Department of Ophthalmology,Second Hospital,Jilin University,;
Department of Ophthalmology,Second Hospital,Jilin University,;
Department of Ophthalmology,Second Hospital,Jilin University,;
Jinlin Dipensary of Ophthalmopathy,;
human fetus; retina; bolld vessels; proliferation cell nuclear antigen (PCNA); vascular endothelial growth factor(VEGF);