Intermediate Capillary Plexus Research Articles

Investigating the Impact of Bariatric Surgery on Macular and Peripapillary Vessel Density in Obese Individuals without Metabolic Disease.

It is well established that microvascular structures are affected in obese people with metabolic disease. We aimed to evaluate the effect on microvascular structures by examining macular and peripapillary vessel density with optical coherence tomography angiography after bariatric surgery in obese individuals without metabolic disease. This prospective study included 96 eyes of 48 obese patients. Body mass index (BMI), macular vessel density in the superficial, intermediate, and deep capillary plexus, and peripapillary vessel density were measured before and 6 months after bariatric surgery. BMI decreased significantly to 43.75 ± 4.4 kg/m2 postoperatively compared to 55.31 ± 5.1 kg/m2 preoperatively (p < 0.05). A significant increase was observed in macular vessel density in the deep capillary plexus postoperatively (p < 0.01). However, no significant postoperative increase occurred in macular vascular density in the superficial and intermediate capillary plexus (p > 0.05). Moreover, there was no change in peripapillary vascular density (p > 0.05). Postoperative thickening of the foveal, parafoveal, and perifoveal retinal layers was significant (p < 0.001). No significant correlation was detected between BMI change and macular and peripapillary vessel density changes (p > 0.05). An increase in macular vascular density, particularly in the deep capillary plexus, and retinal layer thickness has been observed following bariatric surgery performed on obese individuals without metabolic disease. This increase may indicate that microvascular structures are affected even in the absence of metabolic disease and that microperfusion improves with surgery.

An OCT-A Analysis of the Importance of Intermediate Capillary Plexus in Diabetic Retinopathy: A Brief Review.

Optical coherence tomography-angiography is a technique that allows us to non-invasively study in vivo the different retinal vascular networks. This allows a deeper understanding of retinal capillary anatomy and function, in addition to the pathophysiologic changes encountered in diverse diseases. The four retinal capillary layers have different anatomies and functions, implying distinct adaptation and roles in the course of the diseases. Diabetic retinopathy is the leading cause of blindness in working-age adults. Several studies have evaluated how each retinal capillary layer is specifically affected according to the stage of the disease. Unfortunately, too few studies have considered the intermediate capillary plexus as a separate layer, as it has often been incorporated in another layer. In this review, we shed light on the potential role the intermediate capillary plexus plays in the physiopathology of diabetic retinal disease as well as its potential use in grading diabetic retinopathy and its clinical added value in estimating the disease prognosis.

RETINAL MICROVASCULOPATHY WITH DIFFERENT INSULIN INFUSION THERAPIES IN CHILDREN WITH TYPE 1 DIABETES MELLITUS WITHOUT CLINICAL DIABETIC RETINOPATHY.

To explore the characteristics and associated factors of retinal microvasculopathy and neurodegeneration with different insulin therapies in children with type 1 diabetes mellitus (T1DM) but without diabetic retinopathy. Forty-one children with T1DM with multiple daily insulin injections (MDI), 22 children with T1DM with continuous subcutaneous insulin infusion, and 62 age-matched normal control children were enrolled. SPECTRALIS Optical coherence tomography was used to scan 6×6 mm square area of posterior retina. The vessel density of superficial vascular plexus, intermediate capillary plexus, and deep capillary plexus in T1DM-MDI group were all significantly lower than those in the T1DM-CSII and control groups (0.39 ± 0.05 vs. 0.44 ± 0.04 and 0.42 ± 0.06, P < 0.001; 0.26 ± 0.04 vs. 0.30 ± 0.02 and 0.28 ± 0.04, P = 0.003; 0.30 ± 0.04 vs. 0.33 ± 0.04 and 0.32 ± 0.04, P = 0.027). In T1DM-MDI group, lower vessel density of superficial vascular plexus was associated with higher hemoglobin A1c (r = -0.377, P = 0.015). Foveal avascular zone morphology index in T1DM-MDI and T1DM-CSII groups were smaller than that in the control group (0.63 ± 0.11 and 0.63 ± 0.12 vs. 0.69 ± 0.15, P = 0.040). There was no statistically significant difference in the thickness of the retina among the three groups ( P > 0.05). The vessel density of posterior retina was lower in children with T1DM with MDI than in healthy control children and associated with higher hemoglobin A1c. There was a significant difference on vessel density betweenT1DM-MDI and T1DM-CSII, with the similar hemoglobin A1c. This study suggested that optical coherence tomography angiography could be beneficial for the detection of retinal abnormalities in children with early T1DM, and continuous subcutaneous insulin infusion may be a better choice than MDI for children with T1DM to prevent the retinal complication.

Potential ocular indicators to distinguish posterior cortical atrophy and typical Alzheimer’s disease: a cross-section study using optical coherence tomography angiography

BackgroundPosterior cortical atrophy (PCA) is a form of dementia that frequently displays significant visual dysfunction and relatively preserved cognitive and executive functions, thus hindering early diagnosis and treatment. This study aimed to investigate possible fundus markers in PCA patients and compare them with those of typical Alzheimer’s disease (AD) patients to seek potential diagnostic patterns.MethodsAge-matched PCA and AD patients and healthy controls (HC) completed optometry, intraocular pressure measurement, neuropsychologic assessments, optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA) examination in one visit. Overall, six outcomes of thicknesses of various retinal layers and seven outcomes of the retinal microvascular network were calculated. After adjusting for age, sex, and years of education, the OCT and OCTA results were analyzed using analysis of covariance and generalized linear models. Correlation analyses were performed using Spearman correlation, and ROC curves were plotted.ResultsTwelve PCA patients, nineteen AD patients, and thirty HC, aged 45–80 years were included. Fifty HC, thirty AD, and twenty PCA eyes were available for foveal avascular zone (FAZ) area analysis; forty-nine HC, thirty-four AD, and eighteen PCA eyes were available for OCT and OCTA assessments. PCA patients had thinner retinal nerve fiber layer and ganglion cell layer + inner plexiform layer than HC in the 0–3 mm circle and 1–3 mm ring. Few structural differences were observed between the AD group and the other two groups. The flow area of the superficial capillary plexus and the intermediate capillary plexus was smaller in the PCA group than in the HC group in the 0–1 mm circle, 0–3 mm circle. MMSE performed better than any combination of optical parameters in identifying AD and PCA from HC (AUC = 1), while the combination of MoCA, retinal thickness and vascular density of ICP in the 1-3 mm ring, with flow area of ICP in the 0-1 mm circle showed the strongest ability to distinguish PCA from AD (AUC = 0.944).ConclusionsPCA patients exhibited similar impairment patterns to AD patients in the fundus structure and microvascular network. OCTA may aid in the non-invasive detection of AD and PCA, but still remains to be substantiated.

Optical coherence tomography angiography suggests choriocapillaris perfusion deficit as etiology of acute macular neuroretinopathy.

Acute macular neuroretinopathy (AMN) can cause sudden-onset and permanent scotoma in healthy young patients. Analysis of optical coherence tomography (OCT) and OCT angiography (OCTA) of AMN patients may provide insights into disease mechanism. We conducted a retrospective study of consecutive SARS-Cov-2-related AMN patients that presented in our clinic between Jan 1st, 2022, and April 30th, 2023, within 30days of symptom onset. Retinal vessel area density (VAD) of AMN lesions in OCTA was quantified and compared to an adjacent tissue control (ATC). This quantification was performed for the superficial vascular plexus (SVP), the intermediate capillary plexus (ICP), the deep capillary plexus (DCP), the choriocapillaris (CC), and choroid. Furthermore, en face OCT images were analyzed. Nine AMN patients were identified, 6 of these (4 female, 2 male, average age 25years) fulfilled the inclusion criteria and were included into this study. Average time from symptom onset to OCTA was 14.3days. No VAD differences between AMN and adjacent tissue were found in either retinal layer (SVP, ICP, DCP). In contrast, VAD in CC was reduced by 27% against the ATC (p = 0.007) and choroidal VAD was reduced by 41% (p = 0.017). Further analysis of en face OCT could show that the pathognomonic infrared hyporeflectivity in AMN is caused by photoreceptor alterations rather than changes in the inner retinal layers. Our data suggests that a perfusion deficit in the choroidal layers is responsible for AMN rather than in the DCP, which is the predominant hypothesis in current literature.

Retinal vascular density as a potential biomarker of diabetic cerebral small vessel disease.

The retina and brain share similar anatomical and physiological features. Thus, retinal imaging by optical coherence tomography angiography (OCTA) might be a potential tool for the early diagnosis of diabetic cerebral small vessel disease (CSVD). In this study, we aimed to evaluate retinal vascular density (VD) in diabetic CSVD by OCTA imaging and explore the associations between retinal VD and cerebral magnetic resonance imaging (MRI) markers and cognitive function. In total, 131 patients were enrolled, including CSVD (n = 43) and non-CSVD groups (n = 88). The VD and foveal avascular zone of the retinal capillary plexus were measured with OCTA. A brain MRI was performed. MRI imaging showed that in the diabetic CSVD group, white matter hyperintensities (WMHs), particularly deep WMHs (58.82%), are the most common MRI marker, followed by cerebral microbleeds in the subtentorial and cortical areas (34.78%). The CSVD group showed increases in the prevalence of cognitive dysfunction (p = .034) and depression (p = .033) and decreases in visuospatial/executive ability and delayed recall ability. In the CSVD group, VDs of the macular superficial vascular plexus (32.93 ± 7.15% vs. 36.97 ± 6.59%, p = .002), intermediate capillary plexus (20.87 ± 4.30% vs. 23.08 ± 4.30%, p = .005) and deep capillary plexus (23.54 ± 5.00% vs. 26.05 ± 4.20%, p = .003) were lower than those of the non-CSVD group. Multiple linear regression analysis showed that VD of the macular superficial vascular plexus was independently associated with cerebral microbleeds. Meanwhile, VD of the macular intermediate capillary plexus was associated with white matter lacunar infarcts after adjustment. Diabetic CSVDs are characterized by MRI markers, including deep WMHs and cerebral microbleeds, and showed impaired cognition with decreased visuospatial/executive ability and delayed recall ability. OCTA imaging revealed a significant decrease in retinal microvascular perfusion in diabetic CSVD, which was related to MRI markers and cognitive function. OCTA might be a valuable potential measurement for the early diagnosis of CSVD.

Clinical Features Related to OCT Angiography Artifacts in Patients with Diabetic Macular Edema

To investigate the frequency and type of artifacts on OCT angiography (OCTA) images and the relationship with clinical features in eyes with diabetic macular edema (DME). Retrospective, cross-sectional comparative study. One hundred ninety-two eyes of 140 patients with DME were included. Medical records, OCT and OCTA images (Spectralis), and ultrawidefield color fundus photographs (Optos plc) were evaluated. The frequency of artifact types (segmentation, motion, projection artifact, and low signal) was determined. The relationships between artifact types and clinical features such as best-corrected visual acuity (BCVA), mean central retinal thickness (CRT), foveal avascular zone (FAZ) area, perimeter, circularity index, perfusion density (PD), vessel density (VD), fractal dimension (FD) in the superficial capillary plexus, intermediate capillary plexus (ICP), and deep capillary plexus (DCP), flow voids (FVs) in the choriocapillaris, presence of hard exudate (HE), and cataract were determined. The mean age was 71.6 ± 11.4 years, and 86 (61.4%) out of 140 were men. Artifacts were present in 63 (32.8%) of 192 eyes. Twenty-nine (15.1%) eyes had segmentation artifacts, 12 (6.3%) had motion artifacts, 11 (5.7%) had projection artifacts, and 18 (9.4%) had low signal. Best-corrected visual acuity, PD, VD, and FD in ICP and DCP were significantly lower; and CRT, FAZ area and perimeter in ICP and DCP, and presence of cystoid macular edema, HE, and cataract were higher in eyes with artifacts versus eyes without artifacts (P < 0.05 for each). Multivariate linear regression analysis showed a significant association between segmentation artifacts and decreased BCVA (odds ratio [OR],5.277; P= 0.02), increased CRT (OR, 1.015; P < 0.001), increased area of FAZ in DCP (OR, 6.625; P= 0.02), and increased perimeter of FAZ in DCP (OR, 1.775; P < 0.04); there was also a significant association between projection artifacts and presence of HE (OR, 2.017; P= 0.02) and between motion artifacts and presence of cataract (OR, 4.102; P= 0.01). OCT angiography artifacts were present in one third of DME eyes, with segmentation artifacts being the most frequent type. Determining OCTA artifacts is crucial to ensure accurate clinical evaluation. These data could help in developing more standardized clinical protocols for image acquisition and interpretation used in clinical practice and research. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

The neurovascular retinal involvement in a large population of patients recovered from COVID-19: an OCT and OCT angiography study.

This study aimed to assess the neuronal and microvascular retinal and choroidal involvement in COVID-19 recovered patients using optical coherence tomography (OCT) and OCT angiography (OCTA). This observational cross-sectional study recruited patients recovered from COVID-19 and a group of healthy controls for comparisons. OCT (peripapillary scan and macular map) and OCTA (macular map) were performed to obtain: the central subfield thickness (CST), the macular volume (MV), the peripapillary retinal nerve fibre layer (pRNFL) thickness, the vessel area density (VAD), vessel length fraction (VLF), vessel diameter index (VDI) and fractal dimension (FD) of the superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP), and the vessel density (VD), stromal density (SD) and vascular/stromal (V/S) ratio of the choriocapillaris (CC) and choroid (Ch). Data regarding disease severity, administered therapy and prior comorbidities were collected. We recruited 676 eyes from 338 patients and 98 eyes from 49 healthy controls. VAD of all the three retinal plexuses, VLF and VDI of ICP and DCP and VD of CC were significantly reduced in patients versus controls. No differences were found in CST, MV and pRNFL. A multivariate analysis showed that oxygen therapy, previous cardio/cerebrovascular events and hypertension negatively influenced vascular parameters. A microvascular retinal and choriocapillaris damage may be identified secondary to SARS-CoV-2 infection, even after recovery. OCTA may represent a reproducible and non-invasive tool to assess microangiopathy in these patients, with particular regard to those with previous cardio/cerebrovascular events, hypertension and those who received oxygen therapy.

Quantitative Analysis of the Vasculature and Cone Photoreceptors in Subjects With Diabetes Without Diabetic Retinopathy

Purpose To characterize any differences in the vasculature and cone photoreceptor packing geometry (CPG) between subjects with diabetes without/no diabetic retinopathy (NDR) and healthy controls. Methods Eight NDR and five controls were enrolled. Optical coherence tomography angiography (OCTA) taken at the macula was used to measure vessel density, vessel length density, and vessel density index (VDI) in three vascular plexuses, namely, the superficial vascular plexus, intermediate capillary plexus, and deep capillary plexus (DCP). The choriocapillaris (CC) flow deficit (FD) was also measured. OCTA images were binarized and processed to extrapolate the parafovea and parafoveal quadrants and the OCTA indices mentioned above. The CC was processed with six different radii to quantify FD. Adaptive optics - scanning laser ophthalmoscopy images were acquired and processed to extract CPG indices, i.e., cone density (CD), cone-to-cone spacing (CS), linear dispersion index, heterogeneity packing index and percent of cells with six neighbors at 3.6° in the temporal retina. Results In all eyes, statistically significant differences were found (i) in parafoveal FD across the six radii (p < 0.001) and (ii) in the correlation between the parafoveal temporal quadrant (PTQ) DCP VDI and CS (r = 0.606, p = 0.048). No other significant correlations were found. For OCTA or CPG indices, no significant differences were found between the cohorts in the parafovea or parafoveal quadrants. Conclusions CS is the most sensitive CPG index for detecting alterations in the cone mosaic. The DCP and the cone photoreceptors are significantly correlated, indicating that alterations in the DCP can affect the cones. Future work elucidating the vascular alterations and neurodegeneration present in diabetic eyes should focus on the DCP and multiple CPG indices, not solely CD. Moreover, such alterations are highly localized, hence using larger regions e.g. parafovea versus smaller areas, such as the PTQ, will potentially mask significant correlations.

The Association of Retinal Microvasculature With Gray Matter Changes and Structural Covariance Network: A Voxel-Based Morphometry Study.

Increasing evidence suggests that retinal microvasculature may reflect global cerebral atrophy. However, little is known about the relation of retinal microvasculature with specific brain regions and brain networks. Therefore, we aimed to unravel the association of retinal microvasculature with gray matter changes and structural covariance network using a voxel-based morphometry (VBM) analysis. One hundred and forty-four volunteers without previously known neurological diseases were recruited from West China Hospital, Sichuan University between April 1, 2021, and December 31, 2021. Retinal microvasculature of superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP) were measured by optical coherence tomography angiography using an automatic segmentation. The VBM and structural covariance network analyses were applied to process brain magnetic resonance imaging (MRI) images. The associations of retinal microvasculature with voxel-wise gray matter volumes and structural covariance network were assessed by linear regression models. In the study, 137 participants (mean age = 59.72 years, 37.2% men) were included for the final analysis. Reduced perfusion in SVP was significantly associated with reduced voxel-wise gray matter volumes of the brain regions including the insula, putamen, occipital, frontal, and temporal lobes, all of which were located in the anterior part of the brain supplied by internal carotid artery, except the occipital lobe. In addition, these regions were also involved in visual processing and cognitive impairment (such as left inferior occipital gyrus, left lingual gyrus, and right parahippocampal gyrus). In regard to the structural covariance, the perfusions in SVP were positively related to the structural covariance of the left lingual gyrus seed with the left middle occipital gyrus, the right middle occipital gyrus, and the left middle frontal gyrus. Poor perfusion in SVP was correlated with reduced voxel-wise gray matter volumes and structural covariance networks in regions related to visual processing and cognitive impairment. It suggests that retinal microvasculature may offer a window to identify aging related cerebral alterations.

Non-Invasive Evaluation of Retinal Vascular Alterations in a Mouse Model of Optic Neuritis Using Laser Speckle Flowgraphy and Optical Coherence Tomography Angiography.

Optic neuritis, a characteristic feature of multiple sclerosis (MS), involves the inflammation of the optic nerve and the degeneration of retinal ganglion cells (RGCs). Although previous studies suggest that retinal blood flow alterations occur during optic neuritis, the precise location, the degree of impairment, and the underlying mechanisms remain unclear. In this study, we utilized two emerging non-invasive imaging techniques, laser speckle flowgraphy (LSFG) and optical coherence tomography angiography (OCTA), to investigate retinal vascular changes in a mouse model of MS, known as experimental autoimmune encephalomyelitis (EAE). We associated these changes with leukostasis, RGC injury, and the overall progression of EAE. LSFG imaging revealed a progressive reduction in retinal blood flow velocity and increased vascular resistance near the optic nerve head in the EAE model, indicating impaired ocular blood flow. OCTA imaging demonstrated significant decreases in vessel density, number of junctions, and total vessel length in the intermediate and deep capillary plexus of the EAE mice. Furthermore, our analysis of leukostasis revealed a significant increase in adherent leukocytes in the retinal vasculature of the EAE mice, suggesting the occurrence of vascular inflammation in the early development of EAE pathology. The abovechanges preceded or were accompanied by the characteristic hallmarks of optic neuritis, such as RGC loss and reduced visual acuity. Overall, our study sheds light on the intricate relationship between retinal vascular alterations and the progression of optic neuritis as well as MS clinical score. It also highlights the potential for the development of image-based biomarkers for the diagnosis and monitoring of optic neuritis as well as MS, particularly in response to emerging treatments.

Chronic Central Serous Chorioretinopathy in Elderly Subjects: Structure and Blood Flow Characteristics of Retina and Choroid.

With advancements in imaging technology, researchers have been able to identify more distinctive imaging features of central serous chorioretinopathy (CSC). However, existing research primarily concentrates on young patients aged 50years and below, leaving a dearth of studies on elderly CSC patients. Previous studies indicate that elderly CSC patients may exhibit unique imaging characteristics and have a clinical prognosis that significantly differs from younger patients. This study aimed to evaluatethe characteristics of retina, choroid structure, and blood flow in elderly patients with chronic CSC (cCSC) examined multimode imaging and try to find new pathogenesis information of it. Using a cut-off age of 50years, patients with chronic central serous chorioretinopathy were divided into two groups: older and younger. The control group consisted of 40 healthy individuals, with their right eyes assigned. Various clinical features were recorded, including the incidence of ellipsoid zone rupture (EZ-), fibrin in the subretinal fluid (SRF), pachydrusen, subretinal drusenoid deposits (SDD), pigment epithelial detachment (PED), double-layer sign (DLS), and choroidal lipid globule cavern. Measurements were taken for the thickness of the outer nuclear layer (ONL), the length of the extended outer photoreceptor segment (POS), the height and width of SRF, the vascular density of each layer of the retinal capillary plexus, the central macular thickness (CMT), and the subfoveal choroidal thickness (SFCT). The proportion of females in the elderly group (43.75%) was significantly higher than that in the youth group (22.41%) (p = 0.034). The degree of hyperopia in the elderly group (1.03 ± 0.73) was higher than that in the youth group (0.26 ± 1.06), with a significant difference in BCVA (p = 0.05). The thickness of SFCT, CMT, ONL in the elderly group, and the length of photoreceptor outer segment in the elderly group were thinner than those in the youth group (p < 0.05). Choroidal capillary perfusion area (CCPA), macular area, and paramacular area were lower in the elderly group than those in the youth group in the full scan range (p < 0.05). The blood flow densities of deep capillary plexus (DCP), intermediate capillary plexus (ICP), and superficial capillary plexus (SCP) in the whole scan range, macular area, and paramacular area were lower in the elderly group than in the youth group, but the differences were not statistically significant. In conclusion, our data suggest that elderly patients with cCSC may experience different disease outcomes. Elderly cCSC patients exhibit less gender bias, poorer vision, more severe structural damage and ischemia in the choroid and retina, and have a higher risk of developing choroidal neovascularization.

Subclinical macular vessel density alterations in patients with juvenile systemic lupus erythematosus.

The aim is to evaluate subclinical alterations of macular microvasculature in patients with juvenile systemic lupus erythematosus (JSLE). This is a cross-sectional study of 29 eyes of 29 patients diagnosed with JSLE and 29 eyes of 29 healthy controls. The vessel density (VD) of the superficial capillary plexus (SCP), intermediate capillary plexus (ICP), deep capillary plexus (DCP), choriocapillaris (CC), and area of foveal avascular zone (FAZ) was measured using optical coherence tomography angiography (OCTA). A multiple linear regression analysis was performed to evaluate the effects of disease duration and activity on OCTA parameters. The VD of total (p = .007) and the superior (p = .014) and inferior (p = .004) quadrants in SCP was significantly lower in children with JSLE. The VD of total and all quadrants in ICP decreased (p = .015, p = .0045, p = .015, p = .033), except that of the temporal quadrant (p = .366). The total (p = .011) and superior quadrant (p<.01) DCP-VD showed a significant decrease in children with JSLE. The decrease in VD in the total (p = .003) and nasal quadrant (p = .017) of CC was also remarkable. No significant difference in the FAZ area was found between the two groups (p = .774). Multiple linear regression analyses adjusted for age, spherical equivalent, and intraocular pressure were conducted. No contributing factor to OCTA parameters was found. We demonstrated decreased VD in all layers of the retina and CC in patients with JSLE without ocular involvement. Early screening and close follow-up were recommended.

Detection of Paracentral Acute Middle Maculopathy Can Prevent Blindness and Death.

Depth resolved imaging tools such as optical coherence tomography (OCT) are at the forefront of a new era of retinal diagnostics. These advancements have remarkably broadened our understanding of macular ischemia and the structure of the retinal capillary plexus (RCP). Because of the predominant vertical organization of the RCP, the middle retinal layer is at greater risk of ischemia and infarction. Paracentral acute middle maculopathy (PAMM) is a manifestation of this risk and is the result of infarction of the inner nuclear layer (INL), detectable on OCT as a hyperreflective band within the INL. On OCT angiography (OCTA), PAMM is the result of hypoperfusion of the deep retinal vascular complex i.e the intermediate retinal capillary plexus and the deep retinal capillary plexus.

Correlation of retinal vascular characteristics with laboratory and ocular findings in Fabry disease: exploring ocular diagnostic biomarkers

BackgroundThe goal of this study was to evaluate macular microvascular changes in patients with Fabry disease (FD) using optical coherence tomography angiography (OCTA) and to explore their correlation with laboratory and ocular findings.MethodsA total of 76 eyes (38 patients) and 48 eyes of 24 healthy controls were enrolled in this prospective study. Vessel Area Density (VAD) and Foveal Avascular Zone (FAZ) area were calculated on 2.9 × 2.9 mm OCTA images scanned with the Heidelberg Spectralis II (Heidelberg, Germany). VAD was measured in three layers: Superficial Vascular Plexus (SVP), Intermediate Capillary Plexus (ICP), and Deep Capillary Plexus (DCP). All scans were analyzed with the EA-Tool (Version 1.0), which was coded in MATLAB (The MathWorks Inc, R2017b). FAZ area was manually measured in full-thickness, SVP, ICP and DCP scans.ResultsAverage VAD in SVP, ICP and DCP was higher in Fabry disease patients than in controls (49.4 ± 11.0 vs. 26.5 ± 6.2, 29.6 ± 7.4 vs. 20.2 ± 4.4, 32.3 ± 8.8 vs. 21.7 ± 5.1 respectively, p < 0.001). Patients with cornea verticillata (CV) had a higher VAD in ICP and DCP compared to patients without CV (p < 0.01). Patients with increased lysoGb3 concentration had a higher VAD in DCP when compared to patients with normal lysoGb3 concentration (p < 0.04). There was no difference in VAD in patients with and without vascular tortuosity. However, a significantly higher VAD was observed in patients with vascular tortuosity compared to controls (p < 0.03).ConclusionsIncreased lysoGb3 and VAD in DCP could be reliable biomarkers of disease activity. Cornea verticillata could be adopted as a predictive biomarker for VAD changes and disease progression. The combination of cornea verticillata and increased VAD may serve as a diagnostic biomarker for Fabry disease, however due to the discrepancies in VAD values in various studies, further research has to be done to address this claim.

Optic Nerve Head Changes Measured by Swept Source Optical Coherence Tomography and Angiography in Patients with Intracranial Hypertension.

This study explored the structural and microvascular changes in the optic nerve head (ONH) of patients with intracranial hypertension (IH) by using swept-source optical coherence tomography (SS-OCT)/OCT angiography (OCTA) and evaluated their association with clinical features. The optic disc morphology, peripapillary retinal nerve fiber layer (pRNFL), ganglion cell-inner plexiform layer (GCIPL), and microvascular densities of the nerve fiber layer plexus (NFLP), superficial vascular plexus (SVP), intermediate capillary plexus (ICP), and deep capillary plexus (DCP) were measured by the SS-OCT/OCTA tool. Frisen score, visual acuity, and intracranial pressure were assessed and recorded in patients with IH. Sixty-one patients with IH and 65 controls were included in this study. Patients with IH showed thicker pRNFL and GCIPL thickness with larger ONH rim area when compared to controls (P < 0.001). Microvascular densities were increased in NFLP while densities were reduced in SVP, ICP, and DCP when compared to controls (P < 0.001). Structural thickness and microvascular densities were significantly correlated with Frisen scores (P < 0.05) and intracranial pressure (P < 0.05) in patients with IH. Structural and microvasculature variations of the ONH were found in patients with IH compared to controls. Importantly, we showed that structural and microvascular changes in the ONH were correlated with their Frisen score and intracranial pressure in patients with IH.

Investigation of OCTA Biomarkers in Fabry Disease: A Long Term Follow-Up of Macular Vessel Area Density and Foveal Avascular Zone Metrics.

Retinal microvasculature is known to be altered in patients with Fabry disease (FD). We aimed to investigate the long-term changes in macular microvasculature and explore a reliable retinal biomarker for treatment monitoring in FD. Prospective study of 26 eyes with FD followed up to 48months (mean 24, range 8-48). OCT angiography (OCTA) images (2.9 × 2.9mm) were obtained using Heidelberg Spectralis II at baseline and follow-up. Macular vessel area density (VAD, %) was measured in three layers: superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP) in three peri-macular circular sectors (c1, c2, c3). Additionally, foveal avascular zone (FAZ) area (mm2) and horizontal and vertical diameters (µm) were assessed. VAD decreased over time in SVP, ICP (in sectors c2 and c3) and DCP (all sectors) (p < 0.04). VAD reduction was predominantly seen in treated FD patients. FAZ and horizontal diameters increased at follow-up in FD patients compared to baseline (p ≤ 0.025). Correlation analysis showed a moderate to strong negative correlation between VAD of SVP and DCP in the innermost circle and FAZ in treated patients (r = - 0.6; p < 0.0001). This is the first long-term follow-up OCTA study in FD to our knowledge. A decrease in VAD, pronounced in the peripheral circle and deeper layers, as well as an enlargement of the FAZ could be observed over time. These changes reflect the vascular remodelling during the course of the disease. Interestingly, the reduction of VAD was more pronounced in treated patients. This could be a result of enzyme replacement therapy and could be potentially used as a reliable biomarker for monitoring the treatment of the disease. A baseline examination of VAD and FAZ before treatment initiation is meaningful. Larger studies are needed to establish the use of VAD and FAZ as biomarkers for treatment monitoring.

The preliminary study of diabetic retinopathy detection based on intensity parameters with optical coherence tomography angiography

In this study, the diagnostic abilities of intensity parameters of optical coherence tomography angiography (OCTA) images in the early detection of diabetic retinopathy (DR) were determined. 78 normal healthy eyes, 10 diabetic eyes with mild non-proliferative diabetic retinopathy (NPDR), and 10 diabetic eyes with moderate NPDR were employed. Four retinal vascular plexuses were generated by using OCTA, which included the nerve fiber layer vascular plexus (NFLVP), superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP). The parafoveal zone in each OCTA image was divided into four sectors which were the superior, temporal, inferior, and nasal sectors. Five intensity parameters including the mean, median, variance, skewness, and kurtosis of intensities were calculated for each sector. The factor of aging was evaluated among normal healthy subgroups. The diagnostic abilities of intensity parameters were evaluated between normal healthy subjects and diabetic patients with DR. Our results showed that the variance of intensities in superior sector in ICP achieved the highest AUROC value of 0.95 with the sensitivity of 0.87 and the specificity of 1.000 when comparing the diabetic patients with the mild NPDR to normal healthy subjects. The mean intensity in superior sector in ICP achieved the second highest AUROC value of 0.95 with the sensitivity of 0.90 and the specificity of 0.90 when comparing the diabetic patients with the moderate NPDR to normal healthy subjects. The proposed approach could offer a simple way to differentiate diabetic patients with early DR from normal healthy subjects without performing the relatively complicated image processing techniques.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY BIOMARKERS AND MICROPERIMETRY FEATURES IN BEHÇET'S UVEITIS.

To evaluate the parafoveal macular microvasculature and the macular function in patients with retinal vasculitis associated with Behçet's uveitis. In 14 patients with inactive Behçet's uveitis and 26 control individuals (13 with nonocular Behçet's syndrome and 13 healthy subjects), we analyzed the retinal nerve fiber layer, ganglion cell layer, full retinal thickness, foveal avascular zone area and sectorial parafoveal vascular density in the superficial vascular plexus, intermediate capillary plexus, and deep capillary plexus using SPECTRALIS optical coherence tomography (OCT) 2 and OCT angiography. Macular sensitivity was analyzed using an MP-3 microperimeter. Eighteen eyes (78%) had a best-corrected visual acuity ≥ 20/25. Significant differences were found in Behçet's uveitis in comparison with the controls on the OCT and OCT angiography: 14.8%, 22.4%, and 14.9% ganglion cell layer thinning in the global, nasal, and inferior sectors, respectively; 6%, 13.2%, and 7.5% full retinal thickness thinning in the superior, nasal, and inferior sectors; and 16.8%, 14.9%, 23.6%, 15.8%, and 12.6% mean deep capillary plexus density reduction in the global, superior, nasal, inferior, and temporal sectors. Microperimetry data demonstrated significant mean reductions of 21% and 23.6% in central and average macular sensitivities and 28.8%, 40.4%, 27.7%, and 24.2% in the superior, nasal, inferior, and temporal sectors, respectively. Outer plexiform layer elevations were observed in Behçet's uveitis (69.6%). Behçet's uveitis presented structural and functional macular damage despite good best-corrected visual acuity, mainly affecting the nasal sector and the deep capillary plexus. On OCT and OCT angiography, quantitative and qualitative changes can be valuable biomarkers of ocular involvement in Behçet's syndrome.

The retinal deep capillary plexus as a venous outflow system; insights from Sturge Weber Syndrome.

To report on the venous abnormalities of a patient with Sturge-Weber syndrome (SWS). Case report. A 29-year-old woman with a history of SWS since infancy was referred for evaluation of possible diffuse choroidal hemangioma. Multimodal imaging, including ultra-widefield fluorescein, indocyanine green, and optical coherence tomography-angiography (OCTA) were performed. Dilated fundus examination was remarkable for increased cupping of the optic disc in the right eye, venous tortuosity, and marked dilation of the choroidal vessels. Ultra-widefield fluorescein angiography confirmed marked venous tortuosity and dilation, as well as anastomoses of the retinal veins ipsilateral to the port wine stain. Indocyanine green angiography revealed marked engorgement of the vortex veins and choroidal vasculature. OCTA revealed dilated vascular channels in the deep capillary plexus (DCP) that were directly anastomosing to the superficial capillary plexus, but not the intermediate capillary plexus. Engorgement of the ampullae of the DCP vortex system was also observed. The normal contralateral eye was used as comparison for all imaging studies. These findings support the notion of generalized venous hypertension state in adult eyes with SWS and corroborate prior evidence that the deep capillary plexus acts as a venous outflow system.