AIM: To quantitatively evaluate the changes of macular blood flow in patients with type 1 diabetes mellitus using optical coherence tomography angiography(OCTA).

METHODS: Totally 20 healthy controls, 20 type 1 diabetes patients with no-diabetic retinopathy(NDR)and 20 type 1 diabetes patients with mild or moderate non-proliferative diabetic retinopathy(NPDR)were enrolled. The area of fovea avascular area(FAZ), vessel density of FD-300 and vessel density of superficial capillary plexus(SCP)and deep capillary plexus(DCP)in macular were automatic measured by built-in software.

RESULTS: The vessel density of DCP in NDR group(54.99%±2.27% in paramacular and 53.13%±2.15% in macular)decreased significantly compared with the controls(P<0.05). For the mild or moderate NPDR group, the vessel density of FD-300, SCP and DCP(49.11%±4.78% in FD-300, 48.74%±4.78% in parafovea and 45.43%±3.70% in macular of SCP, 53.20%±4.19% in parafovea and 50.84%±3.99% in macular of DCP)all decreased significantly when compared with controls(P<0.05).

CONCLUSION: In the preclinical stage of type 1 diabetes mellitus, vessels density has already started to decrease in the DCP of macular. For patients with mild or moderate NPDR, vessel density in the SCP and DCP of the macular area both decrease.