The eye and the heart

Phenotypic and genetic characteristics of retinal vascular parameters and their association with diseases

Fundus images allow for non-invasive assessment of the retinal vasculature whose features provide important information on health. Using a fully automated image processing pipeline, we extract 17 different morphological vascular phenotypes, including median vessels diameter, diameter variability, main temporal angles, vascular density, central retinal equivalents, the number of bifurcations, and tortuosity, from over 130,000 fundus images of close to 72,000 UK Biobank subjects. We perform genome-wide association studies of these phenotypes. From this, we estimate their heritabilities, ranging between 5 and 25%, and genetic cross-phenotype correlations, which mostly mirror the corresponding phenotypic correlations, but tend to be slightly larger. Projecting our genetic association signals onto genes and pathways reveals remarkably low overlap suggesting largely decoupled mechanisms modulating the different phenotypes. We find that diameter variability, especially for the veins, associates with diseases including heart attack, pulmonary embolism, and age of death. Mendelian Randomization analysis suggests a causal influence of blood pressure and body mass index on retinal vessel morphology, among other results. We validate key findings in two independent smaller cohorts. Our analyses provide evidence that large-scale analysis of image-derived vascular phenotypes has sufficient power for obtaining functional and causal insights into the processes modulating the retinal vasculature.

Optical coherence tomography angiography of the retina and choroid in systemic diseases

Optical coherence tomography angiography (OCTA) has transformed ocular vascular imaging, revealing microvascular changes linked to various systemic diseases. This review explores its applications in diabetes, hypertension, cardiovascular diseases, and neurodegenerative diseases. While OCTA provides a valuable window into the body's microvasculature, interpreting the findings can be complex. Additionally, challenges exist due to the relative non-specificity of its findings where changes observed in OCTA might not be unique to a specific disease, variations between OCTA machines, the lack of a standardized normative database for comparison, and potential image artifacts. Despite these limitations, OCTA holds immense potential for the future. The review highlights promising advancements like quantitative analysis of OCTA images, integration of artificial intelligence for faster and more accurate interpretation, and multi-modal imaging combining OCTA with other techniques for a more comprehensive characterization of the ocular vasculature. Furthermore, OCTA's potential future role in personalized medicine, enabling tailored treatment plans based on individual OCTA findings, community screening programs for early disease detection, and longitudinal studies tracking disease progression over time is also discussed. In conclusion, OCTA presents a significant opportunity to improve our understanding and management of systemic diseases. Addressing current limitations and pursuing these exciting future directions can solidify OCTA as an indispensable tool for diagnosis, monitoring disease progression, and potentially guiding treatment decisions across various systemic health conditions.

Association of subretinal drusenoid deposits and cardiovascular disease

The presence of subretinal drusenoid deposits (SDDs) in patients with age-related macular degeneration (AMD) appears to be correlated with cardiovascular disease (CVD) and may serve as a useful tool for predicting certain forms of CVD. Here, we tested this hypothesis by examining whether patients with AMD with SDDs are more likely to have a cardiovascular-related condition and/or undergo a cardiovascular procedure. This is a retrospective cohort study. We included a total of 597 patients with AMD either with SDDs (n = 332) or without SDDs (n = 265). All patients underwent spectral-domain optical coherence tomography (SD-OCT). The SD-OCT scans were annotated by masked, experienced graders. We also extracted data from the patients' electronic medical records (EMRs), including patient demographics, cardiovascular diagnoses, and CVD-related procedures based on ICD-9 codes. AMD patients with SDDs were more likely to be diagnosed with CVD or undergo a cardiovascular procedure compared to AMD patients without SDDs, particularly percutaneous transluminal coronary angioplasty (PTCA; OR 2.73, 95% CI [1.21, 6.13], p = 0.02). Multivariate analysis confirmed the association between the presence of SDDs and a background of PTCA in the presence of other covariates. These data suggest that the presence of SDDs in patients with AMD correlates with certain severe cardiovascular conditions; SDDs and CVD may share common pathogenic pathways.

GWAS-by-subtraction reveals an IOP-independent component of primary open angle glaucoma

The etiology of primary open angle glaucoma is constituted by both intraocular pressure-dependent and intraocular pressure-independent mechanisms. However, GWASs of traits affecting primary open angle glaucoma through mechanisms independent of intraocular pressure remains limited. Here, we address this gap by subtracting the genetic effects of a GWAS for intraocular pressure from a GWAS for primary open angle glaucoma to reveal the genetic contribution to primary open angle glaucoma via intraocular pressure-independent mechanisms. Seventeen independent genome-wide significant SNPs were associated with the intraocular pressure-independent component of primary open angle glaucoma. Of these, 7 are located outside known normal tension glaucoma loci, 11 are located outside known intraocular pressure loci, and 2 are novel primary open angle glaucoma loci. The intraocular pressure-independent genetic component of primary open angle glaucoma is associated with glaucoma endophenotypes, while the intraocular pressure-dependent component is associated with blood pressure and vascular permeability. A genetic risk score for the intraocular pressure-independent component of primary open angle glaucoma is associated with 26 different retinal micro-vascular features, which contrasts with the genetic risk score for the intraocular pressure-dependent component. Increased understanding of these intraocular pressure-dependent and intraocular pressure-independent components provides insights into the pathogenesis of glaucoma.

The Multifaceted Non-Genetic Risk Factors for Primary Open-Angle Glaucoma - An Overview of Systematic Reviews

TOPIC

A synthesis of the current knowledge on risk factors for primary open-angle glaucoma (POAG).

METHOD

We conducted a systematic search of PubMed, Embase, Web of Science, and the Cochrane Library to identify relevant systematic reviews (SR) published in English after 2012. The inclusion criteria focused on SRs investigating risk factors for POAG. We registered the study prospectively in the PROSPERO database (CRD42022351372) and used Covidence and the Risk Of Bias In Systematic reviews (ROBIS) tool to manage article selection and assess the risk of bias in the included SRs. Data was extracted independently by two authors.

RESULTS

After removing duplicate SRs, we assessed 2,542 SRs. Of these, 2,396 were determined to be irrelevant, leaving 138 for a full text review. Following this, 78 were excluded with reasons, resulting in 57 SRs. Of these, 30 had a low risk of bias. In our bias assessment, SRs categorized as high risk of bias were characterized by 1) lack of sufficient detail in the bias assessment of the SR and 2) insufficient information or missing calculations of heterogeneity among the included studies. In our study, we identified 22 risk factors associated with POAG. The SRs covered a wide range of risk factors for POAG. Among these, the strongest associations with glaucoma, based on effect size, were observed in two SRs related to obstructive sleep apnea (OSA), with a pooled odds ratio (OR) of 3.66 (95% CI: 1.70-7.90) and an adjusted OR of 2.46 (95% CI: 1.32-4.59). Similarly, two SRs investigating Helicobacter pylori (H. pylori) infections showed significant associations, with pooled ORs of 2.08 (95% CI: 1.48-2.93) and 2.08 (95% CI: 1.42-3.04), respectively.

CONCLUSION

This article summarizes the current knowledge on risk factors for POAG from published SRs. Our findings highlight the complexity of the disease and the nature of the factors that may affect various populations. Among the reported associations with low risk of bias, we found the highest effect estimates for OSA and H. pylori infections in relation to POAG. Our review helps advance understanding, guide future research and inform strategies for the prevention and treatment of POAG.

Endoplasmic Reticulum Stress Delays Choroid Development in the HCAR1 Knockout Mouse

The subretina, composed of the choroid and the retinal pigment epithelium (RPE), bears a critical role in proper vision. In addition to phagocytosis of photoreceptor debris, the RPE shuttles oxygen and nutrients to the neuroretina. For their own energy production, RPE cells mainly rely on lactate, a major by-product of glycolysis. Lactate, in turn, is believed to convey most of its biological effects via the hydroxycarboxylic acid receptor 1 (HCAR1). Here, the lactate-specific receptor, HCAR1, is found to be exclusively expressed in the RPE cells within the subretina, and Hcar1-/- mice exhibit a substantially thinner choroidal vasculature during development. Notably, the angiogenic properties of lactate on the choroid are impacted by the absence of Hcar1. HCAR1-deficient mice exhibit elevated endoplasmic reticulum stress along with eukaryotic initiation factor 2α phosphorylation, a significant decrease in the global protein translation rate, and a lower proliferation rate of choroidal vasculature. Strikingly, inhibition of the integrated stress response using an inhibitor that reverses the effect of eukaryotic initiation factor 2α phosphorylation restores protein translation and rescues choroidal thinning. These results provide evidence that lactate signalling via HCAR1 is important for choroidal development/angiogenesis and highlight the importance of this receptor in establishing mature vision.

Cardio-ocular syndrome: Retinal microvascular changes in acutely decompensated heart failure

AIMS

To investigate the changes in retinal microvasculature by contemporary imaging techniques during episodes of acute decompensated heart failure (ADHF) and following recompensation compared to age-matched controls without known cardiac or retinal disease.

METHODS AND RESULTS

Adult patients hospitalized with a primary diagnosis of ADHF, regardless of left ventricular ejection fraction (LVEF) and treated with a minimum dose of 40 mg of intravenous furosemide or equivalent were included. Transthoracic echocardiography was conducted in all patients. Eye examinations were performed out within the initial 24 h after admission and after recompensation before discharge. All eyes underwent a general examination, including a best corrected visual acuity test, dilated fundoscopy, spectral-domain optical coherence tomography (OCT) as well as OCT angiography (OCT-A). In addition, 40 participants without documented cardiac or retinal diseases served as controls. Forty patients with ADHF (mean age 78.9 ± 8.8 years; 32% female) with a mean LVEF of 43 ± 12.8% were included. All patients were treated with intravenous diuretics for a median of 4.3 ± 2.8 days. There was a significant reduction in N-terminal pro-B-type natriuretic peptide from baseline up to discharge (10 396 [interquartile range 6410] vs. 6380 [interquartile range 3933] pg/ml, p ≤ 0.001) and inferior vena cava diameters (2.13 ± 0.4 vs. 1.63 ± 0.3 cm, p = 0.003). Compared to the control group, patients with ADHF showed on admission impaired visual acuity (0.15 ± 0.1 vs. 0.35 ± 0.1 logMAR, p < 0.001), reduced macular vessel density (18.0 ± 1.9 vs. 14.3 ± 3.6 mm/mm2, p < 0.001) and perfusion density (42.6 ± 3.2 vs. 35.2 ± 9.7%, p < 0.001). After recompensation, the mean overall vessel density and mean overall perfusion density were markedly increased at discharge (14.3 ± 3.6 vs. 19.7 ± 2.6 mm/mm2, p = 0.001, and 35.2 ± 9.7 vs. 39.2 ± 6.5%, p = 0.005, respectively). The mean diameter of the superior temporal retinal vein at admission was significantly larger compared to the control group (136 ± 19 vs. 124 ± 22 μm, p = 0.008) and decreased significantly to 122 ± 15 μm at discharge (p < 0.001).

CONCLUSION

This analysis revealed a remarkable reversible change in retinal microvasculature after ADHF. This could provide a valuable evidence for use of OCT-A in the assessment of overall microperfusion and haemodynamic status in patients with acute heart failure.

Randomized 20-year infancy-onset dietary intervention, life-long cardiovascular risk factors and retinal microvasculature

BACKGROUND AND AIMS

Retinal microvasculature characteristics predict cardiovascular morbidity and mortality. This study investigated associations of lifelong cardiovascular risk factors and effects of dietary intervention on retinal microvasculature in young adulthood.

METHODS

The cohort is derived from the longitudinal Special Turku Coronary Risk Factor Intervention Project study. The Special Turku Coronary Risk Factor Intervention Project is a 20-year infancy-onset randomized controlled dietary intervention study with frequent study visits and follow-up extending to age 26 years. The dietary intervention aimed at a heart-healthy diet. Fundus photographs were taken at the 26-year follow-up, and microvascular measures [arteriolar and venular diameters, tortuosity (simple and curvature) and fractal dimensions] were derived (n = 486). Cumulative exposure as the area under the curve for cardiovascular risk factors and dietary components was determined for the longest available time period (e.g. from age 7 months to 26 years).

RESULTS

The dietary intervention had a favourable effect on retinal microvasculature resulting in less tortuous arterioles and venules and increased arteriolar fractal dimension in the intervention group when compared with the control group. The intervention effects were found even when controlled for the cumulative cardiovascular risk factors. Reduced lifelong cumulative intake of saturated fats, main target of the intervention, was also associated with less tortuous venules. Several lifelong cumulative risk factors were independently associated with the retinal microvascular measures, e.g. cumulative systolic blood pressure with narrower arterioles.

CONCLUSIONS

Infancy-onset 20-year dietary intervention had favourable effects on the retinal microvasculature in young adulthood. Several lifelong cumulative cardiovascular risk factors were independently associated with retinal microvascular structure.

Factors associated with early hydroxychloroquine-induced retinal toxicity in patients with systemic lupus erythematosus

PURPOSE

Hydroxychloroquine is currently recommended for the treatment of systemic lupus erythematosus (SLE), but it can cause irreversible retinal toxicity. This study aimed to identify factors associated with early hydroxychloroquine-induced retinal toxicity in patients with SLE from a single centre for 20 years.

METHODS

SLE patients diagnosed between 1998 and 2017 and followed up for at least 1 year were included. Demographic, clinical, laboratory and therapeutic data were collected from the electronic medical records and retrospectively analysed. Early hydroxychloroquine-induced retinal toxicity was defined as the development of macular toxicity within the first 5 years of hydroxychloroquine treatment.

RESULTS

A total of 345 patients followed for a median of 15 years were analysed; 337 (97.7%) patients received hydroxychloroquine, 38 (11.3%) of them presented with retinal toxicity, and 10 (3%) developed early retinal toxicity. These patients had a mean treatment duration of 3.3 years with a mean cumulative dose of 241 g. Patients were diagnosed by visual field (VF) and fundoscopy, and two were also assessed using spectral domain optical coherence tomography (SD-OCT). The median (IQR) age of patients with early toxicity was 56 (51-66) years, and 80% were female. Factors independently associated with early hydroxychloroquine-induced retinal toxicity were lupus anticoagulant positivity (OR 4.2; 95% CI 1.2-15.5) and hypercholesterolaemia (OR 5.6; 95% CI 1.5-21.5).

CONCLUSION

Our results suggest that lupus anticoagulant positivity and hypercholesterolaemia among SLE patients may be risk factors for early hydroxychloroquine-induced retinal toxicity, regardless of the dose or duration of treatment.

Shared whole environmental etiology between Alzheimer's disease and age-related macular degeneration

The comorbidity of Alzheimer's disease (AD) and age-related macular degeneration (AMD) has been established in clinical and genetic studies. There is growing interest in determining the shared environmental factors associated with both conditions. Recent advancements in record linkage techniques enable us to identify the contributing factors to AD and AMD from a wide range of variables. As such, we first constructed a knowledge graph based on the literature, which included all statistically significant risk factors for AD and AMD. An environment-wide association study (EWAS) was conducted to assess the contribution of various environmental factors to the comorbidity of AD and AMD based on the UK biobank. Based on the conditional Q-Q plots and Bayesian algorithm, several shared environmental factors were identified, which could be categorized into the domains of health condition, biological sample parameters, body index, and attendance availability. Finally, we generated a shared etiology landscape for AD and AMD by combining existing knowledge with our novel findings.

Age-related macular degeneration and cardiovascular disease in US population: an observational study

BACKGROUND

As far as we know, age-related macular degeneration (AMD) has become one of the predominant causes of visual impairments. Previous studies have revealed that AMD and many cardiovascular diseases (CVDs) share the same pathologic and genotypic factors, making the connection between AMD and CVD a hot topic. However, the conclusions of the available studies on the relationship between them are somewhat divergent.

METHODS

We screened 5523 eligible participants from the National Health and Nutrition Examination Survey (NHANES) database from 2005 through 2008 for an observational clinical study design. Binary logistic regression modelling was used to estimate the relations between AMD and various CVDs with and without adjustment for demographics, health status, and behaviours related to health.

RESULTS

Binary logistic regression analyses showed that AMD was able to increase the risk of CVDs in patients both unadjusted and after adjusting for confounding variables.

CONCLUSIONS

Within this study, preventing the development of AMD might cut down the incidence of several CVDs, in particular, significantly lowering the stroke risk. These findings indicate that interventions to prevent AMD may also help to prevent CVDs. In general, late AMD has a more severe impact on the risk of CVDs compared with early AMD. These results could help clinical ophthalmology and cardiovascular medicine in their clinical education and interventions.

Associations Between Life's Essential 8 and Major Ocular Diseases in the American Middle-Aged and Elderly Population

PURPOSE

To explore the correlation between cardiovascular health (CVH) and ocular diseases, given their shared risk factors and biological mechanisms, this study utilizes the newly updated Life's Essential 8 (LE8) algorithm.

DESIGN

A cross-sectional study.

METHODS

This analysis, conducted from February 15 to April 1, 2024, in Changchun, includes data from 4146 participants aged 40 and above, drawn from the National Health and Nutrition Examination Survey database (2005-2008). It covers information on visual health status, dietary habits through interviews, and professional ophthalmological examinations. Participants' CVH status was assessed using the LE8 algorithm, and relationships with major ocular diseases such as retinopathy, cataracts, diabetic retinopathy, glaucoma, and age-related macular degeneration were explored through weighted logistic regression analysis, restricted cubic splines, stratified analysis, and sensitivity analysis.

RESULTS

After multivariable adjustment, lower LE8 scores showed a significant positive relationship with any ocular disease (odds ratio [OR]: 2.03, 95% confidence interval [CI]: 1.39-2.96, P = .001), any objectively determined ocular disease (OR: 2.24, 95% CI: 1.48-3.38, P < .001), retinopathy (OR: 2.88, 95% CI: 1.89-4.41, P < .001), diabetic retinopathy (OR: 10.23, 95% CI: 3.11-33.61, P < .001), and glaucoma (OR: 2.76, 95% CI: 1.47-5.21, P = .003), with all trends significant (all P < .01). Additionally, lower scores in the behavioral subdomain were significantly correlated with an elevated risk of cataracts (OR: 1.45, 95% CI: 1.03-2.04). Subgroup analyses revealed more pronounced negative correlations between LE8 and retinopathy among females and those suffering from chronic kidney disease.

CONCLUSIONS

A low CVH score was linked to an increased likelihood of ocular diseases in a US-populated-based study. This correlation supports the potential benefits of enhancing cardiovascular wellness to mitigate the development of ocular conditions.

Dual anti-angiogenic and anti-inflammatory action of tRNA-Cys-5-0007 in ocular vascular disease

BACKGROUND

Intravitreal injections of angiogenesis inhibitors have proved efficacious in the majority of patients with ocular angiogenesis. However, one-fourth of all treated patients fail to derive benefits from intravitreal injections. tRNA-derived small RNA (tsRNA) emerges as a crucial class of non-coding RNA molecules, orchestrating key roles in the progression of human diseases by modulating multiple targets. Through our prior sequencing analyses and bioinformatics predictions, tRNA-Cys-5-0007 has shown as a potential regulator of ocular angiogenesis. This study endeavors to elucidate the precise role of tRNA-Cys-5-0007 in the context of ocular angiogenesis.

METHODS

Quantitative reverse transcription PCR (qRT-PCR) assays were employed to detect tRNA-Cys-5-0007expression. EdU assays, sprouting assays, transwell assays, and Matrigel assays were conducted to elucidate the involvement of tRNA-Cys-5-0007 in endothelial angiogenic effects. STZ-induced diabetic model, OIR model, and laser-induced CNV model were utilized to replicate the pivotal features of ocular vascular diseases and evaluate the influence of tRNA-Cys-5-0007 on ocular angiogenesis and inflammatory responses. Bioinformatics analysis, luciferase activity assays, RNA pull-down assays, and in vitro studies were employed to elucidate the anti-angiogenic mechanism of tRNA-Cys-5-0007. Exosomal formulation was employed to enhance the synergistic anti-angiogenic and anti-inflammatory efficacy of tRNA-Cys-5-0007.

RESULTS

tRNA-Cys-5-0007 expression was down-regulated under angiogenic conditions. Conversely, tRNA-Cys-5-0007 overexpression exhibited anti-angiogenic effects in retinal endothelial cells, as evidenced by reduced proliferation, sprouting, migration, and tube formation abilities. In diabetic, laser-induced CNV, and OIR models, tRNA-Cys-5-0007 overexpression led to decreased ocular vessel leakage, inhibited angiogenesis, and reduced ocular inflammation. Mechanistically, these effects were attributed to the targeting of vascular endothelial growth factor A (VEGFA) and TGF-β1 by tRNA-Cys-5-0007. The utilization of an exosomal formulation further potentiated the synergistic anti-angiogenic and anti-inflammatory efficacy of tRNA-Cys-5-0007.

CONCLUSIONS

Concurrent targeting of tRNA-Cys-5-0007 for anti-angiogenic and anti-inflammatory therapy holds promise for enhancing the effectiveness of current anti-angiogenic therapy.

Deep learning based retinal vessel segmentation and hypertensive retinopathy quantification using heterogeneous features cross-attention neural network

Retinal vessels play a pivotal role as biomarkers in the detection of retinal diseases, including hypertensive retinopathy. The manual identification of these retinal vessels is both resource-intensive and time-consuming. The fidelity of vessel segmentation in automated methods directly depends on the fundus images' quality. In instances of sub-optimal image quality, applying deep learning-based methodologies emerges as a more effective approach for precise segmentation. We propose a heterogeneous neural network combining the benefit of local semantic information extraction of convolutional neural network and long-range spatial features mining of transformer network structures. Such cross-attention network structure boosts the model's ability to tackle vessel structures in the retinal images. Experiments on four publicly available datasets demonstrate our model's superior performance on vessel segmentation and the big potential of hypertensive retinopathy quantification.

Non-Invasive Retinal Vessel Analysis as a Predictor for Cardiovascular Disease

Cardiovascular disease (CVD) is the most frequent cause of death worldwide. The alterations in the microcirculation may predict the cardiovascular mortality. The retinal vasculature can be used as a model to study vascular alterations associated with cardiovascular disease. In order to quantify microvascular changes in a non-invasive way, fundus images can be taken and analysed. The central retinal arteriolar (CRAE), the venular (CRVE) diameter and the arteriolar-to-venular diameter ratio (AVR) can be used as biomarkers to predict the cardiovascular mortality. A narrower CRAE, wider CRVE and a lower AVR have been associated with increased cardiovascular events. Dynamic retinal vessel analysis (DRVA) allows the quantification of retinal changes using digital image sequences in response to visual stimulation with flicker light. This article is not just a review of the current literature, it also aims to discuss the methodological benefits and to identify research gaps. It highlights the potential use of microvascular biomarkers for screening and treatment monitoring of cardiovascular disease. Artificial intelligence (AI), such as Quantitative Analysis of Retinal vessel Topology and size (QUARTZ), and SIVA-deep learning system (SIVA-DLS), seems efficient in extracting information from fundus photographs and has the advantage of increasing diagnosis accuracy and improving patient care by complementing the role of physicians. Retinal vascular imaging using AI may help identify the cardiovascular risk, and is an important tool in primary cardiovascular disease prevention. Further research should explore the potential clinical application of retinal microvascular biomarkers, in order to assess systemic vascular health status, and to predict cardiovascular events.

Cold hypersensitivity in the hands and feet is associated with erectile dysfunction in young Taiwanese men

Cold hypersensitivity in the hands and feet (CHHF) is a protective or predisposing factor for many diseases; however, the relationship between CHHF and erectile dysfunction (ED) remains unclear. We aimed to investigate associations between CHHF and ED among young men of Southeast Asian origin. In this cross-sectional study, sexually active Taiwanese men aged 20-40 years were enrolled via an online questionnaire comprising general demographic information, comorbidities, subjective thermal sensations of their hands and feet in the past 6 months, and their erectile function using the International Index of Erectile Function-5 (IIEF-5). Participants who reported cold sensation of hands and feet were classified to have CHHF; those with IIEF-5 score ≤ 21 were considered to have ED. Total 54.2% and 27.9% of participants had ED and CHHF, respectively. Men with CHHF were significantly younger, had lower body mass index and IIEF-5 scores (p < 0.001), and a lower prevalence of diabetes mellitus (p = 0.033) along with higher prevalence of ED, psychiatric disorders, and insomnia (p < 0.001). After adjusting for predisposing factors of ED, CHHF (odds ratio 1.410, 95% confidence interval 1.159-1.714; p = 0.001) remained an independent predictor of ED. Thus, CHHF is independently associated with ED, affecting more than a quarter of young Taiwanese men. Autonomic dysregulation and subclinical endothelial dysfunction may be common pathophysiologies of CHHF and ED.

Retinal microcirculation: A window into systemic circulation and metabolic disease

The retinal microcirculation system constitutes a unique terminal vessel bed of the systemic circulation, and its perfusion status is directly associated with the neural function of the retina. This vascular network, essential for nourishing various layers of the retina, comprises two primary microcirculation systems: the retinal microcirculation and the choroidal microcirculation, with each system supplying blood to distinct retinal layers and maintaining the associated neural function. The blood flow of those capillaries is regulated via different mechanisms. However, a range of internal and external factors can disrupt the normal architecture and blood flow within the retinal microcirculation, leading to several retinal pathologies, including diabetic retinopathy, macular edema, and vascular occlusions. Metabolic disturbances such as hyperglycemia, hypertension, and dyslipidemia are known to modify retinal microcirculation through various pathways. These alterations are observable in chronic metabolic conditions like diabetes, coronary artery disease, and cerebral microvascular disease due to advances in non-invasive or minimally invasive retinal imaging techniques. Thus, examination of the retinal microcirculation can provide insights into the progression of numerous chronic metabolic disorders. This review discusses the anatomy, physiology and pathophysiology of the retinal microvascular system, with a particular emphasis on the connections between retinal microcirculation and systemic circulation in both healthy states and in the context of prevalent chronic metabolic diseases.

Cross-patch feature interactive net with edge refinement for retinal vessel segmentation

Retinal vessel segmentation based on deep learning is an important auxiliary method for assisting clinical doctors in diagnosing retinal diseases. However, existing methods often produce mis-segmentation when dealing with low contrast images and thin blood vessels, which affects the continuity and integrity of the vessel skeleton. In addition, existing deep learning methods tend to lose a lot of detailed information during training, which affects the accuracy of segmentation. To address these issues, we propose a novel dual-decoder based Cross-patch Feature Interactive Net with Edge Refinement (CFI-Net) for end-to-end retinal vessel segmentation. In the encoder part, a joint refinement down-sampling method (JRDM) is proposed to compress feature information in the process of reducing image size, so as to reduce the loss of thin vessels and vessel edge information during the encoding process. In the decoder part, we adopt a dual-path model based on edge detection, and propose a Cross-patch Interactive Attention Mechanism (CIAM) in the main path to enhancing multi-scale spatial channel features and transferring cross-spatial information. Consequently, it improve the network's ability to segment complete and continuous vessel skeletons, reducing vessel segmentation fractures. Finally, the Adaptive Spatial Context Guide Method (ASCGM) is proposed to fuse the prediction results of the two decoder paths, which enhances segmentation details while removing part of the background noise. We evaluated our model on two retinal image datasets and one coronary angiography dataset, achieving outstanding performance in segmentation comprehensive assessment metrics such as AUC and CAL. The experimental results showed that the proposed CFI-Net has superior segmentation performance compared with other existing methods, especially for thin vessels and vessel edges. The code is available at https://github.com/kita0420/CFI-Net.

The impact of serum BNP on retinal perfusion assessed by an AI-based denoising optical coherence tomography angiography in CHD patients

Background

To investigate the correlation between retinal vessel density (VD) parameters with serum B-type natriuretic peptide (BNP) in patients with coronary heart disease (CHD) using novel optical coherence tomography angiography (OCTA) denoising images based on artificial intelligence (AI).

Methods

OCTA images of the optic nerve and macular area were obtained using a Canon-HS100 OCT device in 176 patients with CHD. Baseline information and blood test results were recorded.

Results

Retinal VD parameters of the macular and optic nerves on OCTA were significantly decreased in patients with CHD after denoising. Retinal VD of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and radial peripapillary capillary (RPC) was strongly correlated with serum BNP levels in patients with CHD. Significant differences were noted in retinal thickness and retinal VD (SCP, DCP and RPC) between the increased BNP and normal BNP groups in patients with CHD.

Conclusion

Deep learning denoising can remove background noise and smooth rough vessel surfaces. SCP,DCP and RPC may be potential clinical markers of cardiac function in patients with CHD. Denoising shows great potential for improving the sensitivity of OCTA images as a biomarker for CHD progression.

Impact of Shiftwork on Retinal Vasculature Diameters over a 5-Year Period: A Preliminary Investigation Using the BCOPS Study Data

Our aim was to investigate the impact of shiftwork on changes in central retinal arteriolar equivalent (CRAE), a measure of arteriolar width, and central retinal venular equivalent (CRVE), a measure of venular width, over five years. The participants were 117 officers (72.7% men) examined at the first (2011-2014) and second (2015-2019) follow-up examinations in the Buffalo Cardio-Metabolic Occupational Police Stress study. Shiftwork data were obtained from the City of Buffalo, NY payroll records. Retinal diameters were measured using a standardized protocol. ANCOVA was used to compare mean change in CRAE and CRVE between the two examinations across shiftwork categories. Among men only, those who worked ≥70% hours on day shifts had a larger decrease in mean CRAE (-7.13 µm ± 2.51) compared to those who worked <70% day (-0.08 ± 0.96; p = 0.011). Among patrol officers, those who worked ≥70% day had a larger decrease in CRAE compared to those who worked <70% day (p = 0.015). Also, officers who worked ≥70% day had an increase in mean CRVE (µm) (4.56 ± 2.56) compared to those who worked <70% (-2.32 ± 1.32; p = 0.027). Over the five-year period, we observed adverse changes in arteriolar and venular diameters among officers who worked ≥70% on day shifts. The results should be interpreted with caution due to the small sample sizes.

Role of noninvasive ocular imaging as a biomarker in peripheral artery disease (PAD): A systematic review

This study aimed to review the current literature exploring the utility of noninvasive ocular imaging for the diagnosis of peripheral artery disease (PAD). Our search was conducted in early April 2022 and included the databases Medline, Scopus, Embase, Cochrane, and others. Five articles were included in the final review. Of the five studies that used ocular imaging in PAD, two studies used retinal color fundus photography, one used optical coherence tomography (OCT), and two used optical coherence tomography angiography (OCTA) to assess the ocular changes in PAD. PAD was associated with both structural and functional changes in the retina. Structural alterations around the optic disc and temporal retinal vascular arcades were seen in color fundus photography of patients with PAD compared to healthy individuals. The presence of retinal hemorrhages, exudates, and microaneurysms in color fundus photography was associated with an increased future risk of PAD, especially the severe form of the disease. The retinal nerve fiber layer (RNFL) was significantly thinner in the nasal quadrant in patients with PAD compared to age-matched healthy individuals in OCT. Similarly, the choroidal thickness in the subfoveal region was significantly thinner in patients with PAD compared to controls. Patients with PAD also had a significant reduction in the retinal and choroidal circulation in OCTA compared to healthy controls. As PAD causes thinning and ischemic changes in retinal vessels, examination of the retinal vessels using retinal imaging techniques can provide useful information about early microvascular damage in PAD. Ocular imaging could potentially serve as a biomarker for PAD. PROSPERO ID: CRD42022310637.

Prognostic significance of the wall to lumen ratio of retinal arterioles evaluated by adaptive optics

OBJECTIVE

Microvascular structural alterations may be considered an important form of hypertension-mediated organ damage. An increased media-to-lumen ratio of subcutaneous small arteries evaluated with locally invasive techniques (micromyography) predicts the development of cardiovascular (CV) events. However, it is not known whether retinal arteriole structural alterations evaluated with a noninvasive approach (Adaptive Optics) may have a prognostic significance.

DESIGN AND METHODS

Two-hundred and thirty-seven subjects (mean age 58.7 ± 16.1 years, age range 13-89 years; 116 males) were included in the study: 65 normotensive subjects (27.4 %) and 172 patients with essential hypertension or primary aldosteronism (72.6 %). All subjects underwent a non-invasive evaluation of retinal arteriolar wall-to-lumen ratio (WLR) by Adaptive Optics. Subjects were re-evaluated after an average follow-up time of 4.55 years in order to assess the occurrence of clinical events (non CV and/or CV death or events).

RESULTS

Fifty-four events occurred in the study population:26 were cardio-cerebrovascular events (ischemic or hemorragic stroke, atrial fibrillation, heart failure, coronary artery disease, peripheral artery disease, cardiac valvular disease) while the remaining were deaths for any cause, or neoplastic diseases. Subjects with events were older and had a WLR of retinal arterioles significantly greater than those without events. The event-free survival was significantly worse in those with a baseline WLR above the median value of the population (0.28) according to Kaplan-Mayer survival curves and multivariate analysis (Cox's proportional hazard model). The evidence was confirmed after restricting the analysis to CV events.

CONCLUSIONS

Structural alterations of retinal arterioles evaluated by Adaptive Optics may predict total and CV events.

Retinal Microcirculation Measurements in Response to Endurance Exercises Analysed by Adaptive Optics Retinal Camera

This study aimed to precisely investigate the effects of intensive physical exercise on retinal microvascular regulation in healthy volunteers through adaptive optics retinal camera (AO) measurement. We included healthy volunteers (11 men and 14 women) aged 20.6 ± 0.9. The heart rate (HR) and systolic and diastolic blood pressures (SBP, DBP) were recorded before and after a submaximal physical exertion of continuously riding a training ergometer. The superior temporal retinal artery measurements were captured using the AO-rtx1TM (Imagine Eyes, Orsay, France) without pupil dilation. We compared measures of vessel diameter (VD), lumen diameter (LD), two walls (Wall 1, 2), wall-to-lumen ratio (WLR), and wall cross-sectional analysis (WCSA) before and immediately after the cessation of exercise. Cardiovascular parameter results: After exercise, SBP, DBP, and HR changed significantly from 130.2 ± 13.2 to 159.7 ± 15.6 mm Hg, 81.2 ± 6.3 to 77.1 ± 8.2 mm Hg, and 80.8 ± 16.1 to 175.0 ± 6.2 bpm, respectively (p < 0.002). Retinal microcirculation analysis showed no significant decrease in LD, Wall 1 after exercise: from 96.0 ± 6.8 to 94.9 ± 6.7 (p = 0.258), from 11.0 ± 1.5 to 10.4 ± 1.5 (p = 0.107), respectively, and significant reduction in VD from 118.5 ± 8.3 to 115.9 ± 8.3 (p = 0.047), Wall 2 from 11.5 ± 1.0 to 10.7 ± 1.3 (p = 0.017), WLR from 0.234 ± 0.02 to 0.222 ± 0.010 (p = 0.046), WCSA from 3802.8 ± 577.6 to 3512.3 ± 535.3 (p = 0.016). The AO is a promising technique for investigating the effects of exercise on microcirculation, allowing for the tracking of changes throughout the observation. Intensive dynamic physical exertion increases blood pressure and heart rate and causes the vasoconstriction of small retinal arterioles due to the autoregulation mechanism.

Inflammatory mechanisms contributing to retinal alterations in HIV infection and long-term ART

People living with HIV (PLWH) may face an increased risk of eye complications associated with ageing, chronic inflammation, and the toxicity arising from long-term antiretroviral therapy (ART). This review aims to understand how inflammatory pathways contribute to retinal alterations observed in PLWH on long-term ART. This review was conducted using four electronic database searches, namely Scopus, Hinari, Google Scholar, and PubMed; from 1996 (when ART became available) until January 2022, without language restriction. Sources from clinical trials, meta-analyses, randomised controlled trials, and systematic reviews were used. Dysregulated para-inflammation (chronic inflammation) damages the blood-retina barrier, resulting in the altered retinal immune privilege and leading to the development of retinal and blood vessel changes. There is an interplay between the effects of the disease versus ART. ART causes mitochondrial toxicity, which affects the retinal ganglion cells and retinal pigment epithelium (RPE) due to oxidative stress. Infection by HIV also affects retinal microglia, which contributes to RPE damage. Both of these mechanisms affect the blood vessels. Assessing the integrity of the inner and outer blood-retina barrier is a pivotal point in pinpointing the pathogenesis of inner retinal alterations. Optical coherence tomography is a valuable tool to assess these changes. There is a paucity of research to understand how these structural changes may affect visual function, such as contrast sensitivity and colour vision.

Denoising OCT videos based on temporal redundancy

The identification of eye diseases and their progression often relies on a clear visualization of the anatomy and on different metrics extracted from Optical Coherence Tomography (OCT) B-scans. However, speckle noise hinders the quality of rapid OCT imaging, hampering the extraction and reliability of biomarkers that require time series. By synchronizing the acquisition of OCT images with the timing of the cardiac pulse, we transform a low-quality OCT video into a clear version by phase-wrapping each frame to the heart pulsation and averaging frames that correspond to the same instant in the cardiac cycle. Here, we compare the performance of our one-cycle denoising strategy with a deep-learning architecture, Noise2Noise, as well as classical denoising methods such as BM3D and Non-Local Means (NLM). We systematically analyze different image quality descriptors as well as region-specific metrics to assess the denoising performance based on the anatomy of the eye. The one-cycle method achieves the highest denoising performance, increases image quality and preserves the high-resolution structures within the eye tissues. The proposed workflow can be readily implemented in a clinical setting.

Explainable artificial intelligence for the automated assessment of the retinal vascular tortuosity

Retinal vascular tortuosity is an excessive bending and twisting of the blood vessels in the retina that is associated with numerous health conditions. We propose a novel methodology for the automated assessment of the retinal vascular tortuosity from color fundus images. Our methodology takes into consideration several anatomical factors to weigh the importance of each individual blood vessel. First, we use deep neural networks to produce a robust extraction of the different anatomical structures. Then, the weighting coefficients that are required for the integration of the different anatomical factors are adjusted using evolutionary computation. Finally, the proposed methodology also provides visual representations that explain the contribution of each individual blood vessel to the predicted tortuosity, hence allowing us to understand the decisions of the model. We validate our proposal in a dataset of color fundus images providing a consensus ground truth as well as the annotations of five clinical experts. Our proposal outperforms previous automated methods and offers a performance that is comparable to that of the clinical experts. Therefore, our methodology demonstrates to be a viable alternative for the assessment of the retinal vascular tortuosity. This could facilitate the use of this biomarker in clinical practice and medical research.

Addressing the functional needs of left ventricular assist device candidates: Development and feasibility of an occupational therapy pre-operative evaluation

BACKGROUND

Everyday living with a left ventricular assist device (LVAD) is complex, particularly for people with physical or cognitive impairments or limited social supports. There is a need for standardized pre-operative functional evaluations.

OBJECTIVES

Our objectives were to describe a pre-operative occupational therapy (OT) evaluation for LVAD candidates, assess its feasibility in routine care, and characterize functional needs.

METHODS

We retrospectively reviewed electronic medical records of pre-operative OT consultations for LVAD candidates over four years (n = 209). Occupational profile, vision, and sensation were operationalized from documentation narratives. Daily functioning was measured with Activity Measure for Post-Acute Care, grip strength with dynamometer, cognition with Montreal Cognitive Assessment and Allen Cognitive Level Screen-5, and LVAD self-management with a performance-based ordinal scale.

RESULTS

89.5 % of consultations were completed, averaging 61.2 min (n = 187): 79.1 % (148/187) inpatient and 20.9 % (39/187) outpatient. Patients completed 87.7 % (164/187) to 100.0 % (187/187) of evaluation components. 21.9 % (41/187) of candidates lived alone. 6.4 % (12/187) and 7.0 % (13/185) had visual and sensory dysfunction. 57.4 % were independent with daily activities (104/181). 17.7 % (32/181) had impaired grip strength. 69.3 % (124/179) had impaired cognition, 29.7 % (51/172) with impaired functional cognition for everyday activities. 88.4 % (145/164) required physical or cueing assistance while practicing LVAD batteries management. OTs interpreted that 20.9 % (39/187) would likely require 24/7 post-operative support with LVAD self-care.

CONCLUSION

Pre-operative OT evaluations were feasible and emphasized complex functional needs. Assessing LVAD self-care abilities may inform candidacy and facilitate early interventions to optimize functioning. OT should be consulted within interprofessional teams for all LVAD candidates.

Impaired retinal micro-vascular function in patients with atrial fibrillation

BACKGROUND

Cardiovascular (CV) risk factors and CV diseases, in particular heart failure, are strongly associated with impaired microvascular retinal endothelial function. Whether atrial fibrillation (AF) contributes to vascular dysfunction is not clear. Therefore, the aim of this study was to investigate the impact of AF on retinal microvascular function.

METHODS

In this study, vascular function was measured non-invasively with flicker-light induced vasodilatation of retinal arterioles (FIDart%). Patients with a history of AF and risk factors for heart failure (HF) or heart failure (n = 69; age 67.9 ± 9.2 years, 71% male, 35% HFrEF, 56% paroxysmal, 25% persistent, 19% permanent AF), as well as age, sex and ejection fraction matched patients with absent history of AF (n = 66; age 63.4 ± 10.6 years, 67% male, 47% HFrEF) were included. Patients with AF were further divided into those with paroxysmal AF (in sinus rhythm - AFSR: n = 38, age 71.4 ± 9.2, 73% male), and those with AF at the time of the study visit.

RESULTS

Retinal microvascular function was impaired in patients with AF compared to patients without AF (FIDart% 1.1% [0.3-2.8] vs. 2.7% [1.3-5.1], p < 0.001). Patients currently in AF have poorer retinal microvascular function (FIDart% 0.8% [0.1-1.9) compared to patients with a history of AF but currently in SR at the time of retinal function measurement (1.5% [0.6-4.9] p = 0.017). In patients with AF, impaired retinal vascular function was independently associated with larger left atrial volume (mean 49.8 ± 18.4), even after correction for confounding factors in different models (SCR = -0. 251 to -0.256, p = 0.035-0.01).

CONCLUSIONS

AF in patients with heart failure is associated with impaired vascular function, even if currently in sinus rhythm. The association of retinal microvascular dysfunction with left atrial volume, a surrogate for elevated cardiac filling pressures, may further highlight the important interplay between the vasculature and elevated filling pressures in the development of AF.

Retinal microvascular alterations in patients with active rheumatoid arthritis without cardiovascular risk factors: the potential effects of T cell co-stimulation blockade

Background

The evaluation of microvascular alterations might provide clinically useful information for patients with an increased cardiovascular (CV) risk, such as those with rheumatoid arthritis (RA), being the small artery remodeling the earliest form of target organ damage in primary CV diseases, such as arterial hypertension. The evaluation of retinal arterioles is a non-invasive technique aimed to identify an early microvascular damage, represented by the increase of the wall-to-lumen ratio (WLR) index. Abatacept (ABA), a T-cell co-stimulator blocker, is used to treat RA. A CV protective action was hypothesized for its peculiar mechanism of action in the modulation of T-cells, potentially involved in the pathogenesis of CV comorbidity. The study aimed to non-invasively investigate morphological characteristics of retinal arterioles in a cohort of RA patients treated with ABA.

Materials and methods

Seventeen RA patients [median (25th-75thpercentile) age = 58 (48-64) years, baseline 28-joint Disease Activity Score DAS28-C-reactive protein (DAS28-CRP) = 4.4 (3.9-4.6), body mass index (BMI) = 24.2 (23.4-26) kg/m2, rheumatoid factor positive:52.9%, anti-citrullinated peptide autoantibodies positive:76.5%] without known CV risk factors (arterial hypertension, diabetes, hypercholesterolemia, previous CV events, smoking) were evaluated by the adaptive optics imaging system of retinal arterioles before and every 6 months of therapy with ABA (T0, T6 and T12). Office blood pressure evaluation, 24-h ambulatory blood pressure monitoring and tissue-doppler echocardiography were also performed.

Results

A progressive significant reduction of the WLR of retinal arterioles was observed [T0 = 0.28 (0.25-0.30), T6 = 0.27 (0.24-0.31), T12 = 0.23 (0.23-0.26); p T0 vs. T6 = 0.414; p T6 vs. T12 = 0.02; p T0 vs. T12 = 0.009], without significant variations in other parameters. The T0-T12 reduction of WLR was correlated with that of DAS28-CRP (r:0.789; p = 0.005). Moreover, a significant reduction of diastolic office blood pressure and a trend for reduction of daily pressure measured by ambulatory monitoring were observed.

Conclusion

In a cohort of RA patients without known CV risk factors, a reduction of retinal microvascular alterations was demonstrated after treatment for 12 months with ABA, in parallel with the reduction of disease activity. These results might suggest the possibility of microvascular abnormalities regression induced by the immune system modulation.

AI-integrated ocular imaging for predicting cardiovascular disease: advancements and future outlook

Cardiovascular disease (CVD) remains the leading cause of death worldwide. Assessing of CVD risk plays an essential role in identifying individuals at higher risk and enables the implementation of targeted intervention strategies, leading to improved CVD prevalence reduction and patient survival rates. The ocular vasculature, particularly the retinal vasculature, has emerged as a potential means for CVD risk stratification due to its anatomical similarities and physiological characteristics shared with other vital organs, such as the brain and heart. The integration of artificial intelligence (AI) into ocular imaging has the potential to overcome limitations associated with traditional semi-automated image analysis, including inefficiency and manual measurement errors. Furthermore, AI techniques may uncover novel and subtle features that contribute to the identification of ocular biomarkers associated with CVD. This review provides a comprehensive overview of advancements made in AI-based ocular image analysis for predicting CVD, including the prediction of CVD risk factors, the replacement of traditional CVD biomarkers (e.g., CT-scan measured coronary artery calcium score), and the prediction of symptomatic CVD events. The review covers a range of ocular imaging modalities, including colour fundus photography, optical coherence tomography, and optical coherence tomography angiography, and other types of images like external eye images. Additionally, the review addresses the current limitations of AI research in this field and discusses the challenges associated with translating AI algorithms into clinical practice.

Optical Coherence Tomography Angiography Changes in Patients Diagnosed With Acute Coronary Syndrome: A Systematic Review and Meta-Analysis

We conducted a systematic review and meta-analysis to assess the association between optical coherence tomography angiography (OCTA) parameters and acute coronary syndrome (ACS). Two independent reviewers searched the electronic databases (MEDLINE (Medical Literature Analysis and Retrieval System Online), Scopus, Embase (Excerpta Medica Database), Cochrane Library, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform) from inception until April 2023. According to the inclusion criteria of this review, eligible were observational studies, randomized control trials, and registry/database studies that included the eyes of adult ACS patients and assessed OCTA parameters within the macula. The pooled standardized mean differences (SMD) between patients diagnosed with ACS and healthy controls with a confidence interval (CI) of 95% were calculated using the Hartung-Knapp-Sidik-Jonkman random-effects method. The heterogeneity was assessed by I2 and the Cochran Q and a random effects model was applied. Seven studies were eligible and included in our systematic review (n = 898), of which three were included in the meta-analysis (n = 341). The pooled SMD in the superficial vascular plexus (SVP), deep vascular plexus (DVP), and foveal avascular zone (FAZ) were -0.46 (95% CI: -0.94 to 0.01, p = 0.05, I2 = 0%, three studies), -0.10 (95% CI: -3.20 to 3.00, p = 0.75, I2 = 67%, two studies), and 0.43 (95% CI: -1.22 to 2.09, p = 0.38, I2 = 92%, three studies), respectively. Our findings suggest that there are no differences in OCTA metrics between ACS patients and healthy individuals.

Unveiling the silent link: Normal-tension glaucoma's enigmatic bond with cardiac blood flow

This comprehensive review embarks on a captivating journey into the complex relationship between cardiology and normal-tension glaucoma (NTG), a condition that continues to baffle clinicians and researchers alike. NTG, characterized by optic nerve damage and visual field loss despite normal intraocular pressure, has long puzzled clinicians. One emerging perspective suggests that alterations in ocular blood flow, particularly within the optic nerve head, may play a pivotal role in its pathogenesis. While NTG shares commonalities with its high-tension counterpart, its unique pathogenesis and potential ties to cardiovascular health make it a fascinating subject of exploration. It navigates through the complex web of vascular dysregulation, blood pressure and perfusion pressure, neurovascular coupling, and oxidative stress, seeking to uncover the hidden threads that tie the heart and eyes together in NTG. This review explores into the intricate mechanisms connecting cardiovascular factors to NTG, shedding light on how cardiac dynamics can influence ocular health, particularly in cases where intraocular pressure remains within the normal range. NTG's enigmatic nature, often characterized by seemingly contradictory risk factors and clinical profiles, underscores the need for a holistic approach to patient care. Drawing parallels to cardiac health, we examine into the shared vascular terrain connecting the heart and the eyes. Cardiovascular factors, including systemic blood flow, endothelial dysfunction, and microcirculatory anomalies, may exert a profound influence on ocular perfusion, impacting the delicate balance within the optic nerve head. By elucidating the subtle clues and potential associations between cardiology and NTG, this review invites clinicians to consider a broader perspective in their evaluation and management of this elusive condition. As the understanding of these connections evolves, so too may the prospects for early diagnosis and tailored interventions, ultimately enhancing the quality of life for those living with NTG.

The Association Between Frailty and Visual Field Loss in US Adults

PURPOSE

To describe the association between visual field loss and frailty in a nationally representative cohort of US adults.

DESIGN

Retrospective cross-sectional study.

METHODS

The cohort included adults 40 years or older with complete eye examination data from the 2005-2006 and 2007-2008 National Health and Nutrition Examination Surveys (NHANES). Visual field loss (VFL) was determined by frequency doubling technology and a 2-2-1 algorithm. A 36-item deficit accumulation-based frailty index was used to divide subjects into 4 categories of increasing frailty severity.

RESULTS

Of the 4897 participants, 4402 (93.2%) had no VFL, 301 (4.1%) had unilateral VFL, and 194 (2.73%) had bilateral VFL. Within the sample, 2 subjects197 (53.1%) were categorized as non-frail, 1659 (31.3%) as vulnerable, 732 (11.3%) as mildly frail, and 312 (4.3%) as most frail. In multivariable models adjusted for demographics, visual acuity, and history of cataract surgery, subjects with unilateral VFL had higher adjusted odds of being in a more frail category (adjusted odds ratio [aOR], 2.07; 95% CI, 1.42-3.02) than subjects without VFL. Subjects with bilateral VFL also had higher odds of a more frail category compared to subjects without VFL (aOR, 1.74; 95% CI, 1.20-2.52).

CONCLUSIONS

In the 2005-2008 NHANES adult population, VFL is associated with higher odds of frailty, independent of central visual acuity loss. Frail individuals may be more susceptible to diseases that can cause VFL, and/or VFL may predispose to frailty. Additional studies are needed to determine the directionality of this relationship and to assess potential interventions.

Evaluation of retinal and peripapillary vessel density and subfoveal choroidal thickness changes in patients undergoing cardiopulmonary bypass: An OCTA study

PURPOSE

We aimed to investigate hemodynamic changes in the retina, peripapillary area, and choroid in patients undergoing coronary artery bypass grafting (CABG).

METHODS

This prospective case series included 35 eyes of 35 patients. Vessel density (VD) of superficial capillary plexus, deep capillary plexus, radial peripapillary capillary, foveal avascular zone area, and subfoveal choroidal thickness changes were evaluated using optical coherence tomography angiography (OCTA) 1 day before and 2 weeks after surgery. The correlation of these parameters with aortic cross-clamp (ACC) duration and cardiopulmonary bypass (CPB) duration was evaluated.

RESULTS

There were no differences in the OCTA measurements of the patients after CABG compared to before surgery (P > 0.05). Inside-disc VD showed a negative correlation with both ACC (P = 0.036) and CPB duration (P = 0.048); peripapillary inferior hernia showed a negative correlation with both ACC (P = 0.042) and CPB duration (P = 0.027). Another negative correlation was observed between mean peripapillary VD and CPB duration (P = 0.039).

CONCLUSION

The CPB procedure had no permanent effect on retinal choroid and optic disc blood flow postoperatively. Prolonged ACC and CPB times seem to be important in terms of optic nerve blood flow. Clinicians should be alert for postoperative ocular complications after long surgeries.

Effects of high-intensity interval training on retinal vessel diameters and oxygen saturation in patients with hypertension: A cross-sectional and randomized controlled trial

INTRODUCTION

Arterial hypertension is a global healthcare burden that affects macrovascular and microvascular structure and function and can promote vascular end-organ damage. This study aimed 1) to evaluate differences in microvascular health between normotensive individuals and patients with arterial hypertension and 2) to assess the effects of short-term high-intensity interval training (HIIT) on microvascular health in the subgroup with arterial hypertension as add-on treatment to antihypertensive medication.

METHODS

In the cross-sectional part, central retinal arteriolar (CRAE) and venular diameter equivalent (CRVE), arteriolar-to-venular diameter ratio (AVR), and retinal oxygen saturation (O2-saturation) were investigated in 19 normotensive healthy controls (mean age 56 ± 7 years) and 41 patients with arterial hypertension (mean age 59 ± 7 years). In the subsequent randomized controlled trial (RCT), patients with arterial hypertension were randomized to an intervention group (HIIT 3×/week) or a control group that received standard physical activity recommendations after baseline assessment. Assessments of retinal vessel biomarkers and patients` characteristics were repeated after the intervention period of 8 weeks.

RESULTS

In the cross-sectional part, individuals with normal blood pressure (BP) showed lower body mass index (BMI), body fat, 24 h systolic and diastolic BP, higher peak oxygen uptake, wider CRAE (174 ± 17 μm vs. 161 ± 17 μm, p = 0.009), and higher AVR (0.84 ± 0.05 vs. 0.79 ± 0.05, p = 0.003) compared to patients with hypertension. In the RCT, patients with arterial hypertension showed reduced BMI and fasting glucose levels after HIIT and control condition. In addition, the intervention group reduced body fat percentage (27.0 ± 5.5 vs. 25.8 ± 6.1, p = 0.023) and increased peak oxygen uptake (33.3 ± 5.7 vs. 36.7 ± 5.1, p < 0.001). No changes in BP were found in either group. The intervention group showed narrower CRVE (β -4.8 [95 % CI, -8.85, -0.81] p = 0.020) and higher AVR (0.03 [0.01, 0.04] p < 0.001) after eight weeks of HIIT compared to the control group. No statistically significant changes in retinal O2-saturation were found in either group.

CONCLUSION

Short-term HIIT proved to be an effective treatment to ameliorate hypertension-induced retinal microvascular abnormalities in patients with hypertension. Retinal vessel diameters may prove to be a sensitive biomarker to quantify treatment efficacy at the microvascular level, at the earliest possible stage in patients with hypertension.

Food intake in South African children and retinal microvascular health: The ExAMIN Youth SA study

BACKGROUND AND AIMS

Retinal arteriolar narrowing and venular widening are associated with increased cardiovascular risk, even at young ages. Whether diet contributes to early microvascular changes in children is not widely explored. We explored the associations of frequency of healthy and unhealthy food group intake with retinal vessel calibers in black and white children.

METHODS AND RESULTS

This study included school-aged (5-9 years) black (N = 433, 7.46 ± 0.98 years), and white (N = 403, 7.43 ± 0.82 years) children. Anthropometric and blood pressure measurements were taken, along with retinal vessel calibers (central retinal arteriolar (CRAE) and venular (CRVE) equivalents). Frequencies of food group intake were assessed using a food-frequency questionnaire. A factor analysis was performed to describe food group patters. Independent associations between retinal vessel calibers and frequencies of food group intake and food group patters were explored. In black children, cookies, cakes, and biscuits were associated with narrower arterioles (p < 0.05). In white children, cold sweetened beverages were associated with narrower arterioles (p = 0.02), whereas salty snacks were associated with narrower arterioles (p = 0.01) and wider venules (p < 0.05). Fruits were positively associated with CRAE (p = 0.03) in white children only.

CONCLUSION

A higher frequency of unhealthy food group consumption was associated with retinal arteriolar narrowing and venular widening in both black and white children. However, fruit intake was shown beneficial for retinal microvascular health in white children only. Our findings may highlight the importance of promoting healthy eating patterns from early childhood which may reduce the risk of premature cardiovascular disease development.

Association of preoperative retinal microcirculation and perioperative outcomes in patients undergoing congenital cardiac surgery

BACKGROUND

Microcirculatory dysfunction is associated with increased morbidity and mortality in cardiac surgery patients. This study aimed to investigate the association between preoperative retinal microcirculation evaluated using optical coherence tomography angiography (OCTA) and perioperative outcomes in patients with congenital heart disease (CHD).

METHODS

This prospective, observational study was performed from May 2017 to January 2021. OCTA was used to automatically quantify the vessel density (VD) of the superficial capillary plexus, deep capillary plexus (DCP), and radial peripapillary capillary (RPC) preoperatively. The primary outcome was excessive postoperative bleeding, defined as bleeding volume > 75th percentile for 24-hour postoperative chest tube output. The secondary outcome was composite adverse outcomes, including one or more operative mortalities, early postoperative complications, and prolonged length of stay. The association between retinal VD and outcomes was assessed using Poisson regression.

RESULTS

In total, 173 CHD patients who underwent cardiac surgery were included (mean age, 26 years). Among them, 43 (24.9%) and 46 (26.6%) developed excessive postoperative bleeding and composite adverse outcomes, respectively. A lower VD of DCP (odds ratio [OR], 1.24; 95% confidence interval [CI], 1.08-1.43; P = 0.003) was independently associated with excessive postoperative bleeding, and a lower VD of RPC (OR, 1.97; 95% CI, 1.08-3.57; P = 0.027), and DCP (OR, 2.17; 95% CI, 1.08-4.37; P = 0.029) were independently associated with the postoperative composite adverse outcomes.

CONCLUSION

Preoperative retinal hypoperfusion was independently associated with an increased risk of perioperative adverse outcomes in patients with CHD, suggesting that retinal microcirculation evaluation could provide valuable information about the outcomes of cardiac surgery, thereby aiding physicians in tailoring individualized treatment.

Diverging role of epicardial adipose tissue across the entire heart failure spectrum

AIMS

Epicardial adipose tissue (EAT) is a metabolically highly active tissue modulating numerous pathophysiological processes. The aim of this study was to investigate the association between EAT thickness and endothelial function in patients with heart failure (HF) across the entire ejection fraction spectrum.

METHODS AND RESULTS

A total of 258 patients with HF with an ejection fraction across the entire spectrum [HF with reduced ejection fraction (HFrEF), n = 168, age 60.6 ± 11.2 years; HF with preserved ejection fraction (HFpEF), n = 50, mean age 65.1 ± 11.9 years; HF with mildly reduced ejection fraction (HFmrEF), n = 32, mean age 65 ± 12] were included. EAT was measured with transthoracic echocardiography. Vascular function was assessed with flicker-light-induced vasodilation of retinal arterioles (FIDart%) and flow-mediated dilatation (FMD%) in conduit arteries. Patients with HFrEF have less EAT compared with patients with HFpEF (4.2 ± 2 vs. 5.3 ± 2 mm, respectively, P < 0.001). Interestingly, EAT was significantly associated with impaired microvascular function (FIDart%; r = -0.213, P = 0.012) and FMD% (r = -0.186, P = 0.022), even after multivariate correction for confounding factors (age, body mass index, hypertension, and diabetes; standardized regression coefficient (SRC) = -0.184, P = 0.049 for FIDart% and SRC = -0.178, P = 0.043 for FMD%) in HFrEF but not in HFpEF.

CONCLUSIONS

Although less EAT is present in HFrEF than in HFpEF, only in HFrEF EAT is associated with vascular dysfunction. The diverging role of EAT in HF and its switch to a functionally deleterious tissue promoting HF progression provide the rationale to specifically target EAT, in particular in patients with reduced ejection fraction.

Six-Year Incidence of Visual Impairment in a Multiethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

Purpose

To examine the 6-year incidence of visual impairment (VI) and identify risk factors associated with VI in a multiethnic Asian population.

Design

Prospective, population-based, cohort study.

Participants

Adults aged ≥ 40 years were recruited from the Singapore Epidemiology of Eye Diseases cohort study at baseline. Eligible subjects were re-examined after 6 years. Subjects included in the final analysis had a mean age of 56.1 ± 8.9 years, and 2801 (50.5%) were female.

Methods

All participants underwent standardized examination and interviewer-administered questionnaire at baseline. Incidences were standardized to the Singapore Population Census 2010. A Poisson binomial regression model was used to evaluate the associations between baseline factors and incident presenting VI.

Main Outcome Measures

Incident presenting VI was assessed at the 6-year follow-up visit. Visual impairment (presenting visual acuity < 20/40), low vision (presenting visual acuity < 20/40 but ≥ 20/200), and blindness (presenting visual acuity < 20/200) were defined based on United States definition.

Results

A total of 5551 subjects (2188 Chinese, 1837 Indians, and 1526 Malays) were evaluated, of whom 514 developed incident presenting VI over 6 years. Malays had a higher incidence of low vision and blindness (13.0%; 0.6%) than Indians (7.0%; 0.1%) and Chinese (7.7%; 0.2%). Among Malay individuals with VI at baseline, 52.8% remained visually impaired after 6 years, which was considerably higher than Chinese (32.4%) and Indians (37.2%). Older age (per decade; relative risk [RR] = 1.59), a history of cardiovascular disease (RR = 1.38), current smoking (RR = 1.31), smaller housing type (1- to 2-room public flat; RR = 2.01), and no formal education (RR = 1.63) at baseline were associated with a higher risk of incident VI (all P ≤ 0.027). Older age (> 60 years) contributed the highest population attributable risk to incident VI (27.1%), followed by lower monthly income (Singapore dollar < $2000; 26.4%) and smaller housing type (24.7%). Overall, undercorrected refractive error (49.1%) and cataract (82.6%) were leading causes for low vision and blindness, respectively. This was consistently observed across the 3 ethnicities.

Conclusions

In this multiethnic Asian population, Malays had a higher VI incidence compared to Indians and Chinese. Leading causes of VI are mostly treatable, suggesting that more efforts are needed to further mitigate preventable visual loss.

Financial Disclosures

The authors have no proprietary or commercial interest in any materials discussed in this article.

Genome-wide Association Studies of Retinal Vessel Tortuosity Identify Numerous Novel Loci Revealing Genes and Pathways Associated With Ocular and Cardiometabolic Diseases

Purpose

To identify novel susceptibility loci for retinal vascular tortuosity, to better understand the molecular mechanisms modulating this trait, and reveal causal relationships with diseases and their risk factors.

Design

Genome-wide Association Studies (GWAS) of vascular tortuosity of retinal arteries and veins followed by replication meta-analysis and Mendelian randomization (MR).

Participants

We analyzed 116 639 fundus images of suitable quality from 63 662 participants from 3 cohorts, namely the UK Biobank (n = 62 751), the Swiss Kidney Project on Genes in Hypertension (n = 397), and OphtalmoLaus (n = 512).

Methods

Using a fully automated retina image processing pipeline to annotate vessels and a deep learning algorithm to determine the vessel type, we computed the median arterial, venous and combined vessel tortuosity measured by the distance factor (the length of a vessel segment over its chord length), as well as by 6 alternative measures that integrate over vessel curvature. We then performed the largest GWAS of these traits to date and assessed gene set enrichment using the novel high-precision statistical method PascalX.

Main Outcome Measure

We evaluated the genetic association of retinal tortuosity, measured by the distance factor.

Results

Higher retinal tortuosity was significantly associated with higher incidence of angina, myocardial infarction, stroke, deep vein thrombosis, and hypertension. We identified 175 significantly associated genetic loci in the UK Biobank; 173 of these were novel and 4 replicated in our second, much smaller, metacohort. We estimated heritability at ∼25% using linkage disequilibrium score regression. Vessel type specific GWAS revealed 116 loci for arteries and 63 for veins. Genes with significant association signals included COL4A2, ACTN4, LGALS4, LGALS7, LGALS7B, TNS1, MAP4K1, EIF3K, CAPN12, ECH1, and SYNPO2. These tortuosity genes were overexpressed in arteries and heart muscle and linked to pathways related to the structural properties of the vasculature. We demonstrated that retinal tortuosity loci served pleiotropic functions as cardiometabolic disease variants and risk factors. Concordantly, MR revealed causal effects between tortuosity, body mass index, and low-density lipoprotein.

Conclusions

Several alleles associated with retinal vessel tortuosity suggest a common genetic architecture of this trait with ocular diseases (glaucoma, myopia), cardiovascular diseases, and metabolic syndrome. Our results shed new light on the genetics of vascular diseases and their pathomechanisms and highlight how GWASs and heritability can be used to improve phenotype extraction from high-dimensional data, such as images.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Evaluation of Arterial Stiffness and Subfoveal Choroidal Thickness in Patients with Coronary Slow Flow

Background

Coronary slow flow may not only affect the coronary arteries, but it may also be a vascular problem affecting the rest of the arterial system.

Objective

The aim of this study was to determine peripheral arterial stiffness and the thickness of the choroid layer in patients with slow coronary flow.

Methods

Fifty consecutive patients (age, 54.3 ± 11.4 years, 38 male) with coronary slow flow and 25 consecutive patients (age, 50.5 ± 9.9 years, 16 male) with normal coronary arteries both documented by coronary angiography were included. Arterial stiffness parameters were measured noninvasively using a Mobil-O-Graph arteriography system. The choroidal thickness was assessed using the enhanced depth imaging optical coherence tomography method.

Results

The patients with coronary slow flow had significantly higher peripheral systolic blood pressure, peripheral pulse pressure, central pulse pressure, and pulse wave velocity (PWV) and significantly thinner choroidal thickness compared to the controls. Thrombolysis in myocardial infarction frame count was positively correlated with PWV (r: 0.237, p = 0.041) and negatively correlated with choroidal thickness (r: -0.249, p = 0.031). There was also a negative correlation between PWV and mean choroidal thickness (r: -0.565, p < 0.001). Linear regression analysis showed that coronary slow flow was an independent predictor of both PWV and choroidal thickness when adjusted by age and sex.

Conclusions

The acceleration of average peripheral arterial PWV with a thinning of choroidal thickness in patients with coronary slow flow may support the idea that this phenomenon may be a coronary presentation of a systemic microvascular disorder.

Association of retinal microvascular density and complexity with incident coronary heart disease

BACKGROUND AND AIMS

The high mortality rate and huge disease burden of coronary heart disease (CHD) highlight the importance of its early detection and timely intervention. Given the non-invasive nature of fundus photography and recent development in the quantification of retinal microvascular parameters with deep learning techniques, our study aims to investigate the association between incident CHD and retinal microvascular parameters.

METHODS

UK Biobanks participants with gradable fundus images and without a history of diagnosed CHD at recruitment were included for analysis. A fully automated artificial intelligence system was used to extract quantitative measurements that represent the density and complexity of the retinal microvasculature, including fractal dimension (Df), number of vascular segments (NS), vascular skeleton density (VSD) and vascular area density (VAD).

RESULTS

A total of 57,947 participants (mean age 55.6 ± 8.1 years; 56% female) without a history of diagnosed CHD were included. During a median follow-up of 11.0 (interquartile range, 10.88 to 11.19) years, 3211 incident CHD events occurred. In multivariable Cox proportional hazards models, we found decreasing Df (adjusted HR = 0.80, 95% CI, 0.65-0.98, p = 0.033), lower NS of arteries (adjusted HR = 0.69, 95% CI, 0.54-0.88, p = 0.002) and venules (adjusted HR = 0.77, 95% CI, 0.61-0.97, p = 0.024), and reduced arterial VSD (adjusted HR = 0.72, 95% CI, 0.57-0.91, p = 0.007) and venous VSD (adjusted HR = 0.78, 95% CI, 0.62-0.98, p = 0.034) were related to an increased risk of incident CHD.

CONCLUSIONS

Our study revealed a significant association between retinal microvascular parameters and incident CHD. As the lower complexity and density of the retinal vascular network may indicate an increased risk of incident CHD, this may empower its prediction with the quantitative measurements of retinal structure.

Predicting ischemic stroke risk from atrial fibrillation based on multi-spectral fundus images using deep learning

Background

Ischemic stroke (IS) is one of the most common serious secondary diseases of atrial fibrillation (AF) within 1 year after its occurrence, both of which have manifestations of ischemia and hypoxia of the small vessels in the early phase of the condition. The fundus is a collection of capillaries, while the retina responds differently to light of different wavelengths. Predicting the risk of IS occurring secondary to AF, based on subtle differences in fundus images of different wavelengths, is yet to be explored. This study was conducted to predict the risk of IS occurring secondary to AF based on multi-spectrum fundus images using deep learning.

Methods

A total of 150 AF participants without suffering from IS within 1 year after discharge and 100 IS participants with persistent arrhythmia symptoms or a history of AF diagnosis in the last year (defined as patients who would develop IS within 1 year after AF, based on fundus pathological manifestations generally prior to symptoms of the brain) were recruited. Fundus images at 548, 605, and 810 nm wavelengths were collected. Three classical deep neural network (DNN) models (Inception V3, ResNet50, SE50) were trained. Sociodemographic and selected routine clinical data were obtained.

Results

The accuracy of all DNNs with the single-spectral or multi-spectral combination images at the three wavelengths as input reached above 78%. The IS detection performance of DNNs with 605 nm spectral images as input was relatively more stable than with the other wavelengths. The multi-spectral combination models acquired a higher area under the curve (AUC) scores than the single-spectral models.

Conclusions

The probability of IS secondary to AF could be predicted based on multi-spectrum fundus images using deep learning, and combinations of multi-spectrum images improved the performance of DNNs. Acquiring different spectral fundus images is advantageous for the early prevention of cardiovascular and cerebrovascular diseases. The method in this study is a beneficial preliminary and initiative exploration for diseases that are difficult to predict the onset time such as IS.

Cardiac toxicity of phenanthrene depends on developmental stage in Atlantic cod (Gadus morhua)

Complex mixtures like crude oil, and single components such as Phenanthrene (Phe), induce cardiotoxicity by interfering with excitation-contraction coupling. However, recent work has demonstrated that the timing of pollutant exposure during embryogenesis greatly impacts the degree of cardiac dysfunction caused. Here, we aimed to clarify the temporal dependence of Phe toxicity and the downstream effects of cardiac dysfunction using Atlantic cod (Gadus morhua). Phe (nominal concentration, 1.12 μmol/L), or the L-type‑calcium channel blocker Nicardipine (Nic) (nominal concentration, 2 and 4 μmol/L), were individually applied to cod embryos either during cardiogenesis (early) or after the onset of cardiac function (late). Phe toxicity was highly dependent on the timing of exposure. Exposure after the onset of cardiac function (i.e. late) caused more severe cardiac and extracardiac abnormalities at 3 days post hatching (dph) than early exposure. Late Phe exposure resulted in a smaller ventricle, eliminated ventricular contraction, and reduced atrial contraction. In contrast, early Phe exposure did not have an effect on cardiac development and function. This temporal difference was not as evident in the Nic treatment. Early Nic exposure created similar morphological phenotypes to the late Phe exposure. The two treatments (early Nic and late Phe) also shared a cardiofunctional phenotype, comprised of eliminated ventricular, and reduced atrial, contraction. These data suggest that extracardiac abnormalities, such as the craniofacial deformities seen after late embryonic exposure to cardiotoxic oil components and mixtures, are mostly downstream effects of cardiac dysfunction.

A Systematic Review and Meta-Analysis of Applying Deep Learning in the Prediction of the Risk of Cardiovascular Diseases From Retinal Images

Purpose

The purpose of this study was to perform a systematic review and meta-analysis to synthesize evidence from studies using deep learning (DL) to predict cardiovascular disease (CVD) risk from retinal images.

Methods

A systematic literature search was performed in MEDLINE, Scopus, and Web of Science up to June 2022. We extracted data pertaining to predicted outcomes, model development, and validation and model performance metrics. Included studies were graded using the Quality Assessment of Diagnostic Accuracies Studies 2 tool. Model performance was pooled across eligible studies using a random-effects meta-analysis model.

Results

A total of 26 studies were included in the analysis. There were 42 CVD risk-related outcomes predicted from retinal images were identified, including 33 CVD risk factors, 4 cardiac imaging biomarkers, 2 CVD risk scores, the presence of CVD, and incident CVD. Three studies that aimed to predict the development of future CVD events reported an area under the receiver operating curve (AUROC) between 0.68 and 0.81. Models that used retinal images as input data had a pooled mean absolute error of 3.19 years (95% confidence interval [CI] = 2.95-3.43) for age prediction; a pooled AUROC of 0.96 (95% CI = 0.95-0.97) for gender classification; a pooled AUROC of 0.80 (95% CI = 0.73-0.86) for diabetes detection; and a pooled AUROC of 0.86 (95% CI = 0.81-0.92) for the detection of chronic kidney disease. We observed a high level of heterogeneity and variation in study designs.

Conclusions

Although DL models appear to have reasonably good performance when it comes to predicting CVD risk, further work is necessary to evaluate the real-world applicability and predictive accuracy.

Translational Relevance

DL-based CVD risk assessment from retinal images holds great promise to be translated to clinical practice as a novel approach for CVD risk assessment, given its simple, quick, and noninvasive nature.

The short-term effects of blood donation on the ocular parameters including blood flow of the retina and choroid in healthy people using OCT- angiography

BACKGROUND

To investigate the short-term effects of blood donation on the morphology and blood flow of the retina and choroid in healthy people using optical coherence tomography angiography (OCTA).

METHODS

Twenty-eight healthy blood donors (56 eyes) who participated in the 200 ml voluntary blood donation between March 2, 2021 and January 20, 2022 were included. The best corrected visual acuity (BCVA), systolic (SBP) and diastolic blood pressure (DBP), intraocular pressure (IOP), subfoveal choroid thickness (SFCT), retinal thickness (RT), retinal superficial vascular density (SVD), deep vascular density (DVD) and foveal avascular were a (FAZ) were measured and statistically analysed 10 min before, 30 min and 24 h after the blood donation.

RESULTS

The 200 ml blood donation could cause significant IOP reduction at 24 h (P = 0.006), which was negatively correlated with SBP (r = -0.268, P = 0.046), while SBP, DBP, or ocular perfusion pressure were not affected (> 0.05). Moreover, no significant difference existed in the OCT and OCTA indexes, including SFCT, RT, SVD, DVD, and FAZ, before and after the 200 ml blood donation (P > 0.05). The visual acuity was not affected either (P > 0.05).

CONCLUSIONS

The 200 ml blood donation was noted to be associated with statistically significant IOP reduction at 24 h, while SBP, DBP, or OPP was not affected. The blood flow of the retina and choroid or the visual acuity did not change significantly after the blood donation. Larger studies with different volumes of blood donation were needed to further analysis the effect of blood donation on ocular parameters.

Analysis of Plasma Metabolic Profile on Ganglion Cell-Inner Plexiform Layer Thickness With Mortality and Common Diseases

Importance

The neural retina is considered a unique window to systemic health, but its biological link with systemic health remains unknown.

Objective

To investigate the independent associations of retinal ganglion cell-inner plexiform layer thickness (GCIPLT) metabolic profiles with rates of mortality and morbidity of common diseases.

Design, Setting, and Participants

This cohort study evaluated UK Biobank participants enrolled between 2006 and 2010, and prospectively followed them up for multidisease diagnosis and mortality. Additional participants from the Guangzhou Diabetes Eye Study (GDES) underwent optical coherence tomography scanning and metabolomic profiling and were included for validation.

Main Outcomes and Measures

Systematic analysis of circulating plasma metabolites to identify GCIPLT metabolic profiles; prospective associations of these profiles with mortality and morbidity of 6 common diseases with their incremental discriminative value and clinical utility.

Results

Among 93 838 community-based participants (51 182 [54.5%] women), the mean (SD) age was 56.7 (8.1) years and mean (SD) follow-up was 12.3 (0.8) years. Of 249 metabolic metrics, 37 were independently associated with GCIPLT, including 8 positive and 29 negative associations, and most were associated with the rates of future mortality and common diseases. These metabolic profiles significantly improved the models for discriminating type 2 diabetes over clinical indicators (C statistic: 0.862; 95% CI, 0.852-0.872 vs clinical indicators only, 0.803; 95% CI, 0.792-0.814; P < .001), myocardial infarction (0.792; 95% CI, 0.775-0.808 vs 0.768; 95% CI, 0.751-0.786; P < .001), heart failure (0.803; 95% CI, 0.786-0.820 vs 0.790; 95% CI, 0.773-0.807; P < .001), stroke (0.739; 95% CI, 0.714-0.764 vs 0.719; 95% CI, 0.693-0.745; P < .001), all-cause mortality (0.747; 95% CI, 0.734-0.760 vs 0.724; 95% CI, 0.711-0.738; P < .001), and cardiovascular disease mortality (0.790; 95% CI, 0.767-0.812 vs 0.763; 95% CI, 0.739-0.788; P < .001). Additionally, the potential of GCIPLT metabolic profiles for risk stratification of cardiovascular diseases were further confirmed in the GDES cohort using a different metabolomic approach.

Conclusions and Relevance

In this prospective study of multinational participants, GCIPLT-associated metabolites demonstrated the potential to inform mortality and morbidity risks. Incorporating information on these profiles may facilitate individualized risk stratification for these health outcomes.

Microvascular and structural analysis of the retina and choroid in heart failure patients with reduced ejection fraction

This cross-sectional study was designed to assess alterations of choroidal and retinal microvasculature in patients with Heart Failure with Reduced Ejection Fraction (HFrEF) and compare them with a normal age and sex-matched population. Fifty-two eyes of 26 patients with HFrEF (left ventricular ejection fraction [LVEF] < 40%) and 64 eyes of 32 healthy individuals were considered as the patient and the control groups, respectively. We found no statistically significant differences in age-adjusted mean central macular thickness (CMT), superficial or deep retinal capillary plexus vascular densities, and choriocapillaris flow (CC flow) density between the HFrEF group and the normal controls, with the exception of the parafoveal mean superficial capillary plexus vascular density (P = 0.023), which remained statistically significant after adjusting for age (P = 0.034). The patients with HFrEF had a significantly lower subfoveal choroidal thickness (SFCT) than the normal subjects (264 ± 82 vs 313 ± 72; P = 0.009), and the difference was still statistically significant after age adjustment (P = 0.026). Although choroidal vascularity index (CVI) was lower in the HFrEF group than in the control group, the difference was not statistically significant before and after age adjustment (73.45 ± 6.67 vs 75.77 ± 5.92; P = 0.118 and P = 0.096, respectively). In conclusion, in patients with HFrEF, we observed a reduction in parafoveal retinal VD in the superficial capillary plexus, as well as SFCT, but no significant change in CVI, CMT, or CC flow density.

Retinal age gap as a predictive biomarker for mortality risk

AIM

To develop a deep learning (DL) model that predicts age from fundus images (retinal age) and to investigate the association between retinal age gap (retinal age predicted by DL model minus chronological age) and mortality risk.

METHODS

A total of 80 169 fundus images taken from 46 969 participants in the UK Biobank with reasonable quality were included in this study. Of these, 19 200 fundus images from 11 052 participants without prior medical history at the baseline examination were used to train and validate the DL model for age prediction using fivefold cross-validation. A total of 35 913 of the remaining 35 917 participants had available mortality data and were used to investigate the association between retinal age gap and mortality.

RESULTS

The DL model achieved a strong correlation of 0.81 (p<0·001) between retinal age and chronological age, and an overall mean absolute error of 3.55 years. Cox regression models showed that each 1 year increase in the retinal age gap was associated with a 2% increase in risk of all-cause mortality (hazard ratio (HR)=1.02, 95% CI 1.00 to 1.03, p=0.020) and a 3% increase in risk of cause-specific mortality attributable to non-cardiovascular and non-cancer disease (HR=1.03, 95% CI 1.00 to 1.05, p=0.041) after multivariable adjustments. No significant association was identified between retinal age gap and cardiovascular- or cancer-related mortality.

CONCLUSIONS

Our findings indicate that retinal age gap might be a potential biomarker of ageing that is closely related to risk of mortality, implying the potential of retinal image as a screening tool for risk stratification and delivery of tailored interventions.

Low ambient temperature and temperature drop as novel risk factors of acute glaucoma: a case-crossover study

The prevalence of glaucoma has seasonal variation in population, but the role of ambient temperature and its variation remains unclear in this seasonal trend. So, we conducted a time-stratified case-crossover study to examine the association of ambient temperature and temperature change between neighboring days (TCN) with the risk of acute glaucoma. Data on meteorological parameters and glaucoma outpatient visit between 2015 and 2021 covered all districts of Shanghai. Conditional logistic regression with distributed lag nonlinear model was applied to estimate the association of temperature or TCN with the risk of acute glaucoma. A total of 7,746 patients diagnosed with acute primary angle-closure glaucoma (APACG) were included in this analysis. We observed a significant increase in the risk of acute glaucoma with cold temperature and temperature drop. Compared with the referent temperature (32℃), moderate low (12 °C) and extreme low (4 °C) temperature exposures were associated with higher risk of acute glaucoma outpatient visit, with the highest cumulative OR of 1.46 (95% CI: 1.11, 1.91) and 1.50 (95% CI: 1.09, 2.06) over lag 0-2 days. Temperature drop (TCN =  - 4 °C) also increases the risk of acute glaucoma (OR = 1.34, 95% CI: 1.07, 1.67) over lag 0-7 days, comparing with no temperature change. Patients of female and above age 65 were more vulnerable to cold exposure and temperature drop. This case-crossover study provided novel and robust individual-level evidence that low ambient temperature and temperature drop significantly increase the acute glaucoma risk. The findings provide protective strategies for glaucoma patient, especially for female and the old, under cold exposure and sudden temperature decline.