Therefore, we speculated the mechanisms underlying significantly thickened outer layer in DME+DT–group as follows: 1) chronic hyperglycemic condition caused by untreated DM deteriorated choroidal microcirculatory system in DME eyes, 2) more increase in VEGF protein associated with DME, led to vasodilatation of outer choroid layer, increased choroidal blood flow and/or vascular hyperpermeability, 3) increased accumulation of several diabetes-related proteins including advanced glycation end products in choroidal tissues, as shown in DM donor eyes with immunohistochemistry [36]. Here, VEGFA is linked to diabetes mellitus.