Belgian photographer Sanne de Wilde is fascinated by the colourblind people of the Pacific island of Pingelap.

A significant proportion of residents suffer from achromatopsy - total colourblindness.

It's thought that in 1780 the population was all but wiped out by a tsunami.

As few as 20 people survived, one of whom was the king, who was believed to have had a genetic fault that caused colour-blindness, and which was passed on to his descendants.

Sanne de Wilde's images are in a new photobook, The Island of the Colorblind.