Vascular Caliber Research Articles

Analysis of the Vascular Morphology of the Fibrotic Choroidal Neovascularization in Neovascular Age-Related Macular Degeneration Using Optical Coherence Tomography Angiography.

Choroidal neovascularization (CNV) in neovascular age-related macular degeneration (nAMD) undergoing anti-VEGF therapy transforms into a fibrotic lesion. This fibrovascular transformation is associated with a great variety of functional and morphological effects. The aim of this study was to investigate the vascular morphology of fibrotic CNV, to compare it with its surrounding tissue and to identify phenotypes using optical coherence tomography angiography (OCTA). In 18 eyes with fibrotic CNV in nAMD spectral domain OCT (SD-OCT) and OCTA were performed. The automated segmentation lines were manually adjusted. A slab from 60 µm beneath Bruch's membrane to the inner edge of the subretinal hyperreflective material was applied. Quantitative analysis of the vascular morphology was performed using skeletonized OCTA images. Compared to the perilesional rim, the number of segments per area was significantly lower (234.75 ± 25.68 vs. 255.30 ± 20.34 1/mm2, p = 0.0003) within the fibrovascular lesion. Two phenotypes could be identified within the lesion. The phenotypic traits of cluster 1 were few, long and thick vascular segments; Cluster 2 was characterized by many, short and thin vascular segments (number of segments per area: 219.4 ± 18.8 vs. 258.8 ± 13.2 1/mm2, p = 0.00009, segment length: 49.6 ± 2.7 vs. 45.0 ± 1.3 µm, p = 0.0002, vascular caliber: 26.6 ± 1.2 vs. 23.5 ± 1.8 µm, p = 0.003). The clusters did not differ significantly regarding visual acuity (0.52 ± 0.44 vs. 0.54 ± 0.18 logMAR, p = 0.25), differentiability of subretinal (OR = 3.43, CI = [0.30, 39.64], p = 0.6) and intraretinal fluid (OR = 5.34, CI = [0.48, 89.85], p = 0.14). Less normalized ellipsoid zone (EZ) loss could be observed in cluster 1 (131.0 ± 161.3 vs. 892.4 ± 955.6 1/m, p = 0.006). In this study the vascular morphology of fibrotic CNV was analyzed using OCTA. Differences between the lesion and a perilesional rim could be detected. Two phenotypes within the fibrovascular lesion were identified. These morphological clusters could indicate different patterns of fibrovascular transformation of the CNV under long-term anti-VEGF therapy and be useful identifying possible predictive biomarkers in future studies.

A systematic review and participant-level meta-analysis found little association of retinal microvascular caliber with reduced kidney function

Previously, variation in retinal vascular caliber has been reported in association with chronic kidney disease (CKD) but findings remain inconsistent. To help clarify this we conducted individual participant data meta-analysis and aggregate data meta-analysis on summary estimates to evaluate cross-sectional associations between retinal vascular caliber and CKD. A systematic review was performed using Medline and EMBASE for articles published until October 2018. The aggregate analysis used a two-stage approach combining summary estimates from eleven studies (44,803 patients) while the individual participant analysis used a one-stage approach combining raw data from nine studies (33,222 patients). CKD stages 3-5 was defined as an estimated glomerular filtration rate under 60 mL/min/1.73m2. Retinal arteriolar and venular caliber (central retinal arteriolar and venular equivalent) were assessed from retinal photographs using computer-assisted methods. Logistic regression estimated relative risk of CKD stages 3-5 associated with a 20 μm decrease (approximately one standard deviation) in central retinal arteriolar and venular equivalent. Prevalence of CKD stages 3-5 was 11.2% of 33,222 and 11.3% of 44,803 patients in the individual participant and aggregate data analysis, respectively. No significant associations were detected in adjusted analyses between central retinal arteriolar and venular equivalent and CKD stages 3-5 in the aggregate analysis for central retinal arteriolar relative risk (0.98, 95% confidence interval 0.94-1.03); venular equivalent (0.99, 0.95-1.04) or individual participant central retinal arteriolar (0.99, 0.95-1.04) or venular equivalent (1.01, 0.97-1.05). Thus, meta-analysis provided little evidence to suggest that cross sectional direct measurements of retinal vascular caliber was associated with CKD stages 3-5 in the general population. Hence, meta-analyses of longitudinal studies evaluating the association between retinal parameters and CKD stages 3-5 may be warranted.

Comprehensive retinal vascular measurements: a novel association with renal function in type 2 diabetic patients in China

To examine the association between various retinal vascular measurements and microalbuminuria in patients with type 2 diabetes in a northwestern China study. Data from 911 patients with type 2 diabetes were analyzed. Novel retinal vascular measurements from the whole vascular tree were extracted using a validated fully automatic computer program. Retinal vascular measurements were analyzed continuously and categorically for associations with microalbuminuria using multiple logistic regressions, adjusted for related variables. In logistic regression adjusting for multiple variables, microalbuminuria was associated with smaller peripheral arteriolar caliber, larger peripheral venular caliber, larger arteriolar tortuosity, and smaller arteriolar fractal dimension (p = 0.028, p < 0.001, p = 0.038, p = 0.035, respectively). In further categorical analyses, microalbuminuria was related to smaller peripheral arteriolar caliber [T1 vs. T3: odds ratio (OR) 2.029; 95% confidence interval (CI) 1.186–3.473], larger peripheral venular caliber (T1 vs. T3: OR 0.609; 95% CI 0.362–1.024), and smaller arteriolar fractal dimension (T1 vs. T3: OR 1.659; 95% CI 1.028–2.675). Microalbuminuria in type 2 diabetes is associated with both retinal vascular caliber and geometry. These noninvasive vascular measurements serve as potential preclinical markers to identify populations at high risk of early kidney disease in the course of diabetes.

Micro-anatomic alterations of the placenta in a non-human primate model of gestational protein-restriction

ObjectivesMaternal protein malnutrition is associated with impaired fetal growth, and lifetime consequences for the offspring. Our group has previously developed a model of protein-restriction in the non-human primate, which was associated with fetal growth restriction, stillbirth, decreased placental perfusion, and evidence of fetal hypoxia, suggesting perturbed vascular development. Our objective was to histologically characterize the micro-anatomic alterations associated with adverse pregnancy outcomes taking an approach that permits investigation of the 3D vascular structure and surrounding histology without the requirement for 3D vascular casting or relying on 2D stereology which both have methodological limitations.MethodsRhesus macaques were assigned in the pre-gestational period to a control diet that contained 26% protein, or study diet containing 13% protein (50% PR diet). Placental tissue was collected at delivery and processed using a clarification, immunohistochemistry, and confocal microscopy protocol published previously by our group. Three dimensional reconstructions and quantitative assessment of the vascular micro-anatomy was performed using analysis software (Imaris®) and statistical analysis accounted for maternal and fetal confounders.ResultsIn unadjusted analysis, when comparing those pregnancies on a 50% PR diet (n = 4) with those on a control diet (n = 4), protein-restriction diet was associated with decreased maternal pre-pregnancy weight (difference of -1.975kg, 95% CI -3.267 to -0.6826). When controlling for maternal pre-pregnancy weight, fetal sex, and latency from tissue collection to imaging, a gestational protein-restriction diet was associated with decreases in total vascular length, total vascular surface area, total vascular volume, and vascular density.ConclusionIn this pilot study, a gestational protein-restriction diet altered the placental micro-vasculature with decreased vascular caliber and density, which may be related to the observed adverse pregnancy outcomes and perturbed placental perfusion previously demonstrated in this model.

Retinal microvascular metrics in untreated essential hypertensives using optical coherence tomography angiography.

To quantify early changes of macular microvascular density, complexity, and peripapillary vessel caliber in hypertension using optical coherence tomography angiography (OCTA). Hypertension (137 eyes) and healthy eyes (79 eyes) as control were involved in this prospective observational study. Indices of the microcirculation included vessel density (VD), skeleton density (SD), vessel diameter index (VDI), fractal dimension (FD) and foveal avascular zone (FAZ) of superficial retinal layer (SRL) and deep retinal layer (DRL), and peripapillary vessel calibers. The correlation of these indices with mean arterial pressure (MAP) and ocular perfusion pressure (OPP) was analyzed. Mean VD of DRL, SD of SRL and DRL, and FD of SRL and DRL were significantly reduced in the macula of hypertensive eyes (all P < 0.01). Meanwhile, hypertensive eyes had margin results of narrower peripapillary arteriolar caliber (P = 0.04). No significant finding was demonstrated on VD of SRL, VDI and FAZ of SRL and DRL, peripapillary total vascular caliber, and peripapillary venal caliber (all P > 0.05). SD and VD of the DRL correlated negatively with MAP (both R = - 0.152, P = 0.03). OCTA algorithms may provide an additional inexpensive tool to aid in the preclinical assessment of hypertensive subject.

Influence of CNV vascular morphology in exudative age-related macular degeneration on development of visual acuity and need for anti-VEGF therapy after 1 year

The aim of this pilot study was to investigate vascular morphological characteristics of choroidal neovascularization (CNV) at the time of the initial diagnosis of exudative age-related macular degeneration (nAMD), which enable a prognosis for the development of visual acuity and the necessity for treatment in the first year. In 57patients with the initial diagnosis of nAMD, CNV was detected by optical coherence tomography angiography (OCT-A) and an automated quantitative vessel analysis was performed with respect to area, total vessel length, flow value and average vessel caliber of the CNV. After 12months patients were divided into 2 groups based on visual acuity (visual loss vs. visual gain) and necessity of anti-VEGF therapy (<7 intravitreal injections, IVOM vs. ≥7 IVOM). The mean CNV area was 0.95 mm2 ± 1.07 mm2 (group visual loss 1.56 mm2 ± 1.54 mm2; group visual gain 0.65 mm2 ± 0.53 mm2; p = 0.002/<7 IVOM 1.05 mm2 ± 1.40 mm2; ≥7 IVOM 0.98 mm2 ± 0.94 mm2, p = 0.60). The average total vessel length of the CNV was 9.84 mm ± 11.35 mm (visual loss 16.00 mm ± 16.58 mm; visual gain 6.74 mm ± 5.42 mm; p < 0.003/<7 IVOM 11.21 mm ± 15.10; ≥7 IVOM 9.90 mm ± 9.68 mm; p = 0.68). The mean flow value of the CNV was 0.40 ± 0.06 (visual loss 0.37 ± 0.04; visual gain 0.41 ± 0.07; p = 0.004/<7 IVOM 0.42 ± 0.08; ≥7 IVOM 0.38 ± 0.06; p = 0.02). The average vessel caliber was 28.86 µm ± 2.93 µm (visual loss 28.39 µm ± 2.97 mm; visual gain 29.32 µm ± 3.05 µm; p = 0.24/<7 IVOM 30.26 µm ± 3.49 µm; ≥7 IVOM 28.23 µm ± 2.25 µm; p = 0.02). The results show that amathematical quantification of the CNV in nAMD is possible using OCT‑A. This analysis confirmed again that the size of the CNV (area and total vessel length) is decisive for the prognosis of visual acuity. It also shows that alarger flow value as asign of awell-differentiated CNV is associated with abetter functional prognosis. The number of IVOMs required, however, depends primarily on the composition of the CNV (flow value and vascular caliber). More precise imaging and larger examination cohorts could possibly reveal further relevant biomarkers.

Extended-Zone Retinal Vascular Caliber and Risk of Diabetic Retinopathy in Adolescents with Type 1 Diabetes

Retinal vascular caliber has been linked to diabetic retinopathy (DR). Newer imaging technologies allow analysis of retinal vascular caliber beyond the standard areas surrounding the optic disc. We investigated the vascular caliber in extended zones in prediction of DR in adolescents with type 1 diabetes. Prospective, longitudinal study. Adolescents (n = 904) who attended the diabetes complications assessment service at the Children's Hospital at Westmead. Retinal caliber was assessed from baseline retinal photographs with a semiautomated computer software Singapore I Vessel Assessment: standard zone retinal vessel calibers were summarized as central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE), and extended-zone vessels (>2 disc diameters from the optic disc margin) were summarized as mean width of arterioles (MWa) and mean width of venules (MWv). Retinal vessel calibers at baseline (upper 3 quartiles vs. lowest quartiles [Q2-4 vs. Q1]) and moderate DR (stage 3 or more) were analyzed using multivariate generalized estimating equations, with results expressed as odds ratios (OR) and 95% confidence intervals (CIs). Among the 904 participants, baseline mean age ± standard deviation was 14.0 ± 1.5 years, hemoglobin A1C (HbA1C) level was 8.5 ± 1.3%, and median diabetes duration 4.6 years. After a median 3-year follow-up, 15% of adolescents demonstrated moderate DR. Wider extended-zone retinal arteriolar caliber (MWa; OR, 3.6 [95% CI, 2.06-6.1], comparing Q2-4 vs. Q1) and venular caliber (MWv; OR, 4.2 [95% CI, 2.2-7.5]) predicted moderate DR after adjusting for HbA1C and blood pressure. Standard zone CRAE and CRVE were not associated with moderate DR. Extended-zone retinal vessel caliber predicts moderate DR in adolescents with type 1 diabetes.

Do body mass index and waist-to-height ratio over the preceding decade predict retinal microvasculature in 11-12 year olds and midlife adults?

Microvascular changes may contribute to obesity-associated cardiovascular disease. We examined whether body mass index (BMI) and waist-to-height ratio (WHtR) (1) at multiple earlier time points and (2) decade-long trajectories predicted retinal microvascular parameters in mid-childhood/adulthood. Participants/design: 1288 11-12 year olds (51% girls) and 1264 parents (87% mothers) in the population-based Child Health CheckPoint (CheckPoint) module within the Longitudinal Study of Australian Children (LSAC). LSAC exposure measures: biennial BMI z-score and WHtR for children at five time points from age 2-3 to 10-11 years and self-reported parent BMI at six time points from child age 0-1 years to 10-11 years. CheckPoint outcome measures: retinal arteriolar and venular caliber. BMI/WHtR trajectories were identified by group-based trajectory modeling; linear regression models estimated associations between BMI/WHtR at each time point/trajectories and later retinal vascular caliber, adjusted for age, sex, and family socioeconomic status. In time point analyses, higher child BMI/WHtR from age 4 to 5 years was associated with narrower arteriolar caliber at the age of 11-12 years, but not venular caliber. For example, each standard deviation higher in BMI z-score at 4-5 years was associated with narrower arteriolar caliber at 11-12 years (standardized mean difference (SMD): -0.05, 95% confidence interval (CI): -0.10 to 0.01); by 10-11 years, associations had doubled to -0.10 (95% CI: -0.16 to -0.05). In adults, these finding were similar, except the magnitude of BMI and arteriolar associations were similar across all time points (SMD: -0.11 to -0.13). In child and adult BMI trajectory analyses, less favorable trajectories predicted narrower arteriolar (p-trend < 0.05), but not venular (p-trend > 0.1), caliber. Compared with those in the average BMI trajectory, SMDs in arterial caliber for children and adults in the highest trajectory were -0.25 (95% CI: -0.44 to -0.07) and -0.42 (95% CI: -0.73 to -0.10), respectively. Venular caliber showed late associations with child WHtR, but not with BMI in children or adults. Associations of decade-long high BMI trajectories with narrowed retinal arteriolar caliber emerge in children, and are clearly evident by midlife. Adiposity appears to exert its early adverse life course impacts on the microcirculation more via arteriolar than venular mechanisms.

Retinal vascular diameter changes assessed with a computer-assisted software after strabismus surgery.

To quantitatively investigate the retinal vascular diameter changes, analyzing the early and long-term effects on the retinal circulation, with 6-month follow-up. Patients underwent horizontal strabismus surgery were enrolled prospectively. Retinal vessel diameters on color fundus photographs were assessed before and 1, 7d, 6mo after surgery, using a computer-assisted quantitative assessment software. To evaluate the retinal vascular caliber changes, retinal vascular diameters were calculated by means of the Parr-Hubbard formula as the central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE). The arteriovenous ratio (AVR) was calculated as CRAE divided by CRVE. A total of 154 eyes of 104 consecutive patients were included. Compared with the data before surgery (121.55±24.67), the mean CRAE (131.18±28.29) significantly increased 1d after surgery (P=0.003), but went back to baseline level at 7d (118.89±30.35, P=0.15), and 6mo (123.22±15.32, P=0.60), so did the AVR (P<0.001, P=0.08, P=0.07). As for the mean CRVE, there was no significant difference between those four time points (172.43±33.25, 175.57±36.98, 174.03±40.18, 174.86±20.46, P=1.00). Strabismus surgery on both lateral and media rectus muscles, or single media rectus muscle may increase retinal blood flow during the early postoperative period, but would return to normal later. The number of transected anterior ciliary arteries rather might be the main cause of retinal hemodynamic changes early after strabismus surgery.

Exploring Associations Between Cardiac Structure and Retinal Vascular Geometry.

BackgroundRetinal arteriolar narrowing and venular widening has been widely suggested to be associated with subclinical changes in cardiac structure. The novel retinal vascular geometric indices might reflect more comprehensive information on microvasculature other than vascular caliber alone. However, the association between suboptimal retinal vascular geometry and cardiac structural alteration has not been studied.Methods and ResultsWe recruited 50 participants without cardiovascular disease from the Cardiac Aging Study conducted between 2014 and 2016. We performed transthoracic echocardiography imaging to measure cardiac structure indices such as left ventricular internal diameter end diastole index, left ventricular internal diameter end systole index, left ventricular mass index, and left atrial volume index, and retinal imaging to measure retinal vascular geometric indices including branching angle, curvature tortuosity, and fractal dimension. We applied multiple linear regressions to examine associations between indices of cardiac structure and retinal vascular geometry, adjusting for age, sex, body mass index, mean blood pressure, and comorbidity. The average age of all participants was 62.54 years old and slightly more than half were male (27; 54%). Each unit increase in a set of cardiac structure indices was associated with larger retinal arteriolar branching angle (β and 95% CI: for left ventricular internal diameter end systole index, 26.93°; 6.00–47.86; for left ventricular internal diameter end diastole index, 17.86°; 1.61–34.11; for left ventricular mass index, 0.39°; 0.10–0.67; for left atrial volume index, 0.91°; 0.24–1.58).ConclusionsAdverse retinal arteriolar geometric morphology mirrored suboptimal cardiac structural alteration.

Association Between Caliber of Retinal Vessels and Cardiovascular Disease: a Systematic Review and Meta-Analysis.

The aim of this study to is report the findings of a systemic review and meta-analysis of the literature on the association between retinal vascular caliber and cardiovascular diseases. The caliber of retinal vessels has been recognized as an important biomarker for risk stratification in various cardiovascular diseases, such as coronary artery disease, heart failure, stroke, and mortality. Non-invasively quantifying retinal vasculature may be useful in screening individuals who are at risk of cardiovascular disease. Further evaluating the role of retinal vessel anatomy and incorporating it into a scoring system on risk of cardiovascular diseases are needed in future studies.

Inflammation mediates the relationship between obesity and retinal vascular calibre in 11-12 year-olds children and mid-life adults

Obesity predicts adverse microvasculature from childhood, potentially via inflammatory pathways. We investigated whether inflammation mediates associations between obesity and microvascular parameters. In 1054 children (mean age 11 years) and 1147 adults (44 years) from a cross-sectional study, we measured BMI (z-scores for children) and WHtR, Glycoprotein acetyls (GlycA), an inflammatory marker, and retinal arteriolar and venular calibre. Causal mediation analysis methods decomposed a “total effect” into “direct” and “indirect” components via a mediator, considering continuous and categorical measures and adjusting for potential confounders. Compared to normal-weight BMI children, those with overweight or obesity had narrower arteriolar calibre (total effects −0.21 to −0.12 standard deviation (SD)): direct (not mediated via GlycA) effects were similar. Children with overweight or obesity had 0.25 to 0.35 SD wider venular calibre, of which 19 to 25% was mediated via GlycA. In adults, those with obesity had 0.07 SD greater venular calibre, which was completely mediated by GlycA (indirect effect: 0.07 SD, 95% CI −0.01 to 0.16). Similar findings were obtained with other obesity measures. Inflammation mediated associations between obesity and retinal venules, but not arterioles from mid-childhood, with higher mediation effects observed in adults. Interventions targeting inflammatory pathways may help mitigate adverse impacts of obesity on the microvasculature.

Retinal Vascular Signs and Cerebrovascular Diseases.

Cerebrovascular disease (CeVD), including stroke, is a leading cause of death globally. The retina is an extension of the cerebrum, sharing embryological and vascular pathways. The association between different retinal signs and CeVD has been extensively evaluated. In this review, we summarize recent studies which have examined this association. We searched 6 databases through July 2019 for studies evaluating the link between retinal vascular signs and diseases with CeVD. CeVD was classified into 2 groups: clinical CeVD (including clinical stroke, silent cerebral infarction, cerebral hemorrhage, and stroke mortality), and sub-clinical CeVD (including MRI-defined lacunar infarct and white matter lesions [WMLs]). Retinal vascular signs were classified into 3 groups: classic hypertensive retinopathy (including retinal microaneurysms, retinal microhemorrhage, focal/generalized arteriolar narrowing, cotton-wool spots, and arteriovenous nicking), clinical retinal diseases (including diabetic retinopathy [DR], age-related macular degeneration [AMD], retinal vein occlusion, retinal artery occlusion [RAO], and retinal emboli), and retinal vascular imaging measures (including retinal vessel diameter and geometry). We also examined emerging retinal vascular imaging measures and the use of artificial intelligence (AI) deep learning (DL) techniques. Hypertensive retinopathy signs were consistently associated with clinical CeVD and subclinical CeVD subtypes including subclinical cerebral large artery infarction, lacunar infarction, and WMLs. Some clinical retinal diseases such as DR, retinal arterial and venous occlusion, and transient monocular vision loss are consistently associated with clinical CeVD. There is an increased risk of recurrent stroke immediately after RAO. Less consistent associations are seen with AMD. Retinal vascular imaging using computer assisted, semi-automated software to measure retinal vascular caliber and other parameters (tortuosity, fractal dimension, and branching angle) has shown strong associations to clinical and subclinical CeVD. Other new retinal vascular imaging techniques (dynamic retinal vessel analysis, adaptive optics, and optical coherence tomography angiography) are emerging technologies in this field. Application of AI-DL is expected to detect subclinical retinal changes and discrete retinal features in predicting systemic conditions including CeVD. There is extensive and increasing evidence that a range of retinal vascular signs and disease are closely linked to CeVD, including subclinical and clinical CeVD. New technology including AI-DL will allow further translation to clinical utilization.

Relation between retinal vascular abnormalities and working memory impairment in patients with schizophrenia and bipolar disorder.

Emerging evidence indicates abnormal retinal micro-vasculature in schizophrenia (SCZ) and bipolar disorder (BD) and its relation to cognitive functions. However, the association of these abnormalities with the cognitive deficits in these disorders has not been examined till date. Hence, we explored this aspect in patients with SCZ, BD, and healthy volunteers (HV). We examined 34 with SCZ, 39 with BD, and 45 HV. Retinal images were acquired using nonmydriatic fundus camera. The retinal images were analyzed, and average diameters of retinal arterioles and venules were calculated. Working memory was assessed using computerized one-back test from Cogstate® battery. There was significant difference between groups in retinal venules and arterioles caliber (p < 0.001). Both SCZ and BD patients had wider venules and narrower arterioles. They had significantly lower working memory accuracy (p = 0.008) and higher log mean speed (p < 0.001). There was significant positive correlation between one-back test accuracy and retinal arteriolar caliber (r = 0.22; p = 0.01) and between log mean speed score and retinal venular caliber (r = 0.20; p = 0.02). Findings suggest association between working memory and retinal vascular caliber, a potential pointer towards understanding the vascular pathology in cognitive deficits in SCZ and BD. Future studies need to examine whether retinal vascular could be a biomarker for SCZ and BD.

QUANTITATIVE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY FEATURES FOR OBJECTIVE CLASSIFICATION AND STAGING OF DIABETIC RETINOPATHY.

This study aims to characterize quantitative optical coherence tomography angiography (OCTA) features of nonproliferative diabetic retinopathy (NPDR) and to validate them for computer-aided NPDR staging. One hundred and twenty OCTA images from 60 NPDR (mild, moderate, and severe stages) patients and 40 images from 20 control subjects were used for this study conducted in a tertiary, subspecialty, academic practice. Both eyes were photographed and all the OCTAs were 6 mm × 6 mm macular scans. Six quantitative features, that is, blood vessel tortuosity, blood vascular caliber, vessel perimeter index, blood vessel density, foveal avascular zone area, and foveal avascular zone contour irregularity (FAZ-CI) were derived from each OCTA image. A support vector machine classification model was trained and tested for computer-aided classification of NPDR stages. Sensitivity, specificity, and accuracy were used as performance metrics of computer-aided classification, and receiver operation characteristics curve was plotted to measure the sensitivity-specificity tradeoff of the classification algorithm. Among 6 individual OCTA features, blood vessel density shows the best classification accuracies, 93.89% and 90.89% for control versus disease and control versus mild NPDR, respectively. Combined feature classification achieved improved accuracies, 94.41% and 92.96%, respectively. Moreover, the temporal-perifoveal region was the most sensitive region for early detection of DR. For multiclass classification, support vector machine algorithm achieved 84% accuracy. Blood vessel density was observed as the most sensitive feature, and temporal-perifoveal region was the most sensitive region for early detection of DR. Quantitative OCTA analysis enabled computer-aided identification and staging of NPDR.

Does established vascular kidney disease exist?

Does established vascular kidney disease exist?

Morphologic Analysis of Peripapillary Retinal Arteriole Using Adaptive Optics in Primary Open-angle Glaucoma.

The purpose of this study was to better understand the role of vascular risk factors in the pathogenesis of primary open-angle glaucoma (POAG), a detailed analysis of retinal arterial wall thickness is needed. The purpose of the present study was to make a morphologic analysis of peripapillary arteriole in POAG using adaptive optics (AO) technology. We included otherwise healthy subjects with an isolated confirmed diagnosis of bilateral POAG. Patients' clinical characteristics were noted. AO imaging followed by a complete ophthalmic examination was performed. A single operator masked to clinical data performed 5 measurements at different locations of each analyzed vessel. For each location, lumen diameter and wall thickness were measured. Total diameter, wall-to-lumen ratio (WLR), and whole cross-sectional area were calculated. Lumen diameter and total diameter were significantly lower in the glaucoma group (n=31) than in the control group (n=29): [median (interquartile ranges)] 88.3 (82.6-99.2) versus 102.3 (87-113.1) (P=0.03) and 121.1 (109.3-130.5) versus 134.4 (112.7-144.4), respectively (P=0.015). Wall thickness, WLR, and whole cross-sectional area were not significantly different. Apart from a significantly higher WLR in subjects with reported high cholesterol levels, we did not observe any correlation between patients' clinical characteristics and any of the parameters. We observed in POAG a narrowing of the arteriolar lumen without modification of the vessel wall thickness. To date, it is the first time that these data are obtained using AO. This suggests that the vascular risk factor in POAG only reduces the vascular caliber without inducing any patent atherosclerosis of the retinal arterial wall.

Association between hypertension and retinal vascular features in ultra-widefield fundus imaging

ObjectiveChanges to the retinal vasculature are known to be associated with hypertension independently of traditional risk factors. We investigated whether measurements of retinal vascular calibre from ultra-widefield fundus imaging were...

Sex-Specific Association Between Serum Uric Acid and Retinal Microvessels.

BackgroundAs epidemiological findings are still controversial, animal experiments have probed into the potential link between uric acid and damage to microvessels. The present study examined the association of serum uric acid (SUA) with the retinal vascular caliber and retinal vascular fractal dimension (Df) in males and females utilizing a cross-sectional study design.Material/MethodsA total of 2169 subjects from 7 sampling units were enrolled. Retinal vascular parameters were analyzed with a semi-automated computer-based program. The central retinal arteriolar equivalent, central retinal venular equivalent, and Df were linearly and categorically measured in males and females and at various SUA levels.ResultsThe analysis revealed that per SD SUA increase was associated with an increase of 0.848 μm in the arteriolar caliber, and an increase of 1.618 μm in the venular caliber only in females. No significant correlation was found between Df and SUA in females or in males. Further adjusted for more cardiovascular risk factors did not change the results.ConclusionsBy exploring a Chinese coastal population, we elucidate the association between SUA with retinal arterioles and venules in females. Df, as a mathematical index of retinal blood vascular complexity, is not correlated with SUA or hyperuricemia.

Cardiovascular health and retinal microvascular geometry in Australian 11–12 year-olds

Traditional retinal microvascular parameters (smaller arteriolar and greater venular caliber) are associated with cardiovascular risk factors, pre-clinical vascular phenotypes and clinical cardiovascular events in adults. Although novel retinal microvascular geometric parameters showed analogous associations in adults, less is known whether these parameters are associated with cardiovascular health from childhood. In a population-based cross-sectional study in children (n = 1126, mean age 11.4 years, 50.3% girls), we examined associations of cardiovascular risk factors and pre-clinical arterial phenotypes with retinal geometric parameters. Cardiovascular parameters included body mass index (BMI), an inflammatory marker (GlycA), low-density lipoprotein and high-density lipoprotein (HDL) cholesterol, systolic (SBP) and diastolic blood pressure, large artery functional (pulse wave velocity, PWV and carotid arterial elasticity) and structural (carotid intima-media thickness) phenotypes. Retinal geometric parameters (fractal dimension (Df) and tortuosity) were quantified from retinal images. Multivariable regression models were performed and adjusted for potential confounders. Higher values for BMI, SBP and PWV showed weak associations with lower (i.e. worse) arteriolar but not venular Df (standardized mean difference (SMD) ranging from −0.07 to −0.09, 95% CIs −0.15 to −0.01). Higher HDL was associated with greater arteriolar Df (SMD 0.07, 95% CI 0.01 to 0.13). Only higher SBP was associated with higher (i.e. worse) arteriolar but not venular tortuosity (SMD 0.09, 95% CI 0.02 to 0.16). In generally healthy children, some risk factors and pre-clinical arterial phenotypes show small associations with retinal geometric parameters. In childhood, emerging relationships between microvascular parameters and cardiometabolic risk may be better described by retinal vascular caliber than by geometric parameters.