[1] Zoucheng Peoples Hosp, Dept Ophthalmol, Zoucheng, Shandong, Peoples R China
[2] LinQing Peoples Hosp, Dept Ophthalmol, Linqing, Shandong, Peoples R China
[3] Qingdao Univ, Dept Ophthalmol, Med Coll, Affiliated Yantai Yuhuangding Hosp, Yantai 264000, Shandong, Peoples R China