Improved microvascular imaging with optical coherence tomography using 3D neural networks and a channel attention mechanism.

Skin microvasculature is vital for human cardiovascular health and thermoregulation, but its imaging and analysis presents significant challenges. Statistical methods such as speckle decorrelation in optical coherence tomography angiography (OCTA) often require multiple co-located B-scans, leading to lengthy acquisitions prone to motion artefacts. Deep learning has shown promise in enhancing accuracy and reducing measurement time by leveraging local information. However, both statistical and deep learning methods typically focus solely on processing individual 2D B-scans, neglecting contextual information from neighbouring B-scans. This limitation compromises spatial context and disregards the 3D features within tissue, potentially affecting OCTA image accuracy. In this study, we propose a novel approach utilising 3D convolutional neural networks (CNNs) to address this limitation. By considering the 3D spatial context, these 3D CNNs mitigate information loss, preserving fine details and boundaries in OCTA images. Our method reduces the required number of B-scans while enhancing accuracy, thereby increasing clinical applicability. This advancement holds promise for improving clinical practices and understanding skin microvascular dynamics crucial for cardiovascular health and thermoregulation.

Factors Affecting Disease Stability After Intravitreal Brolucizumab Injection for Refractory Neovascular Age-Related Macular Degeneration.

INTRODUCTION: The purpose of this study is to identify the factors affecting neovascular age-related macular degeneration (nAMD) disease stability after brolucizumab treatment. METHODS: We retrospectively analyzed the medical records of 31 patients (31 eyes) with recalcitrant nAMD who were switched to brolucizumab after conventional anti-vascular endothelial growth factor (VEGF) treatment. We divided patients into two groups by treatment extension (TE) period: group 1 with TE < 12 weeks (N = 16) and group 2 with TE ≥ 12 weeks (N = 15). We compared outcomes between the groups at 2, 4, 8, and 12 weeks, including morphological characteristics of choroidal neovascularization (CNV). Logistic regression analysis identified factors associated with TE ≥ 12 weeks. RESULTS: Group 2 had a significantly greater proportion of patients with dry macula (subretinal and intraretinal fluids absent) than group 1 (60 vs. 12.5%) at 2 weeks (P < 0.05). Best-corrected visual acuity (BCVA) and subfoveal choroidal thickness (SFCT) did not differ significantly between groups at all timepoints. Central subfield retinal thickness (CST) was significantly lower in group 2 at 2 (237.1 vs. 280.8 µm; P < 0.05), 4 (224.0 vs. 262.9 µm; P < 0.05), and 8 weeks (216.8 vs. 331.1 µm; P < 0.05). Group 2 had less vessel area (0.63 vs. 1.27 mm2; P < 0.05) and total vessel length (0.22 vs. 0.42 mm; P < 0.05). Choriocapillaris flow deficit (CCFd) was significantly lower in group 2 (42.7 vs. 48.2%; P < 0.05). Dry macula at 2 weeks (odds ratio [OR] = 8.3; P < 0.05) and a lower CCFd (OR = 0.73; P < 0.05) were associated with TE ≥ 12 weeks. CONCLUSIONS: Early fluid-free status after switching to brolucizumab and choriocapillary function around CNV were prognostic factors for disease stability in nAMD refractory to anti-VEGF treatment.

Uveal colobomas with pseudo-duplication of the optic disc in both eyes: imaging by ultra-widefield swept-source optical coherence tomography angiography: a case report.

BACKGROUND: Duplication of the optic disc is a rare phenomenon. Differentiating between true duplication and pseudo-duplication requires a comprehensive set of diagnostic procedures. Advancements in imaging provide new insights into this condition. CASE PRESENTATION: This report details a unique case involving an 8-year-old Han Chinese girl diagnosed with uveal colobomas and pseudo-duplication of the optic disc in both eyes. The extensive multimodal examination included assessments of vision, fundus examination, fundus photography, B-scan ultrasonography, ultra-widefield swept-source optical coherence tomography angiography, fundus fluorescein angiography, fundus autofluorescence, and magnetic resonance imaging. CONCLUSION: Ultra-widefield swept-source optical coherence tomography angiography proves to be a vital tool for examining and monitoring uveal colobomas with pseudo-duplication of the optic disc.

Neuroretinal and microvascular retinal features in dementia with Lewy body assessed by optical coherence tomography angiography.

OBJECTIVE: To explore retinal changes in patients with Dementia with Lewy Bodies (DLB) using Spectral Domain-Optical Coherence Tomography (SD-OCT) and Optical Coherence Tomography Angiography (OCTA), aiming to identify potential biomarkers for diagnosis and monitoring. METHODS: A cross-sectional study analyzed 15 DLB patients and 18 matched controls. Participants underwent physical, neurological, neuropsychological, and ophthalmological evaluations, including SD-OCT and OCTA. Logistic regression, adjusted for age, sex, and inter-eye correlation, was employed to identify retinal alterations in patients affected by DLB. RESULTS: OCTA revealed that DLB is associated with reduced superficial and deep vessel densities (SVD and DVD) in the macula (p < 0.01), as well as decreased peripapillary vessel density (ppVD, p < 0.01). SD-OCT parameters showed correlations with DLB, including reduced central macular thickness (CMT, p < 0.001) and thinning of the ganglion cell layer-inner plexiform layer (GCL-IPL, p < 0.01). Logistic regression (R²=0.26) identified reduced ppVD as a significant predictor of DLB (p = 0.030). CONCLUSIONS: Impairments in retinal capillaries, especially lower ppVD, might mirror cerebral hypoperfusion in DLB, potentially due to reduced Vascular Endothelial Growth Factor (VEGF) levels and increased α-synuclein. Further investigations are warranted to confirm the causal relationship between these observations, disease severity, and progression, as well as their potential role as biomarkers for DLB.

Investigation of the effects of single and two-muscle horizontal rectus surgeries on macular microvasculature.

PURPOSE: To investigate the changes in posterior segment hemodynamics caused by horizontal rectus muscle surgeries using the optic coherence tomography angiography (OCTA). METHODS: Patients who underwent at least one horizontal rectus recession, resection, or combination surgery were included. The patients were evaluated with an OCTA preoperatively and 30 days postoperatively. Postoperative changes in superficial capillary plexus (SCP)-vessel density (VD), deep capillary plexus (DCP)-VD, foveal avascular zone (FAZ) area and choriocapillaris (CC)-flow area parameters were examined. The mean differences (Δ) for the parameters in which significant changes were detected in the whole operated eyes group were compared between the single- and two-muscle surgery groups. RESULTS: Twenty-five eyes of 24 patients with an average age of 16.40 ± 6.75 years (5-29) were included. Of the eyes, 10 underwent single muscle recession surgery. Two-muscle surgeries were performed in 15 eyes. SCP-VD in the superior parafoveal region increased significantly postoperatively (53.23 ± 4.11% vs. 54.54 ± 3.67%, p = 0.032). For DCP-VD, there was a statistically significant increase in all zones, except the superior hemisphere and fovea regions (p < 0.05 for all). FAZ area did not change significantly (p = 0.207). There was a significant increase in the CC-flow area (2.171 ± 0.146 mm2 vs. 2.232 ± 0.115 mm2, p = 0.013). There was a significant difference between the two groups only for the Δ SCP-VD/parafovea superior value (-0.62 ± 0.98 vs. 1.57 ± 3.07, p = 0.019). CONCLUSIONS: Conventional horizontal rectus muscle surgeries may cause alterations in posterior segment hemodynamics. The number of muscles incised does not seem to greatly affect the magnitude of changes that occur. KEY MESSAGES: What is known • After conventional horizontal rectus muscle surgeries, the anterior ciliary arteries are not recanalized, instead, anterior segment blood flow is maintained by increasing the flow in the long posterior ciliary arteries. • Previous studies using Doppler ultrasonography have shown increased flow in the ophthalmic artery, central retinal artery and long posterior ciliary arteries. What is new • In this study, significant increases were observed in superficial and deep capillary plexus-vessel density and choriocapillaris-flow area parameters in the first postoperative month with optic coherence tomography angiography device. • Hemodynamic increases in both retinal and choroidal vasculature were detected in the early period after conventional horizontal rectus muscle surgeries. • The number of muscles incised does not seem to greatly affect the magnitude of changes that occur.

Retinal vascular reactivity in carriers of X-linked inherited retinal disease - a study using optical coherence tomography angiography.

Purpose: Female carriers of X-linked inherited retinal diseases (IRDs) can show highly variable phenotypes and disease progression. Vascular reactivity, a potential disease biomarker, has not been investigated in female IRD carriers. In this study, functional optical coherence tomography angiography (OCT-A) was used to dynamically assess the retinal microvasculature of X-linked IRD carriers. Methods: Genetically confirmed female carriers of IRDs (choroideremia or X-linked retinitis pigmentosa), and healthy women were recruited. Macular angiograms (3x3mm, Zeiss Plex Elite 9000) were obtained in 36 eyes of 15 X-linked IRD female carriers and 21 age-matched control women. Two tests were applied to test vascular reactivity: (i) mild hypoxia and (ii) handgrip test, to induce a vasodilatory or vasoconstrictive response, respectively. Changes to vessel density (VD) and vessel length density (VLD) were independently evaluated during each of the tests for both the superficial and deep capillary plexuses. Results: In the control group, the superficial and deep VD decreased during the handgrip test (p<0.001 and p=0.037, respectively). Mean superficial VLD also decreased during the handgrip test (p=0.025), while the deep plexus did not change significantly (p=0.108). During hypoxia, VD and VLD increased in the deep plexus (p=0.027 and p=0.052, respectively) but not in the superficial plexus. In carriers, the physiologic vascular responses seen in controls were not observed in either plexus during either test, with no difference in VD or VLD noted (all p>0.05). Conclusions: Functional OCT-A is a useful tool to assess dynamic retinal microvascular changes. Subclinical impairment of the physiological vascular responses seen in carriers of X-linked IRDs may serve as a valuable clinical biomarker.

Quantitative optical coherence tomography angiography assessments in the fellow eyes of those with central serous chorioretinopathy.

BACKGROUND: To analyze the vessel density (VD) of the retina and choriocapillaris (CC) layer and the structure of the foveal avascular zone (FAZ) in the fellow eyes of central serous chorioretinopathy (CSC) patients by using optical coherence tomography angiography (OCTA). METHODS: This was a case-control study. Unilateral CSC patients and age-matched healthy subjects were recruited from the Affiliated Eye Hospital of Wenzhou Medical University between July 2016 and July 2021. All eyes were divided into three groups: acute CSC (aCSC), chronic CSC (cCSC), and healthy controls. Both aCSC and cCSC were again divided into two subgroups: the affected eyes and the fellow eyes. In this study, all parameters of VD and FAZ were measured by self-software of OCTA. RESULTS: A total of 231 eyes of 137 subjects were included, with 47 aCSC patients, 47 cCSC patients, and 43 healthy controls. In the fellow eyes of CSC, the retinal VD was significantly lower (all P < 0.05), and the FAZ was significantly larger (all P < 0.05) in the cCSC group than in healthy controls, while no difference was detected in the CC layer. There was no significant difference between the aCSC group and healthy controls in all OCTA parameters. In the affected eyes of CSC, the superficial retinal vessel density (SRVD) was significantly higher (all P < 0.05) in healthy controls than in the aCSC and cCSC groups, while the deep retinal vessel density (DRVD) was significantly lower (all P < 0.05) and the FAZ was larger (all P < 0.05) in the cCSC group than in the aCSC group and healthy controls. A liner regression equation was established: Y (BCVA, best corrected visual acuity) = 3.692-0.036✱X1 (DRVD-Fovea)-0.031✱X2 (FD-300, vessel density around the 300 µm width of the FAZ), R2 = 0.427. CONCLUSION: Based on OCTA measurements, this study revealed that the retinal microvascular network was impaired even in the fellow eyes of those with cCSC, which should arouse attention to the observation of unilateral CSC.

Skeleton density and ellipsoid zone loss are prognostic for progression in Macular Telangiectasia Type 2.

Macular Telangiectasia Type 2 (MacTel) is a chronic, progressive disease of the central retina characterized by vascular and neurodegenerative changes. As there is currently no treatment for non-neovascular MacTel, there is a dearth for biomarkers identifying eyes with an increased risk for disease progression for patient counseling and clinical trial recruitment. Eyes were classified to be stable or progressive, defined by the fundus photography-based grading system by Gass and Blodi. First, structural differences between these two groups were assessed, employing optical coherence tomography (OCT) and OCT-angiography. Univariate regression analyses revealed evidence towards a lower superficial retinal layer (SRL) vessel density (VD), skeleton density (SD) and deep retinal layer (DRL) SD in progressing compared to stable eyes (p = 0.05, p = 0.05, p = 0.07). Second, a multivariable predictive model was employed to examine the predictive value of structural and functional parameters for disease progression. Baseline best corrected visual acuity (BCVA) and SRL SD are prognostic for disease progression (p < 0.001, p = 0.05). The presence of ellipsoid zone (EZ) loss is prognostic for future central retinal thickness (p < 0.01). We propose SRL SD, BCVA, and EZ loss as prognostic biomarkers and as possible outcome measures in future interventional studies in MacTel.

Retinal Vascular and Structural Changes in the Murine Alzheimer's APPNL-F/NL-F Model from 6 to 20 Months.

Alzheimer's disease (AD) may manifest retinal changes preceding brain pathology. A transversal case-control study utilized spectral-domain OCT angiography (SD-OCTA) and Angio-Tool software 0.6a to assess retinal vascular structures and OCT for inner and outer retina thickness in the APPNL-F/NL-F AD model at 6, 9, 12, 15, 17, and 20 months old. Comparisons to age-matched wild type (WT) were performed. The analysis focused on the three vascular plexuses using AngiooTool and on retinal thickness, which was represented with the Early Treatment Diabetic Retinopathy Study (ETDRS) sectors. Compared to WT, the APPNL-F/NL-F group exhibited both vascular and structural changes as early as 6 months persisting and evolving at 15, 17, and 20 months. Significant vascular alterations, principally in the superficial vascular complex (SVC), were observed. There was a significant decrease in the vessel area and the total vessel length in SVC, intermediate, and deep capillary plexus. The inner retina in the APPNL-F/NL-F group predominantly decreased in thickness while the outer retina showed increased thickness in most analyzed time points compared to the control group. There are early vascular and structural retinal changes that precede the cognitive changes, which appear at later stages. Therefore, the natural history of the APPNL-F/NL-F model may be more similar to human AD than other transgenic models.

Advanced OCTA imaging segmentation: Unsupervised, non-linear retinal vessel detection using modified self-organizing maps and joint MGRF modeling.

BACKGROUND AND OBJECTIVE: This paper proposes a fully automated and unsupervised stochastic segmentation approach using two-level joint Markov-Gibbs Random Field (MGRF) to detect the vascular system from retinal Optical Coherence Tomography Angiography (OCTA) images, which is a critical step in developing Computer-Aided Diagnosis (CAD) systems for detecting retinal diseases. METHODS: Using a new probabilistic model based on a Linear Combination of Discrete Gaussian (LCDG), the first level models the appearance of OCTA images and their spatially smoothed images. The parameters of the LCDG model are estimated using a modified Expectation Maximization (EM) algorithm. The second level models the maps of OCTA images, including the vascular system and other retina tissues, using MGRF with analytically estimated parameters from the input images. The proposed segmentation approach employs modified self-organizing maps as a MAP-based optimizer maximizing the joint likelihood and handles the Joint MGRF model in a new, unsupervised way. This approach deviates from traditional stochastic optimization approaches and leverages non-linear optimization to achieve more accurate segmentation results. RESULTS: The proposed segmentation framework is evaluated quantitatively on a dataset of 204 subjects. Achieving 0.92 ± 0.03 Dice similarity coefficient, 0.69 ± 0.25 95-percentile bidirectional Hausdorff distance, and 0.93 ± 0.03 accuracy, confirms the superior performance of the proposed approach. CONCLUSIONS: The conclusions drawn from the study highlight the superior performance of the proposed unsupervised and fully automated segmentation approach in detecting the vascular system from OCTA images. This approach not only deviates from traditional methods but also achieves more accurate segmentation results, demonstrating its potential in aiding the development of CAD systems for detecting retinal diseases.

Neurovascular retinal impairment in early-treated adults with phenylketonuria.

Purpose: To compare radial peripapillary capillary (RPC) vascular plexus parameters and peripapillary retinal nerve fiber layer (pRNFL) thickness between Early-Treated Adults with Phenylketonuria (ETPKU) and controls. Methods: This observational study was a monocentric, case control study including 36 eyes of 36 participants. Among these, 18 were early-treated PKU (ETPKU) and 18 were controls. A SD-OCTA (XR Avanti AngioVue OCTA; Optovue Inc., Fremont, CA) was employed to assess the OCT and OCTA parameters of all the participants. The main outcome measures were the RPC vessels density (VD) %, and the pRNFL thickness. Results: The average pRNFL thickness was significantly reduced in ETPKU (110.78 ± 12.48 µm) compared to controls (113.22 ± 13.95 µm), p = 0.046. The mean VD% of the small vessels of the RPC plexus was 52.31 ± 2.2 in ETPKU and 50.71 ± 3.2 in controls (p = 0.049), while the VD% of all the radial peripapillary capillary plexus (RPCP) was 58.5 ± 2.2 in ETPKU and 55.08 ± 3.4 in controls (p < 0.001). By contrast, there were no differences in age, sex, and IOP between the two groups. Conclusion: Through structural OCT and OCTA, we observed thinning of the nerve fibers accompanied by an increase in perfusion of the RPC plexus. Thus, our conclusions suggest that OCTA may serve as a noninvasive method to identify novel retinal biomarkers in ETPKU.

Triaceto-nitrile-(1,4,7-trimethyl-1,4,7-tri-aza-cyclonona-ne)cobalt(II) bis-(tetra-phenyl-borate).

The title cobalt(II) complex, [Co(C2H3N)3(C9H21N3)](C24H20B)2 or [(tacn)Co(NCMe)3][BPh4]2, has been characterized by single-crystal X-ray diffraction. It incorporates the well-known macrocyclic tacn (1,4,7-trimethyl-1,4,7-tri-aza-cyclo-nona-ne) ligand, which is coordinated facially to the metal center. The complex crystallizes in space group P21/c with Z = 4. The divalent cobalt ion exhibits a six-coordinate octa-hedral geometry by one tacn and three aceto-nitrile ligands. Two non-coordinating tetra-phenyl-borate (BPh4 -) anions are also present.

OCTA-based research on changes of retinal microcirculation in digestive tract malignancy.

PURPOSE: This cross-sectional study measured retinal vessel density (VD) in patients with digestive tract malignancy by optical coherence tomography angiography (OCTA), and compared them with healthy controls to explore the retinal microcirculation changes in patients with digestive tract malignancy. METHODS: 106 eligible participants were divided into three groups: gastric cancer (GC) group (36 individuals), colorectal cancer (CRC) group (34 individuals), and healthy control group (36 individuals). Angio 6*6 512*512 R4 and ONH Angio 6*6 512*512 R4 modes were performed to collect retinal vessel density data centered on fovea and papillary, respectively. The retina was automatically segmented into different layers (superficial vascular plexus (SVP), the inner retinal layer, radial peripapillary capillary plexus (RPCP), deep vascular plexus (DVP)) and areas to analyze. RESULTS: At the optic nerve head (ONH) region, the VD of the inner retinal layer increased in both GC and CRC groups in all quadrants and areas. In the papillary area, VD in the inner retinal layer, SVP, and RPCP increased in the GC and CRC groups. In the parapapillary area, VD in the inner retinal layer increased in the GC and the CRC groups. Significant increase in the global VD were found in the GC group of the RPCP and SVP. Regarding the macular region, no statistical differences were observed in each layer. CONCLUSIONS: The study suggested that retinal vessel density changed in patients with digestive tract malignancy, especially in the inner retinal layer of the ONH region, revealing the potential relevance of the relation between gastrointestinal cancer and retinal microcirculation.

Multimodal phenotyping of foveal hypoplasia in albinism and albino-like conditions: a pediatric case series with adaptive optics insights.

Aim of the present study is to evaluate the relationship between genetic and phenotypic data in a series of patients affected by grade I and II of foveal hypoplasia with stable fixation and good visual acuity using multimodal imaging techniques. All patients underwent complete clinical and instrumental assessment including structural Optical Coherence Tomography (OCT), OCT Angiography and Adaptive Optics (AO) imaging. Central macular thickness (CMT), inner nuclear layer (INL), vessel density in superficial capillary plexus were the main variables evaluated with OCT technology. Cone density, cone spacing, cone regularity, cone dispersion and angular density were the parameters evaluated with AO. Genetic evaluation and trio exome sequencing were performed in all affected individuals. Eight patients (3 males and 5 females) with a mean age of 12.62 years (range 8-18) were enrolled. The mean best corrected visual acuity (BCVA) was 0.18 ± 0.13 logMAR, mean CMT was 291.9 ± 16.6 µm and INL was 26.2 ± 4.6 µm. The absence of a foveal avascular zone (FAZ) was documented by examination of OCT-A in seven patients in the superficial capillary plexus. However, there was a partial FAZ in the deep plexus in patients P5 and P8. Of note, all the patients presented with major retinal vessels clearly crossing the foveal center. All individuals exhibited a grade I or II of foveal hypoplasia. In 5 patients molecular analyses showed an extremely mild form of albinism caused by compound heterozygosity of a TYR pathogenic variant and the hypomorphic p.[Ser192Tyr;Arg402Gln] haplotype. One patient had Waardenburg syndrome type 2A caused by a de novo variant in MITF. Two patients had inconclusive molecular analyses. All the patients displayed abnormalities on OCT-A. Photoreceptor count did not differ from normal subjects according to the current literature, but qualitative analysis of AO imaging showed distinctive features likely related to an abnormal pigment distribution in this subset of individuals. In patients with foveal hypoplasia, genetic and multimodal imaging data, including AO findings, can help understand the physiopathology of the foveal hypoplasia phenotype. This study confirms that cone density and visual function can both be preserved despite the absence of a pit.

Robust Ultrafast Projection Pipeline for Structural and Angiography Imaging of Fourier-Domain Optical Coherence Tomography.

The current methods to generate projections for structural and angiography imaging of Fourier-Domain optical coherence tomography (FD-OCT) are significantly slow for prediagnosis improvement, prognosis, real-time surgery guidance, treatments, and lesion boundary definition. This study introduced a robust ultrafast projection pipeline (RUPP) and aimed to develop and evaluate the efficacy of RUPP. RUPP processes raw interference signals to generate structural projections without the need for Fourier Transform. Various angiography reconstruction algorithms were utilized for efficient projections. Traditional methods were compared to RUPP using PSNR, SSIM, and processing time as evaluation metrics. The study used 22 datasets (hand skin: 9; labial mucosa: 13) from 8 volunteers, acquired with a swept-source optical coherence tomography system. RUPP significantly outperformed traditional methods in processing time, requiring only 0.040 s for structural projections, which is 27 times faster than traditional summation projections. For angiography projections, the best RUPP variation took 0.15 s, making it 7518 times faster than the windowed eigen decomposition method. However, PSNR decreased by 41-45% and SSIM saw reductions of 25-74%. RUPP demonstrated remarkable speed improvements over traditional methods, indicating its potential for real-time structural and angiography projections in FD-OCT, thereby enhancing clinical prediagnosis, prognosis, surgery guidance, and treatment efficacy.

Anomaly Detection in Optical Coherence Tomography Angiography (OCTA) with a Vector-Quantized Variational Auto-Encoder (VQ-VAE).

Optical coherence tomography angiography (OCTA) provides detailed information on retinal blood flow and perfusion. Abnormal retinal perfusion indicates possible ocular or systemic disease. We propose a deep learning-based anomaly detection model to identify such anomalies in OCTA. It utilizes two deep learning approaches. First, a representation learning with a Vector-Quantized Variational Auto-Encoder (VQ-VAE) followed by Auto-Regressive (AR) modeling. Second, it exploits epistemic uncertainty estimates from Bayesian U-Net employed to segment the vasculature on OCTA en face images. Evaluation on two large public datasets, DRAC and OCTA-500, demonstrates effective anomaly detection (an AUROC of 0.92 for the DRAC and an AUROC of 0.75 for the OCTA-500) and localization (a mean Dice score of 0.61 for the DRAC) on this challenging task. To our knowledge, this is the first work that addresses anomaly detection in OCTA.

Retinal thickness and microvascular alterations observed by optical coherence tomography in antineutrophil cytoplasmic antibody-associated vasculitis: a cross-sectional study.

Background: As an autoimmune disease, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) often affects multiple organs, including the ocular system. This study aims to investigate differences in retinal thickness (RT) and retinal superficial vascular density (SVD) between patients with AAV and healthy controls (HCs) using optical coherence tomography angiography (OCTA). Currently, these differences are not clear. Methods: A total of 16 AAV individuals (32 eyes) and 16 HCs (32 eyes) were recruited to this cross-sectional study conducted in the First Affiliated Hospital of Nanchang University from June 2023 to September 2023. The study protocol conformed with the tenets of the Declaration of Helsinki (as revised in 2013). Each image observed by OCTA was divided into 9 regions using the Early Treatment Diabetic Retinopathy Study (ETDRS) subzones as a guide. Results: In the full layer, the RT of AAV patients was found to be significantly reduced in the inner superior (IS, P<0.001), outer superior (OS, P=0.003), inner temporal (IT, P=0.003), and outer temporal (OT, P<0.001) regions; inner RT was significantly lower in the IS (P=0.006), OS (P<0.001), inner nasal (IN, P=0.005), outer nasal (ON, P<0.001), and center (C, P=0.01) regions than that in HCs. Outer RT of AAV patients showed a reduction in the IS (P<0.001), as well as IT (P=0.008), and OT (P<0.001) regions. No statistically significant differences were seen in the different subregions in other different layers (P>0.05). Only the inner inferior (II) and outer inferior (OI) regions of SVD in AAV patients did not differ significantly from controls. All other regions showed a reduction in SVD. The details are as follows: IS (P<0.001), OS (P<0.001), IT (P=0.005), OT (P<0.001), IN (P<0.001), ON (P<0.001), and C (P=0.003). According to receiver operating characteristic (ROC) curve analysis, the full IS region [area under the curve (AUC): 0.8892, 95% confidence interval (CI): 0.8041-0.9742, P<0.001] had the highest diagnostic value for AAV-induced reduction in RT. The IS (AUC: 0.9121, 95% CI: 0.8322-0.9920, P<0.001) region was also the most sensitive to changes in SVD of AAV individuals. In addition, we found that SVD in the IN region (r=-0.4224, 95% CI: -0.6779 to -0.0757, P=0.02) as well as mean visual acuity (r=-0.3922, 95% CI: -0.6579 to -0.0397, P=0.03) of AAV patients were negatively correlated with disease duration. However, we did not find an association between SVD and RT in this study. Conclusions: The findings from OCTA indicated a reduction in RT and SVD among patients with AAV. OCTA allows for the evaluation of AAV-related ocular lesions and holds promise for monitoring of disease progression through regular evaluations.

Optical coherence tomography angiography features in Waldenström macroglobulinemia patients without Hyperviscosity syndrome: A pilot prospective study.

PURPOSE: To evaluate the retinal vessel density (VD) with optical coherence tomography angiography (OCTA) in asymptomatic patients affected by Waldenström macroglobulinemia (WM) without hyperviscosity syndrome (HVS) and to highlight the presence of microvascular damage in theese clinically asymptomatic WD patients. DESIGN: Prospective study. METHODS: A total of 43 eyes from 43 WM patients (24 females, 19 males, mean age 55.1 ± 13.6 years) were enrolled from January 2023 to December 2023 in the Eye Clinic of the University of Naples Federico II. Along with WM patients, 40 healthy subjects (HS) (20 females, 20 males, mean age 52.3 ± 15.6 years) with a normal ophthalmic examination and no history of intraocular surgery or retinal pathologic features were included as control group All patients and controls underwent OCTA RESULTS: The two groups were not significantly different for age and sex Visual acuity examination showed no statistically significant difference in BCVA between controls and patients Compared to HS, WD patients showed lower VD values in the SCP in the whole image (47.95 ± 5.17% vs. 52.99 ± 2.52 %; p < 0.001), as well as in the parafovea (53.01 ± 6.69% vs. 55.30 ± 2.61 %; p = 0.002), and fovea (21.38 ± 9.01% vs. 30.31 ± 5.84 %; p < 0.0001). On the other hand, in the DCP VD values were significantly higher in patients compared to controls in the whole image (55.82 ± 8.07% vs. 50.83 ± 5.46 %; p = 0.005), as well as in the parafovea (56.76 ± 6.26% vs. 52.59 ± 5.46 %; p = 0.0001), and fovea (38.75 ± 8.59% vs. 33.43 ± 8.68 %; p < 0.0001). CONCLUSION: The finding that OCTA confirmed the presence of widespread microvascular damage in WD patients clinically silent. Thus, OCTA is a safe rapid imaging technique that could represent a valid biomarker of systemic vascular dysfunction.

Factors affecting choroidal circulation parameters in 4-14-year-old Chinese children measured by SS-OCT/OCTA.

PURPOSE: To measure the choroidal circulatory parameters Han Chinese children aged 4-14 years from Southwest China, and to explore the relationships between these parameters and age, axial length (AL), and choroidal thickness (ChT). METHODS: 284 eyes from 142 subjects were included in this cross-sectional study. All participants underwent cycloplegic refraction and IOLMaster500 examination. Swept-source optical coherence tomography (SS-OCT) was used to measure submacular choroidal thickness, choroidal vascular volume (CVV), choroidal stromal volume (CSV), choroidal vascularity index (CVI), and CVV/CSV ratio. RESULTS: In this population, the mean CVV was 2.92 ± 0.55 mm3, CSV was 4.69 ± 0.68 mm3, CVI was 38.22 ± 2.46 %, and CVV/CSV ratio was 62.11 ± 6.44 %. Multivariable regression analyses showed that both CVV and CSV were negatively correlated with AL (both P < 0.001) and positively correlated with ChT (both P < 0.001), while age showed no significant correlation with them (both P > 0.05). However, the correlations between CVI and age were not uniform rectilinear. Among participants aged ≤8 years, CVI showed no correlation with age (P > 0.05), while among those aged >8 years, it was positively correlated with age (P < 0.01). CVV/CSV ratio was positively correlated with ChT and age (both P < 0.01). CONCLUSION: After the age of 8, age was positively correlated with CVI. ChT was well correlated with CVI. Longer AL and thinner ChT were associated with reduced CVV and CSV, with CVV decreasing more rapidly than CSV.

Repeatability of retinal and choroidal optical coherence tomography angiography indices in healthy children and young adults.

PURPOSE: To evaluate the repeatability of retinal and choroidal optical coherence tomography angiography (OCT-A) indices among healthy children and compare it to healthy young adults. METHODS: This prospective study captured 3 mm × 3 mm and 6 mm × 6 mm macular OCT-A scans including superficial and deep retinal layers, choriocapillaris and deep choroid over two visits, 1 week apart at approximately the same time of day, for 22 healthy adults (18-30 years) and 21 children (6-15 years). Magnification and projection-artefact corrected indices extracted using a custom image analysis program and individual biometry were compared between visits using Bland-Altman analysis and intraclass correlation (ICC). Retinal indices included foveal avascular zone metrics, perfusion and vessel density and choroidal indices included choriocapillaris flow deficit metrics and deep choroid perfusion density, in the foveal, parafoveal and perifoveal regions. Repeatability between adults and children was compared with F-test. RESULTS: Bland-Altman analysis showed that the mean differences between repeated OCT-A indices were not significantly different from zero for either of the zones, layers and scan sizes in the two age groups (p > 0.05) except for foveal vessel density and foveal avascular zone perimeter (p = 0.04 for both) of 6-mm-deep retinal layer scans. The ICC ranged between 0.67 and 0.99. Significantly higher variability between visits (p < 0.05) in the indices was noted among adults than children, especially for choroidal indices of larger scan size. CONCLUSION: The retinal and choroidal OCT-A indices in the foveal, parafoveal and perifoveal zones were repeatable in healthy children except for the foveal vessel density and foveal avascular zone perimeter of the 6-mm-deep retinal layer, which exhibited statistically borderline differences between visits. The adult group showed more variability between visits compared to children, especially in the larger scan size for choroidal OCT-A indices.