1. Department of Ophthalmology, Affiliated to Qingdao University Yuhuangding Hospital of Yantai, Yantai, Shandong 264000, P.R. China
2. Department of Ophthalmology, Yantaishan Hospital, Yantai, Shandong 264000, P.R. China
3. Department of Ophthalmology and Otolaryngology, Qingdao Fuwai Cardiovascular Disease Hospital, Qingdao, Shandong 266034, P.R. China
4. Department of Ophthalmology, Laizhou People's Hospital of Yantai, Yantai, Shandong 261400, P.R. China