Retinal Vasculature Research Articles

Retinal Microvascular Alterations in Hidradenitis Suppurativa Patients: A Pilot Study Using Optical Coherence Tomography Angiography.

Background: Hidradenitis suppurativa (HS) is a relapsing-remitting inflammatory disease characterized by the progression of asymptomatic nodules to deep-seated lesions and fistula formation that leads to suppuration and scarring. Optical coherence tomography angiography (OCTA) is a new non-invasive imaging technique that carefully analyzes retinal microvasculature networks with high-resolution imaging. Recent studies have demonstrated that retinal vessel density and retinal perfusion reflect systemic inflammatory responses. This study's aim was to analyze OCTA-derived retinal microvasculature parameters to understand if patients affected by HS and without any relevant ocular or systemic comorbidities showed impaired retinal vascular function and morphology. Method: We performed a case-control study of HS patients and age- and sex-matched control cohort. A total of 20 eyes from 10 HS patients and 30 eyes from 15 healthy controls were analyzed, and OCTA-derived microvasculature parameters were compared between groups. Results: OCTA images showed that HS patients, compared to healthy controls, were typically characterized by higher values of the foveal avascular zone (FAZ) both in the superficial capillary plexus (SCP) and in the deep capillary plexus (DCP), and by lower values of vessel density (VD)-SCP, VD-DCP, and vessel length density (VLD)-SCP in the foveal region. These findings partially reflect changes that have been demonstrated in diabetic patients that could be induced by a protracted metabolic or systemic inflammatory dysregulation. Conclusions: In conclusion, OCTA enables large-scale, non-invasive visual screening and follow-up of the retinal vasculature features, providing a new strategy for the prevention and monitoring of visual changes in HS patients.

Distinctive Phase Interdependency Model for Retinal Vasculature Delineation in OCT-Angiography Images.

Automatic detection of retinal vasculature in optical coherence tomography angiography (OCTA) images faces several challenges such as the closely located capillaries, vessel discontinuity and high noise level. This paper introduces a new distinctive phase interdependency model to address these problems for delineating centerline patterns of the vascular network. We capture the inherent property of vascular centerlines by obtaining the inter-scale dependency information that exists between neighboring symmetrical wavelets in complex Poisson domain. In particular, the proposed phase interdependency model identifies vascular centerlines as the distinctive features that have high magnitudes over adjacent symmetrical coefficients whereas the coefficients caused by background noises are decayed rapidly along adjacent wavelet scales. The potential relationships between the neighboring Poisson coefficients are established based on the coherency of distinctive symmetrical wavelets. The proposed phase model is assessed on the OCTA-500 database (300 OCTA images + 200 OCT images), ROSE-1-SVC dataset (9 OCTA images), ROSE-1 (SVC+ DVC) dataset (9 OCTA images), and ROSE-2 dataset (22 OCTA images). The experiments on the clinically relevant OCTA images validate the effectiveness of the proposed method in achieving high-quality results. Our method produces average FScore of 0.822, 0.782, and 0.779 on ROSE-1-SVC, ROSE-1 (SVC+ DVC), and ROSE-2 datasets, respectively, and the FScore of 0.910 and 0.862 on OCTA_6mm and OCT_3mm datasets (OCTA-500 database), respectively, demonstrating its superior performance over the state-of-the-art benchmark methods.

Stem cell factor protects against chronic ischemic retinal injury by modulating on neurovascular unit

Retinal ischemia is a significant factor in various vision-threatening diseases, but effective treatments are currently lacking. This study explores the potential of stem cell factor (SCF) in regulating the neurovascular unit as a therapeutic intervention for retinal ischemic diseases. A chronic retinal ischemia model was established in Brown Norway rats using bilateral common carotid artery occlusion (BCCAO). Subsequent SCF treatment resulted in a remarkable recovery of retinal function, as indicated by electroretinogram, light/dark transition test, and optokinetic head tracking test results. Histological examination demonstrated a significant increase in the number of retinal neurons and an overall thickening of the retina. Immunofluorescence confirmed these findings and further demonstrated that SCF treatment regulated retinal remodeling. Notably, SCF treatment ameliorated the disrupted expression of synaptic markers in the control group's BCCAO rats and suppressed the activation of Müller cells and microglia. Retinal whole-mount analysis revealed a significant improvement in the abnormalities in retinal vasculature following SCF treatment. Transcriptome sequencing analysis revealed that SCF-induced transcriptome changes were closely linked to the Wnt7 pathway. Key members of the Wnt7 pathway, exhibited significant upregulation following SCF treatment. These results underscore the protective role of SCF in the neurovascular unit of retinal ischemia rats by modulating the Wnt7 pathway. SCF administration emerges as a promising therapeutic strategy for retinal ischemia-related diseases, offering potential avenues for future clinical interventions.

Decreased retinal vascular density is associated with cognitive impairment in CADASIL: an optical coherence tomography angiography study.

This study aimed to assess alterations in retinal vascular density in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) patients using optical coherence tomography angiography (OCTA) and investigate their association with MRI and cognitive features. Twenty-five patients with CADASIL and forty healthy controls were evaluated by Cirrus HD-OCT 5000 with AngioPlex OCTA to determine changes in macular retinal vasculature. Retinal vasculature parameters between two groups were compared. The MRI lesion burden and neuropsychological scales were also examined in patients. The association between OCTA parameters and MRI/cognitive features was evaluated using partial Spearman rank correlation. The vessel density and perfusion density of whole image in macular region (vessel density: t = - 2.834, p = 0.005; perfusion density: t = - 2.691, p = 0.007) were significantly decreased in patients with CADASIL. Moreover, vessel density of whole image in macular region was negatively associated with Fazekas scores (ρ = - 0.457; p = 0.025) and the number of lacunar infractions (ρ = - 0.425, p = 0.038) after adjustment for age. Decreased macular vessel density and perfusion density of whole image were also associated with MoCA scores (vessel density: ρ = 0.542, p = 0.006; perfusion density: ρ = 0.478, p = 0.018) and other domain-specific neuropsychological tests (p < 0.05) after adjustment for age. Decreased retinal vascular density was associated with increased MRI lesion burden and cognitive impairment in patients with CADASIL. Our findings suggest that the degree of retinal vascular involvement, as demonstrated by OCTA, may be consistent with the severity of MRI lesions and the degree of cognitive impairment in patients.

Repeatability of swept-source optical coherence tomography angiography automated macular vessel density.

Optical Coherence Tomography Angiography Ratio Analysis (OCTARA) is capable of visualizing inner and outer retinal vascular plexuses, choriocapillaris, and larger choroidal vasculature in vivo without contrast injection. The aim of this study was to assess the intrasession repeatability of automated vessel density measurements using Triton Swept-Source Optical Coherence Tomography Angiography (OCTA) innovative algorithm OCTARA in retinal and choroidal vasculature. To study population between 65-90 years old with no eye diseases. For each subject measurements were performed four times. The intraclass correlation coefficient and the coefficient of variation were calculated to analyze repeatability of the OCTARA automatically generated vessel density measurements. A total of 35 eyes were included in the study. The intraclass correlation coefficient of the global vessel density in the superficial capillary plexus and the deep capillary plexus were 0.963 and 0.975, respectively, and the coefficient of variation were 5.4% and 4.4%, respectively. The intraclass correlation coefficient of the rest of the global measurements was indicative of good reliability with the exception of the deep choroid layer with an intraclass correlation coefficient of 0.6 indicative of moderate reliability. Our results proved excellent repeatability of automated vessel density measurements in the superficial and deep capillary plexus layers in our cohort using a OCTARA algorithm indicating that it may be a reliable diagnostic tool. It also showed good reliability in choriocapillary and mid choroid layer. These findings may be of value in assessing the significance of differences in capillary density measurements over time and across different settings.

OCTA characteristics in non-arteritic central retinal artery occlusion and correlation with visual acuity.

To observe the retinal and choroidal circulations in patients with non-arteritic permanent central retinal artery occlusion (NA-CRAO) via optical coherence tomography angiography (OCTA) and analyze their correlation with visual acuity. Sixty-two eyes with clinically confirmed acute NA-CRAO were included in the study and divided into: A type (mild n=29), B type (moderate n=27) and C type (severe n=6) based on the degree of visual loss, retinal edema, and arterial blood flow delay in fundus fluorescence angiography (FFA). Contralateral healthy eyes were used as the control group. Best-corrected visual acuity (BCVA), slit lamp microscopy, indirect ophthalmoscopy, fundus color photography, OCTA, and FFA were performed. Spearman's correlation analysis was used to determine the correlations between retinal and choroidal vessels and visual acuity. There were no statistically significant differences in age, gender, and intraocular pressure among the three types and the control group (P>0.05). Vessel density in deep capillary plexus (VD-DCP) significantly decreased (P<0.05) in all three types of NA-CRAO patients compared to the control group. Vessel density in superficial vascular plexus (VD-SVP) significantly decreased (P<0.05) in type A patients and choriocapillaris flow area significantly decreased (P<0.05) in type B and type C patients compared to the control group; while outer retinal flow areas significantly increased in the type A (P<0.05) and decreased in type C patients (P<0.05). The retinal thickness significantly increased in type C group (P<0.05). The VD-SVP at fovea in the type A was significantly lower than both of type B and C. The VD-SVP at nasal parafovea in type A and B was significantly lower than type C (P<0.05). The logMAR BCVA of type A was significantly better than that of type B and C groups (P<0.05). Spearman's correlation analysis showed that the logMAR BCVA was positively correlated with VD-SVP at fovea (r=0.679, P=0.031) and nasal parafovea (r=0.826, P=0.013). OCTA is valuable for assessing retinal ischemia, and evaluating visual impairment. Deep retinal vasculature is commonly affected in all NA-CRAO types. VD-SVPs at fovea and nasal parafovea can serve as reliable markers of visual impairment in NA-CRAO.

The visual field-testing maze and vision maze: Feasible techniques to evaluate visual field loss in animals

Visual field loss due to glaucoma is a severe and concerning problem, leading to limited visual range and poor quality vision. The progression of this loss begins with a para-central arcuate scotoma which eventually advances to a ring scotoma and constricted visual fields in later stages. Currently, no animal model is available for screening this pattern of vision loss. However, we have successfully developed two mazes to evaluate visual field loss - the visual field-testing maze (VFTZ) for peripheral vision loss and the vision maze (VM) for central vision loss. Our studies involved inducing glaucoma in Wistar and Sprague Dawley rats using lipopolysaccharide (LPS) and testing them in VFTZ and VM. We used Latanoprost and dorzolamide eye drops as standard drug candidates during the study. We evaluated the animals for intraocular pressure, retinal vasculature imaging, and anxiety using tonometry, ophthalmoscopy, and light and dark model techniques. Furthermore, we quantified the antioxidant parameters of the retina using UV spectroscopy. Our findings showed that animals with peripheral visual field loss in VFTZ took significantly more time to reach the goal and spent more time within the maze compared to normal or drug-treated animals (P < 0.001). Additionally, animals with compromised central visual field in VM spent more time in a particular arm and changed arms less frequently (P < 0.001) compared to normal or drug-treated animals. Moreover, we observed that glaucomatous rats exhibited elevated anxiety levels and impaired performance in the mazes, emphasizing the impact of vision loss on anxiety. Finally, the antioxidant and ATPase alterations in the retinal layers verified the glaucomatous changes in the experimental animals. Based on our remarkable findings, we strongly recommend the use of VFTZ and VM to evaluate visual field loss in animals.

Current understanding of subclinical diabetic retinopathy informed by histology and high-resolution in vivo imaging.

The escalating incidence of diabetes mellitus has amplified the global impact of diabetic retinopathy. There are known structural and functional changes in the diabetic retina that precede the fundus photography abnormalities which currently are used to diagnose clinical diabetic retinopathy. Understanding these subclinical alterations is important for effective disease management. Histology and high-resolution clinical imaging reveal that the entire neurovascular unit, comprised of retinal vasculature, neurons and glial cells, is affected in subclinical disease. Early functional manifestations are seen in the form of blood flow and electroretinography disturbances. Structurally, there are alterations in the cellular components of vasculature, glia and the neuronal network. On clinical imaging, changes to vessel density and thickness of neuronal layers are observed. How these subclinical disturbances interact and ultimately manifest as clinical disease remains elusive. However, this knowledge reveals potential early therapeutic targets and the need for imaging modalities that can detect subclinical changes in a clinical setting.

Indocyanine green fluorescence imaging: A novel adjunct to gastrointestinal surgery

Indocyanine Green (ICG) has been applied in medicine since the late 50s for cardiac output measurement, to study the anatomy of Retinal vasculature, and liver functional reserve before major hepatectomy in cirrhotic livers. The dye can be injected into the human bloodstream with practically no adverse effects. ICG fluorescence imaging is advantageous in being compatible with the biochemical characteristics of living tissues. ICG has been used in medical science for the last several decades. However, its use in surgery has recently been explored and has found vast applications in the surgical field. In particular, its use in Gastrointestinal (GI) surgery including hepatobiliary surgery has started to define new trends and techniques to guide the modern surgeon in both simple and complex procedures. In this review we thus explore in light of recent literature the potential uses of ICG in GI surgery.

Deep learning-based optical coherence tomography angiography image construction using spatial vascular connectivity network

Optical coherence tomography angiography (OCTA) provides unrivaled capability for depth-resolved visualization of retinal vasculature at the microcapillary level resolution. For OCTA image construction, repeated OCT scans from one location are required to identify blood vessels with active blood flow. The requirement for multi-scan-volumetric OCT can reduce OCTA imaging speed, which will induce eye movements and limit the image field-of-view. In principle, the blood flow should also affect the reflectance brightness profile along the vessel direction in a single-scan-volumetric OCT. Here we report a spatial vascular connectivity network (SVC-Net) for deep learning OCTA construction from single-scan-volumetric OCT. We quantitatively determine the optimal number of neighboring B-scans as image input, we compare the effects of neighboring B-scans to single B-scan input models, and we explore different loss functions for optimization of SVC-Net. This approach can improve the clinical implementation of OCTA by improving transverse image resolution or increasing the field-of-view.

Analysis of the Retinal and Choroidal Vasculature Using Ultrawidefield Fundus Imaging in Mild Cognitive Impairment and Normal Cognition

PurposeTo utilize ultra-widefield (UWF) imaging to evaluate retinal and choroidal vasculature and structure in individuals with mild cognitive impairment (MCI) compared to controls with normal cognition. DesignProspective cross-sectional study ParticipantsOne hundred thirty-one eyes of 82 MCI patients and 231 eyes of 133 cognitively normal participants from the Eye Multimodal Imaging in Neurodegenerative Disease (iMIND) Study. MethodsA scanning laser ophthalmoscope (SLO) (California, Optos Inc, Marlborough, MA) was used to obtain UWF fundus color images. Images were analyzed with the Vasculature Assessment Platform for Images of the Retina UWF (VAMPIRE-UWF 2.0, Universities of Edinburgh and Dundee, United Kingdom) software. Main outcome measuresImaging parameters included vessel width gradient, vessel width intercept, large vessel choroidal vascular density, vessel tortuosity, and vessel fractal dimension. ResultsBoth retinal artery and vein width gradients were less negative in MCI patients compared to controls, demonstrating decreased rates of vessel thinning at the periphery (p < 0.001, p = 0.027). Retinal artery and vein width intercepts, a metric that extrapolates the width of vessel at the center of the optic disc, were smaller in MCI patients compared to controls (p < 0.001, p = 0.017). The large vessel choroidal vascular density, which quantifies the vascular area versus total choroidal area, was greater in MCI patients compared to controls (p = 0.025). ConclusionsWhen compared to controls with normal cognition, MCI patients had thinner retinal vasculature manifested in both the retinal arteries and in the veins. In MCI, these thinner arteries and veins attenuated at a lower rate when traveling towards the periphery. MCI patients also had increased choroidal vascular density.

Abstract TP35: A 2-Stage Recruitment Design to Reduce MRI Screening Costs for a Theoretical Clinical Trial of WMH Progression

Background: White matter hyperintensities (WMH) are associated with risk of dementia and stroke, so are an important therapeutic target for clinical trials. The cost of broad MRI screening to identify those individuals with significant WMH, however, limits the feasibility of designing clinical trials which target WMH presence and which test treatments that slow progression. Hypothesis: A low-cost retinal or clinical screening measure prior to an MRI screening stage reduces the cost of recruiting persons with significant WMH burden in a hypothetical clinical trial vs an MRI-only screening design. Method: Data were from participants in the Atherosclerosis Risk in Communities-Neurocognitive study with clinical, retinal and WMH measurements ( N = 1311) at ages 53-70 years. Significant WMH burden was defined as a Cardiovascular Health Study score &gt;2. Three low-cost pre-screening measures were assessed: (1) retinal: a score incorporating multiple markers of abnormal retinal vasculature, (2) clinical: a score incorporating hypertension, diabetes, and age, (3) combined retinal-clinical: a score incorporating retinal and clinical factors. Given a prior published target sample for a WMH clinical trial (N= 646), we calculated a theoretical screening sample size based on the proportion of each pre-screening measure in the population multiplied by the proportion of significant WMH burden among those with a prevalent pre-screening feature. Total recruitment cost was calculated using standard retinal ($32.50) and MRI ($650) cost estimates. Results: Compared to the estimated cost of MRI-only screening (&gt;$4.24M, requiring MRI screening 6,526 participants), pre-screening for a high clinical score reduced total cost to $2.47M, but increased the initial screening group to 52,778 participants, of whom 3,801 would be screened by MRI). A high retinal-clinical score cutoff reduced costs to $2.9M while only requiring 13,572 screened participants (of these only 3,801 would require MRI). Conclusion: A 2-stage recruitment design with a low-cost pre-screening retinal and clinical measure is a promising approach, resulting in a reduction of theoretical recruitment costs for recruiting persons with significant WMH burden compared to an MRI-only design.

Copper oxide nanoparticles suppress retinal angiogenesis via inducing endothelial cell cuproptosis.

Background: Copper oxide nanoparticles (CuO NPs) exhibit antitumor activity; however, their potential as anantiangiogenesis agent is unknown. Materials & methods: The antiangiogenesis properties of CuO NPs were evaluated in vitro and in vivo and the underlying mechanism was examined using RNAsequencing and metabolomic analyses. Results: CuO NPs inhibited endothelial cell function in vitro. They also mitigated retinal vasculature development and alleviated pathological retinal angiogenesis in vivo. RNAsequencing and metabolomic analyses revealed that CuO NPs disrupt the tricarboxylicacid cycle and induce cuproptosis, which was further supported by evaluating cuproptosis-related metabolites and proteins. Conclusion: CuO NPs may be aneffective antiangiogenic agent for the treatment of retinal angiogenesis.

Response of Diabetic Macular Edema to Anti-VEGF Medications Correlates with Improvement in Macular Vessel Architecture Measured with OCT Angiography

PurposeImprovement in best corrected visual acuity (BCVA) and central subfield thickness (CST) have been well documented after intravitreal injection of anti-VEGF medications in diabetic macular edema (DME), however their effect on the vasculature of the macula in diabetic retinopathy (DR) remains poorly understood. Our aim was to explore the effect of intravitreal injection of anti-VEGF on parameters of retinal vascular microstructure in DR with optical-coherence tomography angiography (OCT-A). DesignRetrospective study of adult patients with DME that were treated with anti-VEGF intravitreal injections at the University of Illinois at Chicago between 2017-2022. Subjects, Participants, and/or Controls41 eyes from 30 patients with non-proliferative or proliferative DR with a mean age of 58.83 ± 11.71years, mean number of intravitreal injections of 2.8 ± 1.4, and mean follow up of 6.5 ± 1.7 months. Methods, Intervention, or TestingImageJ was employed to measure parameters of retinal vascular microstructure in OCT-A images, which included perfusion density, vessel length-density (VLD), vessel diameter, and FAZ characteristics (area, perimeter, circularity). Student’s T-tests and ANOVA were used to determine statistical significance. Main Outcome MeasuresA primary analysis was performed comparing the mean of each parameter of all patients as a single group at the beginning and end of the study period. A subgroup analysis was then performed after stratifying patients based on visual improvement, change in CST, prior injection history, and number of injections. ResultsEyes demonstrated statistical improvement in BCVA logMAR score and CST after anti-VEGF treatment. Primary analysis showed a reduction in the vessel diameter of the superficial and deep retinal vasculature as well as an increase in the circularity of the FAZ within the superficial retinal vasculature after anti-VEGF treatment. Subgroup analysis revealed that eyes with improvement in BCVA exhibited reduced vessel diameter in the superficial retinal vasculature and that eyes with the largest decrease in CST displayed increased perfusion density and VLD in the deep retinal vasculature. ConclusionsIntravitreal injection of anti-VEGF agents to treat DME improved parameters of retinal vascular microstructure on OCT-A over a period of 3-9 months, and this effect was most pronounced in eyes that experienced improvement in BCVA and CST.

Artificial Intelligence, Digital Imaging, and Robotics Technologies for Surgical Vitreoretinal Diseases

ObjectiveTo review recent technological advancement in imaging, surgical visualization, robotics technology and the use of artificial intelligence in surgical vitreoretinal (VR) diseases. BackgroundTechnological advancements in imaging enhance both pre-operative and intra-operative management of surgical VR diseases. Widefield imaging in fundal photography and optical coherence tomography (OCT) can improve assessment of peripheral retinal disorders like retinal detachments, degeneration, and tumors. OCT angiography provides a rapid and non-invasive imaging of the retinal and choroidal vasculature. Surgical visualization has also improved with intraoperative OCT providing a detailed real-time assessment of retinal layers to guide surgical decisions. Heads-up display and head-mounted display utilize three-dimensional technology to provide surgeons with enhanced visual guidance and improved ergonomics during surgery. Intraocular robotics technology allows for greater surgical precision and is shown to be useful in retinal vein cannulation and subretinal drug delivery. In addition, deep learning techniques leverages on diverse data including widefield retinal photography and OCT for better predictive accuracy in classification, segmentation, and prognostication of many surgical VR diseases. ConclusionThis review article summarized the latest updates in these areas and highlights the importance of continuous innovation and improvement in technology within the field. These advancements have the potential to reshape management of surgical VR diseases in the very near future and to ultimately improve patient care.

Retinal capillary perfusion heterogeneity in diabetic retinopathy detected by optical coherence tomography angiography

BackgroundDiabetic retinopathy (DR) is a leading cause of blindness and involves retinal capillary damage, microaneurysms, and altered blood flow regulation. Optical coherence tomography angiography (OCTA) is a non-invasive way of visualizing retinal vasculature but has not been used extensively to study blood flow heterogeneity. The purpose of this study is to detect and quantify blood flow heterogeneity utilizing en-face swept source OCTA in patients with DR.MethodsThis is a prospective clinical study which examined patients with either type 1 or 2 diabetes mellitus. Each included eye was graded clinically as no DR, mild DR, or moderate-severe DR. Ten consecutive en face 6 × 6 mm foveal SS-OCTA images were obtained from each eye using a PLEX Elite 9000 (Zeiss Meditec, Dublin, CA). Built-in fixation-tracking, follow-up functions were utilized to reduce motion artifacts and ensure same location imaging in sequential frames. Images of the superficial and deep vascular complexes (SVC and DVC) were arranged in temporal stacks of 10 and registered to a reference frame for segmentation using a deep neural network. The vessel segmentation was then masked onto each stack to calculate the pixel intensity coefficient of variance (PICoV) and map the spatiotemporal perfusion heterogeneity of each stack.ResultsTwenty-nine eyes were included: 7 controls, 7 diabetics with no DR, 8 mild DR, and 7 moderate-severe DR. The PICoV correlated significantly and positively with DR severity. In patients with DR, the perfusion heterogeneity was higher in the temporal half of the macula, particularly in areas of capillary dropout. PICoV also correlates as expected with the established OCTA metrics of perfusion density and vessel density.ConclusionPICoV is a novel way to analyze OCTA imaging and quantify perfusion heterogeneity. Retinal capillary perfusion heterogeneity in both the SVC and DVC increased with DR severity. This may be related to the loss of retinal capillary perfusion autoregulation in diabetic retinopathy.

Assessment of Retinal Microangiopathy in Patients with Balkan Endemic Nephropathy Using Optical Coherence Tomography Angiography-A Pilot Study.

Background and Objectives: It is well known that alterations in microvascular structure and function contribute to the development of ocular, renal, and cardiovascular diseases. Accordingly, the presence of fundus vascular changes in patients suffering from chronic kidney disease (CKD) and Balkan endemic nephropathy (BEN) may provide information of prognostic value regarding the progression of renal disease. This study aimed to examine the associations between clinical characteristics and retinal optical coherence tomography angiography (OCTA) parameters in patients with BEN and compare them with those in CKD. Materials and Methods: This pilot study, conducted from March 2021 to April 2022, included 63 patients who were divided into two groups: the first group consisted of 29 patients suffering from BEN, and the second was a control group of 34 patients with CKD. Demographic, laboratory, clinical, and medication data were noted for all the patients included in this study. Each eye underwent OCT angiography, and the results were interpreted in accordance with the practical guide for the interpretation of OCTA findings. Results: Statistically significantly higher levels of total serum protein and triglycerides were recorded in the BEN group than in the CKD group, while the level of HDL cholesterol was lower. Based on the performed urinalysis, statistically significantly higher values of total protein and creatinine were detected in patients with CKD compared to the BEN group. It was demonstrated that the OCTA vascular plexus density of certain parts of the retina was in significant association with systolic and diastolic blood pressure, creatinine clearance, urinary creatinine, total cholesterol, diabetes mellitus type 2, age, body mass index, total serum and urinary protein, sCRP, and diuretic and antihypertensive treatment. Conclusions: In comparison with CKD, BEN leads to more significant disturbances in retinal vasculature density.

Visualization Materials Using Silicon-Based Optical Nanodisks (ViSiON) for Enhanced NIR Imaging in Ophthalmology.

ViSiON (visualization materials composed of silicon-based optical nanodisks) is presented, which offers a unique optical combination of near-infrared (NIR) optical properties and biodegradability. Initially, numerical simulations are conducted to calculate the total extinction and scattering effects of ViSiON by the diameter-to-thickness ratio, predicting precise control over its scattering properties in the NIR region. A top-down patterning technique is employed to synthesize ViSiON with accurate diameter and thickness control. ViSiON with a 50nm thickness exhibits scattering properties over 400 times higher than that of 30nm, rendering it suitable as a contrast agent for optical coherence tomography (OCT), especially in ophthalmic applications. Furthermore, ViSiON possesses inherent biodegradability in media, with ≈95% degradation occurring after 48 h, and the degradation rate can be finely tuned based on the quantity of protein coating applied to the surface. Subsequently, the OCT imaging capability is validated even within vessels smaller than 300µm, simulating retinal vasculature using a retinal phantom. Then, using an ex ovo chick embryo model, it is demonstrated that ViSiON enhances the strength of protein membranes by 6.17 times, thereby presenting the potential for ViSiON as an OCT imaging probe capable of diagnosing retinal diseases.

Impacts of angiotensin II on retinal artery changes in apolipoprotein E deficient mice.

To investigate the impacts of angiotensin II (Ang II) on retinal artery changes in apolipoprotein E deficient (apoE-/-) mice. apoE-/- male mice were infused by minipumps with Ang II at 1000 ng/kg·min (Ang II group) or saline (control group) for 28d. They were underwent ophthalmic fundus examination on day 0, 14, and 28 of infusion. Histopathologic examination, ribonucleic acid (RNA) sequencing and local Ang II measurement of retinas were conducted. Ophthalmic fundus examination showed Ang II infusion promoted the formation of retinal arterial aneurysm-like lesions on day 28. Optical coherence tomography revealed the ganglion cell and inner plexiform layer (GCIPL) thickness in the control group was significantly thinner than that in Ang II group (P<0.001). Hematoxylin-eosin staining demonstrated diffused swelling of GCIPL layer and its disordered structure in Ang II group. Transmission electron microscopy showed Ang II infusion caused aggravation of atherosclerotic lesions, including increased swelling, roughness, disorganization of the retinal vasculature, and vacuoles formation. RNA-sequencing and gene ontology enrichment analysis demonstrated that the structure and function of cellular membrane might be disturbed and visual function might be compromised by Ang II. The local level of Ang II was higher in Ang II infusion group but did not show significant differences compared to the control group (P=0.086). Ang II infusion promotes the formation of retinal arterial aneurysm-like lesions in apoE-/- mice, causing aggravation of atherosclerotic lesions, more severe disorganization of the retinal vasculature and disturbance of the cellular membrane.

Ultra-Widefield Imaging of the Retinal Macrovasculature in Parkinson Disease Versus Controls With Normal Cognition Using Alpha-Shapes Analysis.

To investigate retinal vascular characteristics using ultra-widefield (UWF) scanning laser ophthalmoscopy in Parkinson disease (PD). Individuals with an expert-confirmed clinical diagnosis of PD and controls with normal cognition without PD underwent Optos California UWF imaging. Patients with diabetes, uncontrolled hypertension, glaucoma, dementia, other movement disorders, or known retinal or optic nerve pathology were excluded. Images were analyzed using Vasculature Assessment and Measurement Platform for Images of the Retina (VAMPIRE-UWF) software, which describes retinal vessel width gradient and tortuosity, provides vascular network fractal dimensions, and conducts alpha-shape analysis to further characterize vascular morphology (complexity, Opαmin; spread, OpA). In the PD cohort, 53 eyes of 38 subjects were assessed; in the control cohort, 51 eyes of 33 subjects were assessed. Eyes with PD had more tortuous retinal arteries in the superotemporal quadrant (P = 0.043). In eyes with PD, alpha-shape analysis revealed decreased OpA, indicating less retinal vasculature spread compared to controls (P = 0.032). Opαmin was decreased in PD (P = 0.044), suggesting increased vascular network complexity. No differences were observed in fractal dimension in any region of interest. This pilot study suggests that retinal vasculature assessment on UWF images using alpha-shape analysis reveals differences in retinal vascular network spread and complexity in PD and may be a more sensitive metric compared to fractal dimension. Retinal vasculature assessment using these novel methods may be useful in understanding ocular manifestations of PD and the development of retinal biomarkers.