1. Department of Ophthalmology, People's Hospital of Rizhao, Rizhao, Shandong 276800, P.R. China
2. Department of Oncology, Binzhou People's Hospital, Binzhou, Shandong 256610, P.R. China
3. Department of Ophthalmology, Weifang Ophthalmic Hospital, Weifang, Shandong 261041, P.R. China