Lower Vessel Density Research Articles

Vessel Density Features of Optical Coherence Tomography Angiography for Classification of Glaucoma Using Machine Learning.

Machine learning (ML) based on the optical coherence tomography angiography vessel density features with different thresholds using a support vector machine (SVM) model provides excellent performance for glaucoma detection. To assess the classification performance of ML based on the 4 vessel density features of peripapillary optical coherence tomography angiography for glaucoma detection. Images from 119 eyes of 119 glaucoma patients and 76 eyes of 76 healthy individuals were included. Four vessel density features of optical coherence tomography angiography images were developed using a threshold-based segmentation method and were integrated into 3 models of machine learning classifiers. Images were divided into 70% training set and 30% test set. Classification performances of SVM, random forest, and Gaussian Naive Bayes models were evaluated with the area under the receiver operating characteristic curve (AUC) and accuracy. Glaucoma eyes had lower vessel densities at different thresholds. For differentiating glaucoma eyes, the best results were achieved with 70% and 100% thresholds, in which SVM classifier discriminated glaucoma from healthy eyes with an AUC of 1 and accuracy of 1. After SVM, the random forest classifier with 100% thresholds showed an AUC of 0.993 and an accuracy of 0.994. Furthermore, the AUC of our ML performance (SVM) was 0.96 in a subgroup analysis of mild and moderate glaucoma eyes. ML based on the combined peripapillary vessel density features of total vessels and capillaries in the whole image and ring image could provide excellent performance for glaucoma detection.

Comprehensive Assessment of Eyes in Kidney Transplant Recipients after Recovering from COVID-19.

Patients after organ transplantation with COVID-19 have a higher risk of morbidity and mortality than patients in the general population. There are single studies that assess the eyes of COVID-19 patients, but there are no such studies on organ transplant recipients. The purpose of this study was to comprehensively examine the eyes of kidney transplant recipients (KTR) after recovery from mild to moderate SARS-CoV-2 infection. A total of 40 KTR after COVID-19 and 20 KTR without clinical and immunological symptoms of SARS-CoV-2 infection as a control group was qualified for the cross-sectional study. A total of 76 eyes from 38 KTR on an average of 7 weeks after COVID-19 and 36 eyes from 18 KTR from the control group were studied. The participants underwent an ophthalmological examination, and the retinal and choroid vessels and nerves were assessed by optical coherence tomography angiography. We found a lower vessel density (VD) in the deep capillary plexus in the central part of the retina (VD deep central) of the study group. Women had significantly lower VD deep central in the study group (15.51 vs. 18.91, p < 0.001). Multivariate linear regression analysis confirmed an independent, negative impact of COVID-19 (p < 0.001) and female gender (p = 0.001) on VD deep central. The results of our study confirmed that changes in microcirculation induced by SARS-CoV-2 infection may affect the retinal vessels in KTR. Mild to moderate COVID-19 in KTR resulted in a significant reduction in VD deep central of the retina, with these changes being more common in females.

Do root secondary xylem functional traits differ between growth forms in Fabaceae species in a seasonally dry Neotropical environment?

Whole-plant performance in water-stressed and disturbance-prone environments depends on a suitable supply of water from the roots to the leaves, storage of reserves during periods of shortage, and a morphological arrangement that guarantees the maintenance of the plants anchored to the soil. All these functions are performed by the secondary xylem of roots. Here, we investigate whether different growth forms of Fabaceae species from the seasonally dry Neotropical environment have distinct strategies for water transport, mechanical support and non-structural carbon and water storage in the root secondary xylem. We evaluated cross-sections of root secondary xylem from species of trees, shrubs and subshrubs. We applied linear models to verify the variability in secondary xylem anatomical traits among growth forms. Secondary xylem with larger vessels and lower vessel density was observed in tree species. Vessel wall thickness, vessel grouping index, potential hydraulic conductivity and cell fractions (vessels, fibres, rays and axial parenchyma) were not statistically different between growth forms, owing to the high interspecific variation within the groups studied. Our results showed that the variability in anatomical traits of the secondary xylem of the root is species specific. In summary, the cellular complexity of the secondary xylem ensures multiple functional strategies in species with distinct growth forms, a key trait for resource use in an environment with strong water seasonality.

Vessels characteristics in familial exudative vitreoretinopathy and retinopathy of prematurity based on deep convolutional neural networks.

The purpose of this study was to investigate the quantitative retinal vascular morphological characteristics of Retinopathy of Prematurity (ROP) and Familial Exudative Vitreoretinopathy (FEVR) in the newborn by the application of a deep learning network with artificial intelligence. Standard 130-degree fundus photographs centered on the optic disc were taken in the newborns. The deep learning network provided segmentation of the retinal vessels and the optic disc (OD). Based on the vessel segmentation, the vascular morphological characteristics, including avascular area, vessel angle, vessel density, fractal dimension (FD), and tortuosity, were automatically evaluated. 201 eyes of FEVR, 289 eyes of ROP, and 195 eyes of healthy individuals were included in this study. The deep learning system of blood vessel segmentation had a sensitivity of 72% and a specificity of 99%. The vessel angle in the FEVR group was significantly smaller than that in the normal group and ROP group (37.43 ± 5.43 vs. 39.40 ± 5.61, 39.50 ± 5.58, P = 0.001, < 0.001 respectively). The normal group had the lowest vessel density, the ROP group was in between, and the FEVR group had the highest (2.64 ± 0.85, 2.97 ± 0.92, 3.37 ± 0.88 respectively). The FD was smaller in controls than in the FEVR and ROP groups (0.984 ± 0.039, 1.018 ± 0.039 and 1.016 ± 0.044 respectively, P < 0.001). The ROP group had the most tortuous vessels, while the FEVR group had the stiffest vessels, the controls were in the middle (11.61 ± 3.17, 8.37 ± 2.33 and 7.72 ± 1.57 respectively, P < 0.001). The deep learning technology used in this study has good performance in the quantitative analysis of vascular morphological characteristics in fundus photography. Vascular morphology was different in the newborns of FEVR and ROP compared to healthy individuals, which showed great clinical value for the differential diagnosis of ROP and FEVR.

Trajectory Planning Software for Deep Brain Stimulation Driven by Patient-Specific Data

Abstract Deep brain stimulation (DBS) is a treatment for several neurological disorders including Parkinson's disease, essential tremor, and epilepsy. The neurosurgical procedure involves implanting a lead of electrodes to a deep brain target and thereafter electrically stimulating that target to suppress symptoms. To reduce the probability of intracranial bleeding during implantation, neurosurgeons carefully plan out a patient-specific lead trajectory that avoids passing the lead through regions with major blood vessels. This process can be tedious, and there is a need to provide neurosurgeons with a more efficient and quantitative means to identify major blood vessels on a patient-specific basis. Here, we developed a modular graphical user interface (GUI) containing anatomically segmented digital reconstructions of patient vasculature, cortex, and deep brain target anatomy from preoperative high-field (3T and 7T) MRI. The system prompts users to identify the deep brain target, and then algorithmically calculates a log-scale blood vessel density along the length of potential lead trajectories that pivot around the deep brain target. Heatmaps highlighting regions with low blood vessel density were calculated for cortical and subcortical vasculature models. The modeling framework enabled users to further interact with the models by panning, rotating, zooming, showing, or hiding the various anatomical reconstructions and heatmaps. Providing surgeons with quantitative, patient specific vasculature data has the potential to further reduce the likelihood of hemorrhage events during microelectrode mapping and DBS lead implantation.

Impaired retinal microcirculation in patients with non-obstructive coronary artery disease.

To quantitatively investigate alterations of retinal microcirculation in patients with non-obstructive coronary artery disease (NOCAD) using optical coherence tomography angiography (OCTA), and to identify the ability of retinal microcirculation parameters in differentiating coronary artery disease (CAD) subtypes. All participants with angina pectoris underwent coronary computed tomography angiography. Patients with lumen diameter reduction of 20-50% in all major coronary arteries were defined as NOCAD, while patients with at least one major coronary artery lumen diameter reduction ≥ 50% were recruited as obstructive coronary artery disease (OCAD). Participants without a history of ophthalmic or systemic vascular disease were recruited as healthy controls. Retinal neural-vasculature was measured quantitatively by OCTA, including peripapillary retinal nerve fiber layer (RNFL) thickness and vessel density (VD) of the optic disc, superficial vessel plexus (SVP), deep vessel plexus (DVP), and foveal density (FD 300). p<0.017 is considered significant in multiple comparisons. A total of 185 participants (65 NOCAD, 62 OCAD, and 58 controls) were enrolled. Except for the DVP fovea (p=0.069), significantly reduced VD in all other regions of SVP and DVP was detected in both the NOCAD and OCAD groups compared to control group (all p<0.017), while a more significant decrease was found in OCAD compared to NOCAD. Multivariate regression analysis showed that lower VD in superior hemi part of whole SVP (OR: 0.582, 95% CI: 0.451-0.752) was an independent risk factor for NOCAD compared to controls, while lower VD in the whole SVP (OR: 0.550, 95% CI: 0.421-0.719) was an independent risk factor for OCAD compared to NOCAD. Using the integration of retinal microvascular parameters, the area under the receiver operating characteristic curve (AUC) for NOCAD versus control and OCAD versus NOCAD were 0.840 and 0.830, respectively. Significant retinal microcirculation impairment, while milder than that in OCAD was observed in NOCAD patients, indicating retinal microvasculature assessment might provide a new systemic microcirculation observation window for NOCAD. Furthermore, retinal microvasculature may serve as a new indicator to assess the severity of CAD with good performance of retinal microvascular parameters in identifying different CAD subtypes.

#5761 THE ASSOCIATION OF EGFR SLOPE WITH VISUAL IMPAIRMENT, RETINAL VESSEL DENSITY, AND EYE PATHOLOGIES IN THE EYE DETERMINANTS OF COGNITION (EYEDOC) STUDY

Abstract Background and Aims Previous studies have identified chronic kidney disease (CKD) as a risk factor for poor ocular health. However, the effect of faster decline in estimated glomerular filtration rate (eGFR) on visual function, retinal markers, and eye conditions is unclear. We therefore examined the association of eGFR slope with visual function measures, retinal vessel density (VD), and common ocular pathologies in a bi-racial general population cohort. Method We studied 823 participants with normal kidney function or mild CKD (eGFR ≥ 60 ml/min per 1.73 m²) at baseline from the Eye Determinants of Cognition (EyeDOC) Study. Exposure was change in eGFR (ml/min per 1.73 m² per year) over 4 study visits between 1996 and 2019, calculated using linear mixed-effect models with unstructured covariance matrix. Outcomes (recorded between 2017 and 2019) were visual function (near visual acuity, presenting distance visual acuity, contrast sensitivity), retinal VD in the superficial, intermediate, and deep capillary plexus layers, and common ocular pathologies, such as retinopathy, age-related macular degeneration, and glaucoma. We used linear regression to model the associations of eGFR slope with visual function and retinal VD. We used logistic regression to study the association of eGFR slope with ocular pathologies. All models were adjusted for age, sex, race, education, smoking, body mass index, diabetes, hypertension, and hyperlipidemia. The models for retinal VD were additionally adjusted for signal strength index. Results In our study cohort, the mean age was 79 (±4) years with 62% females and 48% African Americans. The prevalence of diabetes and hypertension was 38% and 82%, respectively. The mean [SD] eGFR slope was −1.6 [0.6] ml/min per 1.73 m² per year. A faster eGFR decline of 1 ml/min per 1.73 m² per year was significantly associated with worse near visual acuity (0.04 logMAR [95% Confidence Interval 0.003; 0.08], p = 0.03), worse contrast sensitivity (−0.03 log [−0.05; −0.001], p = 0.01), lower VD in the deep capillary plexus layer (−0.99% per mm² [−1.96; −0.02], p = 0.04), and higher odds of retinopathy (odds ratio 2.44 [1.06; 6.63], p = 0.04). Associations of eGFR slope with the remaining measures of visual function and eye conditions were not significant. Conclusion In our bi-racial general population cohort with an eGFR ≥ 60 ml/min per 1.73 m² at baseline, a faster decline in eGFR was associated with worse visual function, reduced retinal vascular health, and higher odds of retinopathy. Our results support the potential usefulness of eGFR slope for risk assessment of ocular outcomes, even in patients with normal kidney function or mild CKD.

Retinal microvasculature in schizophrenia: A meta-analysis with trial sequential analysis of studies assessing vessel density using Optical Coherence Tomography Angiography.

We performed a series of random-effects meta-analyses on cross-sectional studies assessing vessel density (VD) using Optical Coherence Tomography Angiography (OCTA) in schizophrenia. Five studies with a total sample size of 410 (schizophrenia-192;healthy-218) were analysed. Supplementary Trial Sequential Analyses (TSA) was also performed. Meta-analyses revealed significantly lower VD in schizophrenia patients compared to healthy controls in the peripapillary region of the optic disc, including both superior hemisphere and inferior hemisphere. TSA validated these significant effects. We conclude that reduced VD at the peripapillary region of the optic disc as measured by OCTA may have the potential to be a schizophrenia biomarker.

The Association of Neovascularization With Optical Coherence Tomography Angiography Parameters in Proliferative Diabetic Retinopathy.

We aim to find an association between neovascularization (NVn) and optical coherence tomography angiography (OCTA) parameters in proliferative diabetic retinopathy (PDR). In a prospective study, 41 subjects including 28 (68%) males and 13 (32%) femaleshaving PDR were examined for neovascularization disc (NVD) and neovascularization elsewhere (NVE) clinically and with fundus fluorescein angiography (FFA). A total of 79 eyes were found to be involved. We examined OCTA parameters including foveal avascular zone (FAZ) size, perimeter and circularity, and vessel density (VD) in the superficial capillary plexus (SCP), deep capillary plexus (DCP), outer retina (OR), outer retinal chorio-capillaries (ORCC), chorio-capillaries (CC), and choroid (C) in these subjects. In eyes with NVD, the central foveal thickness (CFT) (p=0.83) and sub-foveal choroidal thickness (SFCT) (p=0.08) were higher, the FAZ area was significantly larger (p=0.005), and the VD was lower in all retino-choroidal layers. However, it was significantly lower in SCP foveal (p=0.005) and ORCC foveal (p=0.05) than in eyes not having NVD. For NVE, the CFT (p=0.03) and SFCT (p=0.01) were more in affected eyes. The eyes without NVE had a better circularity index (p=0.07) and the highest VD in OR slab (p=0.02) than those eyes that had NVE < ½ disc area (DA) and NVE > ½ DA. On comparing eyes without NVE, NVE < ½ DA, and NVE > ½ DA, the latest had the highest VD in SCP (p=0.59) and lowest VD in DCP (p=0.43) and OR (p=0.02). The VD in ORCC, CC, and choroid was highest in the no NVE group, followed by the NVE > ½ DA and NVE < ½ DA groups in that order. The subjects having vitreous hemorrhage (VH) and intra-retinal microvascular abnormalities (IRMA) had higher values for CFT and SFCT than eyes without these. An increased CFT and SFCT are associated with the appearance of NVD, NVE, VH, and IRMA. The presence of NVD, VH, and IRMA is associated with a larger FAZ area, while that of IRMA and NVE is associated with reduced FAZ circularity. Eyes with NVD, VH, and IRMA had lesser VD in all the retino-choroidal layers. Eyes with NVE > ½ DA had the highest VD in SCP and lowest in DCP and OR; this pattern of VD foretells severer affection in NVE. IRMA was associated with a larger FAZ area, larger FAZ perimeter, and lesser circularity, indicating the presence of central ischemia.

Molecular Ultrasound Imaging Depicts the Modulation of Tumor Angiogenesis by Acetylsalicylic Acid.

Acetylsalicylic acid (ASA) is a well-established drug for heart attack and stroke prophylaxis. Furthermore, numerous studies have reported an anti-carcinogenic effect, but its exact mechanism is still unknown. Here, we applied VEGFR-2-targeted molecular ultrasound to explore a potential inhibitory effect of ASA on tumor angiogenesis in vivo. Daily ASA or placebo therapy was performed in a 4T1 tumor mouse model. During therapy, ultrasound scans were performed using nonspecific microbubbles (CEUS) to determine the relative intratumoral blood volume (rBV) and VEGFR-2-targeted microbubbles to assess angiogenesis. Finally, vessel density and VEGFR-2 expression were assessed histologically. CEUS indicated a decreasing rBV in both groups over time. VEGFR-2 expression increased in both groups up to Day 7. Towards Day 11, the binding of VEGFR-2-specific microbubbles further increased in controls, but significantly (p = 0.0015) decreased under ASA therapy (2.24 ± 0.46 au vs. 0.54 ± 0.55 au). Immunofluorescence showed a tendency towards lower vessel density under ASA and confirmed the result of molecular ultrasound. Molecular US demonstrated an inhibitory effect of ASA on VEGFR-2 expression accompanied by a tendency towards lower vessel density. Thus, this study suggests the inhibition of angiogenesis via VEGFR-2 downregulation as one of the anti-tumor effects of ASA.

The association between retinal microvasculature derived from optical coherence tomography angiography and systemic factors in type 2 diabetics.

To investigate the correlation between the retinal microvasculature using optical coherence tomography angiography (OCTA) and systemic factors in type 2 diabetes mellitus (T2DM) patients. This cross-sectional study obtained OCTA data from patients with T2DM administered at hospital and referred to ophthalmic services. Patient data about demographics, comorbid conditions, and blood biomarkers were extracted from electronic medical records. Data from OCTA scans obtained by CIRRUS HD-OCT Model 5,000 were obtained. Vessel density (VD) and perfusion density (PD) within the superficial capillary plexus, and foveal avascular zone (FAZ) area were automatically segmented. These parameters were tested for their correlations with systemic factors by univariate and multivariable linear regression analyses. A total of 144 T2DM patients (236 eyes) were available for analysis, with mean age of 53.6 (SD = 10.34) and 56.9% were male. Chronic kidney disease, cardiovascular disease, increased serum creatinine (Scr), red blood cell count (RBC), platelets (PLT), apolipoprotein B (APOB), and decreased urine albumin to creatinine ratio (UACR) were significantly associated with lower VD and PD (all p < 0.013). UACR and triglyceride (TRIG) were significantly correlated with FAZ area (all p < 0.017). In multivariate analyses, PLT, eGFR, and APOB were independent risk factors for retinal rarefaction, and UACR was a significant predictor of FAZ area. We found several systemic risk factors, such as PLT, renal function and lipid profiles were associated with PD, VD, and FAZ area among Chinese T2DM patients.

Central retinal microvasculature damage is associated with orthostatic hypotension in Parkinson’s disease

Orthostatic hypotension (OH) is a common non-motor symptom in Parkinson’s disease (PD). OH can cause cerebral and retinal hypoperfusion and is associated with microvascular damage in PD. Optical coherence tomography angiography (OCTA) is a non-invasive technology that can be used to visualize the retinal microvasculature and detect microvascular damage in PD. In the present study, 51 PD patients (OH+, n = 20, 37 eyes; OH−, n = 32, 61 eyes) and 51 healthy controls (100 eyes) were evaluated. The Unified Parkinson’s Disease Rating Scale III, Hoehn and Yahr scale, Montreal Cognitive Assessment, levodopa equivalent daily dose, and vascular risk factors, including hypertension, diabetes, and dyslipidemia, were investigated. PD patients underwent a head-up tilt (HUT) test. The PD patients had a lower superficial retinal capillary plexus (SRCP) density in the central region than control patients. The PDOH+ group had lower vessel density in the SRCP of the central region compared with the control group and lower vessel density in the DRCP of the central region than the PDOH− and control groups. The changes in systolic and diastolic blood pressure during the HUT test in PD patients showed a negative correlation with the vessel density in the DRCP central region. The presence of OH was a critical factor associated with central microvasculature damage in PD. These findings indicate that OCTA can be a useful and non-invasive tool for detecting microvasculature damage in PD patients.

Application of optical coherence tomography angiography for microvascular changes in patients treated with hydroxychloroquine: a systematic review and meta-analysis.

Retinal toxicity with long-term hydroxychloroquine (HCQ) treatment is a major concern. This systematic review aims to assess the application of optical coherence tomography angiography (OCTA) to detect microvascular alterations in patients under HCQ. PubMed, Scopus, Web of Science, and Cochrane Library databases were systematically searched until January 14, 2023. Studies using OCTA as a primary diagnostic method to evaluate the macular microvasculature of HCQ users were included. Primary outcomes were macular vessel density (VD) and foveal avascular zone (FAZ) at the superficial (SCP) and deep (DCP) capillary plexus. Meta-analysis was performed using a random-effects model. Of 211 screened abstracts, 13 were found eligible, enrolling 989 eyes from 778 patients. High-risk patients due to longer duration of treatment presented lower VD in the retinal microvasculature than those with low-risk in SCP (P = 0.02 in fovea; P = 0.004 in parafovea) and in DCP (P = 0.007 in fovea; P = 0.01 in parafovea). When compared with healthy controls, HCQ users had lower VD in both plexus-no quantitative synthesis was presented. Microvascular changes were found in autoimmune patients under HCQ treatment without any documented retinopathy. However, the evidence produced so far does not allow to draw conclusion concerning the effect of drug as studies were not controlled for disease duration.

Longitudinal study on MRI and neuropathological findings: Neither DSC-perfusion derived rCBVmax nor vessel densities correlate between newly diagnosed and progressive glioblastoma.

When evaluating MRIs for glioblastoma progression, previous scans are usually included into the review. Nowadays dynamic susceptibility contrast (DSC)-perfusion is an essential component in MR-diagnostics of gliomas, since the extent of hyperperfusion upon first diagnosis correlates with gene expression and survival. We aimed to investigate if this initial perfusion signature also characterizes the glioblastoma at time of progression. If so, DSC-perfusion data from the initial diagnosis could be of diagnostic benefit in follow-up assessments. We retrospectively identified 65 patients with isocitrate dehydrogenase wildtype glioblastoma who had received technically identical DSC-perfusion measurements at initial diagnosis and at time of first progression. We determined maximum relative cerebral blood volume values (rCBVmax) by standardized re-evaluation of the data including leakage correction. In addition, the corresponding tissue samples from 24 patients were examined histologically for the maximum vessel density within the tumor. Differences (paired t-test/ Wilcoxon matched pairs test) and correlations (Spearman) between the measurements at both timepoints were calculated. The rCBVmax was consistently lower at time of progression compared to rCBVmax at time of first diagnosis (p < .001). There was no correlation between the rCBVmax values at both timepoints (r = .12). These findings were reflected in the histological examination, with a lower vessel density in progressive glioblastoma (p = .01) and no correlation between the two timepoints (r = -.07). Our results suggest that the extent of hyperperfusion in glioblastoma at first diagnosis is not a sustaining tumor characteristic. Hence, the rCBVmax at initial diagnosis should be disregarded when reviewing MRIs for glioblastoma progression.

Optical Coherence Tomography Angiography in CRB1-Associated Retinal Dystrophies.

To report optical coherence tomography angiography (OCTA) findings in patients affected by CRB1-associated retinal dystrophies. Patients affected by a genetically confirmed CRB1-associated retinal dystrophy were prospectively enrolled in an observational study, along with age- and sex-matched healthy volunteers as control subjects. All study and control subjects received a complete ophthalmic examination and multimodal retinal imaging, including OCTA. A total of 12 eyes from 6 patients were included in the study. The mean BCVA of patients was 0.42 ± 0.25 logMAR. Two patients showed large central atrophy, with corresponding definite hypo-autofluorescence on fundus autofluorescence (FAF). Another four patients disclosed different degrees of RPE mottling, with uneven FAF. On OCTA, the macular deep capillary plexus and choriocapillaris had a lower vessel density in eyes affected by CRB1-associated retinopathy when compared to healthy controls. On the other hand, vessel density at the peripapillary radial capillary plexus, superficial capillary plexus, and deep capillary plexus was significantly altered with respect to control eyes. Statistical analyses disclosed a negative correlation between the deep capillary plexus and both LogMAR best corrected visual acuity and central retinal thickness. Our study reveals that CRB1-associated retinal dystrophies are characterized by vascular alterations both in the macular and peripapillary region, as assessed by OCTA.

A normative database of wide-field swept-source optical coherence tomography angiography quantitative metrics in a large cohort of healthy adults.

Data from healthy eyes is needed to interpret optical coherence tomography angiography (OCTA) findings. However, very little normative data is available for wide-field swept-source OCTA (WF SS-OCTA), particularly 12 × 12-mm and disc-centered angiograms. Therefore, we aim to report quantitative metrics in a large sample of control eyes. In this cross-sectional observational study, 482 eyes of 375 healthy adults were imaged on the 100kHz Zeiss PLEX® Elite 9000 using protocols centered on the fovea (3 × 3, 6 × 6, and 12 × 12-mm) and optic disc (6 × 6 and 12 × 12-mm) between December 2018 and January 2022. The ARI Network (Zeiss Portal v5.4) was used to calculate vessel density (VD) and vessel skeletonized density (VSD) in the superficial capillary plexus, deep capillary plexus, and whole retina, as well as foveal avascular zone (FAZ) parameters. Mixed-effect multiple linear regression models were used for statistical analysis. The subjects' median age was 55 (38-63) years, and 201 (53.6%) were female. Greater age and worse best-corrected visual acuity (BCVA) were associated with significantly lower VD and VSD (p < 0.05). VD and VSD differed based on race and cataract status, but not sex, on some scan protocols (p < 0.05). FAZ circularity decreased with age, and FAZ dimensions differed based on race and ethnicity in certain scan protocols. We report a large database of parafoveal and peripapillary vascular metrics in several angiogram sizes. In referencing these values, researchers must consider characteristics such as age, race, and BCVA, but will have a valuable point of comparison for OCTA measurements in pathologic settings.

Long-Term Postoperative Perfusion Indices in Surgically Resolved Myopic Traction Maculopathy

Background: Pathological myopia can be complicated by the presence of posterior staphyloma, macular atrophy, ruptures in Bruch’s membrane, pathologic choroidal neovascularization, and different degrees of myopic traction maculopathy. Purpose: To report the structural, functional and perfusional outcomes in patients underwent surgery for different stages of myopic traction maculopathy (MTM). Methods: A retrospective, consecutive, comparative, interventional, one-surgeon, case-control study was conducted in 46 eyes of 34 individuals between April 2015 and May 2021. Participants included normal emmetropic eyes (Control emmetropia, n = 25), healthy myopic eyes (Control high myopia, n = 20), and operated and structurally fully resolved myopic eyes with different stages of MTM (Surgically treated group, n = 46). Long-term postoperative functional and perfusional follow-up evaluations were performed with spectral domain-optical coherence tomography (SD-OCT) and OCT angiography. The primary outcome measure included long-term functional, structural and perfusion macular status across groups. Results: Forty-six eyes in 34 patients were included in the study group, with both eyes affected in 12 (26.3%) patients. The mean axial length was 29.89 ± 1.67 mm. The preoperative logMAR was 1.29 ± 0.54 and the postoperative logMAR was 0.60 ± 0.52 (P < 0.001), with the biggest reduction in eyes with more advanced MTM. The fellow-eye prevalence rate was 53.85%, with a mean time to surgery of 43 ± 26.77 months. The fellow-eye final VA was 0.34 ± 0.29, and the first-eye final VA was 0.80 ± 0.72 logMAR (P < 0.05). Majority of eyes showed abnormal macula morphology post-operation, where eyes with normal postoperative macula showed better visual improvement (P = 0.022). Conclusion: Compared to emmetropic and healthy myopic eyes, surgically-resolved MTM eyes generally have larger superficial foveal avascular zone area, lower vessel density, smaller choriocapillaris flow area, thinner central subfoveal thickness, and more macular defects. Eyes with stage III or IV MTM had larger deviation compared to eyes at earlier stages. Visual function change after surgery was associated with superficial foveal avascular zone area. Better functional, structural and perfusion index outcomes were observed when highly myopic eyes underwent early surgery.

Analysis of the Optic Nerve Head Microcirculation Using Optical Coherence Tomography Angiography and the Upstream Macrocirculation Using Color Doppler Imaging in Low-Tension and High-Tension Glaucoma Patients

Introduction: The aim of the study was to analyze the optic nerve head (ONH) microcirculation using optical coherence tomography angiography (OCT-A) and the upstream macrocirculation using color Doppler imaging (CDI) in low-tension and high-tension glaucoma (LTG and HTG, respectively). Methods: This cross-sectional study included 67 eyes of 67 HTG patients, 55 eyes of 55 LTG patients, and 42 eyes of 42 healthy controls. We recorded the complete ophthalmological examination, visual fields, retinal nerve fiber layer (RNFL) thickness, ONH vessel density (VD) measured using OCT-A, peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) measured using CDI. SPSS software was used for data analysis. Data are presented as mean ± standard deviation or median (interquartile range) and compared using t test or Mann-Whitney U test, as appropriate. Pearson χ2 test or Fisher’s exact test was used for comparisons, as appropriate. Pearson correlation analysis was used to evaluate the correlations between variables. p < 0.05 was considered statistically significant. Results: The ONH VD and RNFL thickness were considerably lower in glaucomatous eyes than in healthy eyes (both p < 0.001). Compared with the HTG group, the LTG group had lower VD in the peripapillary region (p = 0.027). Compared with the healthy group, the HTG group had lower PSV (p = 0.029 and = 0.023, respectively), lower EDV (p = 0.023 and <0.001, respectively), and higher RI (p = 0.019 and = 0.006, respectively) of the internal carotid artery (ICA) and central retinal artery (CRA). The LTG group had lower PSV (p = 0.015 and <0.001, respectively) and EDV (p = 0.047 and = 0.001, respectively) of the ophthalmic artery (OA) and CRA. The LTG group had lower PSV of CRA than the HTG group (p = 0.034). In glaucomatous eyes, peripapillary VD had a significant association with the mean defect (p < 0.001) and RNFL thickness (p < 0.001), but not with the other CDI indices (all p > 0.05). Conclusion: The ONH microcirculation and upstream macrocirculation of the large arteries exhibited differences in the blood flow characteristics between the LTG and HTG groups. These differences may improve our understanding of glaucoma. There was no correlation between the characteristics of the ONH microcirculation and the upstream macrocirculation of large vessels in the LTG and HTG groups.

Retinochoroidal microvascular changes in newly developed obese children: an optical coherence tomography angiography study

BackgroundChildhood obesity was associated with retinochoroidal microvascular changes using optical coherence tomography angiography (OCTA), but obesity duration was neglected. Obesity is chronic and progressive and obesity duration is related to microvascular function. Thus, it is important to identify microvascular changes in obese children timely to allow possible interventions with the increase in the number of obese children. This pilot study aimed to characterize retinochoroidal microvascular changes in newly developed obese children compared to age- and sex-matched controls.MethodsForty newly developed obese children and 40 age- and sex-matched controls were recruited. All subjects completed comprehensive eye examinations, including axial length, cycloplegic refraction, optical coherence tomography angiography scans (AngioVue; Optovue Inc), etc.ResultsThere were no statistically significant differences between groups in terms of month age (P = 0.927), spherical equivalent refraction (P = 0.753) and axial length (P = 0.196). Newly developed obese children had lower vessel density (VD) in the inferior parafovea (P = 0.026), nasal parafovea (P = 0.038) and temporal perifovea (P = 0.026) of deep vascular complex (DVC), higher VD in the fovea of superficial vascular complex (P = 0.021) and the fovea of DVC (P = 0.016), and smaller foveal avascular zone (P = 0.003) when compared to controls. Also, no apparent differences in any quadrant of total retinal thickness, subfoveal choroidal thickness (SFCT), and choriocapillaries fow voids were detected (all P > 0.05).ConclusionRetinochoroidal microvascular changes had already occurred in newly developed obese children, so early screening and close follow-up eye examinations were recommended; Retinal microvascular insult may precede its structural change and that retina may be a better candidate to predict the onset of retinochoroidal microvascular changes than choroid in obese children.

Post-COVID-19 Syndrome: Retinal Microcirculation as a Potential Marker for Chronic Fatigue.

Post-COVID-19 syndrome (PCS) is characterized by persisting sequelae after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). PCS can affect patients with all COVID-19 disease severities. As previous studies have revealed impaired blood flow as a provoking factor triggering PCS, it was the aim of the present study to investigate the potential association between self-reported chronic fatigue and retinal microcirculation in patients with PCS, potentially indicating an objective biomarker. A prospective study was performed, including 201 subjects: 173 patients with PCS and 28 controls. Retinal microcirculation was visualized by OCT angiography (OCT-A) and quantified using the Erlangen-Angio-Tool as macula and peripapillary vessel density (VD). Chronic fatigue (CF) was assessed according to the variables of Bell's score, age and gender. VDs in the superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP) were analyzed, considering the repetitions (12 times). Seropositivity for autoantibodies targeting G protein-coupled receptors (GPCR-AAbs) was determined by an established cardiomyocyte bioassay. Taking account of the repetitions, a mixed model was performed to detect possible differences in the least square means between the different groups included in the analysis. An age effect in relation to VD was observed between patients and controls (p &lt; 0.0001). Gender analysis showed that women with PCS showed lower VD levels in the SVP compared to male patients (p = 0.0015). The PCS patients showed significantly lower VDs in the ICP as compared to the controls (p = 0.0001 (CI: 0.32; 1)). Moreover, considering PCS patients, the mixed model revealed a significant difference between those with chronic fatigue (CF) and those without CF with respect to VDs in the SVP (p = 0.0033 (CI: -4.5; -0.92)). The model included variables of age, gender and Bell's score, representing a subjective marker for CF. Consequently, retinal microcirculation might serve as an objective biomarker in subjectively reported chronic fatigue in patients with PCS.