AIM: To evaluate the differences of macular vascular network measured by optical coherence tomography angiography(OCTA)between severe non-proliferative diabetic retinopathy(S-NPDR)eyes and health eyes, and explore the changes of these OCTA characteristics in patients with S-NPDR before and after panretinal photocoagulation(PRP).

METHODS: This was a prospective study including 31 eyes from 18 consecutive patients with S-NPDR and 31 eyes of healthy subjects. We measured macular vascular density and foveal avascular zone(FAZ)area and volume by an OCTA device.

RESULTS: Compared to the normal control group, in superficial retinal capillary plexus(SCP), macular vascular density decreased in S-NPDR group, except foveal vascular density unchanged. Consistently, in deep retinal capillary plexus(DCP), macular vascular density was also lower in S-NPDR group. In addition, FAZ area and volume expanded in S-NPDR eyes. At 6mo post-PRP in S-NPDR eyes, foveal SCP and DCP densities increased significantly, while FAZ area and volume decreased. At 3mo post-PRP, only foveal vascular density in DCP increased. The changes of foveal SCP and DCP densities as well as FAZ area and volume were not statically significant at 1mo post-PRP.

CONCLUSION: Macular vascular network was impaired in S-NPDR assessed by OCTA. Although OCTA parameters were not significantly affected by PRP in 1 and 3mo period, at 6mo follow-up parameters became significant after PRP.