Abnormalities also appear in the eyes of vitamin A deficient children. In the mildest form, night blindness occurs because the rods in the eye no longer produce rhodopsin, a pigment essential for seeing in the dark. In more severe forms, lesions occur on the conjunctiva and the cornea that if left untreated can cause irreversible damage, including partial or total blindness.
Vitamin A is found as retinol in breastmilk, liver, eggs, butter and whole cow's milk. Carotene, a precursor of vitamin A that is converted to retinol in the abdominal walls, is found in green leafy vegetables, orange and yellow fruits, and red palm oil.
The regions most affected by vitamin A deficiency are Africa, South Asia, East Asia and the Pacific, Latin America and the Caribbean and the Middle East. Serious deficiencies in vitamin A have been reported in the following countries: [Africa] Angola, Benin, Burundi, Burkina Faso, Chad, Ethiopia, Ghana, Kenya, Malawi, Mali, Mauritania, Mozambique, Niger, Nigeria, Sudan, Tanzania UR, Uganda, Zambia. [America] Bolivia, Brazil, El Salvador, Haiti, Mexico. [Asia] Afghanistan, Bangladesh, Burma, India, Indonesia, Kampuchea Dem, Laos, Nepal, Oman, Philippines, Sri Lanka, Vietnam.