Some patients with proliferative diabetic retinopathy (PDR) have poor responses to anti-vascular endothelial growth factor (anti-VEGF) therapy. This situation highlights the need for additional therapeutic approaches. In proliferative diabetic retinopathy, what is the role of ANGPTL4 that differs from VEGF? We found that ANGPTL4 is elevated in the vitreous humor of patients with PDR who are poorly responsive to anti-VEGF therapy. ANGPTL4, particularly its C-terminal fragment, causes retinal lymp