Retinal small vessel pathology is associated with disease burden in multiple sclerosis.

BACKGROUND: Alterations of the superficial retinal vasculature are commonly observed in multiple sclerosis (MS) and can be visualized through optical coherence tomography angiography (OCTA). OBJECTIVES: This study aimed to examine changes in the retinal vasculature during MS and to integrate findings into current concepts of the underlying pathology. METHODS: In this cross-sectional study, including 259 relapsing-remitting MS patients and 78 healthy controls, we analyzed OCTAs using deep-learning-based segmentation algorithm tools. RESULTS: We identified a loss of small-sized vessels (diameter < 10 µm) in the superficial vascular complex in all MS eyes, irrespective of their optic neuritis (ON) history. This alteration was associated with MS disease burden and appears independent of retinal ganglion cell loss. In contrast, an observed reduction of medium-sized vessels (diameter 10-20 µm) was specific to eyes with a history of ON and was closely linked to ganglion cell atrophy. CONCLUSION: These findings suggest distinct atrophy patterns in retinal vessels in patients with MS. Further studies are necessary to investigate retinal vessel alterations and their underlying pathology in MS.

Imaging Assessment of Peripapillary Vessel Diameters in Postmortem Eyes.

PURPOSE: Proof of concept of ex vivo retinal vessel diameter measurements in human postmortem eyes. METHODS: En face near-infrared (IR) images and optical coherence tomography (OCT) of the optic nerve head (ONH) were captured ex vivo with a Heidelberg Engineering Spectralis (Spectralis, version 7.0.4, Image Capture Module, version 1.2.4, Heidelberg Heidelberg, Germany) device, using a custom-made eye chamber holding and positioning the eyes during the image process. Thirty-two formaldehyde-fixated eyes of 16 patients were imaged. In the IR images, two independent graders measured retinal vessel diameters at the intersection of a drawn circle centered on the ONH with diameters of 2.0 mm and 3.4 mm, respectively. The anatomically corresponding measurements between both graders were statistically analyzed using a Wilcoxon signed-rank test. RESULTS: A total of 246 matched measurements of both graders were analyzed across all 32 imaged eyes. Statistically significant differences between the graders were found for arterioles at 2 mm from the ONH. The other measurements did not show statistically significant intergrader differences. The mean values for arteriole diameters were 72.2 µm at 2.0 mm and 61.5 µm at 3.4 mm for grader 1, and 66.4 µm at 2.0 mm and 63.2 µm at 3.4 mm for grader 2. The mean diameter for venules were 75.5 µm at 2.0 mm and 79.3 µm at 3.4 mm for grader 1, and 67.4 µm at 2 mm and 79.1 µm at 3.4 mm for grader 2. CONCLUSION: To the best of our knowledge, this is the first study to present IR image-based retinal vessel diameters in ex vivo postmortem eyes. Retinal IR/OCT imaging is possible, and measurements are reproducible in formaldehyde-fixated human eyes. Fixation artefacts result in lower image quality, and this can impose challenges in correctly detecting, classifying, and measuring retinal vessels.

Quantitative assessment of retinochoroidal microvasculature in patients with carotid artery stenosis using OCT angiography.

PURPOSE: To investigate the alterations in retinochoroidal parameters measured by optical coherence tomography (OCT) and OCT angiography (OCTA) in patients with carotid artery stenosis (CAS) and assess their associations with digital subtraction angiography (DSA) data. METHOD: This study enrolled patients diagnosed with CAS and age-matched healthy controls. Both groups underwent OCT and OCTA examinations. DSA and assessment of carotid artery stenosis were performed only in the CAS group. The study evaluated various retinochoroidal parameters from OCT and OCTA, including linear vessel density (LVD), foveal avascular zone (FAZ), choroidal thickness (ChT), and retinal nerve fiber layer (RNFL) thickness. DSA-derived measures included cervical segment (C1) diameter, cavernous segment (C4) diameter, stenosis percentage, ophthalmic artery (OA) filling time, C1-OA filling time, and residual stenosis. RESULTS: A total of 42 eyes from 30 CAS patients and 60 eyes from 30 healthy controls were included. Patients with CAS displayed significantly decreased LVD compared to controls (p < 0.001). Additionally, the CAS group had thinner choroid and RNFL (p = 0.047 and p < 0.001, respectively). Macular LVD negatively correlated with both stenosis percentage and C1-OA filling time (p = 0.010 and p = 0.014, respectively). In patients who underwent carotid artery stenting, preoperative ChT significantly correlated with residual stenosis (Pearson r = -0.480, p = 0.020). CONCLUSION: OCT and OCTA provide a quantitative assessment of retinochoroidal microstructural changes associated with CAS, suggesting potential for noninvasive evaluation of the disease. This might contribute to the prevention of irreversible ocular complications and early detection of CAS. Furthermore, ChT may not only aid in diagnosing CAS more reliably but also offer prognostic information.

Retinal imaging for the assessment of stroke risk: a systematic review.

BACKGROUND: Stroke is a leading cause of morbidity and mortality. Retinal imaging allows non-invasive assessment of the microvasculature. Consequently, retinal imaging is a technology which is garnering increasing attention as a means of assessing cardiovascular health and stroke risk. METHODS: A biomedical literature search was performed to identify prospective studies that assess the role of retinal imaging derived biomarkers as indicators of stroke risk. RESULTS: Twenty-four studies were included in this systematic review. The available evidence suggests that wider retinal venules, lower fractal dimension, increased arteriolar tortuosity, presence of retinopathy, and presence of retinal emboli are associated with increased likelihood of stroke. There is weaker evidence to suggest that narrower arterioles and the presence of individual retinopathy traits such as microaneurysms and arteriovenous nicking indicate increased stroke risk. Our review identified three models utilizing artificial intelligence algorithms for the analysis of retinal images to predict stroke. Two of these focused on fundus photographs, whilst one also utilized optical coherence tomography (OCT) technology images. The constructed models performed similarly to conventional risk scores but did not significantly exceed their performance. Only two studies identified in this review used OCT imaging, despite the higher dimensionality of this data. CONCLUSION: Whilst there is strong evidence that retinal imaging features can be used to indicate stroke risk, there is currently no predictive model which significantly outperforms conventional risk scores. To develop clinically useful tools, future research should focus on utilization of deep learning algorithms, validation in external cohorts, and analysis of OCT images.

Quantitative assessment of retinal vasculature changes in systemic lupus erythematosus using wide-field OCTA and the correlation with disease activity.

Purpose: To assess the retinal vasculature changes quantitatively using wide-field optical coherence tomography angiography (OCTA) in systemic lupus erythematosus (SLE), and explore its correlation with systemic clinical features. Design: Prospective, cross-sectional, observational study. Participants and controls: Patients with SLE who presented to the Ophthalmology Department of Peking Union Medical College Hospital from November 2022 to April 2023 were collected. The subjects were divided into retinopathy and without retinopathy groups. Age and gender-matched healthy subjects were selected as controls. Methods: Patients with SLE and control subjects were imaged with 24×20 mm OCTA scans centered on the fovea and 6×6 mm OCTA scans centered on the optic disc. The sub-layers of OCTA images were stratified by the built-in software of the device and then the retinal thickness and vessel density were measured automatically. The characteristics of retinal OCTA parameters of SLE and its correlation with systemic clinical indicators of patients without retinopathy were analyzed. Main outcome measures: OCTA parameters, visual acuity, intraocular pressure, and systemic clinical indicators of patients such as disease activity index, autoimmune antibodies, and inflammatory marker levels were collected. Results: A total of 102 SLE patients were included, 24 of which had retinopathy, and 78 had unaffected retina. Wide-field OCTA could effectively detect retinal vascular obstruction, non-perfusion area, and morphological abnormalities in patients with lupus retinopathy. SLE patients without retinopathy had significantly higher retinal superficial vessel density (SVD) in foveal (P=0.02), para-foveal temporal (P=0.01), nasal (P=0.01), peripheral foveal temporal (P=0.02), and inferior areas (P=0.02), as well as subregion temporal (P=0.01) and inferior areas (P=0.03) when compared with healthy controls (n=65 eyes from 65 participants). The area under curve (AUC) value of subregion inferior SVD combined parafoveal temporal SVD was up to 0.70. There was a significantly positive correlation between SVD and disease activity in SLE without retinopathy group. Patients with severe activity had the most significant increase in SVD. Conclusion: Wide-field OCTA can provide a relatively comprehensive assessment of the retinal vasculature in SLE. In the absence of pathological changes of the retina, the SVD was significantly increased and was positively correlated with the disease activity of SLE.

Optical coherence tomography angiography assessment of retinochoroidal microcirculation differences in preeclampsia.

BACKGROUND: To investigate microvascular changes in pregnant women with preeclampsia using optical coherence tomography angiography (OCTA) and compare the results with healthy pregnant and non-pregnant subjects. METHODS: Superficial capillary plexus (SCP), deep capillary plexus (DCP) choriocapillaris (CC) vessel density (VD) and foveal avascular zone area (FAZ), retina, retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL) and the choroidal thickness were examined and compared in preeclamptic pregnant (group 1), healthy pregnant women (group 2) and non-pregnant, age-matched female controls (group 3). The correlations of the parameters with each other and with blood pressure were evaluated. RESULTS: No significant difference was found between the groups when retinal, RNFL and GCL thickness values (p> 0.05). The choroidal thickness values were significantly lower in group 1 than in group 2 (p = 0.029). The central foveal VD of the SCP and DCP was significantly lower in group 1 compared to groups 2 and 3 (p = 0.03, p< 0.01 respectively). The mean VD of the SCP was significantly higher in groups 1 and 2 than in group 3 (p = 0.01). The FAZ area was statistically significantly lower in group 3 than in group 2 (p = 0.032). The CC VD was lower in group 3 compared to the other groups in all measurements (p < 0.01).The FAZ area was positively correlated with systolic blood pressure in group 1. CONCLUSION: The use of OCTA, a non-invasive imaging technique, to assess the retinal microcirculation appears to have the potential to in the early diagnosis or follow up in preeclampsia before signs of hypertensive retinopathy.

Assessment of early macular microangiopathy in subjects with prediabetes using optical coherence tomography angiography and fundus photography.

AIMS: Early detection of retinal microangiopathy in patients with prediabetes may reduce diabetic retinopathy complications. The aim of this study was to assess early macular vascular changes in prediabetics before development of over diabetes using OCTA and fundus photography. METHODS: In this cross-sectional study, 66 prediabetic individuals and 66 normal controls underwent clinical, laboratory, and fundus photography evaluation followed by OCTA macular imaging to examine for the foveal avascular zone, and area of capillary non-perfusion, thickness, disorganization of vessels, and vessel density perfusion percentage of superficial capillary plexus and deep capillary plexus. RESULTS: Retinal microangiopathy was detected in 36.4% of prediabetics by OCTA and only in 10.6% by fundus photography. None of clinical or laboratory parameters had significant association with DR. Area of capillary non-perfusion and disorganization of SCP were detected in 53.8% and 56.8%, respectively, in prediabetics. VDP of SCP and DCP of whole image, parafoveal, and perifoveal areas was significantly lower in prediabetes group compared to normal control. VDP of DCP of perifoveal area (ß coefficient: - 0.10, OR: 0.91, 95% CI: 0.86-0.96, P < 0.001) and disorganization of DCP (ß coefficient: 1.93, OR: 6.89, 95% CI: 2.5-18.8, P < 0.001) were significant predictors of DR in prediabetics. There was no difference in FAZ in prediabetics with and without retinopathy. CONCLUSIONS: OCTA could detect early retinal vascular changes during the prediabetic state before developing diabetes. VDP was significantly reduced in prediabetic patients. Furthermore, VDP of DCP of perifoveal area and disorganization of DCP were the most important predictors of retinopathy in prediabetic patients.

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

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

Assessment of retinal and choroidal microcirculation after unilateral recession-resection surgery for horizontal strabismus by swept-source optical coherence tomography angiography.

This study explored the possible hemodynamic changes of the retina and choroid after horizontal strabismus surgery using swept-source optical coherence tomography angiography (SS-OCTA). 32 eyes of 32 patients who underwent unilateral horizontal rectus muscle recession-resection surgery were included. SS-OCTA examinations were performed preoperatively and one week postoperatively. Several OCTA measurements were used, including vessel density (VD) of the superficial vascular complex (SVC), VD of the deep vascular complex (DVC), VD of the choriocapillaris (CC), choroidal vascular index (CVI) and choroidal thickness (CT). No significant change in VD of SVC, DVC, and CC was observed whereas CT increased significantly with CVI unchanged. Recession-resection surgery for horizontal strabismus seemed not to significantly influence the microcirculation of the retina and CC in the early postoperative period. However, choroidal thickening happened with a constant CVI probably due to the postoperative inflammation. Further studies are needed to investigate the long-term effects of unilateral recession-resection surgery for horizontal strabismus on the microcirculation of the retina and choroid.

Assessment of alterations in the retina and vitreous in pre- and post-COVID-19 patients using swept-source optical coherence tomography and angiography: A comparative study.

Ocular manifestations have been well recognized in coronavirus disease 2019 (COVID-19) outbreak. Several studies have detected ocular manifestations in patients after COVID-19. However, little is known about the retinal and vitreal alterations in patients before and after COVID-19 infection. This study aimed to investigate the retinal and vitreal alterations in patients before and after contracting COVID-19 infection using swept-source optical coherence tomography (SS-OCT) and angiography (SS-OCTA). A total of 38 participants (76 eyes) were enrolled and followed-up 1 month after COVID-19 infection. Then, 26 patients (52 eyes) were evaluated 3 months after COVID-19 infection. Compared with the pre-COVID-19 status, patients with 1- and 3-month post-COVID-19 statuses had significant thinning of ganglion cell and inner plexiform layer, thickening of inner nuclear layer, a decrease in the vessel density (VD) of superficial vascular complex, and an increase in the VD of deep vascular complex. Meanwhile, alteration in parameters of foveal avascular zone (all p < 0.05) and hyper-reflective dots in the vitreous of 27 patients (54 eyes) (71.1% vs. pre-COVID-19, 34.2%, p = 0.006) were observed. These findings suggest significantly retinal and vitreal alterations occurred in patients after COVID-19 infection, possibly due to direct or indirect virus-induced injuries. Further longitudinal studies are required to investigate the long-term effects of COVID-19 infection on the human eyes.

Quantitative Assessment of Retinal and Choroidal Microvasculature in Asymptomatic Patients with Carotid Artery Stenosis.

SIGNIFICANCE: Carotid disease contributes to 15 to 20% of all ischemic strokes, one of the leading causes of permanent disabilities and mortality globally. With its growing prevalence and the inflicted disability rates, screening for anomalies that precede the onset of its serious complications is of crucial global significance. PURPOSE: This study aimed to assess the relationship between retinal and choroidal perfusion changes with the degree of stenosis using quantitative swept-source optical coherence tomography angiography in patients with internal carotid artery stenosis. METHODS: A retrospective cohort study was conducted in 72 eyes with carotid stenosis. According to the degree of stenosis, the participants were divided into a healthy group (group 1: 34 eyes), a mild-moderate stenosis group (group 2: 22 eyes), and a severe stenosis group (group 3: 16 eyes). Swept-source optical coherence tomography angiography was performed to scan macular fovea. Capillary density values in the different retinal and choroidal layers were the major measurements for our study. RESULTS: Mean vessel density in the midchoroid layer was significantly higher in groups 2 and 3 compared with group 1. Deep choroid disclosed significantly superior vascular density values in group 3 compared with groups 2 and 1. Superficial and deep capillary plexus showed decreased vascular density values when comparing group 3 with groups 1 and 2, although they were not significant. CONCLUSIONS: Our report provides the first evidence that choroidal microvascular changes were correlated with severity of carotid artery stenosis. Optical coherence tomography angiography can sensitively detect subtle, early changes in the ocular blood in carotid disease representing a useful, noninvasive, and objective approach to the retinal microvasculature.

Non-Invasive Retinal Blood Vessel Wall Measurements with Polarization-Sensitive Optical Coherence Tomography for Diabetes Assessment: A Quantitative Study.

Diabetes affects the structure of the blood vessel walls. Since the blood vessel walls are made of birefringent organized tissue, any change or damage to this organization can be evaluated using polarization-sensitive optical coherence tomography (PS-OCT). In this paper, we used PS-OCT along with the blood vessel wall birefringence index (BBI = thickness/birefringence2) to non-invasively assess the structural integrity of the human retinal blood vessel walls in patients with diabetes and compared the results to those of healthy subjects. PS-OCT measurements revealed that blood vessel walls of diabetic patients exhibit a much higher birefringence while having the same wall thickness and therefore lower BBI values. Applying BBI to diagnose diabetes demonstrated high accuracy (93%), sensitivity (93%) and specificity (93%). PS-OCT measurements can quantify small changes in the polarization properties of retinal vessel walls associated with diabetes, which provides researchers with a new imaging tool to determine the effects of exercise, medication, and alternative diets on the development of diabetes.

Optical Coherence Tomography Angiography Assessment in Congenital Aniridia.

PURPOSE: This study aims to characterize foveal vasculature assessed by optical coherence tomography angiography (OCT-A) in congenital aniridia which is hallmarked by foveal hypoplasia (FH). DESIGN: Cross-sectional case-control analysis. METHODS: At the National Referral Center for congenital aniridia, patients with confirmed PAX6-related aniridia and FH diagnosed on spectral-domain OCT (SD-OCT) with available OCT-A and matched control subjects were included. OCT-A was performed in patients with aniridia and control subjects. Foveal avascular zone (FAZ) and vessel density (VD) were collected. VD in the foveal and parafoveal areas at the level of the superficial and deep capillary plexi (SCP and DCP, respectively) were compared between the 2 groups. In patients with congenital aniridia, correlation between VD and the grading of FH was assessed. RESULTS: Among 230 patients with confirmed PAX6-related aniridia, high-quality macular B-scans and OCT-A were available in 10 patients. On the foveal area, mean VD was higher in aniridia patients (41.10%, n = 10) than in control subjects (22.65%, n = 10) at the level of the SCP and the DCP (P = .0020 and P = .0273, respectively). On the parafoveal area, mean VD was lower in patients with aniridia (42.34%, n = 10) than in healthy subjects (49.24%, n = 10) at the level of both plexi (P = .0098 and P = .0371, respectively). In patients with congenital aniridia, a positive correlation was found between the grading of FH and the foveal VD at the SCP (r = 0.77, P = .0106). CONCLUSIONS: Vasculature is altered in PAX6-related congenital aniridia, higher in foveal and lower in parafoveal areas, especially when FH is severe, which is consistent with the concept that the absence of retinal blood vessels is essential for foveal pit development.

Optical coherence tomography angiography for assessment of changes of the retina and choroid in different stages of diabetic retinopathy and their relationship with diabetic nephropathy.

Given the prevalence of diabetes worldwide, diabetic retinopathy (DR) has become the most prominent cause of blindness. However, DR can be diagnosed only when it is severe enough to be clinically detectable. Several studies have evaluated the correlation between DR and diabetic nephropathy (DN) by utilizing optical coherence tomography angiography (OCTA). Compared with other diagnostic techniques, such as fluorescein angiography and fundus photography, OCTA has the ability to directly reflect the condition of the retinal and choroidal microcirculation at an early stage. This review focuses on the following aspects: the advantages of OCTA, the pathophysiology of DR, changes in OCTA images in patients with DR, and the relationships between OCTA parameters and renal function.

Optical coherence tomography-based assessment of macular vessel density, retinal layer metrics and sub-foveal choroidal thickness in COVID-19 recovered patients.

Purpose: The primary objective of the study was to assess the macular retinal vessel density, subfoveal choroidal thickness, and retinal layer metrics by optical coherence tomography angiography (OCTA), enhanced-depth imaging optical coherence tomography (EDI-OCT), and spectral domain optical coherence tomography (SD-OCT), respectively, in recovered COVID-19 patients and its comparison with the same in control subjects. The secondary objective was to evaluate differences in OCTA parameters in relation with the severity of COVID-19 disease and administration of corticosteroids. Methods: A case-control study was performed that included patients who had recovered from COVID-19 and age-matched healthy controls. Complete ocular examination including OCTA, SD-OCT, and EDI-OCT were performed three months following the diagnosis. Results: Three hundred sixty eyes of 180 subjects were enrolled between the two groups. A decreased mean foveal avascular zone area in both superficial capillary plexuses (P = 0.03) and deep capillary plexuses (P < 0.01), reduced average ganglion cell layer-inner plexiform layer thickness (P = 0.04), and increased subfoveal choroidal thickness (P < 0.001) were observed among cases in comparison to the control group. A significant correlation was found between sectoral macular vessel density in relation to disease severity and a decrease in vessel density with greater severity of the disease. Conclusion: OCTA detected retinal microvascular alterations following SARS-CoV-2 infection in subjects with the absence of any clinical ocular manifestation or systemic thrombotic events. These parameters could be used to help identify patients with a higher incidence of systemic thromboembolism on longer follow-ups and identify the impact of corticosteroids on retinal architecture.

Wide-field swept-source optical coherence tomography angiography in the assessment of retinal microvasculature and choroidal thickness in patients with myopia.

BACKGROUND/AIMS: Pathological myopia (PM) is a leading cause of blindness worldwide. We aimed to evaluate microvascular and chorioretinal changes in different stages of myopia with wide-field (WF) swept-source (SS) optical coherence tomography angiography (OCTA). METHODS: This prospective cross-sectional observational study included 186 eyes of 122 patients who had undergone imaging between November 2018 and October 2020. Vessel density (VD) and vessel skeletonised density (VSD) of superficial capillary plexus, deep capillary plexus and whole retina, as well as foveal avascular zone parameters, retinal thickness (RT) and choroidal thickness (CT), were calculated. RESULTS: This study evaluated 75 eyes of 48 patients with high myopia (HM), 43 eyes of 31 patients with mild to moderate myopia and 68 eyes of 53 age-matched controls. Controlling for age and the presence of systemic hypertension, we found that HM was associated with decrease in VD and VSD in all layers on 12×12 mm² scans. Furthermore, HM was associated with a VD and VSD decrease in every Early Treatment Diabetic Retinopathy Study grid, with a larger decrease temporally (ßVD=-0.39, ßVSD=-10.25, p<0.01). HM was associated with decreased RT and CT. Reduction in RT was outside the macular region, while reduction in CT was in the macular region. CONCLUSION: Using WF SS-OCTA, we identified reduction in microvasculature and structural changes associated with myopia. Decrease in VD and VSD was greater in the temporal quadrant, and reductions in RT and CT were uneven across the retina. Further work may help identify risk factors for the progression of PM and associated vision-threatening complications.

Deep learning-based signal-independent assessment of macular avascular area on 6×6 mm optical coherence tomography angiogram in diabetic retinopathy: a comparison to instrument-embedded software.

SYNOPSIS: A deep-learning-based macular extrafoveal avascular area (EAA) on a 6×6 mm optical coherence tomography (OCT) angiogram is less dependent on the signal strength and shadow artefacts, providing better diagnostic accuracy for diabetic retinopathy (DR) severity than the commercial software measured extrafoveal vessel density (EVD). AIMS: To compare a deep-learning-based EAA to commercial output EVD in the diagnostic accuracy of determining DR severity levels from 6×6 mm OCT angiography (OCTA) scans. METHODS: The 6×6 mm macular OCTA scans were acquired on one eye of each participant with a spectral-domain OCTA system. After excluding the central 1 mm diameter circle, the EAA on superficial vascular complex was measured with a deep-learning-based algorithm, and the EVD was obtained with commercial software. RESULTS: The study included 34 healthy controls and 118 diabetic patients. EAA and EVD were highly correlated with DR severity (ρ=0.812 and -0.577, respectively, both p<0.001) and visual acuity (r=-0.357 and 0.420, respectively, both p<0.001). EAA had a significantly (p<0.001) higher correlation with DR severity than EVD. With the specificity at 95%, the sensitivities of EAA for differentiating diabetes mellitus (DM), DR and severe DR from control were 80.5%, 92.0% and 100.0%, respectively, significantly higher than those of EVD 11.9% (p=0.001), 13.6% (p<0.001) and 15.8% (p<0.001), respectively. EVD was significantly correlated with signal strength index (SSI) (r=0.607, p<0.001) and shadow area (r=-0.530, p<0.001), but EAA was not (r=-0.044, p=0.805 and r=-0.046, p=0.796, respectively). Adjustment of EVD with SSI and shadow area lowered sensitivities for detection of DM, DR and severe DR. CONCLUSION: Macular EAA on 6×6 mm OCTA measured with a deep learning-based algorithm is less dependent on the signal strength and shadow artefacts, and provides better diagnostic accuracy for DR severity than EVD measured with the instrument-embedded software.

Assessment of microvascular involvement in lupus nephritis patients by retinal OCT-angiography and kidney biopsies.

OBJECTIVES: Ocular and renal microvascular damage in lupus nephritis (LN) share similar physiopathological pathways that have investigated using traditional fundus examination and high-resolution colour electroretinography. Optical coherence tomography angiography (OCTA) is a recent, non-invasive technique for imaging the microvasculature of retina and choroid. Aim of the study was to investigate through OCTA analysis the relationship between retinal microvascular alterations and renal functional and histologic features. METHODS: Systemic lupus erythematosus (SLE) patients with LN, SLE without renal involvement and healthy controls were recruited and accomplished an ophthalmological evaluation, including OCTA. SLE-LN patients underwent a rheumatological evaluation, including disease-related clinical and laboratory features collection and kidney biopsy examination. RESULTS: This cross-sectional study enrolled forty-six eyes of 23 LN patients, thirty-two eyes of 16 SLE patients and forty-two eyes of 21 controls. Thirteen SLE-LN patients (56.5%) displayed lupus retinopathy, 10 at moderate (77%) and 3 at severe stage (23%) by fundus oculi examination. Analysis of OCTA data showed with high/moderate accuracy a reduction of retinal capillary vessel density in both SLE and SLE-LN patients compared to controls in superficial and deep plexi. A reduction in fovea thickness and an increase in foveal avascular zone were also detected. OCTA data of LN patients correlated with LN duration, disease activity, kidney function and the presence of LN-vascular lesions at kidney biopsy. CONCLUSIONS: Our results suggest the role of OCTA in early detection of systemic vascular involvement in SLE-LN patients and related kidney functional-histological impairment.

Optic disc and retinal vessel densities assessment by optical coherence tomography angiography in patients with keratoconus.

BACKGROUND: This study aimed to evaluate retinal and optic disc vascular changes in patients with keratoconus (KC) using optical coherence tomography angiography (OCTA). METHODS: Thirty-two eyes of 22 patients with KC and 24 eyes of 24 age- and sex-matched healthy controls were included in this study. Corneal topography and OCTA were performed. Quantitative vessel density of the macular superficial capillary plexus (SCP), macular deep capillary plexus (DCP), and radial peripapillary capillaries (RPC); choriocapillaris flow area; and choroidal thickness were compared between the KC and control groups. RESULTS: SCP and DCP vessel densities showed a significant reduction in the KC group compared to that in the control group (p < 0.001 and p < 0.001 in the whole image and parafovea, respectively). Choriocapillaris flow area was significantly higher in patients with KC than in the control group (p = 0.003). The foveal avascular zone area did not significantly differ between the two groups (p = 0.949). RPC inside disc vessel density was significantly decreased in the KC group compared to that in the control group (p < 0.001). CONCLUSION: This study revealed important macular, choroidal, and optic disc vessel densities changes in patients with KC. Macular whole vessel density and parafoveal vessel density of the SCP and DCP decreased, while choriocapillaris flow area increased in patients with KC.

Assessment of the Optic Disc and Retinal Microvasculature by Optical Coherence Tomography Angiography in Patients With Pediatric Migraine.

BACKGROUND: Migraine, as a chronic neurovascular disease, is known to be a risk factor for retinal and optic nerve head damage. Herein, we aimed to evaluate the optic disc and retinal microvasculature in pediatric migraine (PM) patients using optical coherence tomography angiography (OCTA). METHODS: Forty-six eyes of 23 patients with PM without aura (PM group) and 46 eyes of 23 age- and sex-matched healthy subjects (control group) were included in this cross-sectional prospective study. Demographic features and ophthalmological examination including OCTA measurements were evaluated. OCTA was performed with 6- × 6-mm sections for macula and 4.5- × 4.5-mm sections for optic nerve head in all eyes. Foveal retinal thickness (FRT), peripapillary retinal nerve fiber layer (RNFL) thickness, vessel density in different sections of the retina, and optic disc were analyzed and compared between the groups. All measurements of the PM patients were taken in the attack-free period. RESULTS: The mean ages of the PM group and control group were 11.17 ± 3.3 and 11.83 ± 2.8 years, respectively ( P = 0.479). Gender and mean intraocular pressures were similar between the groups. The mean central corneal thickness levels in the PM group were significantly lower than control group, 548.28 ± 26.3 µm and 562.04 ± 24.5 µm, respectively ( P = 0.011). There was no significant difference regarding average and all quadrant RNFL thicknesses, foveal avascular zone and flow areas, deep vessel densities, and optic disc capillary densities between the groups. However, compared with the control group, the PM group showed significant higher values of FRT, and lower values of superficial whole and parafoveal vessel densities (247.28 ± 15.8 µm vs 285.93 ± 11.1, P < 0.001, 51.85 ± 2.4% vs 50.31 ± 4.0%, P = 0.02, 55.09 ± 2.3% vs 53.5 ± 3.5%, P = 0.01, respectively). Disease duration and attacks/year did not show any significant correlations with OCTA values. CONCLUSIONS: PM seems to be associated with lower superficial whole and parafoveal vessel densities because of hypoperfusion and ischemia. OCTA may be suggested for use in follow-up and management of PM patients.