Optical Coherence Tomography Angiography Research Articles

The analysis of foveal microvascular anomalies in retinopathy of prematurity after anti-vascular endothelial growth factor therapy using optical coherence tomography angiography

The analysis of foveal microvascular anomalies in retinopathy of prematurity after anti-vascular endothelial growth factor therapy using optical coherence tomography angiography

Comparative study between swept-source and spectral-domain OCTA for imaging of choroidal neovascularization in age-related macular degeneration

AIM: To compare the differences of choroidal neovascularization (CNV) measurements between swept-source and spectral-domain optical coherence tomography angiography (SS-OCTA and SD-OCTA) in neovascular age-related macular degeneration (nAMD) and the imaging reliability of the two devices. METHODS: Prospective comparative study. SS-OCTA and SD-OCTA were used to scan the same eye with the modes of 3×3 and 6×6 mm2 centered on the neovascularization. Only qualified images were chosen and the border of CNV was manually delineated by two graders independently. The area of CNV (ACNV), vascular perfusion density (PD), and vessel length density (VLD) within the delineation were calculated using Image J. The differences of CNV measurements between the two OCTA devices were compared using Bland-Altman analysis. The agreement between the two graders on the measurements of each device was compared using the intraclass correlation coefficient (ICC). RESULTS: A total of 18 patients (22 eyes) with nAMD were included. The measurements of ACNV, PD, and VLD were 7.247±4.586 and 4.901±3.741 mm2, 43.202±9.636 and 34.904±10.489, 6.339±1.228 and 5.908±1.741 mm-1 for SS-OCTA and SD-OCTA, respectively. The differences between the two devices were 2.346±3.030 mm2 (Z= -3.782, P<0.0001), 8.298±14.160 (Z=-2.419, P=0.016), and 0.431±2.114 mm-1 (Z=-0.828, P=0.408) for ACNV, PD and VLD, respectively. The ICC between two graders were 0.893 (P<0.001), 0.902 (P<0.001), 0.885 (P<0.001) for ACNV, PD, VLD in SS-OCTA, and 0.971 (P<0.001), 0.976 (P<0.001), 0.973 (P<0.001) in SD-OCTA, respectively. CONCLUSION: Both OCTA devices have high imaging reliability. Compared with SD-OCTA, SS-OCTA has a larger ACNV measurements, but doesn't show better resolution of internal vessels of CNV and well signal strength.

Association of macular microcirculation with renal function in Chinese non-diabetic patients with hypertension.

The aim of this study was to investigate the association of macular microcirculation with renal function and the feasibility of using macular microcirculatory parameters to monitor renal function in Chinese non-diabetic patients with hypertension. This case-control study included 62 non-diabetic patients with hypertension, including 31 with renal dysfunction (estimated glomerular filtration rate [eGFR] <90 mL/min/1.73 m2) and 31 with normal renal function (eGFR ≥90 mL/min/1.73 m2). Age, sex and clinic blood pressure were matched between groups. Macular microcirculatory parameters of 124 eyes of the 62 patients were evaluated by optical coherence tomography (OCT) and OCT angiography (OCTA). In comparison with the patients with normal renal function, patients with renal dysfunction had lower macular superficial parafovea vessel density (18.6 vs. 19.4%, P = 0.029), macular cube average thickness (273.0 vs. 280.2 µm, P = 0.003), and average ganglion cell layer and inner plexiform layer (GCL-IPL) thickness (79.5 vs. 82.8 µm, P = 0.006), but similar macular central fovea vessel density and central fovea thickness (P ≥ 0.54). After adjustment for confounders, eGFR was significantly associated with macular superficial parafovea vessel density, cube average thickness and GCL-IPL thickness (P < 0.02). In detecting renal dysfunction, areas under the curve were 0.61, 0.66 and 0.65 for macular superficial parafovea vessel density, cube average thickness and GCL-IPL thickness. In non-diabetic patients with hypertension, macular superficial parafovea vessel density, cube average thickness and GCL-IPL thickness were significantly worse in patients with renal dysfunction than those with normal renal function. Using macular parameters to monitor renal function is feasible.

Clinical and pathologic characteristics of inflamed juvenile conjunctival nevus and its treatment with immunosuppressant eye drops.

To clarify the clinical and pathologic findings of 7 patients with inflamed juvenile conjunctival nevus (IJCN) treated with tacrolimus. Retrospective study. The medical records of 7 male patients diagnosed with IJCN between February 2007 and October 2022 at the Kansai Medical University Hospital and Ideta Eye Hospital were retrospectively reviewed. The patients' mean age was 11.3 (8-20) years, and the average follow-up period was 18 months. The patients underwent anterior segment optical coherence tomography (AS-OCT) and anterior segment optical coherence tomography angiography (AS-OCTA). All the patients were treated with steroids or immunosuppressant eye drops, or both. Histopathologic examinations were performed on specimens resected from 2 patients. The clinical characteristics of IJCN were as follows: (1) presence of cysts within a pigmented conjunctival mass, (2) tumor accompanied by feeder vessels, and (3) predominantly found in boys with allergic diseases. AS-OCT and AS-OCTA revealed the presence of a cystic structure with poor vascular signals within it and numerous vessels distributed on the sclera underlying the lesion. Immunosuppressant eye drops relieved the congestion, diminished the inflow vessels, and induced shrinkage of the cysts in all the patients. Histopathologic examinations revealed infiltration of inflammatory cells such as lymphocytes and macrophages and low proliferative activity of melanocytes with no division pattern. This study clarified the clinical and histologic characteristics of IJCN. Noninvasive AS-OCT and AS-OCTA might be useful for diagnosing IJCN. The histopathologic findings of this study indicate that immunosuppressive and antiallergic agents can effectively bring about disease remission.

Perifoveal Exudative Vascular Anomalous Complex (PEVAC): Retinal Vascular Density Findings

Objectives: This study aimed to describe the clinical, optical coherence tomography (OCT) and OCT angiography (OCTA) findings and characteristics in patients with perifoveal exudative vascular anomalous complex (PEVAC) and compare the macular vascular density with the age-matched control group. Methods: We conducted a case–control study to compare demographic information, clinical observations, and OCT/OCTA findings in eyes with PEVAC (n = 5 eyes in 5 patients) and a control group of subjects matched for age (n = 9). The Advanced Retina Imaging (ARI) network algorithms were utilized to evaluate OCTA observations. Statistical analysis was performed by the nonparametric Mann–Whitney U test. Results: Patients with PEVAC had a mean (±SD) age at presentation of 70 ± 12.6 years, the mean follow-up period was 7.8 ± 5.2 months, and unilateral disease was observed. Four out of the five patients in our cohort had a history of systemically treated hypertension and dyslipidemia. Three eyes had lesions in the inner temporal retinal zone, while the remaining two eyes had lesions in the inner inferior or central zone. Retina slab analysis using OCTA showed no significant difference in vascular density parameters between the PEVAC and control groups. Conclusions: Although limited by a small sample size, our study suggests that macular vessel density shows no significant difference between PEVAC cases and control eyes.

Metabolic, Microvascular, and Structural Predictors of Long-Term Functional Changes Evaluated by Multifocal Electroretinogram in Type 1 Diabetes

Background: This study aimed to analyze the potential pathogenic connection between metabolic factors, photoreceptor cell rearrangements, retinal microvascular perfusion, and functional parameters through multifocal electroretinography (mfERG) in type 1 diabetes mellitus (DM1). Methods: This prospective observational cohort study enrolled DM1 patients (40.5 ± 9.1 years) with mild nonproliferative diabetic retinopathy followed for 4 years. Patients were subjected to multimodal imaging, which included color fundus photography, optical coherence tomography (OCT), OCT angiography, adaptive optics (AO), and mfERG. OCTA slabs were analyzed using ImageJ software (software version 2.3.0/1.53f) to calculate perfusion density (PD) at both superficial (SCP) and deep (DCP) capillary plexuses, as well as flow deficit percentage (FD%) at the choriocapillaris (CC). To calculate cone metrics on AO at the parafovea, including cone density (CD), linear dispersion index (LDi), and heterogeneity packing index (Hpi%) in the parafovea, the images were post-processed using a MATLAB algorithm. The mfERG P1 implicit time (IT) and N1-P1 response amplitude density (RAD) from R1 (foveal area), R2 (parafoveal area), and the unified rings R1 + R2 were evaluated. Results: A total of 22 patients (22 eyes) were enrolled. No significant differences were noted in central mfERG amplitude and implicit time-averaged values (p &gt; 0.05, all). The main factor influencing R1 IT was HbA1c, while R1 RAD was affected by Hpi and CC FD%. R1 + R2 IT was influenced by Hpi, LDi (p &gt; 0.001, all), and modifications in the perfusion density in the SCP (p &lt; 0.001) and DCP (p = 0.03) at the parafovea. In contrast, R1 + R2 RAD were associated with HbA1c (p = 0.02) and Hpi (p &lt; 0.001). Conclusions: Microvascular changes and glucometabolic factors are key elements influencing the long-term morphofunctional alterations at the photoreceptor level in DM1.

Clinical and imaging characteristics associated with foveal neovascularization in proliferative diabetic retinopathy.

To assess the prevalence of foveal neovascularization (FNV) and its associated clinical features in proliferative diabetic retinopathy (PDR) eyes. Cross-sectional observational study. Participants underwent ultra-widefield photography, optical coherence tomography (OCT), and swept-source OCT angiography (SS-OCTA). FNV was defined as a hyperreflective lesion breaching the internal limiting membrane and displaying flow signal on OCTA, within 1-mm of foveal avascular zone. Vascular metrics were obtained from the ARI Network portal. Ischemic index (ISI) and inner choroid flow deficit percentage were calculated using FIJI from 12 × 12 and 6 × 6-mm scans, respectively. Logistic regression models were used to compare eyes with and without FNV. We included 249 eyes of 164 patients (age: 58 [50-65] years). FNV was identified in 20 eyes (8%). Univariate logistic regression revealed significant associations between FNV and younger age (p = 0.03), higher maximal HbA1c (p = 0.04), worse visual acuity (VA) (p = 0.01), presence of disorganization of retinal inner layers (DRIL) (p = 0.01), no macular posterior vitreous detachment (PVD) (p = 0.03), neovascularization elsewhere (NVE) and at the disc (NVD) (p = 0.01 and p = 0.001), and greater ISI (p = 0.04). In multivariable analysis, a significant association remained between FNV and worse VA (p = 0.04), NVD (p < 0.001), DRIL (p < 0.001), and absence of macular PVD (p = 0.01). No associations were found with SS-OCTA vascular metrics. This study provides a comprehensive characterization of FNV in PDR. FNV was identified in 8% of our cohort, being more prevalent in younger patients with severe PDR, as evidenced by NVD and DRIL presence. The absence of macular PVD may explain its association with younger age. What is known • Neovascularization at the fovea occurs rarely in proliferative diabetic retinopathy. • OCT and OCT-angiography can be used to evaluate foveal neovascularization, which may be associated with choroidal vascular abnormalities. What is new • Foveal neovascularization was seen in 8% of eyes with proliferative diabetic retinopathy in this cohort. • Risk factors for foveal neovascularization included younger age, absence of macular posterior vitreous detachment, presence of neovascularization of the disc, and presence of disorganization of retinal inner layers. • We did not identify an association between foveal neovascularization and choroidal perfusion abnormalities in this study.

Clinical and Structural Parameters in Autosomal Dominant Optic Atrophy Patients: A Cross-Sectional Study Using Optical Coherence Tomography

Background: Autosomal Dominant Optic Atrophy (ADOA) is a hereditary optic neuropathy characterized by retinal ganglion cell degeneration and optic nerve fiber loss. This study examined the correlation between clinical and structural parameters in patients with ADOA using optical coherence tomography (OCT) and explored potential clinical biomarkers. Methods: A cross-sectional, case–control observational study included 27 patients with ADOA and 27 age- and sex-matched healthy controls. Clinical examinations, OCT imaging, and OCT angiography (OCTA) were performed. Statistical analyses were conducted to establish correlations between clinical and OCT parameters. Results: Patients with ADOA exhibited gradual bilateral vision loss, central scotomas, and optic disc pallor. Structural OCT analysis revealed significant reductions in central macular thickness, macular volume, ganglion cell complex (GCC), and peripapillary retinal nerve fiber layer compared with controls. Correlation analysis demonstrated associations between worsening clinical parameters (best corrected visual acuity, Sloan Letters Low Contrast Chart 25%, Pseudoisochromatic Test) and increased OCT damage (structural and OCTA). GCC emerged, at least at exploratory terms, as the most important clinical biomarker in patients with ADOA given its multiple positive functional associations, while OCTA parameters correlated with visual field defects. Conclusions: Our study revealed significant correlations between clinical and structural parameters in patients with ADOA, highlighting the importance of OCT in assessing disease severity. GCC measurement shows promise as a clinical biomarker, aiding in disease monitoring. OCTA parameters offer potential early biomarkers for vascular changes. These findings contribute to understanding ADOA pathophysiology and may improve patient diagnosis and management. Further research is warranted to validate these findings and explore potential therapeutic interventions.

Case Report: Periocular Steroid Injection Combined Vemurafenib Therapy in the Long-term Management of Orbital Involvement of Erdheim-Chester Disease.

Abstract Purpose: To report a rare case of vision loss from Erdheim-Chester Disease (ECD) and long term, follow up, management and results. Case Report: A 62-year-old woman presented with bilateral exophthalmos and deterioration in visual acuity of both eyes. Magnetic resonance imaging studies revealed bilateral intraconal orbital tumors. She was diagnosed optic neuropathy in both eyes. The patient was treated with pegylated interferon and systemic pulse steroid. However, recurrences were common. Subsequently, the patient underwent regular corticosteroid injection directly into the retro-orbital region of both eyes monthly, which led to intermittent improvement of vision. At the 8th month of visual impairment, Vemurafenib was initiated. Results: The visual acuity and visual field scores were stable for 6 years during the follow-up. No major complication was observed. Conclusion: Combined vemurafenib and perioculer steroid injection is a well tolerated therapy with less systemic adverse effects which may benefit patients with orbital involvement of ECD. Key words: Erdheim–Chester disease; compressive optic neuropathy; vemurafenib; Optical coherence tomography; Optical coherence tomography angiography.

A clinical study on the therapeutic effects of 577nm micropulse laser photocoagulation treatment in early-stage CSCR patients.

To research the therapeutic effects of 577nm micropulse laser photocoagulation (MLP) treatment in early-stage central serous chorioretinopathy (CSCR) patients. Twenty-two CSCR patients with 24 CSCR eyes were examined prior to MLP treatment. The examinations included best-corrected visual acuity (BCVA), fluorescein fundus angiography (FFA), indocyanine green angiography (ICGA), optical coherence tomography (OCT), optical coherence tomography angiography (OCTA) and microperimetry. After MLP treatment, all the subjects were reviewed at 30 days. The BCVA, macular function on microperimetry, subretinal fluid (SRF) height of the macula on OCT, and choroid vascular density (VD) of the macular area on OCTA were compared before and after MLP treatment. The correlations between SRF height and visual function, choroid VD was analyzed separately. BCVA and macular function significantly increased and the SRF height of the macula significantly decreased after MLP treatment. BCVA and macular function were significantly negatively correlated with SRF height. The choroid VD was significantly increased after MLP treatment, and choroid VD in the leakage site part of the macula were significantly negatively correlated with the height of the SRF. A recurrent patient who received two MLP treatments also had a negative correlation between SRF and choroid VD during the course of disease. 577nm MLP is safe and effective for early-stage CSCR patients, and treatment can restore macular structure and function. The increase in choroid VD of leakage site part after treatment is one of the key effects of MLP treatment for early-stage CSCR patients.

Abstract 4139162: Optical coherence tomography measures mechanical contractile properties of the beating murine heart

Introduction: Optical imaging techniques can characterize properties of tissue at high temporal and spatial resolution, offering unique insights into electrically excitable tissues such as nerve and muscle. We hypothesized that the gated high-speed optical coherence tomography (OCT) could profile the contractile properties of mouse myocardial tissue and facilitate investigations of microscale mechanical function in the beating heart. Methods: C57BL/6 male mice (n=6) underwent a sternotomy while anesthetized and ventilated and were imaged at baseline with OCT. Another cohort of C57BL/6 male mice (n=6) were sacrificed and the hearts were ex vivo perfused with crystalloid using a Langendorff system. These hearts were imaged at baseline and after inhibition of contractile function with blebbistatin. OCT was performed using a custom tissue stabilizer and a Thorlabs TEL 321 OCT system, which was synchronized to physiologic signals using custom hardware and software and cardiac pacing protocols (Fig. 1A and 1B). OCT cross-sectional B-scan images (Fig. 1C) were obtained throughout multiple cardiac cycles in both in vivo and ex vivo preparations. Data were processed in MATLAB and ImageJ using the workflow in Fig. 1D. Results: Highly reproducible cross-sectional mean intensity changes were observed over the contractile cycle in vivo and ex vivo (Fig. 1E, left and middle). With mechanical contraction inhibited by blebbistatin, this cyclical intensity extinguished, linking the optical scattering change measured by OCT to myocardial contraction (Fig. 1E, right). B-scan curves averaged over multiple mice and temporally aligned with the ECG waveform (Fig. 1F) demonstrate a signal intensity waveform that reproducibly varies with the contractile cycle for both in vivo and ex vivo preparations. In vivo and ex vivo baseline waveforms both had peak intensity during systole and minimum in end-diastole (Fig. 1F). Reproducibility in ex vivo beating heart preparations without blood perfusion provides evidence that myocardial mechanical properties, not red blood cell flow, generate the intensity changes. Conclusion: Gated high-speed OCT imaging can quantify the mechanical contraction wave in the myocardium. Combined with gated OCT angiography, OCT techniques will provide high resolution imaging of both blood flow and mechanical contractility of the beating heart in small animal models of heart disease.

SFNet: Spatial and Frequency Domain Networks for Wide-Field OCT Angiography Retinal Vessel Segmentation.

Automatic segmentation of blood vessels in fundus images is important to assist ophthalmologists in diagnosis. However, automatic segmentation for Optical Coherence Tomography Angiography (OCTA) blood vessels has not been fully investigated due to various difficulties, such as vessel complexity. In addition, there are only a few publicly available OCTA image data sets for training and validating segmentation algorithms. To address these issues, we constructed a wild-field retinal OCTA segmentation data set, the Retinal Vessels Images in OCTA (REVIO) dataset. Second, we propose a new retinal vessel segmentation network based on spatial and frequency domain networks (SFNet). The proposed model are tested on three benchmark data sets including REVIO, ROSE and OCTA-500. The experimental results show superior performance on segmentation tasks compared to the representative methods.

Are optic nerve head and choroidal circulation affected by eye movements?

Although it has been reported that the optic nerve can be mechanically affected by the eye's horizontal movements, studies examining horizontal movements with optical coherence tomography angiography (OCTA) have only recently begun to emerge. This study aimed to investigate whether there are changes in the OCTA data of healthy individuals in the primary gaze, abduction, and adduction. Thirty volunteers (15-73 years old) were included in this prospectively designed study. Radial peripapillary capillary density parameters (RPCD) taken with OCTA in cases of primary gaze, abduction, and adduction were examined. With the OCTA device Angio Disc QuickVue that was used in the study, 3 main vessel structures could be examined. In the patients' primary, abduction, and adduction positions, a difference was observed only in the superior hemifield area of the left eye (P = 0.032). The superior hemifield all vessels vessel densities (AV VD) were 60.1 ± 2.7 in the central gaze, 59.9 ± 2.6 in the adduction, and 60.8 ± 2.6 in the abduction positions, with a relative decrease observed in adduction. This was also related to age. No difference was detected in terms of the other RPCD parameters. In healthy individuals, short-term horizontal eye movements may not result in significant changes except for superior hemifield in OCTA data.

Retinal Microvascular Changes in Association with Endothelial Glycocalyx Damage and Arterial Stiffness in Patients with Retinal Vein Occlusion: A Cross-Sectional Study

Background/Objectives: To investigate the potential association between the endothelial dysfunction and arterial stiffness with retinal changes observed through optical coherence tomography (OCT) and OCT-angiography (OCT-A) in patients with retinal vein occlusion (RVO). Methods: Participants in this cross-sectional study were 28 patients with RVO. The demographic and clinical characteristics of all participants were recorded. Comprehensive ophthalmologic examinations were performed, including fundus photography, OCT and OCT-A. Endothelial dysfunction was assessed by measuring the endothelial glycocalyx thickness via the perfused boundary region (PBR5-25). Arterial stiffness was evaluated by measuring the carotid-femoral pulse wave velocity (PWV), the central systolic and diastolic blood pressures (cSBP and cDBP) and the augmentation index (Aix). For each ophthalmological outcome, we generated a saturated linear regression model with demographic and systemic vascular parameters serving as independent variables. Regression coefficients with the corresponding 95% confidence intervals (CIs) were reported. A p value &lt; 0.05 was considered as statistically significant. Results: A 1 m/s increase in PWV was associated with a 0.6% reduction in inferior macular vessel density (VD) (p = 0.050). A 10 mmHg increase in cSBP was associated with a 0.03 mm2 increase in foveal avascular zone (FAZ) area (p = 0.033). A 1% increase in Aix was associated with a 0.005 mm2 increase in FAZ area (p = 0.008). A 1 μm increase in PBR5-25 was associated, on average, with a 4.4% decrease in superior peripapillary VD (p = 0.027). Conclusions: In patients with RVO, structural and microvascular retinal parameters were significantly associated with markers of endothelial dysfunction and arterial stiffness.

Angioarchitectural alterations in the retina and choroid in frontotemporal dementia.

Frontotemporal dementia (FTD) is a progressive neurodegenerative disorder that affects the frontal and temporal lobes of the brain, leading to cognitive decline and personality changes. The objective of this cross-sectional study was to characterize angioarchitectural changes in the retina and choroid of individuals with FTD compared to cognitively normal controls using optical coherence tomography (OCT) and OCT angiography (OCTA). Cross-sectional comparison of patients with FTD and controls with normal cognition. All participants underwent Mini-Mental State Examination (MMSE) at the time of imaging. Outcome measures included OCT parameters: retinal nerve fiber layer (RNFL) thickness, ganglion cell layer-inner plexiform layer (GC-IPL) thickness, central subfield thickness (CST), subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI); and OCTA superficial capillary plexus parameters: foveal avascular zone (FAZ) area, 3x3mm and 6x6mm macular perfusion density (PD) and vessel density (VD), 4.5x4.5mm peripapillary capillary perfusion density (CPD) and capillary flux index (CFI). Generalized estimating equation analysis was used to account for the inclusion of 2 eyes from the same participant. 29 eyes of 19 patients with FTD and 85 eyes of 48 controls were analyzed. In FTD, 3x3mm macular PD (p = 0.02) and VD (p = 0.02) and CFI (p = 0.01) were reduced compared to controls. There was no difference in average 4.5x4.5mm CPD, RNFL thickness, GC-IPL thickness, CST, SFCT, CVI, FAZ, or 6x6mm VD or PD between FTD and controls (all p > 0.05); however, there was a trend toward lower macular 6x6mm PD and VD in patients with FTD. Decline of peripapillary and macular OCT and OCTA parameters merit further investigation as potential biomarkers for FTD detection. Noninvasive retinal and choroidal imaging may hold promise for earlier detection, and future longitudinal studies will clarify their role in monitoring of FTD.

Impairment of Neurovascular Function in Intermediate Age-Related Macular Degeneration.

To investigate neurovascular function in eyes with age-related macular degeneration (AMD). Subjects with bilateral large drusen (intermediate AMD) and healthy controls ≥50years old were recruited. The vasculature within the central 6 × 6-mm retinal area was captured using optical coherence tomography angiography (OCTA) and segmented to return superficial plexus, deep plexus, choriocapillaris, and choroid. OCTA scans were acquired without flicker light stimulation (conventional OCTA) and during flicker light stimulation to increase retinal activity and metabolic demand (functional OCTA). Vascular area density (VAD) and the vascular reactivity index (VRI; change in VAD induced by flicker stimulation) were determined and compared between control and AMD eyes. Thirty-five subjects (19 AMD cases and 16 healthy controls) participated in the study. In healthy eyes, flicker stimulation induced an increase in VAD (positive VRI, vasodilation) in the superficial plexus (P < 0.001) and deep plexus (P < 0.001). There was a trend for increased VAD in the choriocapillaris (P = 0.077), but there was no change in the choroid (P = 0.654). In AMD eyes, there was no change in VAD in response to flicker stimulation in any of the vascular layers examined (P ≥ 0.294). Linear mixed models confirmed that AMD was associated with a reduced VRI in the superficial plexus (P < 0.001) and deep plexus (P < 0.001). Eyes with large drusen show a reduction in retinal vascular reactivity compared to healthy eyes, which suggests that there is impairment of retinal neurovascular function in intermediate AMD. Functional OCTA could be used to study neurovascular function in retinal diseases.

Cross-instrument optical coherence tomography-angiography (OCTA)-based prediction of age-related macular degeneration (AMD) disease activity using artificial intelligence

This study investigates the efficacy of predicting age-related macular degeneration (AMD) activity through deep neural networks (DNN) using a cross-instrument training dataset composed of Optical coherence tomography-angiography (OCTA) images from two different manufacturers. A retrospective cross-sectional study analyzed 2D vascular en-face OCTA images from Heidelberg Spectralis (1478 samples: 1102 training, 276 validation, 100 testing) and Optovue Solix (1003 samples: 754 training, 189 validation, 60 testing). OCTA scans were labeled based on clinical diagnoses and adjacent B-scan OCT fluid information, categorizing activity into normal, dry AMD, active wet AMD, and wet AMD in remission. Experiments explored cross-instrument disease classification using separate and combined datasets for training the DNN. Testing involved 100 Heidelberg and 60 Optovue samples. Training on Heidelberg data alone yielded 73% accuracy on Heidelberg images and 60% on Optovue images. Training on Optovue data alone resulted in 34% accuracy on Heidelberg and 85% on Optovue images. Combined training data from both instruments achieved 78% accuracy on Heidelberg and 76% on Optovue test sets. Results indicate that cross-instrument classifier training demonstrates high classification prediction accuracy, making cross-instrument training viable for future clinical applications. This implies that vascular morphology in OCTA can predict disease progression.

Effect of reduced saturation and elevated D-dimer and interleukin 6 levels on vessel density and foveal avascular zone in patients with COVID-19 bilateral pneumonia.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can affect multiple organs, including the eyes. This study aimed to identify associations between vascular density (VD) and the foveal avascular zone (FAZ), assessed using optical coherence tomography angiography (OCTA), and baseline levels of D-dimers and interleukin 6 (IL-6) in patients with bilateral COVID-19 pneumonia, depending on oxygen saturation (SpO2) on admission. The study included patients with COVID-19 bilateral pneumonia due to SARS-CoV-2 infection who were hospitalized between March and May 2021. Ophthalmological examination was performed 2 months after hospitalization. Optical coherence tomography angiography was used for the automatic assessment of the central retinal VD and the manual assessment of FAZ. A significant monotonic negative relationship was observed between SpO2 . 90% and VD in some areas of the superficial capillary plexus (SCP) (p = 0.048) and choriocapillaris (p = 0.021), and the mean VD in the deep capillary plexus (DCP) (p = 0.048). No significant monotonic negative relationship was noted between SpO2 . 90% and the FAZ in the SCP (p = 0.075). However, there was a significant monotonic positive relationship between VD in the nasal choriocapillaris and D-dimer levels in patients with SpO2 . 90% (p = 0.003, respectively). Finally, a monotonic negative relationship was identified between foveal VD in the DCP and IL-6 levels in patients with SpO2 . 90% (p = 0.027). An OCTA study conducted 2 months after hospitalization for COVID-19 bilateral pneumonia showed reduced VD in those with SpO2 . 90% and elevated levels of D-dimers and IL-6 during hospitalization. Optical coherence tomography angiography testing can provide monitoring of ocular status in patients following SARS-CoV-2 infection, especially those who report visual disturbances.

Retinal vasculature changes in patients with internal carotid artery stenosis.

To evaluate the retinal vasculature in patient with internal carotid artery (ICA) stenosis and to highlight association between ICA stenosis severity and retinal vasculature changes. Seventy-five subjects were included in this prospective study. Twenty-five healthy subjects were included in the Group 1, 25 subjects with 1-49% ICA stenosis were included in the Group 2, and 25 subjects with 50-69% ICA stenosis were included in the Group 3. Visual acuity, intraocular pressure (IOP), and anterior and posterior segment examinations were performed. Macular superficial and deep capillary density, optic nerve head capillary density, and choroidal thickness data were measured using optic coherence tomography angiography. There was a statistically significant difference between the three groups regarding superficial vascular density, deep vascular density, vascular density of radial peripapillary capillary and choroid thickness (p < 0.05 for all). Mean parafoveal and perifoveal area vascular density of the superficial capillary plexus was significantly lower in the Group 3 than Group 1 (p < 0.05 for all). Mean whole area vascular density of the deep capillary plexus was significantly lower in Group 3 than both groups (p < 0.05 for all). Mean parafoveal area vascular density of the deep capillary plexus was significantly lower in the Group 3 than Group 1 (p < 0.05). Mean subfoveal choroid thickness in group 3 was significantly lower in the Group 3 than both groups (p < 0.05 for all). Compared to healthy controls, patients with moderate ICA stenosis revealed decreased density of superficial, deep and radial peripapillary capillary vasculature and subfoveal choroidal thickness.

Evaluation of Retinal and Posterior Segment Vascular Changes Due to Systemic Hypoxia Using Optical Coherence Tomography Angiography

Evaluation of Retinal and Posterior Segment Vascular Changes Due to Systemic Hypoxia Using Optical Coherence Tomography Angiography