A new variety of sweet potato selected by scientists in Peru could help to prevent millions of cases of blindness and disease among children in Africa.

A simple deficiency of vitamin A is the leading cause of childhood blindness in developing countries, where around 251million children are vitamin A deficient, 10 million have xerophthalmia, or “dry eye,” 500000 are irreversibly blinded, and three million die of vitamin A deficiency-related illnesses.

The new bright orange sweet potato, known as …