Level Of Deep Capillary Plexus Research Articles

A gender-based analysis of retinal microvascular alterations in patients with diabetes mellitus using OCT angiography

PurposeTo assess the difference in microvascular changes between males and females with diabetes mellitus (DM) without diabetic retinopathy (NoDR) and with mild-to-moderate non-proliferative diabetic retinopathy (NPDR) using Optical Coherence Tomography Angiography (OCT-A). DesignRetrospective cross-sectional study. Methods267 DM patients, 133 females (49.81 %), 111 with NoDR (41.57 %) and 156 NPDR (58.43 %) were included. Foveal-centered 3 × 3 mm OCT-A images corresponding to the superficial (SCP), intermediate (ICP) and deep capillary plexus (DCP), and full retinal (RET) slab were used for analysis. For each slab, FAZ area, perimeter, and circularity index (CI) were determined, following manual delineation of the FAZ; perfusion (PD) and vessel density (VD), fractal dimension (FD), vessel length density (VLD), geometric perfusion deficits (GPD) were also computed. Flow voids (FV) were determined in the choriocapillaris plexus; and perfused capillary density (PCD) in the RET slab. ResultsFemales showed larger FAZ CI in SCP and greater FAZ area and perimeter than males in NPDR group. Males had higher central macular thickness than females in NPDR group. All density metrics at the level of ICP and DCP were affected in the NPDR group with no gender differences. Of note, the same significant findings were found in type 1 DM patients, and not in type 2 DM patients. ConclusionsOur OCT-A findings suggest significant microvascular changes in females with NPDR compared to males, but no such differences in patients without DR. Therefore, gender-related vascular alterations might be present in early stages of DR with potential role.

Optical Coherence Tomography Angiography Analysis of Vessel Density Indices in Early Post-COVID-19 Patients.

PurposeA hypercoagulable state has been reported to cause potential sight-threatening ischemia in patients suffering from Coronavirus disease 2019 (COVID-19). This study aimed to determine whether vessel density (VD), as measured by optical coherence tomography angiography (OCT-A), has insights into retinal and choriocapillaris vascular changes in patients affected by SARS-CoV-2 infection.MethodsHundred and fifty two patients positive for SARS-CoV-2 infection were enrolled in this observational, retrospective, controlled study. A control group of 60 healthy subjects was selected for statistical comparisons. Raw OCT and OCT-A data were exported and 3D datasets were analyzed to determine VD.ResultsHundred and forty eyes (92.1%) were included for final analysis. The VD of the superficial capillary plexus (SCP) did not differ between the two groups. The mean VD of the deep capillary plexus (DCP) and the choriocapillaris (CC) was significantly lower in the foveal sector of the COVID-19 group compared to healthy controls. Within the post-COVID-19 group, the lowest DCP and CC foveal VD values were recorded in patients treated with antiviral therapy; no differences were observed among COVID-19 patients with other comorbidities (hypertension, diabetes, thyroid disease) or taking antiplatelet therapy. DCP and CC foveal VD were significantly lower in patients hospitalized in an intensive care unit (ICU) than asymptomatic patients.ConclusionFoveal vessel density at the level of DCP and CC was reduced in post-COVID-19 patients. Further studies evaluating these changes over time will be needed to corroborate the hypothesis of a microvascular retinal impairment in individuals who have recently recovered from SARS-CoV-2 infection.

Clinically relevant factors associated with a binary outcome of diabetic macular ischaemia: an OCTA study

AimsWe investigated the demographic, ocular, diabetes-related and systemic factors associated with a binary outcome of diabetic macular ischaemia (DMI) as assessed by optical coherence tomography angiography (OCTA) evaluation of non-perfusion...

Acute macular neuroretinopathy and COVID-19 vaccination

Dear Editor, We read with interest the article by Vinzamuri et al.[1] The hyperreflective lesions seen on ganglion layer could represent sections across the vessels. It would be helpful if the optical coherence tomography images would be accompanied by section through which it was taken. Since acute macular neuroretinopathy (AMN) and paracentral middle maculopathy (PAMM) are possibly related to vascular occlusion either a fundus fluorescein angiography or optical coherence tomography angiography can add value to their case. In AMN, changes occur due to reduced retinal perfusion at the level of deep capillary plexus, which provides retinal perfusion to the zone between the retinal and choroidal circulations.[23] AMN multimodal imaging findings described could be dark lesions on red-free imaging, hypo-autofluorescence on fundus autofluorescence, and early and late hypofluorescence on fluorescein angiography. Infrared imaging also detected the lesions with a darkened outline.[4] Despite complete visual recovery, there is a possibility of persisting scotoma which may be as a result of thinning of the affected retinal layers.[5] We agree with the authors that AMN and PAMM following COVID-19 vaccine may not be causal and may have to be explored further. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Association of Deep Retinal Capillary Plexus ischemia with Inner Segment/Outer Segment Disruption in Diabetic Macular Ischemia

ABSTRACT Background: Diabetic macular ischemia (DMI) is an important cause of visual impairment in patients with diabetic retinopathy. In some patients, it may lead to irreversible visual loss. Purpose: The aim of the work was to assess the presence of outer retinal structural changes at the level of inner segment /outer segment (IS/OS) in relation to macular capillary non-perfusion at the level of deep capillary plexus (DCP) in diabetic retinopathy (DR). Patients and Methods: A prospective observational study was carried on 250 eyes of 125 patients. They underwent scanning using Optical coherence tomography/ Optical coherence tomography angiography (OCT/OCTA) simultaneously. Results: 250 of 125 diabetic patients were classified according to presence of capillary non perfusion (NP), into two groups (ischemic- non ischemic). The incidence of DCP NP was 100% in eyes with DMI while the incidence of superficial capillary plexus (SCP) NP was 71% . The incidence of foveal avascular zone (FAZ) irregularity, inner segment /outer segment (IS/OS) disruption was 100% and 95% respectively among eyes with DMI. DCP NP was more than SCP NP in eyes with FAZ irregularity, which make it the possible main cause of the structural changes in the retina during ischemia. There was a strong association between the presence of IS/OS disruption with duration, severity of DR and BCVA. Conclusion: It could be concluded thatIS/OS disruption is associated with ischemia at DCP. It could be considered a reliable OCT findings that indicate an underling DMI and their presence can affect visual prognosis.

Quantitative evaluation of retinal microvascular circulation in patients with obstructive sleep apnea-hypopnea using optical coherence tomography angiography.

To compare capillaries perfusion in macular areas at different layers and peripapillary region in radial peripapillary capillaries (RPC) between healthy subjects and subjects with obstructive sleep apnea-hypopnea (OSA) using spectral-domain optical coherence tomography angiography (OCTA). Totally 16 eyes with mild-to-moderate OSA, 14 eyes with severe OSA and 22 control eyes were enrolled in this study. Every subject filled out the Berlin questionnaire and received a comprehensive ocular and physical examination. The clinical characteristics were collected, OCT and OCTA scans using OCTA RT XR Avanti (AngioVue software, Optovue Inc., Fremont, CA, USA) were performed and analyzed. Compared to the control group, the severe group had significantly higher VD in parafovea and perifoveal regions (p = 0.031; p = 0.029) at the level of deep capillary plexus (DCP), whereas the mild-to-moderate group had a significantly lower VD in the peripapillary region on RPC network in disc areas (p = 0.013). Blood flow changes in macular areas might first appear at the DCP layer in OSA patients. Reduced VD in the peripapillary region at the RPC layer might be associated with OSA and cause subsequent RNFL changes.

CAPILLARY NONPERFUSION AND PHOTORECEPTOR LOSS IN BRANCH RETINAL VEIN OCCLUSION: Spatial Correlation and Morphologic Characteristics.

To evaluate the photoreceptor layer in eyes with branch retinal vein occlusion associated with macular ischemia, using a method of en face optical coherence tomography (OCT) representation of the ellipsoid zone. Customized macular OCT scans of 9 patients (10 eyes) with branch retinal vein occlusion and macular ischemia were exported and subsequently postprocessed (removal of vascular and cystic spaces' shadows, segmentation, and alignment to the retinal pigment epithelium). The ellipsoid band was then isolated, aligned, and used to produce an en face OCT image. Areas with photoreceptor loss (hyporeflective ellipsoid) were compared with ischemic areas as identified in an early-phase fluorescein angiography. The areas of capillary nonperfusion (as detected in fluorescein angiography) were closely associated with disruption of the ellipsoid zone (depicted as areas of low reflectance in the en face reconstruction of the OCT images). The ellipsoid zone disruption had a patchy appearance and either sharp or fuzzy borders, depending on the grade of the loss of reflectance. En face OCT reconstruction and subsequent representation of ellipsoid zone revealed a close association between capillary nonperfusion and photoreceptor disruption in eyes with branch retinal vein occlusion. It seems that the deep capillary plexus plays an important role on the metabolic demands of outer retina and, consequently, an ischemia at the level of deep capillary plexus has significant impact on the integrity of the photoreceptors.

Evaluation of pseudophakic cystoid macular edema using optical coherence tomography angiography.

To compare the optical coherence tomography angiography (OCT-A) findings of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in eyes with pseudophakic cystoid macular edema (PCME) with those of fluorescein angiography (FA) and spectral-domain optical coherence tomography (SD-OCT) and to compare PCME vascular density values of the SCP and DCP with those of healthy eyes. In this retrospective observational study, 13 eyes (12 patients) with PCME underwent comprehensive ophthalmologic examinations including visual acuity, FA, SD-OCT, and OCT-A. The vascular density of the SCP and DCP were measured using AngioAnalytics software in all PCME eyes and compared with 46 healthy eyes of 25 subjects. In patients with PCME, at the level of SCP, the mean vascular density in the whole en face image was 44.48 ± 3.61% while it was 50.27 ± 5.30% at the level of the DCP. In contrast, the vascular density in the whole en face image was 50.35 ± 3.22 at the level of SCP while it was 56.15 ± 3.28 at the level of DCP in 46 healthy eyes of 25 subjects. The vascular density of patients with PCME was significantly lower than in healthy subjects at the SCP (p<0.0001) and at the DCP (p<0.0001). We report the OCT-A appearance of PCME and vascular density map with values that can be easily interpreted for quantitative evaluation of retina perfusion status using OCT-A. This approach might be the first step in helping us fully understand the pathophysiologic mechanisms underlying PCME.

Deep Retinal Capillary Nonperfusion Is Associated With Photoreceptor Disruption in Diabetic Macular Ischemia

To report outer retinal structural changes associated with macular capillary nonperfusion at the level of deep capillary plexus (DCP) in diabetic patients. Prospective observational cross-sectional study. The study included 14 eyes of 10 patients who were diagnosed as having diabetic retinopathy. To study the outer retina and localize areas of capillary nonperfusion at the superficial (SCP) or DCP, we used the spectral-domain optical coherence tomography (SDOCT) device (RTVue-XR Avanti; Optovue Inc, Fremont, California, USA) with split-spectrum amplitude-decorrelation angiography (SSADA) software for optical coherence tomography angiography (OCTA). Two independent masked graders (F.S. and A.A.F.) qualitatively evaluated SDOCT scans as either normal or having outer retina disruption. The angiographic images were examined to define the presence and location of capillary nonperfusion. Eight eyes showed outer retinal disruption on SDOCT that co-localized to areas of enlarged foveal avascular zone, areas of no flow between capillaries, and capillary nonperfusion of the DCP. Six eyes without outer retinal changes on SDOCT showed robust perfusion of the DCP. Using OCTA, this study shows that macular photoreceptor disruption on SDOCT in patients with diabetic retinopathy corresponds to areas of capillary nonperfusion at the level of the DCP. This is important in highlighting the contribution of the DCP to the oxygen requirements of the photoreceptors as well as the outer retina in diabetic macular ischemia.