Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Stargardt disease ?
    ### Response:
    Stargardt disease is a genetic eye disorder that causes progressive vision loss. It affects the macula, an area of the retina responsible for sharp, central vision. Vision loss is due to abnormal accumulation of a fatty yellow pigment (lipofuscin) in the cells within the macula.
    