Below is an instruction from Human. Write a response.
    ### Instruction:
    How many people are affected by achromatopsia ?
    ### Response:
    Achromatopsia affects an estimated 1 in 30,000 people worldwide. Complete achromatopsia is more common than incomplete achromatopsia.  Complete achromatopsia occurs frequently among Pingelapese islanders, who live on one of the Eastern Caroline Islands of Micronesia.
    