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Swept-source optical coherence tomography angiography(SS-OCTA)is a new vascular imaging technique that was recently proposed. It has the advantages of being non-invasive, quick, high-resolution, and automated vascular stratification imaging. It is extremely helpful in the early diagnosis of ophthalmology-related diseases, as well as in the evaluation of treatment effectiveness and the tracking of disease progression. Based on the foundation of OCTA, SS-OCTA utilizes a fast-tuning laser with a wavelength of 1 050 nm for deeper penetration and non-invasive depth-resolved imaging of the retinal and choroidal microvascular systems, deepening the understanding of the characteristics of a wide range of ophthalmic diseases(fundus lesions, glaucoma, neurodegenerative diseases, etc.). The structures of the anterior segment of the eye can also be studied using SS-OCTA, including changes in the depth and density of corneal neovascularization as well as changes in iris neovascularization before and after therapy. This approach provides a novel tool for ophthalmic clinical practice. The development of the clinical use of SS-OCTA technology in ophthalmology is reviewed in this article.
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AIM: To evaluate the characteristics of choriocapillary blood flow in different patients with diabetic retinopathy(DR)based on the measurement of choriocapillaris(CC)perfusion density(PFD)using ultra-high-speed swept-source optical coherence tomography angiography(SS-OCTA)METHODS: The cross-sectional observational study was conducted on 139 cases(139 eyes)who admitted to the Second People's Hospital of Hefei, including 115 DR cases(115 eyes)and 24 control cases(24 eyes). The color retinal images were graded according to the Early Treatment Diabetic Retinopathy Study(ETDRS)scale, and the DR eyes were classified into non-DR group, nonproliferative diabetic retinopathy(NPDR)group, NPDR combined with diabetic macular edema(DME)group and proliferative diabetic retinopathy(PDR)group. The ultra-high-speed SS-OCTA was used to scan a 3mm×3mm region centered on the macular central fovea, the CC perfusion area was measured by the built-in software, and PFD was calculated. Multivariable linear regressions were used to evaluate the correlation between PFD of CC and DR degree.RESULTS: The degree of DR had a correlation with blood perfusion of CC after adjusting for various confounding factors. When compared to the control group, the PFD of CC in the central fovea of the NPDR group decreased by 9.358 units(95%CI -18.484～-0.232, P=0.045)and 9.284 units in the paracentral fovea(95%CI -18.487～-0.090, P=0.048); In the NPDR combined with DME group, the central fovea CC PFD decreased by 18.173 units(95%CI -28.583～-7.762, P=0.001), while the paracentral fovea decreased by 17.032 units(95%CI -27.521～-6.544, P=0.002); In the PDR group, the central fovea CC PFD decreased by 28.309 units(95%CI -39.978～-16.640, P<0.001), while the paracentral fovea decreased by 25.841 units(95%CI -37.597～-14.085, P<0.001).CONCLUSION: The macular perfusion can be objectively quantified by the measurement of CC PFD with ultra-high-speed SS-OCTA. The CC PFD in the macular region was significantly reduced in more advanced stages of DR. Furthermore, future research should focus on longitudinal studies in the causal relationship between CC perfusion and DR progression.
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AIM: To explore the feasibility of swept source optical coherence tomography angiography(SS-OCTA)in evaluating early retinal and choroidal microcirculation changes in patients with hypertension.METHODS:Prospective clinical study. A total of 27 patients with grade 2 or 3 essential hypertension(hypertension group)diagnosed in the Department of Cardiology of Xi'an First Hospital from July to November 2022 were included in the study. There were 14 males and 13 females. The mean age was(57.11±3.36)years. During the same period, 27 age- and sex-matched normal people without a history of hypertension were selected as the control group, including 12 males and 15 females. The average age was(55.74±2.95)years old. All patients underwent BCVA(LogMAR), intraocular pressure, axial length, slit lamp examination, fundus color photography and SS-OCTA examination. SS-OCTA was used to scan the macular area of the right eye in the range of 6×6 mm. The retina and choroid were divided into three concentric circles with diameters of 0-1 mm, 1-3 mm and 3-6 mm around the fovea according to ETDRS. Macular vessel density(VD), perfusion area(PA), retinal thickness(CMT), choroidal thickness(CT), choroidal vessel volume(CVV)and choroidal vasculr index(CVI)of the superficial capillary plexus(SCP)and the deep capillary plexus(DCP)in the macular area of 0-1 mm, 1-3 mm and 3-6 mm were analyzed and recorded. The changes in VD, PA, CMT, CT, CVV and CVI were compared between the two groups. Independent sample t-test was used to compare VD, PA, CMT and CVI between the two groups; CT, CVV and LogMAR visual acuity were analyzed by Wilcoxon signed rank test of independent samples.RESULTS:Compared with the control group, the hypertensive group had significantly lower VD in the macular area 0-3 mm(0-1 mm, t=-3.144; 1-3 mm, t=-3.611, P<0.05). VD in the area of 3-6 mm showed a tendency to increase compared with the control group(t=1.715, P>0.05). The CMT in the 0-1mm area of the macular area in the hypertension group was lower than that in the control group(t=-2.624, P<0.05). There was no significant difference in CT, CVV and CVI between the two groups(P>0.05).CONCLUSION:The VD of DCP in the 0-3 mm area and the CMT in the 0-1 mm area are decreased in hypertensive patients. There were no significant differences in CT, CVV and CVI between the two groups. VD and CMT in macular DCP may be used as indicators to evaluate the early changes of retinal and choroidal microcirculation in hypertensive patients.
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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.
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Purpose: To investigate the retinal and choroidal microcirculation changes in celiac disease (CD) patients via optical coherence tomography angiography (OCT?A). Methods: This cross?sectional study included 44 pediatric patients with newly diagnosed CD and 44 healthy pediatric subjects. The vascular densities (VD) of the superficial, deep, and choriocapillar plexuses (VDs, VDd, and VDcc, respectively) (%), the superficial and deep foveal avascular zones (FAZs and FAZd) (%), the central macular thickness (CMT) (?m), and the subfoveal choroidal thickness (SFCT) (?m) were measured with swept?source OCT?A in addition to a complete ophthalmological examination. Results: Mean ages of the CD patients and the healthy participants were 12.02 ± 2.9 and 13.6 ± 2.3 years, respectively. The central sectors of the VDs and VDd measurements were found to be significantly higher in the study group compared to the control group (p = 0.006; P = 0.001, respectively), and the temporal and nasal values of the VDcc measurements were significantly lower in the study group than in the control group (p ? 0.05 for both values). CMT and FAZ metrics did not differ between the groups (p ? 0.05). SFCT was significantly reduced (p = 0.001), and choroidal thinning was more considerable in female CD patients (p = 0.045). Conclusion: CD seems to affect macular and choroidal microcirculation. The reduced choriocapillaris plexus parameters and choroidal thickness may provide disease activity information.
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Purpose: To evaluate the potential clinical utility of wide-field swept source optical coherence tomography angiography (SS-OCTA) using a prototype device compared to a wide-field fundus autofluorescence (FAF) for analysis of the disease activity in eyes with tubercular serpiginous-like choroiditis (TBSLC). Methods: Using a prototype SS-OCTA device (PLEX Elite, Carl Zeiss Meditec, Dublin, CA), 17 eyes of 12 consecutive patients with TBSLC were imaged and multiple 12 mm � 12 mm OCTA scans were captured, which were montaged to create wide-field montage OCTA images scans. A wide- FAF (Eidon, CenterVue, Padova, Italy) was performed in the same sitting. Two masked graders independently analyzed OCTA and FAF images for the presence of choroidal lesions, recorded the number of lesions identifiable, and provided a subjective grading for the activity of individual lesion, which were then compared. Results: The total number of lesions identified on FAF were 282 (posterior pole lesions, n = 129 and peripheral lesions n = 153) and on wide-field SS-OCTA were 230 (posterior pole lesions, n = 108 and peripheral lesions n = 122). Active choroidal lesions were comparable on the two machines (n = 28 on FAF and n = 28 on SS-OCTA, respectively); whereas numerous healed lesions were identified on FAF (n = 219) as compared to SS-OCTA (n = 170). There was good correlation among the devices for healed lesions (Pearson correlation, r = 0.82) and active lesions (r = 0.88). Conclusion: There was good correlation between FAF and wide-field SS-OCTA for detection of disease activity in TBSLC; however, FAF depicted greater number of healed lesions compared to wide-field SS-OCTA.