Evaluation of macular microvasculature alterations in patients with proliferative diabetic retinopathy after vitrectomy by swept-source optical coherence tomography angiography

Abstract

AIM: To investigate the changes in retinal and choroidal blood flow after pars plana vitrectomy(PPV)for proliferative diabetic retinopathy(PDR).METHODS: A cross-sectional study was conducted on 35 patients(35 eyes)who were diagnosed as monocular PDR and received 23GPPV in ophthalmology department of the Second People's Hospital of Hefei between September 2020 and July 2022. All eyes underwent swept-source optical coherence tomography angiography(SS-OCTA)examination. Retinal and choroidal vascular parameters within 3mm×3mm of macular zone were measured by built-in analyzer, and its correlation with postoperative best corrected visual acuity(BCVA)was analyzed.RESULTS: The follow-up was 1～22(average 9.72±6.67)mo. At the last follow-up, flow area(FA)of intermediate capillary plexus(ICP)layer in paranasal foveal region was significantly reduced in PPV eyes(0.31±0.06mm2)compared with contralateral eyes(0.38±0.05mm2), and FA of deep capillary plexus(DCP)in temporal foveal region was significantly lower in PPV eyes(0.19±0.08mm2)than contralateral eyes(0.27±0.07mm2; all P<0.05). Choroidal vascularity index(CVI)were lower in PPV eyes than contralateral eyes in parafoveal subregions except temporal region(P<0.05). After PPV, BCVA had a certain correlation with the density and FA of middle and deep retinal vessels.CONCLUSIONS: Eyes with severe PDR may be prone to having a decrease in the DCP and parafoveal choroidal perfusion in the parafoveal regions after PPV than contralateral eyes.

Keywords

• proliferative diabetic retinopathy
• swept-source optical coherence tomography angiography(ss-octa)
• pars plana vitrectomy
• flow area
• vascular density
• choroidal vascular index