Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) neuromyelitis optica ?
    ### Response:
    Neuromyelitis optica is an autoimmune disorder that affects the nerves of the eyes and the central nervous system, which includes the brain and spinal cord. Autoimmune disorders occur when the immune system malfunctions and attacks the body's own tissues and organs.
    