Optical Coherence Tomography Angiography Images Research Articles

Barriers in Healthcare to the Use of Optical Coherence Tomography Angiography in Multiple Sclerosis.

Optical coherence tomography angiography (OCT-A) is a state-of-the-art imaging technique for the retinal vasculature to accurately segment the capillary network and assign it to retinal layers. OCT-A is a promising technique to better understand neurological diseases with visual system manifestations, such as multiple sclerosis (MS), and to identify and characterize vascular biomarkers. Initial studies suggested vascular changes in MS and its differential diagnoses such as myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and neuromyelitis optica spectrum disorder (NMOSD). Here we review clinical and technical aspects of OCT-A imaging and discuss the potential for the MS field as well as barriers that need to be overcome before OCT-A can be established in clinical application.

In vivo assessment of cone loss and macular perfusion in children with myopia

This study evaluated cone density (CD) in the macular region and assess macular perfusion in children with varying degrees of myopia. This was a prospective, cross-sectional, observational study. Children underwent confocal scanning laser ophthalmoscopy (cSLO), optical coherence tomography (OCT), and OCT angiography (OCTA) imaging. A built-in software was used to measure mean CD (cells/mm2), retinal vessel density, choriocapillaris perfusion area, and choroidal thickness (CT). The study included 140 eyes from children categorized into four groups: emmetropia (31 eyes), low myopia (44 eyes), moderate myopia (31 eyes), and high myopia (34 eyes). The high myopia group exhibited significantly lower macular CD than the emmetropia group (P < 0.05). Additionally, the high myopia group showed thinner CT and higher choriocapillaris perfusion area in the macular region than the emmetropia group (all P < 0.01). Macular CD was significantly correlated with age, spherical equivalent, axial length, and CT (all P < 0.05). Generalized linear models revealed CT as the independent factor associated with macular CD (Wald χ2 = 9.265, P = 0.002). Children with high myopia demonstrate reduced CD in the macular region, accompanied by reduced CT. These findings may have important implications for future myopia prevention and management strategies.

Retinal microvascular phenotypes can track small vessel disease burden and CPAP treatment effectiveness in obstructive sleep apnoea.

Optical coherence tomography angiography (OCT-A) retinal imaging enables in vivo visualization of the retinal microvasculature that is developmentally related to the brain and can offer insight on cerebrovascular health. We investigated retinal phenotypes and neuroimaging markers of small vessel disease (SVD) in individuals with obstructive sleep apnoea (OSA). We enrolled 44 participants (mean age 50.1 ± SD 9.1 years) and performed OCT-A imaging before and after continuous positive airway pressure (CPAP) therapy. Pre-treatment analyses using a generalized estimating equations model adjusted for relevant covariates, revealed perivascular spaces (PVS) volume in basal ganglia associated with greater foveal vessel density (fVD) (p-value < 0.001), and smaller foveal avascular zone area (p-value = 0.01), whereas PVS count in centrum semiovale associated with lower retinal vessel radius (p-value = 0.02) and higher vessel tortuosity (p-value = 0.01). A reduction in retinal vessel radius was also observed with increased OSA severity (p-value = 0.05). Post-treatment analyses showed greater CPAP usage was associated with a decrease in fVD (p-value = 0.02), and increased retinal vessel radius (p-value = 0.01). The findings demonstrate for the first time the potential use of OCT-A to monitor CPAP treatment and its possible impact on both retinal and brain vascular health.

Exploring retinal vessel density alterations in prolactinoma patients: Insights from OCTA imaging.

To investigate microvascular changes in the macular and peripapillary area in prolactinoma patients by using optical coherence tomography angiography (OCTA). A retrospective study. This study included 40 patients with treatment-naive prolactinoma and 42 healthy controls. Participants underwent comprehensive ophthalmic examinations, visual field testing, and optical coherence tomography (OCT) assessments, including retinal nerve fiber layer (RNFL) thickness, macular, and peripapillary region OCTA by using the Topcon DRI OCT Triton Swept Source-OCT system. The OCTA results were evaluated between groups and then correlated with PRL levels. The differences in best-corrected visual acuities were statistically significant among the groups. The RNFL thickness in the superior and nasal quadrants was significantly lower in the prolactinoma group. The prolactinoma group showed significant reductions in macular vessel density (VD) across all layers than the control group, except in the deep retinal capillary plexus temporal quadrants. The radial peripapillary capillary (RPC) temporal VD in the prolactinoma group was significantly lower. In patients with optic neuropathy, correlations were observed between the RPC temporal and RNFL temporal sectors (r = 0.650, P = 0.03), and between the RPC inferior and RNFL inferior sectors (r = -0.612, P = 0.045). Between PRL levels and OCTA parameters, negative correlations were observed (RPC inferior: r = -0.452, P = 0.003; DCP superior: r = -0.379, P = 0.016). Our study revealed reduced VD in the macula and RPC temporal regions in patients with treatment-naive prolactinoma. OCTA holds significant importance in detecting potential retinopathies and vasculopathies. Future research should focus on examining pre- and post-treatment changes in treatment-naive patients without ON to better understand the impact of prolactinoma.

Association of Peripapillary Arterial Circle of Zinn-Haller with Glaucoma in Highly Myopic Eyes.

The visualization of circle of Zinn-Haller (CZH) on optical coherence tomography angiography (OCTA) or its pattern does not have a clear effect on glaucoma, while the location of CZH is associated with axial length in highly myopic eyes. To investigate the association between the CZH and the presence of glaucoma using swept-source optical coherence tomography angiography (SS-OCTA) images of the optic nerve of patients with high myopia (HM). This retrospective case series included 227 eyes with HM, comprising 134 and 93 eyes with and without glaucoma, respectively. The characteristics of CZH, including visualization, pattern, and location, were assessed using SS-OCTA. Vascular parameters, such as vessel density and microvascular dropout (MvD), were quantified. The factors affecting the presence of glaucoma and the correlations between the CZH distance and axial length (AXL) were identified using logistic regression analysis and Pearson correlation analysis, respectively. CZH was detected more frequently in HM patients with glaucoma (71.6%) than in patients without glaucoma (51.6%) (P<0.002). However, the visualization of CZH was not related to the presence of glaucoma in multivariate regression analysis (odds ratio [OR], 0.688; 95% confidence interval [CI], 0.328-1.444; P=0.322). Moreover, compared to the annular pattern used as a reference, triangular and irregular patterns were not associated with the presence of glaucoma (OR: 1.043, 95% CI: 0.101-10.763, P=0.971; OR: 0.527, 95% CI: 0.255-1.092, P=0.085, respectively). MvD was significantly higher in patients with glaucoma (61.2%) than that in patients without glaucoma (2.2%) (P<0.001) and was identified as a significant factor affecting the presence of glaucoma (OR, 42.120; 95% CI, 9.416-188.413; P<0.001). AXL showed a significant correlation with CZH distance in all patients (R=0.399; P<0.001). CZH was more commonly detected in HM patients with glaucoma. However, no clear associations of glaucoma with the visualization, pattern, or location of CZH were observed in the present study. The correlation between AXL and CZH distance in eyes with HM warrants further investigation. These results may offer insights into the pathogenesis of glaucoma in eyes with HM as OCTA technology advances.

Longitudinal OCTA vessel density loss in macula and optic nerve head in healthy, glaucoma suspect and established glaucoma eyes.

To examine longitudinal optical coherence tomography angiography (OCTA) changes in macula and optic nerve head (ONH) in healthy, glaucoma suspect (GS) and primary open-angle glaucoma (POAG) eyes. Healthy, GS and POAG eyes from Diagnostic Innovations in Glaucoma Study with ≥2 years follow-up and four visits of macular/ONH OCTA imaging were included. Rates of macular wiVD (whole-image vessel density) and ONH wiCD (whole-image capillary density) changes were calculated for each diagnosis group using join mixed-effect modelling. Differences in wiVD/wiCD change rates across diagnoses were examined through pairwise comparison. Relationships of baseline 24-2 visual field (VF) mean deviation (MD) with wiVD/wiCD change rates were evaluated for POAG eyes. There were 36, 57 and 79 eyes (25, 38 and 50 subjects) in healthy, GS and POAG groups, respectively. Rates of wiVD (range:-0.72 to -0.92 %/year) and wiCD (range:-0.28 to -0.66 %/year) loss were different from zero in all groups (p<0.05). The rates of wiCD loss differed across all diagnosis groups (p<0.001), while wiVD change rates did not increase when comparing healthy to GS eyes (p=0.167). Baseline VF MD showed a significant but modest correlation with the rates of both wiVD and wiCD loss (p<0.05), and the correlation with wiCD change rate was slightly stronger (R2=0.27 vs 0.16). In glaucoma, there is earlier microvasculature loss in the ONH than in the macula. Moreover, ONH VD loss shows a slightly stronger association with baseline VF than macular VD. Observing ONH VD loss with OCTA may help to monitor early glaucoma, which should be confirmed by future larger studies.

Quantitative detection of macular microvascular abnormalities identified by optical coherence tomography angiography in different hematological diseases

It is now understood that hematological diseases can have detrimental effects on the retina, reducing retinal capillaries, compromising visual function, and potentially causing irreversible visual impairment. Over the years, there has been limited research on macular microvascular abnormalities, such as changes in vessel density and the foveal avascular zone (FAZ) and variations in the severity of these effects across different types of blood disorders. This study aims to quantitatively assess the impact of various hematological disorders on the retina using optical coherence tomography angiography (OCTA). Compared with healthy eyes, patients with different blood diseases exhibited reductions in linear vessel density (LVD), perfusion vessel density (PVD), FAZ area, and FAZ perimeter. Notably, patients with erythrocyte diseases showed more significant abnormalities in LVD and PVD, while patients with lymphocytic diseases demonstrated more pronounced abnormalities in the FAZ area and perimeter. OCTA imaging could potentially reflect changes of the retinal microvascular of patients with hematological diseases and may serve as a valuable tool for distinguishing abnormalities affecting different blood cell lines. This approach offers a novel avenue for assessing, treating, and monitoring blood disorders.

Combined evaluation of visual field and optical coherence tomography angiography data in multiple sclerosis patients

Aims: To evaluate Humphrey visual field analyzer (HVFA) data and optical coherence tomography angiography (OCT-A) parameters in multiple sclerosis (MS) patients with optic neuritis (ON) attacks. Methods: 34 eyes of 34 patients with MS diagnosis who had ON attacks were included in the study. After detailed ophthalmoscopic examination, OCT-A and HVFA images were taken. Spearman correlation analysis was used in statistical analysis. Results: The mean age of the participants was 31.52±10.09 years. In the correlation analysis, a moderate correlation was found between mean deviation (MD) and foveal deep blood flow (DF) (rho=0.52), and a weak correlation was found between MD and foveal superficial blood flow (SF) (rho=0.40) and optic disc head blood flow (ODF) (rho=0.38). A weak negative correlation was found between pattern standard deviation (PSD) and DF (rho=-0.37) and ODF (rho=-0.40). Conclusion: This study showed that OCTA data were affected in a manner consistent with HVFA data. More practical and quickly applicable OCTA scans may facilitate the estimation of visual field findings in MS patients.

Intracranial pressure affects retinal venular complexity in idiopathic intracranial hypertension: a retrospective observational study

BackgroundIncreased intracranial pressure (ICP) in patients with idiopathic intracranial hypertension (IIH) affects the retinal microvasculature, which can be imaged and quantified by optical coherence tomography angiography (OCTA). We aimed to identify the mediating factor between ICP and OCTA parameters association in IIH patients.MethodsIIH patients with active intracranial hypertension were enrolled. OCTA imaging was performed after ICP measurement. We quantified the branching complexity of the retinal arterioles and venules from the superficial vascular complex of the OCTA image. Eyes of IIH patients were stratified into eyes with papilledema (IIH-P) and eyes without papilledema (IIH-WP). All participants underwent visual acuity (VA) examination.ResultsOne hundred and thirty-eight eyes from 70 IIH patients and 146 eyes from 73 controls were included. Compared to the control group, IIH patients and IIH-P had reduced arteriole complexity and increased venule complexity (p < 0.05). For IIH patients and IIH-P, increased retinal venule complexity correlated with increased ICP and reduced VA (p < 0.05); while decreased arteriole complexity only correlated with Frisen scores (p = 0.026). Papilledema mediated the effect (p < 0.001) between ICP and arteriole complexity while ICP had a direct effect (p < 0.001) on venule complexity.ConclusionRetinal venules imaged via OCTA may reflect ICP levels and may underpin the direct effect of increased ICP in IIH patients.

Factors Associated with Retinal Microvasculature Dropout Induced by Elevation of Intraocular Pressure in Primary Open-Angle Glaucoma.

To investigate the risk factors related to decrease in vessel density (VD) observed in primary open-angle glaucoma (POAG), due to acute increase in intraocular pressure (IOP) by an ophthalmodynamometer (OPD). This cross-sectional study involved 42 eyes of participants (22 Controls and 20 POAG patients) that underwent optical coherence tomography angiography (OCT-A) to assess VD in the peripapillary region in three examination sets: primary gaze position (1), 25-degree adduction (2) and 25-degree adduction with OPD compression (3). Individual relationships between IOP levels and changes in the superficial complex VD were evaluated after image processing and exclusion of large retinal vessels. Multivariable regression analysis was used to verify factors associated with differences in VD induced by IOP elevation. A significant increase in IOP was induced by OPD compression during adduction (mean ± SD, Control: + 13.8 ± 2.8; POAG: + 13.4 ± 2.1mmHg). Only during IOP elevation (set 3), a significant VD decrease was observed both in POAG eyes (p = 0.008) and controls (p = 0.022). Baseline IOP (p = 0.022), maximum IOP (p = 0.003), and scleral rigidity (p = 0.029) were significantly associated with VD decreases in eyes with POAG. No changes were observed in VD during adduction gaze exclusively. Acute IOP elevation induced with OPD, but not adduction gaze, decreased peripapillary VD measured with OCT-A imaging. IOP levels and scleral rigidity significantly affected VD reduction in POAG patients. Thus, high scleral rigidity may decrease the ability of the globe to dampen the well-known effects of IOP fluctuation on glaucoma onset and progression. What is known Decrease vascular density in the peripapillary retina was associated with POAG, but factors related to the vascular response to elevated IOP are unexplored. What is new OCT-A quantification shows decreases in vascular density of the superficial layers of the peripapillary retina during an acute elevation in IOP. High IOP levels and scleral rigidity significantly affected vascular density reduction in POAG patients.

Severity Stratification of Coronary Artery Disease Using Novel Inner Ellipse-Based Foveal Avascular Zone Biomarkers.

Given the similarities between the retinal and coronary microvasculature, the retina holds promising potential to serve as a non-invasive screening tool for coronary artery disease (CAD). We aimed to develop novel inner ellipse-based metrics and discern whether foveal avascular zone (FAZ) alterations can serve as indicators for CAD presence and severity. Patients admitted to the Department of Cardiology who underwent coronary angiography were included. This resulted in an inclusion of 212 patients, of which 73 had no CAD. During the same visit, 6 × 6-mm (nominal size) fovea-centered optical coherence tomography angiography images of both eyes were acquired. The Gensini score (GS) was utilized to quantify CAD severity. Six known FAZ shape metrics were assessed and three novel biomarkers based on the inner ellipse were defined: absolute inner ellipse difference, Hausdorff distance, and Chamfer distance. Eight out of nine metrics showed significant associations with the GS in the left eye. However, significant differences across three CAD severity groups were only demonstrated by the novel metrics. Utilizing the Chamfer distance, age, and sex, patients with and without CAD could be distinguished with an average area under the curve (AUC) of 0.89 (95% confidence interval [CI], 0.84-0.95). Moreover, three CAD severity groups could be discerned with a macro average AUC of 0.77 (95% CI, 0.72-0.84). A comprehensive assessment of FAZ shape descriptors was performed, and a strong association with CAD was found. The inner ellipse-based biomarkers especially demonstrated high predictive abilities for CAD presence and severity.

Automated grading of diabetic retinopathy and Radiomics analysis on ultra-wide optical coherence tomography angiography scans

Diabetic retinopathy (DR), a progressive condition due to diabetes that can lead to blindness, is typically characterized by a number of stages, including non-proliferative (mild, moderate and severe) and proliferative DR. These stages are marked by various vascular abnormalities, such as intraretinal microvascular abnormalities (IRMA), neovascularization (NV), and non-perfusion areas (NPA). Automated detection of these abnormalities and grading the severity of DR are crucial for computer-aided diagnosis. Ultra-wide optical coherence tomography angiography (UW-OCTA) images, a type of retinal imaging, are particularly well-suited for analyzing vascular abnormalities due to their prominence on these images. However, accurate detection of abnormalities and subsequent grading of DR is quite challenging due to noisy data, presence of artifacts, poor contrast and subtle nature of abnormalities. In this work, we aim to develop an automated method for accurate grading of DR severity on UW-OCTA images. Our method consists of various components such as UW-OCTA scan quality assessment, segmentation of vascular abnormalities and grading the scans for DR severity. Applied on publicly available data from Diabetic retinopathy analysis challenge (DRAC 2022), our method shows promising results with a Dice overlap metric and recall values of 0.88 for abnormality segmentation, and the coefficient-of-agreement (κ) value of 0.873 for DR grading. We also performed a radiomics analysis, and observed that the radiomics features are significantly different for increasing levels of DR severity. This suggests that radiomics could be used for multimodal grading and further analysis of DR, indicating its potential scope in this area.

Vascular changes in the retinal capillary network in fellow eye of the patients with central retinal artery occlusion.

We aimed to evaluate the retinal vascular changes in the superficial and deep retinal vascular networks in the fellow eye of patients with central retinal artery occlusion (CRAO) and compare them with controls using optical coherence tomography angiography (OCT-A). In a cross-sectional study, 27 patients with CRAO and 189 normal controls were included. Ophthalmic examination and OCT-A images were performed on all participants. The total vascular density of the superficial capillary network in the 6-mm scan was significantly lower in the fellow eye of patients with CRAO than in the control group (p = 0.02). No significant difference was observed in the FAZ area of the affected eyes and their fellow eyes compared with the controls. Total vascular density at 300 microns around the fovea was lower in the fellow eye compared with the control group (p = 0.034). The retinal vascular network changes in the fellow eyes of patients with CRAO suggest that persistent microvascular changes may be present before the onset of CRAO. This finding indicates that such changes could serve as an early diagnostic window for systemic vascular changes before catastrophic vascular events occur.

Quantification of capillary blood flow speeds in diabetic retinopathy using variable interscan time analysis (VISTA) OCTA.

To investigate retinal capillary plexus capillary flow speed and vessel density in diabetic retinopathy (DR) and normal subjects using variable interscan time analysis (VISTA) optical coherence tomography angiography (OCTA). High speed swept source OCTA imaging using multiple interscan times was performed over a 5 mm x 5 mm field-of-view with 600 kHz A-scan rate. Second-generation VISTA OCTA was used to measure a surrogate marker for capillary blood flow speed, VISTA flow speed (VFS), in the superficial and intermediate capillary plexuses, (SCP + ICP)VFS, and deep capillary plexus, DCPVFS. Vessel density was measured using OCTA. Fifty-seven eyes with different DR severity and 37 normal eyes were analyzed. VISTA OCTA provided diverse blood flow speed information, including pseudo-color OCTA and mean flow speed in different regions. Both DCPVFS and DCPVFS/(SCP + ICP)VFS were higher in DR compared to normal eyes. Elevated DCPVFS correlated with decreased DCP vessel density in non-proliferative DR. VISTA OCTA can measure a quantitative biomarker for blood flow speed alterations in DR and normal eyes as well as the association with vessel density in different capillary plexuses. VISTA OCTA is promising for studies of pathogenesis and early flow alterations which may precede non-perfusion.

Retinal thickness and macular microvascular changes seen on optical coherence tomography angiography (OCTA) in patients with sickle cell retinopathy in a tertiary care eye hospital

PurposeTo report retinal thickness values and macular vascular flow characteristics identified by optical coherence tomography angiography (OCT-A) in patients with various sickle cell genotypes in a population from sub-Saharan Africa. DesignRetrospective, observational study. MethodsThis is a single-institution case series of adult patients with various sickle cell genotypes who presented to the Eye Foundation Hospital Lagos between January 2022 and December 2023. Case files of patients were reviewed, and macular OCT and OCT-A images analyzed quantitatively for macular thickness, areas of flow loss, size of foveal avascular area, parafoveal flow, as well as vascular density in both the superficial and deep vascular plexi. The findings were compared by sickle cell genotype and comparisons made with age matched normal patients. ResultsA total of 38 eyes of 19 patients’ records were reviewed, and 35 eyes met the inclusion criteria; 16 eyes of 9 age and gender matched controls were included. The mean central foveal thickness (CFT) was 242.4 μm ± 33.3 μm among patients’ eyes, while a mean CFT of 236.1 μm ± 10.1 μm was measured among controls (p = 0.312). A smaller mean FAZ area of 0.270 mm2 ± 0.116 mm2 was seen among the control eyes compared to a mean of 0.314 mm2 ± 0.206 mm2 among patients’ eyes (p = 0.439). The mean flow area was larger among control eyes with 0.849 mm2 ± 0.647 mm2 compared to a mean flow of 0.822 mm2 ± 0.471 mm2 among patients’ eyes (0.868). The mean superficial foveal vessel density was greater among control eyes (19.30 ± 4.58) compared to patient eyes (18.77 ± 7.78) (p = 0.765). The mean deep foveal vessel density was greater among controls (35.30 ± 8.36) than among patients (34.06 ± 9.30) (p = 0.650). The difference between eyes of SC (53.37 ± 5.13) patients and SS (47.94 ± 8.44) patients in the deep temporal perifoveal VD was statistically significant (p = 0.035). ConclusionThe retina in eyes with sickle retinopathy and that of controls tends to be thickest in the nasal quadrant, then the superior, then inferior, and then thinnest in the temporal quadrant. Macular vessel density in both the superficial and deep capillary plexi was thicker among controls compared to eyes with sickle cell retinopathy. Among patients’ eyes, the deep capillary vessel density in the temporal perifoveal quadrant was greater among SC patients compared to SS (p = 0.035).

The role of Perifoveal Arteriolar Tortuosity in Optical Coherence Tomography Angiography (OCTA) images as an early indicator of hypertensive retinopathy.

To assess the value of increased perifoveal retinal vascular tortuosity in optical coherence tomography angiography (OCTA) images as a biomarker of early hypertensive retinopathy and compare its clinical sensitivity and accuracy with traditional morphological changes used for Scheie classification. OCTA images of 81 eyes (40 eyes from 20 hypertensive subjects and 41 eyes from 21 control subjects) were obtained retrospectively. Hypertensive retinopathy changes in randomized eyes were graded according to the Scheie classification, and perifoveal vessels were traced in a masked fashion. Tortuosity values of the perifoveal vessels were then calculated along with interobserver agreement in determining the morphometric values. There were no differences in perifoveal venular tortuosity between the hypertensive and control groups (Mean = 1.13 ± 0.04 vs. 1.13 ± 0.03), but significant differences existed for arterioles (Mean = 1.14 ± 0.05 vs. 1.11 ± 0.04). Tortuosity measurements demonstrated a significant interobserver agreement (p < 0.001), while Scheie ratings had a poor interobserver agreement (p = 0.735). There was a significant difference in Scheie classification between the hypertensive and control groups (Mean = 1.06 ± 0.54 vs. 0.50 ± 0.43, p = 0.005). OCTA-based perifoveal retinal arteriolar tortuosity may be a potential reliable biomarker with certain advantages for detecting early hypertensive retinopathy than morphological changes used for the Scheie classification. This may have broad applications and establish important parameters in utilizing OCTA for screening protocols, considering the importance of early detection of systemic hypertension.

The Current and Novel Imaging Modalities for Ocular Vasculitis in Behcet's Disease: A Review.

Behcet's syndrome is a multisystem inflammatory disorder characterized by a chronic relapsing course and diverse clinical manifestations, prominently affecting young adults along the ancient Silk Road and beyond. The disease pathogenesis involves complex interactions between genetic predisposition, environmental triggers, and dysregulated immune responses, leading to systemic vasculitis and tissue damage. Ocular involvement, a hallmark of Behcet's Disease (BD), significantly impacts morbidity, with uveitis as a common initial presentation that can progress to severe vision-threatening complications like retinal vasculitis and occlusive disease. This review consolidates current knowledge on ocular manifestations in BD, emphasizing the pivotal role of multimodal imaging in diagnostic evaluation and management. Fundus photography serves as a baseline tool for documenting intraocular lesions and monitoring treatment responses. Fluorescein angiography remains the gold standard for detecting acute inflammatory changes and vascular leakage patterns essential for disease staging and prognostication. Recent advancements in imaging, such as ultra-wide field imaging (UWF), indocyanine green angiography (ICGA), Doppler ultrasonography, Optical Coherence Tomography (OCT), OCT angiography (OCTA), adaptive optics (AO), and retinal function imaging (RFI), provide unprecedented insights into microvascular dynamics, structural changes, and functional impairments associated with ocular BD. Integration of these advanced imaging modalities enhances early detection of subclinical disease, facilitates precise localization of inflammatory lesions, guides therapeutic interventions, and monitors treatment efficacy. OCT and OCTA, in particular, offer non-invasive, high-resolution assessments of macular edema, vascular perfusion abnormalities, and choroidal thickness alterations critical for optimizing patient care. In conclusion, multimodal imaging represents the cornerstone in the comprehensive management of ocular manifestations in Behcet's Disease, offering clinicians invaluable tools for accurate diagnosis, treatment planning, and long-term monitoring of disease progression and treatment outcomes.

Correlation between optical coherence tomography angiography measured vessel density and retinal nerve fiber layer thickness in moderate primary open angle glaucoma cases and normal controls

: Aim of this study was to establish a correlation between findings obtained from Optical Coherence Tomography Angiography (OCT-A) and Retinal Nerve Fiber Layer (RNFL) thickness measurements in a series of moderate Primary Open Angle Glaucoma (POAG) cases and normal controls. In this observational cross-sectional study a total of 100 eyes were included, comprising 50 eyes with glaucoma and 50 control eyes without glaucoma. All participants underwent comprehensive anterior and posterior segment evaluations, intraocular pressure (IOP) measurement using Goldmann applanation tonometer, gonioscopy, visual field testing, and OCT imaging, which included OCT-A. The OCT-A imaging was performed using the RTvue XR Avanti by Optovue. Two types of analysis were conducted: a comparative analysis between the normal and glaucomatous groups using an unpaired t-test to assess differences in RNFL thickness and vessel density values, and a correlation analysis within each group to examine the strength of correlation between RNFL loss and reduction in vascular density. The results showed a significant reduction in vessel density index in all quadrants of glaucomatous eyes compared to normal eyes. Moreover, this reduced vessel density was found to be significantly correlated with the reduction in RNFL thickness in glaucoma patients. Specifically, the uperior and inferior quadrants exhibited the strongest correlation with each other. The severity of vascular compromise demonstrated a significant correlation with the extent of retinal nerve fiber loss in patients with glaucoma. OCT-A can serve as a valuable adjunct in the diagnosis of glaucoma and monitoring its progression.

Investigation of optical coherence tomography angiography findings in patients with bipolar disorder

ObjectivesBipolar Disorder (BD) is an important psychiatric disease that progresses with attacks, can be chronic and causes serious mental problems. In this study, we aimed to identify the retinal vascular pathologies in BD patients by optical coherence tomography angiography (OCTA) imaging. MethodsRetinal vascular analysis from 35 BD patients and 30 healthy controls (HCs) were scanned using the OCTA machine. In addition, psychometric tests such as the Young Mania Rating Scale (YMRS) and Clinical Global Impression Scale (CGI-S) were applied to BD patients to assess the severity of the disease and determine the patient's level of functionality. ResultsAs a result of OCTA scans, there were significant differences between the groups as following; Deep retinal vessel density (VD) in the total, parafoveal and perifoveal area, Macular thickness in the inner parafoveal area, VD of retinal capillary plexuses in the inside disk and the Choroidal thickness (p < 0.05). Furthermore, according to the results of Pearson correlation analysis between OCTA scans and YMRS and CGI-S scores, it was determined that there was no significant relationship in any measurement (p > 0.05). ConclusionIn our study, it was determined that there were general differences in deep retinal vascular density and inner macular thickness in BD patients. These findings demonstrate that the deep and inner zone of the retina is affected in BD patients.

Severity Scale of Diabetic Macular Ischemia Based on the Distribution of Capillary Nonperfusion in OCT Angiography

To evaluate the severity scales of diabetic macular ischemia (DMI) by analyzing the quantity and distribution of capillary nonperfusion using OCT angiography (OCTA) images. A single-center, prospective case series. Three hundred one eyes from 301 patients with diabetic retinopathy. We acquired 3× 3-mm swept-source OCTA images and created en face images within a central 2.5-mm circle. The circle was divided into 15× 15-pixel squares and nonperfusion squares (NPSs) were defined as those without retinal vessels. Eyes with high-dimensional spatial data were arranged on a 2-dimensional space using the uniform manifold approximation and projection (UMAP) algorithm and classified by clustering into 5 groups: Initial, Mild, Superficial, Moderate, and Severe. Development of a severity scale for DMI. Eyes arranged on a 2-dimensional UMAP space were divided into 5 clusters, based on the similarity of nonperfusion area distribution. Nonperfusion square counts in the deep layer increased in eyes of the Initial, Mild, Moderate, and Severe groups in a stepwise manner. In contrast, there were no significant changes in superficial NPS counts between eyes of the Initial and Mild groups. In the intermediate stage, eyes of the Superficial group exhibited higher NPS counts in the central sector of the superficial layer compared with those of the Moderate group. The foveal avascular zone extended into the temporal subfield of the deep layer in eyes of the Moderate group. Eyes of the Severe group had significantly poorer visual acuity that was more frequently accompanied with proliferative diabetic retinopathy. The application of dimensionality reduction and clustering has facilitated the development of a novel severity scale for DMI based on the distribution of capillary nonperfusion in OCTA images. The authors have no proprietary or commercial interest in any materials discussed in this article.