Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Bietti crystalline dystrophy ?
    ### Response:
    Bietti crystalline dystrophy is a disorder in which numerous small, yellow or white crystal-like deposits of fatty (lipid) compounds accumulate in the light-sensitive tissue that lines the back of the eye (the retina). The deposits damage the retina, resulting in progressive vision loss.
    