A low - energy laser is applied to the iris to disrupt the brown pigment . This causes body to trigger ' scavenger darts ' to remove dark colours . Process takes 30 seconds , and two weeks later eyes will turn blue . 17 people in Mexico and 20 in Costa countries have undergone surgery . this , which is undergoing clinical trials , has raised health concerns .
A low-energy laser is applied to the iris to disrupt the brown pigment . This causes body to trigger 'scavenger cells ' to remove dark colours . Process takes 30 seconds , and two weeks later eyes will become blue . 17 patients in Mexico and 20 in Costa Rica have undergone treatment . Process , which is undergoing clinical trials , has raised safety concerns .