaris
Actinic keratosis

Hearing loss
Infectious diseases, colds, respiratory infections

Measles[high amounts of vitamin A are given here]
Chalazion and blepharitis[eye]
Celiac disease
Critical illness

For treatment: discuss with your doctor.

Don’t take more than 5000 units of vitamin A in pregnancy! Again: discuss with your doctor.