Microvascular changes after conbercept therapy in central retinal vein occlusion analyzed by optical coherence tomography angiography

AIM: To investigate microvascular changes in eyes with central retinal vein occlusion(CRVO) complicated by macular edema before and after intravitreal conbercept injection and evaluate correlations between these changes and best-corrected visual acuity(BCVA) and retinal thickness. METHODS: Twenty-eight eyes of 28 patients with macular edema caused by CRVO were included in this retrospective study. All patients received a single intravitreal conbercept injection to treat macular edema. BCVA and the results of optical coherence tomography angiography(OCTA) automatic measurements of the vessel density in the superficial(SCP) and deep retinal capillary plexus(DCP), the foveal avascular zone(FAZ) area, the FAZ perimeter(PERIM), the vessel density within a 300-μm wide ring surrounding the FAZ(FD-300), the acircularity index(AI), the choriocapillaris flow area, and retinal thickness were recorded before and at one month after treatment and compared with the results observed in age-and sexmatched healthy subjects. RESULTS: The vessel density in the SCP and DCP, the FD-300, and the flow area of the choriocapillaris were allsignificantly lower in CRVO eyes than in healthy eyes, while the AI and retinal thickness were significantly higher(all P<0.05). After treatment, retinal thickness was significantly decreased, and the mean BCVA had markedly improved from 20/167 to 20/65(P=0.0092). The flow area of the choriocapillaris was also significantly improved, which may result from the reduction of shadowing effect caused by the attenuation of macular edema. However, there were no significant changes in SCP and DCP vessel density after treatment. The flow area of the choriocapillaris at baseline was negatively correlated with retinal thickness.CONCLUSION: OCTA enables the non-invasive, layerspecific and quantitative assessment of microvascular changes both before and after treatment, and can therefore be used as a valuable imaging tool for the evaluation of the follow-up in CRVO patients.

Gold-Nanoparticles/Boron-Doped-Diamond Composites as Surface-Enhanced Raman Scattering Substrates

By vacuum sputtering and annealing processes of gold(Au)films on boron-doped diamond(BDD)surfaces,Aunanoparticles/BDD(AuNP/BDD)composite substrates were prepared as surface-enhanced Raman scattering(SERS)substrates.The SERS performances of the substrate were investigated using methylene blue molecule as a probe.With the AuNPs having an average diameter of 20 nm,high performance of SERS was achieved at an enhancement factor of 9×10~5,arising from the synergistic effect of electromagnetic enhancement from Au NPs and chemical enhancement from diamond.The AuNP/BDD substrate is demonstrated to be highly sensitive,reproducible,stable,and reusable for the SERS examination.Due to the facile preparation process and controllable surface morphology,the AuNP/BDD substrates are favorable as a high performance SERS platform performed in practical applications.