1. Department of Ophthalmology, Peoples’ Hospital of Ningxia Hui Autonomous Region, The Third Affiliated Clinical College of Ningxia Medical University, Yinchuan, Ningxia, P.R. China
2. Medical Science Research Institution of Ningxia Hui Autonomous Region, Medical Sci-Tech Research Center of Ningxia Medical University, Yinchuan, Ningxia, P.R. China
3. Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong, P.R. China
4. Department of Ophthalmology, Guro Hospital, Korea University College of Medicine, Guro-gu, Seoul 152–703, South Korea