Alteration of choroidal vascular structure in diabetic macular edema

Purpose The aim of this study was to analyze choroidal structures in healthy subjects and patients with/without diabetic macular edema (DME). Methods This was a retrospective observation case control study. Four hundred and two eyes of patients with diabetes mellitus (DM), and 124 age-matched eyes of healthy subjects were enrolled in this study. DM patients were divided into 3 groups: presence of central-involved (CI) DME (n = 81) and nonCI-DME/non-DME (n = 321), based on OCT findings. Central choroidal thickness (CCT) and total choroidal, luminal, and stromal areas were determined using EDI-OCT and a binarization method, respectively. The luminal area expressed as a ratio of the total choroidal area was defined as the L/C ratio. Results DM eyes showed a significantly lower L/C ratio than control eyes, whereas there was no significant difference in CCT or total choroidal, luminal, or stromal areas. There was no significant difference between CI-DME and non-DME groups in HbA1c, blood pressure, dyslipidemia, or renal function. CCT and total choroidal, luminal, and stromal areas were significantly greater in the CI-DME group than non-DME group (each P < 0.05). Conclusions These results suggest that CCT was thickened in the presence of DME, associated with both increased luminal and stromal areas, which might be related to the pathology of DME.