<qa>  What is the stimulus of pupil near response?Previous studies suggest that the stimulus of pupil near response PNR may be a conscious perception of a blurred image. Moreover, PNR is a reflex that can be objectively observed and with no motor output, suggesting it might be a more convenient index for consciousness evaluation and consciousness recovery in patients with disorders of consciousness DOC. We thus hypothesized that PNR patients patients show PNR during the assessment would have better prognosis than PNR- patients patients fail to show PNR during the assessment.Based on this hypotheis, researchers will assess pupil near response in patients with unresponsive wakefulness syndrome UWS and compare the prognosis difference between PNR patients and PNR- patients to assess its prognosis value. 