Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Coats disease ?
    ### Response:
    Coats disease is an eye disorder characterized by abnormal development of the blood vessels in the retina (retinal telangiectasia). Most affected people begin showing symptoms of the condition in childhood. Early signs and symptoms vary but may include vision loss, crossed eyes (strabismus), and a white mass in the pupil behind the lens of the eye (leukocoria).
    