In human eyes with DR, PlGF is elevated in addition to VEGF-A (Ando et al., 2014; Noma et al., 2015, 2017), and there are significant increases in the levels of both VEGF-A and PlGF in vitreous samples from eyes of patients with increasing levels of ischemia, i.e. from the normal to diabetic state, or from PDR to neovascular glaucoma (Kovacs et al., 2015; Patel, 1989). Here, PGF is linked to ischemia.