Changes Of Macular Vessel Density And Microperimeter In Diabetic Retinopathy After PRP

Obejective: Using optical coherence tomography angiography(OCTA)and microperimeter to study the changes of macular vessel density in the superficial capillary plexus and deep capillary plexus、retinal sensitivity and best corrected visual acuity of patients with diabetic retinopathy(DR)after panretinal photocoagulation(PRP).And explore the correlation between these indicators.Methods: In this self-control study,40 eyes of 28 patients with severe NPDR and early PDR who visited the ophthalmology clinic of Lanzhou University Second Hospital from June 2019 to September 2020 were included,including 16 males(24eyes)and 12 females(12 eyes),the mean age is(55.20+6.28)years old,the youngest one is 44 years old,and the oldest one is 68 years old.The OCTA and microperimeter examinations were performed within one week before PRP,1 month,3 months and 6months after PRP.The image J software is used to process and calculate the vascular density of the superficial and deep capillary plexus in the 6mm*6mm range centered on the macular fovea obtained by OCTA,and observe the changes of retinal sensitivity measured by the microperimeter and the best corrected visual acuity(BCVA).Results: The BCVA before PRP and 1 month,3 months,and 6 months after PRP were 0.46±0.27,0.48±0.25,0.52±0.27,0.47±0.23 respectively,p=0.026(<0.05),and the BCVA in 3 months after PRP was higher than that before PRP,p=0.019(<0.05),the BCVA in 6 months after PRP decreased compared with 3 months after PRP,p=0.022(<0.05),the difference was statistically significant.The vessel density of the superficial capillary plexus(SCP)in the macular area before PRP and 1 month,3 months,and 6months after PRP were(37.29±2.23)%,(38.40±2.19)%,(39.57±3.02)%,(38.09±3.43)%,p<0.05.The vessel density of SCP in the macular area at 1 month and 3 months after PRP increased compared with that before PRP,and the p values were all less than 0.05,the difference was statistically significant.The vessel density of deep capillary plexus(DCP)in the macular area before PRP and 1 month,3 months,and 6 months after PRP were(40.66±2.88)%,(41.81±3.37)%,(43.50±3.56)%,(40.73±4.12)%,p=0.001(<0.05).The vessel density of DCP in the macular area at 1 month and 3 months after PRP increased compared with that before PRP,and the p value was less than 0.05,the difference was statistically significant.The retinal sensitivity of the macular area before PRP and 1 month,3 months,and 6 months after PRP were(14.30±3.29)d B,(15.05±2.94)d B,(16.07±2.82)d B,(14.72±2.37)d B,p<0.05,of which,the retinal sensitivity of the macular area 3 months after PRP was improved compared with that before PRP,and the p values was less than 0.05,the difference was statistically significant.Correlation analysis of vessel density of SCP and DCP in macular area 、retinal sensitivity and BCVA at different time showed that vessel density of SCP and DCP in the macular area were positively correlated with visual acuity and BCVA(p<0.05).Conclusion: In patients with severe NPDR and early PDR,the BCVA、the vessel density and retinal sensitivity of the macular area increased after PRP.There is a good agreement between the vessel density and retinal sensitivity in the macular area before and after PRP.Both OCTA and microperimeter are noninvasive and reproducible,and can assess the prognosis of patients with DR after PRP.