1. Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, P.R. China
2. Department of Respiration Medicine, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, P.R. China
3. Department of Ophthalmology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710038, P.R. China