Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) achromatopsia ?
    ### Response:
    Achromatopsia is a condition characterized by a partial or total absence of color vision. People with complete achromatopsia cannot perceive any colors; they see only black, white, and shades of gray. Incomplete achromatopsia is a milder form of the condition that allows some color discrimination.
    