Sanne De Wilde's best photograph: the island of the colour blind

'It's the most colour-blind place on Earth. It took me four flights to get there. I wanted to celebrate the islanders' unique way of seeing the world'

I shot this image of Deke, one of the smaller islands of the Pingelap atoll, in 2015. I had travelled to the atoll, in the Federated States of Micronesia, to research achromatopsia, a rare genetic condition that causes colour blindness and hypersensitivity to light. Worldwide, only one in every 30,000 people have achromatopsia. But on Pingelap, one in 10 do. It's the most colour-blind place on Earth.

The prevalence of achromatopsia on the island can be traced back to the 18th century when it was engulfed by a typhoon, leaving around 20 survivors. The ruler carried the recessive gene that causes the condition. After a few generations, more or less everyone on the island was related to him.