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AIM: To quantify early changes of macular capillary parameters in type 2 diabetic patients using optical coherence tomography angiography(OCTA).METHODS: Retrospective case study. A total of 49 healthy subjects, 52 diabetic patients without retinopathy(noDR)patients, and 43 mild nonproliferative diabetic retinopathy(mNPDR)patients were recruited. Capillary perfusion density, vessel length density(VLD), and average vessel diameter(AVD)were calculated from macular OCTA images(3 mm×3 mm)of the superficial capillary plexus after segmenting large vessels and the deep capillary plexus. Parameters were compared among control subjects, noDR, and mNPDR patients. The area under the receiver operating characteristic curve estimated the abilities of these parameters to detect early changes of retinal microvascular networks.RESULTS: Significant differences were found in the VLD and AVD among the three groups(P<0.001). Compared with the control group, the noDR group had significantly higher AVD(P<0.05). VLD of both layers in patients of mNPDR group was significant decreased compared with that of noDR group(all P<0.01). Deep AVD had a higher area under the curve(AUC)of 0.796 than other parameters to discriminate the noDR group from the healthy group. Deep AVD had the highest AUC of 0.920, followed by that of the deep VLD(AUC=0.899)to discriminate the mNPDR group from the healthy group.CONCLUSIONS: NoDR patients had wider AVD than healthy individuals and longer VLD than mNPDR patients in both layers. When compared with healthy individuals, deep AVD had a stronger ability than other parameters to detect early retinal capillary impairments in noDR patients.
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Purpose: To correlate microvascular changes and assess the relationship between microvascular changes and cardiovascular disease (CVD) risk in patients with retinal vein occlusion (RVO). Methods: Patients over 40 years of age with unilateral RVO were included in this prospective study. Those known to have cardiovascular disease were excluded. A detailed medical history was taken and physical exam was done to measure the height, weight, body mass index (BMI), and systolic blood pressure (SBP). A comprehensive eye check?up was followed by optical coherence tomography angiography (OCTA). Microvascular indices such as vessel density (VD) and perfusion density (PD) were noted. A statistical model was developed for prediction of CVD risk and was integrated with the World Health Organization (WHO)’s risk prediction charts. Results: This study included 42 patients with RVO and 22 controls with an age range of 42–82 years. There were 40 males (62.5%) and 24 females (37.5%). Along with age, SBP, and gender, perfusion density was found to have significant impact on CVD risk (P = 0.030). Reduction in PD was associated with increase in CVD risk. PD had a greater influence on CVD in <50 years age than in >70 years group. Using linear regression, a model with accuracy of 72.1% was developed for CVD risk prediction and was converted into color coded charts similar to WHO risk prediction charts. Conclusion: These findings suggest a significant correlation between microvascular parameters and CVD risk in RVO patients. Based on these parameters, an easy?to?use and color?coded risk prediction chart was developed
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Objective To compare the macular structure and microcirculation in both eyes of the patients with myopic anisometropia.Methods Optical coherence tomography angiography(OCTA)was employed to scan the macular areas in both eyes of 44 patients with myopic anisometropia.The patients were assigned into high and low groups based on the refractive diopter,and the parameters such as retinal thickness,choroidal thickness,vascular density,and perfusion density in the macular areas of both eyes were compared between the two groups.Results Other macular areas except the central and external nasal areas and the choroid of the fovea in the high group were thinner than those in the low group(all P<0.05).There was no statistically significant difference in retinal vascular density or perfusion density in different areas between the two groups(all P>0.05).Conclusion In the patients with myopic anisometropia,most areas of the retina in the case of high myopia is thinner than that in the case of low myopia,while there is no difference in retinal vascular density or perfusion density in both eyes.
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Humanos , Anisometropía , Coroides/irrigación sanguínea , Microcirculación , Miopía , Retina , Tomografía de Coherencia Óptica/métodosRESUMEN
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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Purpose: To evaluate the retinal microvascular changes in patients, recovered from severe COVID?19 during the second wave of the pandemic in North India. Methods: In this observational cross?sectional study, 70 eyes of 35 patients who recovered from severe COVID?19 during the second wave underwent detailed ophthalmic evaluation 4–6 weeks after discharge. Twelve controls were also enrolled, and the difference in the findings between the case and control groups on optical coherence tomography (OCTA) were studied. Result: The ages of study participants ranged from 27 to 60 years with the male:female ratio being 1.05:1. The fundus changes suggestive of ischemia in the form of cotton wool spots and vascular tortuosity were seen in 25 eyes (35.71%). Increased venous tortuosity was the most common finding seen in 23 eyes (32.85%), of which 10 eyes (28.57%) had concurrent hypertensive retinopathy (HTR) changes. There was a significant reduction in the mean vascular density (VD) and perfusion density (PD) for both the superficial capillary plexus (SCP) and deep capillary plexus (DCP) at inner, outer ring, and whole (P < 0.05). Foveal avascular zone was significantly enlarged in both the SCP (P = 0.01) and the DCP (P = 0.03). The mean ganglion cell?inner plexiform layer (GC?IPL) was significantly reduced in comparison to controls (P < 0.001). Conclusion: Severe COVID?19 can result in microvascular changes at the macula in the form of reduction in vascular and perfusion density, which can be evaluated using OCTA. As structural changes precede functional changes, a close watch is recommended in patients showing compromise in retinal microvasculature
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Resumen Introducción: Distintos protocolos de angiotomografía de coherencia óptica evalúan la mácula. Objetivo: R2) entre las densidades vascular y de perfusión de dos protocolos de angiotomografía de coherencia óptica, para determinar si sus mediciones podían intercambiarse. Método: Estudio observacional, comparativo, prospectivo, transversal entre dos protocolos de angiotomografía de coherencia óptica (AngioPlex, Zeiss) en sujetos sanos. Se identificó la R2 entre las densidades vascular y de perfusión central, interna y completa (protocolo de 3 x 3 mm), y central, interna, externa y completa (protocolo de 6 x 6 mm). Resultados: 78 ojos, mediana de edad 23 años. Hubo R2 altas entre las densidades interna y completa del protocolo de 3 x 3 mm (0.96), externa y completa del de 6 x 6 mm (0.96), y centrales vasculares y de perfusión (≥ 0.96); la R2 entre las densidades centrales vascular y de perfusión de distintos protocolos fue ≤ 0.71. Conclusiones: Las densidades vasculares y de perfusión tienen R2 alta dentro de un protocolo, pero no entre protocolos, porque estos miden preferentemente zonas distintas, lo cual limita intercambiar mediciones.
Abstract Introduction: Different optical coherence tomography angiography (OCTA) scanning protocols evaluate the macula. Objective: To compare the determination coefficients (R2) between vessel and perfusion densities of two OCTA scanning protocols, to learn whether their metrics could be interchanged. Method: Non-experimental, comparative, prospective, observational, cross-sectional study, between two OCTA scanning protocols (Angioplex, Zeiss) in healthy subjects. We found the R2 between central, inner, and full densities (3 x 3 mm protocol), and between central, inner, outer and full densities (6 x 6 mm protocol), both for vessel and perfusion densities. Results: 78 eyes, median age 23 years. There were high R2 between inner and full densities in the 3 x 3 mm protocol (0.96), between outer and full densities in the 6 x 6 mm protocol (0.96) and between central vessel and perfusion densities (≥0.96); R2 between central vessel and perfusion densities of different protocols (≤0.71). Conclusions: Vessel and perfusion densities have high determination coefficients within a scanning protocol, but not between protocols, because each preferentially measures different macular areas. The metrics of different protocols should not be interchanged for follow-up.