Retinal Vascular Diameter Research Articles

The relationship between retinal vascular parameters measured by artificial intelligence and the risk of new-onset cardiovascular disease in a Chinese community-based population

Abstract Background Studies on the association between retinal vascular diameter and tortuosity and the risk of new-onset cardiovascular disease (CVD) are controversial. The predictive value of retinal vascular parameters, measured through artificial intelligence (AI), for incident CVD risk in the community population, remains to be explored. Objectives Our study aims to investigate the association between retinal vascular parameters (diameter and tortuosity) measured through AI, and the risk of new-onset CVD in the Chinese community-based population. Methods We conducted a prospective cohort study on subjects from a Beijing community in China who were free of prevalent stroke or myocardial infarction and underwent retinal photography at baseline. By deep-learning algorithm, quantitative retinal vascular parameters were measured 0.5 to 1 disc diameter from the optic disc margin, including central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE), arteriolar-to-venular ratio (AVR), curvature tortuosity arteriole (cTORTa), and curvature tortuosity venule (cTORTv). The primary endpoint was a new-onset major adverse cardiovascular event (MACE), defined as a composite of cardiovascular death, first non-fatal stroke, and first non-fatal acute myocardial infarction (AMI). The secondary endpoints included cardiovascular death, first stroke, and first AMI. Cox proportional-hazards regression analyses were performed. Results A total of 3,585 participants were included. The mean age was 56.49 ± 8.94 years, and 2,335 (65.1%) were female. Prevalence of prior hypertension and diabetes was 1594 (44.5%) and 676 (18.9%), respectively. During the follow-up (median, 7.53 years), there were 293 cases of new-onset MACE (8.2%), 44 cardiovascular deaths (1.2%), 226 strokes (6.3%), and 57 AMIs (1.6%). The Kaplan–Meier curves showed significant differences in cumulative hazards of new-onset MACE among tertiles of CRAE, CRVE, AVR, and cTORTa, but not for cTORTv (Figure 1). In Cox proportional-hazards models (Figure 2) adjusting for covariates, CRAE was negatively associated with the risk of new-onset MACE (per 10 μm increase, hazard ratio [HR]=0.95, 95% confidence interval [CI]: 0.92-0.99, P=0.009) and the risk of new-onset stroke (per 10 μm increase, HR=0.96, 95%CI: 0.92-1.00, P=0.04). Similarly, AVR was negatively associated with new-onset MACE risk (per 0.1 increase, HR=0.82, 95%CI: 0.72-0.94, P<0.001) and new-onset stroke risk (per 0.1 increase, HR=0.84, 95%CI: 0.73-0.98, P=0.022). No significant associations were observed between CAVE, cTORTa, and cTORTv with any of the primary or secondary endpoints. Conclusions CRAE and AVR, measured through AI, are associated with the risk of new-onset MACE in the Chinese population. These findings suggest the potential for AI-measured parameters in retinal vasculature to aid in stratifying CVD risk in the general population.

The effect of palm oil-derived tocotrienol-rich fraction in preserving normal retinal vascular diameter in streptozotocin-induced diabetic rats.

Angiogenesis in diabetic retinopathy (DR) is associated with increased retinal expression of angiopoietin-2 (Ang-2) and protein kinase C (PKC). Tocotrienol-rich fraction (TRF) has been shown to reduce the expression vascular endothelial growth factor (VEGF) in several experimental models. However, its effect against other angiogenic markers such as Ang-2 and PKC in rat modelof diabetes remains unknown. Therefore, we investigated the effect of TRF on the retinal vascular changes and Ang-2 and PKC expressions in rats with streptozotocin (STZ)-induced DR. Sprague-Dawley rats were divided into normal control rats (N) which received vehicle, and diabetic rats which either received vehicle (DV) or 100mg/kg of TRF (DT). Diabetes was induced with intraperitoneal injection of STZ (60mg/kg body weight). Treatments were given orally, once daily, for 12weeks after confirmation of hyperglycaemia. Fundus photographs were captured at baseline, 6- and 12-week post-STZ injection and average diameter of retinal veins and arteries were measured. At 12-week post-STZ injection, rats were euthanised, and retinae were collected for measurement of Ang-2 and PKC gene and protein expressions. Retinal venous and arterial diameters were significantly greater in DV compared to DT at week 12 post-STZ injection (p < 0.001 and < 0.05, respectively). The vesseldiameter measurements in DT were comparable to N and this effect of TRF was associated with significantly lower Ang-2 and PKC gene and protein expressions compared to DV. Oral TRF reduces the expression of retinal angiogenic markers and preserves the retinalvascular diameter of rats withSTZ-induced DR.

Association of Retinal Microangiopathy with Albuminuria in Patient with Chronic Kidney Disease: a Meta-analysis Study.

Chronic kidney disease (CKD) patients suffer renal and cardiovascular problems and early death. In 2016, 13.4% of all ages globally had CKD. Kidney disease, diabetes, and hypertension have a microvascular component. Diabetic retinopathy (DR) and diabetic nephropathy (DN) commonly occur concurrently, indicating that the same mechanisms may be at action in the eyes and kidneys. Chronic kidney disease (CKD) has been a tough medical problem because of late signs and late treatment. Retinal vessels are a non-invasive technique to examine systemic microvasculature. Novel predictors may enhance microvascular disease risk categorization, leading to better therapy. Retinal vascular diameter and retinopathy are reported most often. Numerous investigations have linked this condition to kidney or other systemic disorders. The retinal microvasculature was linked with both the incidence and prevalence of renal illness in this investigation. We wanted to determine whether retinal microvasculature might be utilized to diagnose renal disease. Initial searching found 625 papers, of which 542 articles were rejected due to primary screening unrelated titles and/or abstracts. There were a total of 81 papers selected for full-text evaluation and due to insufficient data provided and duplication, we got 5 papers to enter the next step. In five investigations, retinal microvascular symptoms correlated with albuminuria. All studies connected retinal vascular diameter with albuminuria. As a categorical variable, CRAE narrowed. There was a U-shaped relationship between CRAE and albuminuria in quintiles 1 and 5. There were relationship between albuminuria to a larger CRVE and a narrower CRAE. Studies relate AVR to albuminuria were associated as well. Our investigation demonstrated retinal vascular symptoms are linked to renal illness. Retinopathy correlates with CKD and ESRD in diabetic and nondiabetic individuals. Evidence linking retinal vascular width to early renal disease implies fundus photography might be a useful screening technique for CKD patients. Insufficient evidence links retinal vascular diameter to kidney-related morbidity and death. Future studies should stratify by age, gender, obesity, hypertension, ethnicity, and others.

Retinal Vascular Caliber in Coronary Heart Disease and Its Risk Factors

Background: Many clinical and experimental articles have suggested that the retinal vascular diameter can be used as a predictor of coronary heart disease (CHD). However, the results and reliability of the prediction are still controversial. Objective: A meta-analysis of observational study was conducted to clarify the relationships of retinal vessel caliber with CHD and CHD risk factors. Method: PubMed and Embase were searched for all observational studies on the relationship of retinal vessel caliber with CHD and CHD risk factors from 2001 to 2021. The meta-analysis has been registered in PROSPERO (registration number is CRD42021267154). Result: A total of 14 articles were selected for the inclusion in this meta-analysis. In the primary outcome, smaller retinal arteriolar caliber was related to CHD, and the results achieved statistical significance (MD: −5.55, 95% CI: −8.07 to −3.02, p < 0.0001), while there was no significant difference in vein caliber between CHD and healthy people (MD: 1.10, 95% CI: −3.55 to 5.76, p = 0.64 > 0.05). Smaller retinal arteriolar caliber was related to increasing age, male sex, bigger BMI, and hypertension. Bigger retinal arteriolar caliber was related to current smoking. Smaller retinal venule caliber was related to increasing age and hypertension. Bigger retinal venule caliber was related to current smoking, bigger BMI, and diabetes. Conclusion: Smaller retinal arteriolar caliber was related to CHD, while there was no significant difference in venule caliber between CHD and healthy people. Retinal vascular caliber also independently related to CHD risk factors (e.g., age, gender, smoke, BMI, hypertension, and diabetes).

Airborne fine particulate matter (PM2.5) damages the inner blood–retinal barrier by inducing inflammation and ferroptosis in retinal vascular endothelial cells

This study was the first to explore the effect of airborne fine particulate matter (PM2.5) exposure on the inner blood–retinal barrier (iBRB). In this study, retinal vascular permeability and diameter were enhanced in the PM2.5-exposed animal model (1 mg/mL PM2.5, 10 μL per eye, 4 times per day, 3 days), together with observable retinal edema and increased inflammation level in retina. PM2.5-induced cell damage in human retinal microvascular endothelial cells (HRMECs) occurred in a time- and dose-dependent manner. Decreased cell viability, proliferation, migration, and angiogenesis, as well as increased apoptosis and inflammation, were observed. Iron overload and excessive lipid oxidation were also discovered after PM2.5 exposure (25, 50, and 100 μg/mL PM2.5 for 24 h), along with significantly altered expression of ferroptosis-related genes, such as prostaglandin-endoperoxide synthase 2, glutathione peroxidase 4, and ferritin heavy chain 1. Moreover, Ferrostatin-1, an inhibitor of ferroptosis, evidently alleviated the PM2.5-induced cytotoxicity of HRMECs. The present study investigated the in vivo effects of PM2.5 on retinas, revealing that PM2.5 exposure induced retinal inflammation, vascular dilatation, and caused damage to the iBRB. The crucial role of ferroptosis was discovered during PM2.5-induced HRMEC cytotoxicity and dysfunction, indicating a potential precautionary target in air pollution-associated retinal vascular diseases.

Association between retinal vascular measures and brain white matter lesions in schizophrenia.

Recent studies have examined retinal vascular abnormalities in schizophrenia as retinal vascular imaging is a non-invasive proxy to cerebral microvasculature. However, relation between retinal vascular abnormalities and brain structure is not well examined in schizophrenia. Hence in this study, for the first time, we examined the relationship between retinal vascular measures and brain white matter lesions in schizophrenia. We examined brain white matter lesions as they are considered a predictive marker for future adverse cerebrovascular event. We acquired retinal vascular images of both eyes using a non-mydriatic camera and calculated retinal vascular diameter, tortuosity, trajectory and fractal dimension using validated methods. All patients underwent Magnetic Resonance Imaging of bran and we computed white matter hypo-intensities using Freesurfer software. We performed a linear regression analysis to examine the relationship between white matter hypo-intensities and retinal vascular measures controlling for age, sex, fasting blood sugar, creatinine, whole-brain volume, and antipsychotic dose. The regression model was significant in Schizophrenia patients (R=0.983;R2=0.966;-F=10.849;p=0.008) but not in healthy volunteers (R=0.828;R2=0.686;F=0.182; p=0.963). Among the retinal vascular measures, arterial tortuosity (β=0.963;p-0.002), tortuosity (β=-1.002;p=0.001) and fractal dimension (β=-0.688;p=0.014) were significant predictors of white matter lesions. The current study's findings support the conclusion that retinal vascular fractal dimension and tortuosity are associated with changes in cerebral white matter and may be considered proxy markers for cerebral microvasculature in schizophrenia. Considering the relationship between white matter lesions and stroke, these observations could have important clinical implications to screen schizophrenia patients for risk of adverse cerebrovascular event.

Retinal vessel diameters: Can they predict future risk of infertility in patients with varicocele?

The objective of this study was to assess the relationship between retinal vessel diameters, such as retinal arteriolar diameter, retinal venular diameter, and arteriolar/venular ratio (AVR), as clinical parameters of fertility in varicocele patients. Sixty-eight (68) infertile varicocele men with abnormal semen parameters and sixty-one (61) varicocele normozoospermic men were included in the study. Moreover, fifty-eight (58) healthy normozoospermic men without varicocele were enrolled as a control group. For each participant, retinal vascular diameters were measured from the digital retinal photographs as a central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE), and AVR. In addition, hormones (total testosterone and FSH), and semen parameters were assessed and correlated with retinal vessel diameters. The mean CRAE, CRVE, and AVR values were 147.8 ± 15.8 μm, 198.3 ± 39.3 μm, and 0.61 ± 0.01 in infertile varicocele patients, respectively. Significant difference of CRAE, CRVE, and AVR were found when comparing infertile varicocele patients with both varicocele and control normozoospermic male groups (p = 0.01, p = 0.006, and p = 0.007; respectively). Larger retinal venular caliber and smaller AVR ratio showed a significant inverse correlation with both sperm parameters and hormones (total testosterone and FSH) (p < 0.05). No significant correlations were found between CRAE with both sperm parameters and hormonal values (total testosterone and FSH) (p > 0.05). Infertile patients with varicocele showed a significant relationship with the retinal vascular diameter (CRVE and AVR ratio). This finding supports recommendation for regular eye examinations in the varicocele population.

Comparing Measurements of Vascular Diameter Using Adaptative Optics Imaging and Conventional Fundus Imaging.

The aim of this prospective study was to compare retinal vascular diameter measurements taken from standard fundus images and adaptive optics (AO) images. We analysed retinal images of twenty healthy subjects with 45-degree funduscopic colour photographs (CR-2 Canon fundus camera, Canon™) and adaptive optics (AO) fundus images (rtx1 camera, Imagine Eyes®). Diameters were measured using three software applications: the VAMPIRE (Vessel Assessment and Measurement Platform for Images of the REtina) annotation tool, IVAN (Interactive Vessel ANalyzer) for funduscopic colour photographs, and AO_Detect_Artery™ for AO images. For the arterial diameters, the mean difference between AO_Detect_Artery™ and IVAN was 9.1 µm (−27.4 to 9.2 µm, p = 0.005) and the measurements were significantly correlated (r = 0.79). The mean difference between AO_Detect_Artery™ and VAMPIRE annotation tool was 3.8 µm (−34.4 to 26.8 µm, p = 0.16) and the measurements were poorly correlated (r = 0.12). For the venous diameters, the mean difference between the AO_Detect_Artery™ and IVAN was 3.9 µm (−40.9 to 41.9 µm, p = 0.35) and the measurements were highly correlated (r = 0.83). The mean difference between the AO_Detect_Artery™ and VAMPIRE annotation tool was 0.4 µm (−17.44 to 25.3 µm, p = 0.91) and the correlations were moderate (r = 0.41). We found that the VAMPIRE annotation tool, an entirely manual software, is accurate for the measurement of arterial and venular diameters, but the correlation with AO measurements is poor. On the contrary, IVAN, a semi-automatic software tool, presents slightly greater differences with AO imaging, but the correlation is stronger. Data from arteries should be considered with caution, since IVAN seems to significantly under-estimate arterial diameters.

Retinal Vascular Signs as Screening and Prognostic Factors for Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Current Evidence.

Background: The substantial burden of kidney disease fosters interest in new ways of screening for early disease diagnosis, especially by non-invasive imaging. Increasing evidence for an association between retinal microvascular signs and kidney disease prompted us to investigate the relevant current literature on such an association systematically by performing a meta-analysis of our findings. Methods: We scrutinized the current literature by searching PubMed and Embase databases from for clinical studies of the association between retinal microvascular signs and prevalent or incident kidney disease. After excluding cases that did not meet our criteria, we extracted relevant data from 42 published studies (9 prospective, 32 cross-sectional, and 1 retrospective). Results: Our investigation yielded significant associations between retinal vascular changes (including retinopathy and retinal vascular diameter) and kidney dysfunction (including chronic kidney disease (CKD), end-stage renal disease (ESRD), albuminuria, and estimated glomerular filtration rate (eGFR) decline). According to our meta-analysis, retinopathy was associated with ESRD (hazard ratio (HR) 2.12 (95% confidence interval CI; 1.39–3.22)) and with CKD prevalence in the general population (odds ratio (OR) 1.31 (95% CI; 1.14–1.50)), and specifically in type 2 diabetic patients (OR 1.68 (95% CI; 1.68–2.16)). CRAE was associated with prevalent CKD (OR 1.41 (95% CI; 1.09–1.82)). Conclusions: Our findings suggest that the retinal microvasculature can provide essential data about concurrent kidney disease status and predict future risk for kidney disease development and progression.

The performance of an integrated model including retinal information in predicting childhood hypertension.

The objective of this study was to examine the association of an integrated model (composed of retinal arteriolar caliber, height, and sex) with blood pressure (BP) among a group of Chinese children, and assess the predictive value of the integrated model for childhood hypertension. This study included 1460 candidates aged 12.634 ± 0.420 years. Height, weight, waist circumference, and BP were obtained and ophthalmological measurements were taken. The computer-imaging program (IVAN, University of Wisconsin, Madison, WI) was used to measure calibers of retinal vessels. Receiver-operating characteristic curve (ROC) analyses were performed to assess the accuracy of the integrated model as a diagnostic test of elevated BP in children. The accuracy of the integrated model (assessed by area under the curve) for identifying elevated BP was 0.777 (95% confidence interval: 0.742-0.812). The optimal threshold of the integrated model for defining hypertension was 0.153, and the calculation formula for the specific predictive risk was: Logit (p/1 - p) = -5.666 - 0.261 × retinal arteriolar caliber + 0.945 × sex + 0.438 × height. In identifying elevated BP, the sensitivity and specificity were 0.711 and 0.736, respectively. The model containing eye message is a comprehensive and relatively effective index to identify elevated BP in 12-year-old children, which can offer assistance to further understand childhood microcirculation disease. We firstly incorporated retinal vascular diameter, sex, and height into one integrated model to identify hypertension in 12-year-old children. The current discrimination of hypertension in children is difficult. There have been some studies to simplify the diagnosis of children's hypertension, but they were limited to anthropometric measurements. We proposed a composed model containing microcirculation information to predict childhood hypertension. Based on the knowledge that microcirculation is not only a means to study the manifestations but also early pathogenic correlates of hypertension, the combined model containing microcirculation message as a method may provide new insights into the diagnosis of childhood hypertension.

Changes in retinal vascular diameters in senior and geriatric cats in association with variation in systemic blood pressure.

Early diagnosis of arterial hypertension is essential to prevent target organ damage. In humans, retinal arteriolar narrowing predicts hypertension. This blinded prospective observational study investigated the retinal vessel diameters in senior and geriatric cats of varying systolic blood pressure (SBP) status and evaluated retinal vascular changes in hypertensive cats after treatment. Cats with a median age of 14 years (range 9.1-22 years) were categorised into five groups: group 1, healthy normotensive (SBP <140 mmHg; n = 40) cats; group 2, pre-hypertensive (SBP 140-160 mmHg; n = 14) cats; group 3, cats with chronic kidney disease (CKD) and normotensive (n = 26); group 4, cats with CKD and pre-hypertensive (n = 13); and group 5, hypertensive cats (SBP >160 mmHg, n = 15). Colour fundus images (Optibrand ClearView) were assessed for hypertensive lesions. Retinal vascular diameters and bifurcation angles were annotated and calculated using the Vascular Assessment and Measurement Platform for Images of the Retina annotation tool (VAMPIRE-AT). When available, measurements were obtained at 3 and 6 months after amlodipine besylate treatment. Ten hypertensive cats had retinal lesions, most commonly intraretinal haemorrhages and retinal exudates. Arteriole and venule diameters decreased significantly with increasing age (-0.17 ± 0.05 pixels/year [P = 0.0004]; -0.19 ± 0.05 pixels/year). Adjusted means ± SEM for arteriole and venule diameter (pixels) were 6.3 ± 0.2 and 8.9 ± 0.2 (group 1); 7.6 ± 0.3 and 10.1 ± 0.4 (group 2); 6.9 ± 0.2 and 9.5 ± 0.3 (group 3); 7.4 ± 0.3 and 10.0 ± 0.4 (group 4); and 7.0 ± 0.3 and 9.8 ± 0.4 (group 5). Group 1 arteriole and venule diameters were significantly lower than those of groups 2 and 4. Group 2 arteriole bifurcation angle was significantly narrower than those of groups 1 and 3. Post-treatment, vessel diameters decreased significantly at 3 and 6 months in seven hypertensive cats. Increased age was associated with reduced vascular diameters. Longitudinal studies are required to assess if vessel diameters are a risk indicator for hypertension in cats.

Retinal Vascular Tortuosity and Diameter Associations with Adiposity and Components of Body Composition

ObjectiveThe aim of this study was to assess whether adiposity or body composition relates to microvascular characteristics of the retina, indicative of cardiometabolic function.MethodsA fully automated QUARTZ software processed retinal images from 68,550 UK Biobank participants (aged 40-69 years). Differences in retinal vessel diameter and tortuosity with body composition measures from the Tanita analyzer were obtained by using multilevel regression analyses adjusted for age, sex, ethnicity, clinic, smoking, and Townsend deprivation index.ResultsVenular tortuosity and diameter increased by approximately 2% (P < 10–300) and 0.6 μm (P < 10–6), respectively, per SD increase in BMI, waist circumference index, waist-hip ratio, total body fat mass index, and fat-free mass index (FFMI). Venular associations with adiposity persisted after adjustment for FFMI, whereas associations with FFMI were weakened by FMI adjustment. Arteriolar diameter (not tortuosity) narrowing with FFMI was independent of adiposity (–0.6 μm; –0.7 to –0.4 μm per SD increment of FFMI), while adiposity associations with arteriolar diameter were largely nonsignificant after adjustment for FFMI.ConclusionsThis demonstrates, on an unprecedented scale, that venular tortuosity and diameter are more strongly associated with adiposity, whereas arteriolar diameter relates more strongly to fat-free mass. Different attributes of the retinal microvasculature may reflect distinct roles of body composition and fatness on the cardiometabolic system.

Association of Retinal Microvascular Characteristics With Short-term Memory Performance in Children Aged 4 to 5 Years

Neurocognitive functions develop rapidly in early childhood and depend on the intrinsic cooperation between cerebral structures and the circulatory system. The retinal microvasculature can be regarded as a mirror image of the cerebrovascular circulation. To investigate the association between retinal vessel characteristics and neurological functioning in children aged 4 to 5 years. In this cohort study, mother-child pairs were recruited at birth from February 10, 2010, to June 24, 2014, and renewed consent at their follow-up visit from December 10, 2014, to July 13, 2018. Participants were followed up longitudinally within the prospective Environmental Influence on Aging in Early Life birth cohort. A total of 251 children underwent assessment for this study. Data were analyzed from July 17 to October 30, 2019. Retinal vascular diameters, the central retinal arteriolar equivalent (CRAE), central retinal venular equivalent (CRVE), vessel tortuosity, and fractal dimensions were determined. Attention and psychomotor speed, visuospatial working memory, and short-term visual recognition memory were assessed by the Cambridge Neuropsychological Test Automated Battery, including the following tasks: Motor Screening (MOT), Big/Little Circle (BLC), Spatial Span (SSP), and Delayed Matching to Sample (DMS). Among the 251 children included in the assessment (135 girls [53.8%]; mean [SD] age, 4.5 [0.4] years), for every 1-SD widening in CRVE, the children performed relatively 2.74% (95% CI, -0.12 to 5.49; P = .06) slower on the MOT test, had 1.76% (95% CI, -3.53% to -0.04%; P = .04) fewer correct DMS assessments in total, and made 2.94% (95% CI, 0.39 to 5.29; P = .02) more errors given a previous correct answer in the DMS task on multiple linear regression modeling. For every 1-SD widening in CRAE, the total percentage of errors and errors given previous correct answers in the DMS task increased 1.44% (95% CI, -3.25% to 0.29%; P = .09) and 2.30% (95% CI, -0.14% to 4.61%; P = .07), respectively. A 1-SD higher vessel tortuosity showed a 4.32% relative increase in latency in DMS task performance (95% CI, -0.48% to 9.12%; P = .07). Retinal vessel characteristics were not associated with BLC and SSP test outcomes. These findings suggest that children's microvascular phenotypes are associated with short-term memory and that changes in the retinal microvasculature may reflect neurological development during early childhood.

Assessment of retinal vascular oxygenation and morphology at stages of diabetic retinopathy in African Americans

BackgroundDiabetic retinopathy (DR) is a microvascular complication of diabetes and a leading cause of blindness in working-age adults. The likelihood of visual impairment associated with DR is two-fold higher in the African-American (AA) compared to non-Hispanic white. Although alterations in retinal vessel oxygenation and morphology have been reported in DR, there is limited knowledge about these vascular changes in AA subjects. The purpose of the current study was to investigate alterations in retinal vascular oxygen saturation (SO2), vessel diameter (D) and tortuosity at severity stages of DR in AA subjects.MethodsA nested case-control study of 56 AA subjects was conducted. Right eyes were grouped as non-diabetic (ND) (N = 26), no clinical DR (NDR) (N = 19), or moderate/severe non-proliferative DR (NPDR) (N = 11). Imaging was performed using a commercially available scanning laser ophthalmoscope. Images were analyzed to determine retinal arterial and venous SO2 (SO2A and SO2V), diameter (DA and DV), and vessel tortuosity index (VTI) (VTIA and VTIV).ResultsSO2V and DV were higher in NPDR compared to ND and NDR groups (P < 0.05). There were no significant differences in SO2A and DA among ND, NDR, and NPDR groups (P > 0.8). Maximum VTIA was higher in diabetics (NDR and NPDR) compared to non-diabetics (P < 0.03). There was no significant difference in maximum VTIV among the 3 groups (P = 0.5).ConclusionsThe findings advance our understanding of DR pathophysiology in the AA population and may propel identification of race-specific retinal vascular biomarkers for improved diagnosis and monitoring of DR.

Retinal oxygen saturation and vessel diameter in patients with chronic kidney disease.

To investigate changes in retinal oximetry and the diameter of retinal vasculature in patients with chronic kidney disease (CKD) and relationships between retinal vasculature and the estimated glomerular filtration rate (eGFR), provide a scientific basis for the early detection and diagnosis of CKD. Eighty-three patients with CKD and 103 healthy individuals were included after providing informed consent. All participants were examined using a noninvasive technology (Oxymap Inc., Reykjavik, Iceland) for measuring the arterial (SaO2 ) and venous (SvO2 ) oxygen saturation and the arteriovenous difference in oxygen saturation (Sa-vO2 ). The corresponding retinal vessel diameters of these arterioles (D-A) and venules (D-V) were measured. The eGFR of patients with CKD was calculated from the serum creatinine concentration. In general, patients with CKD had higher mean SaO2 values than healthy individuals (100.15±4.68% versus 97.14±4.22%; p<0.001, mean±SD). The mean SaO2 in the superior temporal, superior nasal and inferior nasal quadrants significantly increased. There was no significant difference measured in the SvO2 when patients with CKD (63.66±5.29%) and healthy individuals (62.70±5.27%) were compared. The mean Sa-vO2 of the CKD group (36.49±4.98%) was increased compared with normal subjects (34.44±4.76%) (p=0.005). The retinal arteriole diameter was narrower in patients with CKD than in normal individuals (117.53±14.88μm versus 126.87±14.98μm; p<0.001, mean±SD), and the arteriovenous ratio was smaller than in normal individuals (0.71±0.09 versus 0.77±0.09; p<0.001, mean±SD). Pearson's two-tailed correlation showed a significant correlation between the SaO2 and eGFR (R=-0.363, p=0.001), and narrower retinal arterial calibre was significantly associated with a lower eGFR (R=0.415, p<0.001). Based on our results, there were alterations in retinal oxygen saturation and vascular diameter in patients with CKD. Further studies are needed to determine whether such changes play a role in the development of CKD.

Association between retinal arterial narrowing and left ventricular diastolic dysfunction in masked hypertensives.

Morphological change in retinal vessel diameters has been reported to be associated with negative cardiovascular outcomes, but its association with left ventricular diastolic dysfunction (LVDD) is not clear. This study aimed to examine the association between echocardiographic markers of LVDD and retinal vascular diameters, in untreated masked hypertension (MH). In this observational study, 105 MH patients without other cardiovascular risks were included (mean age 48.4±5.7, female 72.4%). All individuals underwent extensive clinical and laboratory investigations, including echocardiography, ambulatory blood pressure monitoring, and retinal vascular diameters measured by optical coherence tomography. In the group, LVDD was diagnosed in 36 participants evaluated by left ventricular volume index, E/A and E/e' ratio. Compared to non-LVDD, LVDD subjects displayed narrower retinal arteriolar diameter (139.1±33.8 vs 165.1±29.1; adjusted P=.007) and wider retinal venular diameter (237.9±42.2 vs 214.9±44.8; adjusted P=.045). Significant and independent associations were demonstrated for retinal arteriolar narrowing and E/A ratio (adjusted β=0.744, P=.031) and for retinal arteriolar diameter and E/e' ratio (adjusted β=-0.158, P=.001) after controlling for age, gender, body mass index, ambulatory systolic blood pressure, low-density lipoprotein cholesterol, and retinal venular diameter. In untreated MH subjects, retinal arteriolar diameter, a marker of microvascular damage, was independently associated with echocardiographic markers of diastolic dysfunction. These findings might underscore the hypothesis that microvascular disease could contribute to cardiac remodeling.

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

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

Short-time effect of intravitreal injections on retinal vascular oxygenation and vessel diameter in patients with diabetic macular oedema or neovascular age-related macular degeneration.

PurposeTo investigate the short‐time effect of intravitreal injections (IVI) of the vascular endothelial growth factor inhibitors ranibizumab and aflibercept on retinal arterial and venous oxygen saturation (SO2a and SO2v), arteriovenous oxygen saturation difference (AVD) and vessel diameter (VDa and VDv) in patients with diabetic macular oedema (DME) and patients with choroidal neovascularization (CNV) due to age‐related macular degeneration.MethodsUncontrolled prospective observational study in 100 eyes. Retinal vessel oxygen saturation and diameters were assessed using a retinal oximeter before and minutes after IVI of ranibizumab or aflibercept.Results40 eyes with CNV and 34 eyes with DME were included in the analysis. At baseline, SO2a and SO2v were significantly higher in DME (p = 0.043 and p = 0.009, respectively). After IVI, SO2a significantly decreased in CNV and DME eyes by 2.6% (p = 0.016) and 4.6% (p = 0.002) and SO2v decreased by 14.0% (p = 0.004) and 12.4% (p = 0.017), respectively. However, a significant increase in AVD was only found in CNV (15.7%, p = 0.001). VDa decreased significantly only in DME by 5.7% (p = 0.010). No medication‐specific disease effect was found and vice versa.ConclusionsThe observed changes can be interpreted as signs of increased metabolic demand during the physiological stress after an IVI. The abnormal arterial constriction and the abolished increase in AVD seen only in eyes with DME indicate an impairment of vascular autoregulation and oxygen distribution and a reduced neuroretinal metabolism in the diabetic retina with a significant impact on inner retinal oxygen consumption shortly after IVI.

5-year changes of retinal vascular diameters in elderly population in Beijing

5-year changes of retinal vascular diameters in elderly population in Beijing

Relationship between the changes of high-sensitivity C-reactive protein and retinal vessel diameter in the middle-aged and elderly: the Kailuan Study

Objective To investigate the relationship between high-sensitivity C-reactive protein (hsCRP) and retinal vascular diameter. Methods This study was a cross-sectional study, the population was from the Kailuan study (clinical trial research registration NO.: ChiCTR-TNC-1100 1489) in 2012—2013 (age≥40 years). All the people was checked by cardiovascular and epidemiological examination, of which 3 447 people had an analytical results of fundus color photography.The retinal vascular diameter was analyzed by software.Take the value of hsCRP 1% to 99% points and 3 363 people were finally included in the statistical analysis.The mean age of 3 363 people (male 1 880, female 1 483) was 56.69±10.10 years old.The correlation between hsCRP and central retinal artery equivalent(CRAE), central retinal vein equivalent (CRVE), arteriovenous ratio(AVR) were evaluated by Spearman correlation coefficient.Multivariate linear regression analysis was used to futher analyze the association between hsCRP and retinal fundus diameter parameters. Results The median value of hsCRP was 1.10(0.50, 2.21)mmo/L, CRAE was (174.16±24.36)μm, CRVE was (282.70±26.32)μm, AVR was 0.62±0.09.Spearman correlation analysis showed that hsCRP was positively correlated with CRVE (r=0.052, P=0.003) and negatively correlated with AVR (r=-0.052, P=0.002). The non-normal variables hsCRP were transformed into continuous variables lghsCRP, and CRAE, CRVE and AVR were used for multivariate linear regression analysis.After a number of factors were gradually corrected, the results showed that association between lghsCRP and CRVE (β=3.428) or AVR (β=-0.006) was statistically significant (P<0.05). LghsCRP was a risk factor for CRVE both in men and women after the calculation of gender stratification. Conclusions CRVE increased and AVR decreased with the increase of hsCRP.The changes of retinal vascular diameter may be associated with hsCRP as a marker to predict cardiovascular and cerebrovascular disease. Key words: Central retinal artery equivalent; Central retinal vein equivalent; High-sensitivity C-reactive protein