1. School of Electronics and Information Engineering, Soochow University, Suzhou, China
2. Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China
3. Iowa Institute for Biomedical Imaging and Department of Electrical and Computer Engineering, University of Iowa, Iowa City, Iowa
4. Joint Shantou International Eye Center, Shantou University and the Chinese University of Hong Kong, Shantou, China 4Department of Ophthalmology and Visual Sciences, the Chinese University of Hong Kong, Hong Kong, China