Figure 3 gives a brief overview of leukocyte trafficking due to breach in blood–retina barrier after ischemic injury to retina, along with the proposed mechanism about how different subtypes of T cells are involved in ischemia, such as CD4+ T regulatory cells that release anti-inflammatory TGFβ, IL10 (91), and γδT cells that produce IL17 through IL23 stimulation (92), along with the production of IL8 and VEGF from different T-cell subtypes (93). This evidence concerns the gene IL17A and ischemia.