1. School of Automation Sciences and Electrical Engineering, Beihang University, Beijing, China
2. Department of Ophthalmology, Beijing Friendship Hospital, Beijing, China
3. Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China
4. College of Computer Science, Chongqing University, Chongqing, China
5. National Heart and Lung Institute, Imperial College London, London, U.K.