ObjectiveTo observe the flow density (FD) of macular and optic disc and area of foveal avascular zone (FAZ) in severe nonproliferative diabetic retinopathy (S-NPDR).MethodsA prospective cross-sectional study. From October 2019 to April 2020, 31 eyes of 25 S-NPDR patients (S-NPDR group) who were diagnosed in the ophthalmological examination of Jiangsu Province Hospital and 30 eyes of 30 age- and sex-matched healthy volunteers (control group) were included in this study. Optical coherence tomography angiography (OCTA) was used to scan the macular area of 6 mm×6 mm and optic disc of 4.5 mm×4.5 mm. The software automatically divides it into three concentric circles centered on the macular fovea, which were foveal area with a diameter of 1 mm, parafoveal area of 1 to 3 mm, and foveal peripheral area of 3 to 6 mm. The area around the optic disc was divided into 8 areas: nasal upper, nasal lower, inferior nasal, inferior temporal, temporal lower, temporal upper, superior temporal and superior nasal. The FD of the optic disc, the superficial capillary layer (SCP) and deep capillary layer (DCP) of the retina and FAZ area were measured. The FD and FAZ area were compared between the two groups by independent sample t test. The correlation between FAZ area and FD was analyzed by Pearson correlation.ResultsIn parafoveal and perifoveal area, compared with the control group, the FD of SCP (t=6.470, 5.220; P＜0.001) and DCP (t=7.270, 7.370; P＜0.001) decreased in S-NPDR group. In foveal area, there was statistically significant difference in the FD of DCP between the two groups (t=2.250, P=0.030), while the difference in FD of SCP between the two groups was not statistically significant (t=0.000, P=0.900). The FAZ area in S-NPDR group was larger than that in control group, and the difference was statistically significant (t=2.390, P=0.030). The FD in the S-NPDR group was lower than that in the control group except the superior nasal, the difference was statistically significant (t=7.520, 5.000, 4.870, 3.120, 2.360, 2.120, 5.410, 5.560, 2.640; P＜0.05). Pearson correlation analysis showed that the FAZ area of S-NPDR was negatively correlated with FD of SCP (r=－0.513, P=0.004), and had no correlation with FD of DCP (r=0.034, P=0.859).ConclusionThe overall FD in macular area and optic disc of patients with S-NPDR decreased and the FAZ area enlarged.
Objective To observe the clinical efficacy of pars plana vitrectomy (PPV) combined with dexamethasone intravitreal implant (DEX) in the treatment of proliferative diabetic retinopathy (PDR). MethodsA prospective randomized controlled study. A total of 57 PDR patients with 79 eyes diagnosed by Department of Ophthalmology of The First Affiliated Hospital of Nanjing Medical University from May 2021 to February 2023 were included in the study. Best corrected visual acuity (BCVA) and optical coherence tomography (OCT) were performed in all affected eyes. Central macular thickness (CMT) was measured by OCT. The patients were randomly divided into control group and experimental group, with 27 cases and 35 eyes and 30 cases and 44 eyes, respectively. All eyes were treated with routine 25G PPV and intraoperative whole-retina laser photocoagulation. At the end of the operation, the experimental group was given 0.7 mg DEX intravitreal injection. At 1, 4, 12, and 24 weeks after operation, the same equipment and methods were used for relevant examinations. The improvement after surgery was assessed according to the diabetic retinopathy severity score (DRSS). Mixed analysis of variance was used to compare logarithm of the minimum angle of resolution BCVA and CMT between the two groups and within the two groups before and after operation. ResultsAt 1, 4, 12 and 24 weeks after surgery, BCVA was significantly improved at different time points after surgery, and the differences were statistically significant (P＜0.001). At different time after operation, BCVA in experimental groups was significantly better than that in control group, with statistical significance (P＜0.001). Compared with the CMT before surgery, the CMT at no time point after surgery in experimental group was significantly decreased, and the difference was statistically significant (P ＜0.05). There was no significant difference one week after eye operation in control group (P=0.315). At 4, 12 and 24 weeks after operation, CMT decreased, and the differences were statistically significant (P＜0.05). Compared with before surgery, DRSS increased two steps higher at 1, 4, 12 and 24 weeks after surgery in 20 (45.45%, 20/44), 26 (59.10%, 26/44), 32 (72.73%, 32/44) and 31 (70.45%, 31/44) eyes in the experimental groups, respectively. The control group consisted of 15 (42.86%, 15/35), 15 (42.86%, 15/35), 16 (45.71%, 16/35) and 18 (51.43%, 18/35) eyes, respectively. There was no significant difference in DRSS at 1, 4 and 24 weeks after operation between the control group and the experimental group (P=0.817, 0.178, 0.105). At 12 weeks after surgery, the difference was statistically significant (P=0.020). ConclusionPPV combined with intravitreal injection of DEX in the treatment of PDR can improve postoperative visual acuity, alleviate postoperative macular edema and improve the severity of DR.