Deep Capillary Plexus Research Articles

Changes in wider field swept-source OCT angiography vascular metrics with anti-vascular endothelial growth factor therapy in central retinal vein occlusion.

To investigate the impact of anti-VEGF therapy on vascular metrics in eyes with macular edema secondary to central retinal vein occlusion (CRVO) using wider field swept-source OCT angiography (WF SS-OCTA). We included 23 eyes with macular edema associated with non-ischemic CRVOfrom 22 patients treated with anti-VEGF therapy (median number of injections: 5 [2-9]). Changes in vessel density (VD), vessel skeletonized density (VSD), and foveal avascular zone (FAZ) parameters were measured using WF SS-OCTA. Visual acuity (VA) and central subfield thickness (CST) were also measured. Median CST decreased significantly from 369µm (305-531) to 267µm (243-300, p < 0.001). VD and VSD parameters in 12 × 12mm images showed significant reductions. For instance, VSD in the whole retina decreased from a median of 13.37 (11.22-13.74) to 11.29 (9.36-12.97, p = 0.013). Additionally, a significant increase in FAZ circularity was found, suggesting improved microvascular integrity. Significant inverse correlations were found between the number of anti-VEGF injections and all VSD and VD parameters on the 12 × 12mm images (p < 0.05). Notably, the reductions in VSD and VD on 12 × 12mm angiograms in the deep capillary plexus (DCP) after each injection significantly correlated with increased logMAR VA (worse VA). Anti-VEGF therapy in CRVO patients not only mitigates macular edema but also alters the overall microvascular morphology and functionality as revealed by WF SS-OCTA.

OCT angiography 2023 update: focus on diabetic retinopathy.

Optical coherence tomography angiography (OCTA) has become part of the clinical practice and its growing applications are in continuous development. Coherently with the growing concern about the human and economic cost of diabetes, diabetic retinopathy (DR) was the most popular topic for OCTA studies in the past year. The analysis of the literature reveals that applications of OCTA in DR are in continuous growth. In particular, ultrawide field (UWF) OCTA and artificial intelligence (AI) based on OCTA images are affirming as the new frontiers of scientific research in the field. Diagnostic accuracy of AI methods based on OCTA is equal or superior to the one based on OCT methods and also bears potential to detect systemic associations. UWF OCTA is noninvasive method that is reaching similar accuracy of FA in detection of neovascularization and intraretinal microvascular abnormalities (IRMAs) and has allowed better characterization of microvascular peripherical changes in DR. Lastly, deep capillary plexus (DCP) characteristics seem to play a pivotal role in the development of diabetic macular edema (DME) and refinement of biomarkers for different phenotypes of DME and diabetic macular ischemia (DMI) is currently on its way.

Repeatability of swept-source optical coherence tomography angiography automated macular vessel density.

Optical Coherence Tomography Angiography Ratio Analysis (OCTARA) is capable of visualizing inner and outer retinal vascular plexuses, choriocapillaris, and larger choroidal vasculature in vivo without contrast injection. The aim of this study was to assess the intrasession repeatability of automated vessel density measurements using Triton Swept-Source Optical Coherence Tomography Angiography (OCTA) innovative algorithm OCTARA in retinal and choroidal vasculature. To study population between 65-90 years old with no eye diseases. For each subject measurements were performed four times. The intraclass correlation coefficient and the coefficient of variation were calculated to analyze repeatability of the OCTARA automatically generated vessel density measurements. A total of 35 eyes were included in the study. The intraclass correlation coefficient of the global vessel density in the superficial capillary plexus and the deep capillary plexus were 0.963 and 0.975, respectively, and the coefficient of variation were 5.4% and 4.4%, respectively. The intraclass correlation coefficient of the rest of the global measurements was indicative of good reliability with the exception of the deep choroid layer with an intraclass correlation coefficient of 0.6 indicative of moderate reliability. Our results proved excellent repeatability of automated vessel density measurements in the superficial and deep capillary plexus layers in our cohort using a OCTARA algorithm indicating that it may be a reliable diagnostic tool. It also showed good reliability in choriocapillary and mid choroid layer. These findings may be of value in assessing the significance of differences in capillary density measurements over time and across different settings.

OCTA characteristics in non-arteritic central retinal artery occlusion and correlation with visual acuity.

To observe the retinal and choroidal circulations in patients with non-arteritic permanent central retinal artery occlusion (NA-CRAO) via optical coherence tomography angiography (OCTA) and analyze their correlation with visual acuity. Sixty-two eyes with clinically confirmed acute NA-CRAO were included in the study and divided into: A type (mild n=29), B type (moderate n=27) and C type (severe n=6) based on the degree of visual loss, retinal edema, and arterial blood flow delay in fundus fluorescence angiography (FFA). Contralateral healthy eyes were used as the control group. Best-corrected visual acuity (BCVA), slit lamp microscopy, indirect ophthalmoscopy, fundus color photography, OCTA, and FFA were performed. Spearman's correlation analysis was used to determine the correlations between retinal and choroidal vessels and visual acuity. There were no statistically significant differences in age, gender, and intraocular pressure among the three types and the control group (P>0.05). Vessel density in deep capillary plexus (VD-DCP) significantly decreased (P<0.05) in all three types of NA-CRAO patients compared to the control group. Vessel density in superficial vascular plexus (VD-SVP) significantly decreased (P<0.05) in type A patients and choriocapillaris flow area significantly decreased (P<0.05) in type B and type C patients compared to the control group; while outer retinal flow areas significantly increased in the type A (P<0.05) and decreased in type C patients (P<0.05). The retinal thickness significantly increased in type C group (P<0.05). The VD-SVP at fovea in the type A was significantly lower than both of type B and C. The VD-SVP at nasal parafovea in type A and B was significantly lower than type C (P<0.05). The logMAR BCVA of type A was significantly better than that of type B and C groups (P<0.05). Spearman's correlation analysis showed that the logMAR BCVA was positively correlated with VD-SVP at fovea (r=0.679, P=0.031) and nasal parafovea (r=0.826, P=0.013). OCTA is valuable for assessing retinal ischemia, and evaluating visual impairment. Deep retinal vasculature is commonly affected in all NA-CRAO types. VD-SVPs at fovea and nasal parafovea can serve as reliable markers of visual impairment in NA-CRAO.

Microvascular Changes after Epiretinal Membrane Vitrectomy with Intraoperative Intravitreal Dexamethasone Implant: An OCT Angiography Analysis.

We aimed to explore microvascular changes evaluated with optical coherence tomography angiography (OCTA) in patients undergoing epiretinal membrane (ERM) pars-plana vitrectomy (PPV) combined with intravitreal Ozurdex implantation, compared with standard PPV. (2) Methods: Prospective interventional analysis on 25 eyes undergoing PPV + Ozurdex (Group A) and 25 eyes undergoing PPV alone. Best corrected visual acuity (BCVA) and OCTA parameters, such as vessel density (VD) of the superficial and deep capillary plexi (SCP and DCP) in the whole 6.4 mm × 6.4 mm and fovea area, were evaluated preoperatively and 3 months after surgery. (3) Results: Postoperative BCVA significantly improved in both groups. No cases of post-operative cystoid macular edema (CME) were reported in Group A vs. two eyes in Group B. In Group A we found a statistically significant increase of SCP's VD in either the whole image (from 42.1 ± 4.1 to 45.6 ± 4.3%, p = 0.01) and the fovea image (from 38.5 ± 7.5 to 41.7 ± 4.2%, p = 0.03). In Group B, we reported no significant variations in the SCP's VDs. In the DCP, VD significantly increased only in the whole image in Group A. Stage 4 ERMs showed the greatest improvement in VD, especially in Group A. (4) Conclusions: Intraoperative Ozurdex prompted a significant BCVA recovery and limited the occurrence of postoperative CME compared to the standard procedure. Moreover, Ozurdex implant is associated with a better restoration of microvascular structure in SCP and DCP.

Optical coherence tomography angiography assessment of retinochoroidal microcirculation differences in preeclampsia

BackgroundTo investigate microvascular changes in pregnant women with preeclampsia using optical coherence tomography angiography (OCTA) and compare the results with healthy pregnant and non-pregnant subjects. MethodsSuperficial capillary plexus (SCP), deep capillary plexus (DCP) choriocapillaris (CC) vessel density (VD) and foveal avascular zone area (FAZ), retina, retinal nerve fiber layer (RNFL), the ganglion cell layer (GCL) and the choroidal thickness were examined and compared in preeclamptic pregnant (group 1), healthy pregnant women (group 2) and non-pregnant, age-matched female controls (group 3). The correlations of the parameters with each other and with blood pressure were evaluated. ResultsNo significant difference was found between the groups when retinal, RNFL and GCL thickness values (p> 0.05). The choroidal thickness values were significantly lower in group 1 than in group 2 (p = 0.029). The central foveal VD of the SCP and DCP was significantly lower in group 1 compared to groups 2 and 3 (p = 0.03, p< 0.01 respectively). The mean VD of the SCP was significantly higher in groups 1 and 2 than in group 3 (p = 0.01). The FAZ area was statistically significantly lower in group 3 than in group 2 (p = 0.032). The CC VD was lower in group 3 compared to the other groups in all measurements (p < 0.01).The FAZ area was positively correlated with systolic blood pressure in group 1. ConclusionThe use of OCTA, a non-invasive imaging technique, to assess the retinal microcirculation appears to have the potential to in the early diagnosis or follow up in preeclampsia before signs of hypertensive retinopathy.

ASSOCIATION OF MACULAR STRUCTURE WITH MICROPERIMETRY SENSITIVITY FOLLOWING VITRECTOMY FOR PROLIFERATE DIABETIC RETINOPATHY.

To evaluate macular sensitivity using microperimetry in patients with proliferate diabetic retinopathy following vitrectomy and to investigate the relationship between the sensitivity and foveal microstructures with optical coherence tomography/angiography. Eighty-four eyes of 84 patients with proliferative diabetic retinopathy, who were indicated for vitrectomy, had no intraocular surgery history 3 months preoperatively, and were able to ensure fundus examination after the vitrectomy, were included. A logMAR best-corrected visual acuity, macular sensitivity of microperimetry, macular retinal thickness, and macular vessel perfusion using optical coherence tomography/angiography were examined at 1 week, 1 month, and 3 months postoperatively. The logMAR best-corrected visual acuity and mean macular sensitivity of patients with proliferative diabetic retinopathy improved postoperatively (P < 0.05). There was a significant correlation between best-corrected visual acuity and mean sensitivity (P < 0.05). Postoperative mean macular sensitivity was significantly correlated with outer retinal thickness in the 0 to 6 mm macular area (P < 0.05) and also significantly correlated with deep capillary plexus perfusion (P < 0.05). Fixation stability and mean macular sensitivity did not show any correlation with glycated hemoglobin, triglyceride, serum total cholesterol, carbamide, and creatinine and duration of diabetes mellitus (P > 0.05). Postoperative mean macular sensitivity was significantly correlated with outer retinal thickness and deep capillary plexus perfusion for patients with proliferative diabetic retinopathy. The authors found that the visual performance of patients can be evaluated by the outer retinal thickness and deep capillary plexus perfusion, so optical coherence tomography/angiography examination can be an important prognostic factor for visual performance in patients.Clinical Trial Registration: This trial is registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn; Registration No.: ChiCTR2100043399).

Optical coherence tomography angiography of the macula of high myopia in children and adolescents

BackgroundHigh myopia represents a health issue and leads to the development of complications that threaten vision. The study of macular changes in high myopia patients has undergone great advances with updated technology via new spectral optical coherence tomography (OCT) and Optical coherence tomography angiography (OCTA). Most of related studies have focused on the adults and additional studies need to investigate macular changes in children and adolescents. This study aimed to evaluate the changes in the macular structure by OCT and the macular vessel density in high myopia in children and adolescents by OCTA.MethodsA cross-sectional comparative study. The population was divided into two groups: group 1 (4–11 years) and group 2 (12–18 years). The results were comparable to those of control study of the same age group. The two high myopia groups and the control groups were examined by macular OCT and OCTA to evaluate macular thickness and vessel density in the superficial and deep capillary plexuses.ResultsOCT measurements of patients in group 1 revealed that central macular thickness was significantly lower in high myopia group than in the control group and measured 220.91 ± 27.87 μm and 258.23 ± 17.26 μm, respectively, (P < 0.0001). However, in group 2 the central macular thickness in the high myopia group and control group was 236.32 ± 27.76 μm and 247.09 ± 16.81 μm respectively, and the difference was not statistically significant (P = 0.09). The parafoveal macular thickness and the perifoveal macular quadrants thickness were significantly lower in high myopic children and high myopic adolescents (P < 0.0001) than age matched controls. The parafoveal and perifoveal vessel densities in the superficial and deep capillary plexuses were lower in the high myopia groups than in the age-matched controls in both groups with a few segment exceptions in group 1. The FAZ was significantly wider in group 1 than in the age-matched emmetropes (P = 0.02). The FAZ was wider in group 2 than controls, but the difference was not statistically significant, (P = 0.75).ConclusionHigh myopic children and adolescents have thinner macular thickness than comparable age-matched emmetropes and have less vessel density in superficial and deep capillary plexuses with a wider FAZ.

Fractal Changes of the Retinal Microvasculature in Syphilitic Uveitis

ABSTRACT Purpose To quantify chorioretinal microvascular damage and recovery post-treatment in patients with acute syphilitic posterior placoid chorioretinitis (ASPPC) using fractal dimension (FD). Methods Retrospective cohort study of patients with serologically confirmed syphilitic uveitis. We obtained optical coherence tomography angiography (OCTA) scans at baseline and follow-up after intravenous penicillin treatment and computed FD of the superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) using ImageJ. Results We enrolled seven patients with ASPPC (11 eyes), and 17 control subjects (34 eyes). Pre-treatment averages of FD-SCP, FD-DCP, and FD-CC were: 1.672 (±0.115), 1.638 (±0.097), and 1.72 (±0.137); post-treatment: 1.760 (±0.071), 1.764 (±0.043), and 1.898 (±0.047). After treatment FD-CC increased in all 11 eyes with an average of 0.163 (p = 0.003); FD-DCP increased in 10 (91%) eyes with an average of 0.126 (p = 0.003); and FD-SCP increased in seven (64%) eyes with an average of 0.089 (p = 0.059). Compared to the post-treatment FD values in the syphilitic group, controls had similar FD-SCP (p = 0.266), FD-DCP (p = 0.078), and FD-CC (p = 0.449). Conclusions CC and DCP are mostly affected in ASPPC with minimal changes in the SCP. All vascular layers FD recovered after completing antibiotic treatment.

Central and Peripheral Changes in Retinal Vein Occlusion and Fellow Eyes in Ultra-Widefield Optical Coherence Tomography Angiography.

To explore the central and peripheral retinal and choroidal changes in retinal vein occlusion (RVO) and fellow eyes using ultra-widefield swept-source optical coherence tomography angiography (UWF-SS-OCTA). Fifteen ischemic central RVO (CRVO), 15 branch RVO (BRVO), and 15 age-matched healthy controls were prospectively recruited. Retinal and choroidal parameters, including retinal vessel flow density (VFD) and vessel linear density (VLD), choroidal vascularity volume (CVV), choroidal vascularity index (CVI), and VFD in the large and medium choroidal vessels (LMCV-VFD), were measured in the central and peripheral regions of the 24 × 20-mm UWF-SS-OCTA images. Ischemic CRVO and BRVO eyes showed increased foveal avascular zone area, perimeter, and acircularity index (AI) compared to their fellow eyes and healthy control eyes, and RVO fellow eyes also had larger AI values than controls (P < 0.05). For ischemic CRVO and BRVO eyes versus control eyes, VFD, VLD, CVV, CVI, and LMCV-VFD decreased, but retinal thickness and volume in the superficial capillary plexus, deep capillary plexus, and whole retina increased (P < 0.05). Moreover, RVO fellow eyes also showed significantly decreased retinal VFD, LMCV-VFD, and CVI, as well as increased retinal thickness and volume, compared with control eyes (P < 0.05). Alterations were not consistent throughout the retina, as they involved only the peripheral or central regions in some cases. The affected and unaffected fellow eyes of RVO patients both demonstrated central and/or peripheral structural and vascular alterations in the retina and choroid. Because UWF-SS-OCTA enables visualization and evaluation of the vasculature outside the posterior pole, it presents a promising approach to more fully characterize vascular alterations in RVO.

Perfusion Deficits in Diabetes Without Retinopathy Localize to the Perivenular Deep Capillaries Near the Fovea on OCT Angiography

PurposeTo localize early capillary perfusion deficits in patients with diabetes mellitus (DM) without clinical diabetic retinopathy (DR) using averaged optical coherence tomography angiography (OCTA). DesignRetrospective, cross-sectional study. SubjectsPatients with DM without DR and healthy controls. MethodsWe measured perfusion deficits in the full retina, superficial (SCP) and deep capillary plexus (DCP) on averaged 3 x 3 mm OCTA images. Perfusion deficits were defined as the percentage of retinal tissue located further than 30 μm from blood vessels, excluding the foveal avascular zone (FAZ). One eye from each patient was selected based on image quality. We measured deficits in the parafoveal region, the 300 μm surrounding the FAZ, and 300 to 1000 μm surrounding the FAZ. If a capillary layer within one of these regions was significantly different in DM without DR compared to controls, we further characterized the location of perfusion deficit as periarteriolar, perivenular, or the capillaries between these two zones. Main Outcome MeasuresLocation of increased perfusion deficits in patients with DM without DR compared to controls. ResultsSixteen eyes from 16 healthy controls were compared to 16 eyes from 16 patients with DM without DR (age 45.1 ± 10.7 and 47.4 ± 15.2 years respectively, P = 0.64). FAZ area, and perfusion deficits in the entire parafovea and the 300-1000 μm ring around the FAZ were not significantly different between groups (P > 0.05 for all). Perfusion deficits in 300 μm around the FAZ were significantly increased in patients with DM without DR in full retinal thickness, SCP and DCP (P < 0.05 for all). When analyzing the perivenular, periarteriolar and capillary zones, only the perivenular DCP perfusion deficits were significantly increased (5.03 ± 2.92 % in DM without DR and 2.73 ± 1.97 % in controls, P = 0.014). ConclusionsMacular perfusion deficits in patients with DM without DR were significantly increased in the region nearest the FAZ, mainly at the perivenular deep capillaries. Further research on these early changes may improve our understanding of the capillaries most susceptible to vascular injury and disruption during diabetes.

Relationship between visual acuity and OCT angiography parameters in diabetic retinopathy eyes after treatment.

To assess the relationship between visual acuity and OCT angiography parameters in diabetic retinopathy eyes after treatment, and to analyze the relative factors in PDR eyes. A total of 89 eyes, including 42 eyes with non-PDR (NPDR), and 47 eyes after vitrectomy with PDR were included and underwent OCTA. All images were processed by Python or FIJI. Multivariable linear regression models were used to analyze the associations between postoperative BCVA and OCTA parameters in PDR patients. Postoperative OCTA parameters including deep capillary plexus (DCP) parafoveal and perifoveal vessel density (VD), DCP parafoveal and perifoveal vessel length density (VLD), DCP fractal dimension (FD), choriocapillaris plexus (CCP) VD, CCP VLD, were significantly lower in the PDR group than in the NPDR group. In the superficial capillary plexus (SCP), we found a negative correlation between the postoperative BCVA and VD (parafovea: β coefficient = -0.351, p = 0.023; perifovea: β coefficient = -0.338, p = 0.036). Perifoveal VLD (β coefficient = -0.343, p = 0.031) and FD (β coefficient = -0.375, p = 0.016) of the SCP were also negatively correlated with postoperative BCVA. Regarding the DCP, perifoveal VD (β coefficient = -0.396, p = 0.008), perifoveal VLD (β coefficient = -0.334, p = 0.025), vessel tortuosity (VT) (β coefficient = -0.369, p = 0.015) were negatively correlated with postoperative BCVA. In CCP, VLD (β coefficient = -0.373, p = 0.023) and number of flow voids (β coefficient = -0.334, p = 0.036) exhibited a negative association with postoperative BCVA. Postoperative BCVA of PDR patients was related to OCTA parameters of the SCP (parafoveal and perifoveal VD, perifoveal VLD and FD), DCP (perifoveal VD, VLD, and VT) and CCP (VLD and number of flow voids).

Evaluation of retinal and choroidal vascular structures in patients with anxiety disorder.

To evaluate the retinal and choroidal vascular structures in patients with anxiety disorders. Thirthy-four eyes of 34 patients who were diagnosed with any anxiety disorders were compared with 32 eyes of 32 age- and sex-matched controls. Central macular thickness (CMT), foveal vascular zone (FAZ) area, total retinal vascular densities of superficial and deep capillary plexus (VDSCP, VDDCP), outer retinal and choriocapillary layers (ORL, CCL) blood flow rates, central subfoveal choroidal thickness (SFCT) and choriodal vascularity index (CVI) were evaluated with optical coherence tomography angiography (OCT-A) and enhanced depth imaging optical coherence tomography (EDI-OCT). No statistical differences were found between the study and control groups in terms of CMT, FAZ area, VDSCP, VDDCP, ORL and CCL blood flow rates. The mean SFCT was 346.26 ± 64.26 µm in patients with anxiety disorder and was found to be statistically significantly thicker than the control group (319.56 ± 37.19 µm) (p = 0.042). Besides, CVI was significantly lower in the study group (71.09 ± 2.64 vs 73.13 ± 3.31, p = 0.008). In people with anxiety disorders, the SFCT was found to be thicker and CVI was found to be lower than normal subjects. Although anxiety and stress are important factors in central serous chorioretinopathy, multifactorial factors, including ocular factors, play a role in the pathophysiology of the disease. There is a need for prospective studies with larger series on the subject.

Optical coherence tomography angiography macular biomarkers of peripheral retinal ischemia in diabetic macular edema: secondary endpoints from the clinical study "FOVEA".

To investigate the relationship between the macular values of fractal dimension (FD) and lacunarity (LAC) on optical coherence tomography angiography (OCTA) images and the presence of peripheral retina non-perfusion areas (NPAs) on fluorescein angiography (FA) in patients with treatment-naïve diabetic macular edema (DME). Fifty patients with treatment-naïve DME underwent a full ophthalmic examination, including best-corrected visual acuity measurement, FA, spectral-domain optical coherence tomography, and OCTA. Specifically, FA was performed to detect the presence of retinal NPAs, whereas fractal OCTA analysis was used to determine macular FD and LAC values at the level of thesuperficial and deep capillary plexus (SCP and DCP). FA montage frames of the posterior pole and peripheral retina, as well as macular OCTA slabs of the SCP and DCP, were obtained. Thirty (60%) eyes with FA evidence of peripheral retinal NPAs in at least one quadrant showed significantly lower FD and higher LAC in both SCP and DCP, when compared with eyes presenting a well-perfused peripheral retina. Furthermore, macular FD and LAC values were found to be significantly associated with the extent of retinal NPAs. Macular FD and LAC of both SCP and DCP seem to be strongly associated with the extent of peripheral retinal NPAs, thus suggesting that may be useful predictive biomarkers of peripheral ischemia in treatment-naïve DME eyes.

Quantitative Analysis of Retinal Perfusion in Patients with Frontotemporal Dementia Using Optical Coherence Tomography Angiography.

Optical coherence tomography angiography (OCT-A) provides detailed visualization of the perfusion of the vascular network of the eye. While in other forms of dementia, such as Alzheimer's disease and mild cognitive impairment, reduced retinal perfusion was frequently reported, data of patients with frontotemporal dementia (FTD) are lacking. Retinal and optic nerve head perfusion was evaluated in patients with FTD with OCT-A. Quantitative OCT-A metrics were analyzed and correlated with clinical markers and vascular cerebral lesions in FTD patients. OCT-A was performed in 18 eyes of 18 patients with FTD and 18 eyes of 18 healthy participants using RTVue XR Avanti with AngioVue. In addition, patients underwent a detailed ophthalmological, neurological, and neuropsychological examination, cerebral magnetic resonance imaging (MRI), and lumbar puncture. The flow density in the optic nerve head (ONH) and in the superficial capillary plexus (SCP) of the macula of patients was significantly lower compared to that of healthy controls (p < 0.001). Similarly, the VD in the deep capillary plexus (DCP) of the macula of patients was significantly lower compared to that of healthy controls (p < 0.001). There was no significant correlation between the flow density data, white matter lesions in brain MRI, cognitive deficits, and cerebrospinal fluid markers of dementia. Patients with FTD showed a reduced flow density in the ONH, and in the superficial and deep retinal capillary plexus of the macula, when compared with that of healthy controls. Quantitative analyses of retinal perfusion using OCT-A may therefore help in the diagnosis and monitoring of FTD. Larger and longitudinal studies are necessary to evaluate if OCT-A is a suitable biomarker for patients with FTD.

Retinal capillary plexus in Parkinson's disease using optical coherence tomography angiography.

To evaluate the alterations of the retinal microvasculature and foveal avascular zone in patients with Parkinson's disease (PD) using optical coherence tomography angiography (OCT-A). A retrospective study of PD patients examined in the Ophthalmology Department of the General Hospital of Athens, "Georgios Gennimatas" from March 2021 to March 2022 was conducted. Totally 44 patients with PD were included and 18 healthy controls were examined, hence a total of 124 eyes were enrolled in the study. The foveal and parafoveal superficial and deep capillary plexus vascular density (fSCP-VD, fDCP-VD, pSCP-VD, pDCP-CD) and foveal avascular zone (FAZ) were quantified with OCTA. Optical coherence tomography (OCT) was used to measure macular thickness. Our statistical analysis was conducted by using a mixed effect linear regression model. After adjustment for age and gender, the mean parafoveal superficial capillary plexus vascular density (pSCP-VD) and mean parafoveal deep capillary plexus vascular density (pDCP-VD) were significantly decreased in individuals with PD (P<0.001 in both) by -2.35 (95%CI -3.3, -1.45) and -7.5 (95%CI -10.4, -4.6) respectively. fSCP-VD and fDCP-VD didn't approach statistical significance. The FAZ area and perimeter were significantly decreased (P<0.001 in both) by -0.1 mm2 (95%CI -0.13, -0.07) and -0.49 mm2 (95%CI -0.66, -0.32) respectively. Circularity didn't approach statistical significance. Central retinal thickness (CRT) was significantly decreased in individuals with PD (P<0.001) by -23.1 µm (95%CI -30.2, -16) and temporal retinal thickness (TRT) was decreased (P=0.025) by -11 µm (95%CI -22, -1.5) while nasal retinal thickness (NRT) only approached statistical significance (P=0.066). The mean pSCP-VD, pDCP-VD, CRT and TRT are significantly decreased and FAZ is altered in individuals with PD. These findings can be potentially used as biomarkers for the diagnosis and evaluation of early PD.

Baseline imaging characteristics and early structural changes in macula on rhegmatogenous retinal detachment

Animal models have demonstrated that structural changes affect the macula during peripheral rhegmatogenous retinal detachment. This study aimed to assess photoreceptors, retinal and choriocapillaris perfusion in non-macula involving rhegmatogenous retinal detachment by analyzing en-face images from structural OCTA segmented at the ellipsoid zone (EZ) level, calculating (1) “normalized” reflectivity as a surrogate biomarker of photoreceptor damage (2) perfusion density (PD), vessel length density (VLD) and vessel diameter index (VDI) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) (3) perfusion density of choriocapillaris (PDCC). Twenty-one eyes affected by macula-on rhegmatogenous retinal detachment (RRD) were enrolled at the University “G. d’Annunzio”, Chieti-Pescara. The fellow unaffected eye was used as control. The mean age at the onset of RRD was 60.09 ± 10.22 (range 34–83). Compared with fellow eyes, we found lower EZ “normalized” reflectivity in macula-on (0.42 ± 0.15 in fellow eyes and 0.31 ± 0.09 in macula on p = 0.004). The affected eye was also characterized by impaired perfusion in SCP (17.26 ± 3.34% in macula on and 20.56 ± 3.62% in the fellow eye p = 0.004) and CC (50.21 ± 6.20% in macula on the eye and 57.43 ± 6.20% in the fellow eye p = 0.004). Macula-on rhegmatogenous retinal detachment has subclinical changes in photoreceptors, SCP, and CC. Future longitudinal studies should evaluate if early changes could impact post-operative macular function.

OCT angiography indices and the choroidal vascularity index in wild-type transthyretin (TTR) amyloidosis (ATTRwt).

Retinal angiopathy represents a well-known ocular manifestation of hereditary transthyretin amyloidosis (ATTRv). Until recently, there have been no reports on retinal changes in ATTRwt. In this retrospective observational clinical study, we aimed to determine whether vessel density (VD) indices and the choroidal vascularity index (CVI) could offer insights into retinal and choroidal vascular changes among patients affected by ATTRwt. Eighteen patients with a confirmed diagnosis of ATTRwt underwent structural optical coherence tomography (OCT) and OCT angiography (OCTA). We established a control group consisting of 16 healthy subjects for statistical comparisons. The 3D OCT and OCTA datasets were analyzed to assess retinal and choroidal thickness and VD. For measuring CVI, we obtained measurements for the total choroid area (TCA), luminal area (LA), and stromal area (SA). The mean VD exhibited a statistically significant reduction in the superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) among the ATTRwt group in comparison to the control group (p < 0.0001). Notably, ATTRwt patients displayed decreased choroidal thickness (p = 0.08). Additionally, the median CVI was lower in the ATTRwt group than in the control group (p = 0.04). The indices from OCTA and CVI have the potential to serve as non-invasive biomarkers for the quantitative evaluation of retinal and choroidal vascular involvement in patients with ATTRwt.

Retinal and Choroidal Vascularity Evaluation in Pediatric Radiologically Isolated Syndrome and Multiple Sclerosis

BackgroundTo assess vessel density (VD) and flow of retinal plexuses and peripapillary region related with the pediatric radiologically isolated syndrome (RIS) and multiple sclerosis (MS). MethodsWe analyzed 24 eyes of 12 participants with the diagnosis of RIS, 24 eyes of 12 participants with the diagnosis of MS, and 26 eyes of 13 age- and sex-matched healthy controls in this prospective, cross-sectional study. The superficial capillary plexus (SCP) and deep capillary plexus, foveal avascular zone, and the flow of choriocapillaris were investigated using optical coherence tomography angiography. ResultsParafoveal VD and all subregion parameters in SCP were significantly decreased in the MS group compared with the controls, whereas only nasal and inferior VD were significantly decreased in the pediatric RIS group compared with the controls. Ganglion cell layer (GCL) thickness of all subregions of the inner ring was significantly decreased in the pediatric MS group compared with the control group. No significant difference was observed between the pediatric RIS group and the control group regarding thickness. ConclusionsWe showed lower parafoveal VD in all subregions of SCP in pediatric MS, whereas only parafoveal nasal and inferior VD were decreased in pediatric RIS. GCL thickness of inner ring was significantly decreased in the pediatric MS, whereas GCL thickness did not change in pediatric RIS. Therefore, a decrease of parafoveal nasal and inferior VD without a decrease in thickness implies an early impairment of microvasculature in the RIS before impairment of thickness and that microvascular alterations begin from highly vascular superficial parafovea.

Evaluation of Optical Coherence Tomography Angiography in Degenerative and Tractional Lamellar Macular Hole.

This study aims to evaluate the optical coherence tomography angiography (OCTA) findings in cases with degenerative and tractional lamellar macular holes (LMH). Two subtypes of LMH cases were included. Seventeen patients had the degenerative subtype, whereas 18 patients had the tractional subtype of LMH. Twenty healthy individuals were enrolled as the control group. The foveal avascular zone (FAZ) and retinal vascular densities in the superficial, deep capillary, and choriocapillary plexuses were analyzed and compared with fellow eyes and healthy controls using OCTA. The mean FAZ area was wider in the degenerative subtype (0.33 ± 0.14 mm2) compared to the tractional subtype (0.24 ± 0.10 mm2) (p=0.04) and control eyes (0.26 ± 0.10 mm2) (p=0.03). Foveal vessel densities in the superficial and deep capillary plexuses were lower in the degenerative group than in the tractional group, (21.7 ± 9.8% vs. 26.8 ± 6.9%, p=0.01 and 28.5 ± 5.1% vs. 36.9 ± 6.2%, p=0.01). Choriocapillary vascular density in the parafoveal area was also lower in degenerative lamellar macular holes compared to the tractional group (60.4 ± 4.7% vs. 63.7 ± 3.9%, p=0.03). Compared to control eyes, eyes with degenerative and tractional LMH showed lower vessel densities in the parafoveal and perifoveal areas of the SCP, DCP, and all layers of CC (p < 0.05). In the foveal area, the LMH groups showed higher foveal vascular density (FVD) in the SCP than control eyes, while in the DCP, FVD was lower in the degenerative LMH eyes relative to the other groups. The finding of microvascular changes between degenerative and tractional LMH subtypes highlights their distinct pathologies and supports recent changes in the classification and terminology of this macular condition.