Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Familial exudative vitreoretinopathy ?
    ### Response:
    Familial exudative vitreoretinopathy (FEVR) is a hereditary disorder that can cause progressive vision loss. This condition affects the retina, the light-sensitive tissue that lines the back of the eye, by preventing blood vessels from forming at the edges of the retina.
    