Peripapillary Microvasculature Predicts the Incidence and Development of Diabetic Retinopathy: An SS-OCTA Study

Changes in peripapillary microvasculature and retinal nerve fibre layer in diabetes and diabetic retinopathy using optical coherence tomographic angiography: a community-based, cross-sectional study

OBJECTIVE

To evaluate changes in the peripapillary retinal microvasculature and retinal nerve fibre layer (RNFL) in diabetic participants with various stages of diabetic retinopathy (DR) using swept-source optical coherence tomographic angiography (OCTA).

DESIGN

Community-based, cross-sectional study.

SETTING

This study was conducted in a tertiary teaching hospital in Guangzhou, China.

PARTICIPANTS

A total of 1325 ocular-treatment-naive participants, of whom 1115 had no DR and 210 had DR, were recruited in a community in Guangzhou, China.

PRIMARY AND SECONDARY OUTCOME MEASURES

A commercially available OCTA device was used to obtain various peripapillary retinal microvascular metrics centred on the optic disc, including vessel density (VD), vessel length density (VLD) and vessel diameter index (VDI). The peripapillary RNFL thickness was automatically obtained using built-in software. Linear regression analyses were used to evaluate the association of the peripapillary OCTA parameters (VD, VLD and VDI), RNFL thickness with various DR stages and average RNFL thickness with peripapillary OCTA parameters.

RESULTS

Moderate and severe DR had progressively decreased VD in the peripapillary ring (β = -0.72, 95% CI = -1.31 to -0.14 and -1.79, 95% CI = -2.81 to -0.77, respectively) and other regions (all p<0.05). Similar changes were observed between peripapillary VLD and moderate and severe DR (all p<0.05). Moderate (β = -4.56, 95% CI = -8.97 to -0.15, p=0.043) and severe DR (β = -10.12, 95% CI = -18.29 to -1.95, p=0.015) had significant thinner peripapillary RNFL in the inferior quadrant. VD and VLD were linearly associated with the average RNFL in the peripapillary ring and average peripapillary area (all p<0.05).

CONCLUSIONS

The peripapillary retinal microvasculature and RNFL were significantly reduced with the progression of DR, which suggests that monitoring differences in peripapillary microvasculature and the RNFL may be a promising approach to detecting DR progression.

Evaluation of optical coherence tomography angiography metrics in children and adolescents with type 1 diabetes: 4-year longitudinal study

PURPOSE

To evaluate longitudinal changes in optical coherence tomography angiography (OCTA) metrics in children and adolescents with type 1 diabetes (T1D).

METHODS

This prospective observational cohort study included thirty-two eyes from thirty T1D children with no history of diabetic retinopathy (DR) who were followed up for 4 years. Participants underwent OCTA examinations at baseline and during follow-up. Quantitative OCTA metrics were measured using a customized MATLAB algorithm. Generalized mixed-effect models were used to determine their relationship with DR development. Systemic parameters and OCTA metrics were screened using least absolute shrinkage and selection operator to identify predictors for visual function.

RESULTS

Over the 4-year period, seven of the included eyes developed DR, and most OCTA metrics decreased with diabetes duration. Higher peripapillary and parafoveal nasal quadrant vessel area density (VAD) in the superficial capillary plexus (SCP) and vessel skeleton density (VSD) in both the SCP and the deep capillary plexus (DCP) were associated with a lower risk of DR in T1D. Parafoveal DCP VSD and VAD in the temporal and inferior quadrants were anticorrelated with changes in best corrected visual acuity.

CONCLUSIONS

OCTA metrics dynamically change over the duration of diabetes and can be used as biomarkers to improve the risk evaluation of DR development and visual function in T1D children and adolescents.

Imaging Modalities for Assessing the Vascular Component of Diabetic Retinal Disease: Review and Consensus for an Updated Staging System

Purpose

To review the evidence for imaging modalities in assessing the vascular component of diabetic retinal disease (DRD), to inform updates to the DRD staging system.

Design

Standardized narrative review of the literature by an international expert workgroup, as part of the DRD Staging System Update Effort, a project of the Mary Tyler Moore Vision Initiative. Overall, there were 6 workgroups: Vascular Retina, Neural Retina, Systemic Health, Basic and Cellular Mechanisms, Visual Function, and Quality of Life.

Participants

The Vascular Retina workgroup, including 16 participants from 4 countries.

Methods

Literature review was conducted using standardized evidence grids for 5 modalities: standard color fundus photography (CFP), widefield color photography (WFCP), standard fluorescein angiography (FA), widefield FA (WFFA), and OCT angiography (OCTA). Summary levels of evidence were determined on a validated scale from I (highest) to V (lowest). Five virtual workshops were held for discussion and consensus.

Main Outcome Measures

Level of evidence for each modality.

Results

Levels of evidence for standard CFP, WFCP, standard FA, WFFA, and OCTA were I, II, I, I, and II respectively. Traditional vascular lesions on standard CFP should continue to be included in an updated staging system, but more studies are required before they can be used in posttreatment eyes. Widefield color photographs can be used for severity grading within the area covered by standard CFPs, although these gradings may not be directly interchangeable with each other. Evaluation of the peripheral retina on WFCP can be considered, but the method of grading needs to be clarified and validated. Standard FA and WFFA provide independent prognostic value, but the need for dye administration should be considered. OCT angiography has significant potential for inclusion in the DRD staging system, but various barriers need to be addressed first.

Conclusions

This study provides evidence-based recommendations on the utility of various imaging modalities for assessment of the vascular component of DRD, which can inform future updates to the DRD staging system. Although new imaging modalities offer a wealth of information, there are still major gaps and unmet research needs that need to be addressed before this potential can be realized.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Qi-Ju-Di-Huang-Pill delays the progression of diabetic retinopathy

ETHNOPHARMACOLOGICAL RELEVANCE

Qi-Ju-Di-Huang-Pill (QJDH pill) is a Chinese decoction. Although it is commonly used to treat eye conditions, such as diabetic retinopathy (DR), its exact mechanism of action is unknown.

AIM OF THE STUDY

To investigate the specific mechanism by which QJDH pill slows the progression of diabetic retinopathy (DR) based on animal and cellular experiments.

MATERIAL AND METHODS

The major components of QJDH pill were characterized by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLCMS/MS). C57BL/6J mice were randomly divided into five groups as follows: normal group (control group), model group (STZ group), low-dosage QJDH pill group (QJDH-L group), medium-dosage QJDH pill group (QJDH-M group) and high-dosage QJDH pill group (QJDH-H group). Changes in water intake, urination, food intake, and body mass were monitored weekly, while changes in blood glucose were monitored monthly. Fluorescein fundus angiography (FFA), optical coherence tomography angiography (OCTA), and optical coherence tomography (OCT) were utilized to analyze the changes in fundus imaging indications. Hematoxylin & eosin (H&E) and transmission electron microscopy (TEM) were employed to examine histopathologic and ultrastructural changes in retina. The levels of interleukin-6 (IL-6), interleukin-17 (IL-17), tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor (VEGF) in peripheral blood were detected using Enzyme-linked immunosorbent assay (ELISA). The mouse retina apoptotic cells were labeled with green fluorescence via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (Tunel). The protein levels of Bcl-2-Associated X (Bax), B cell lymphoma 2 (Bcl-2), Caspase-3, PI3K, phosphorylated PI3K (p-PI3K), protein kinase B (AKT) and phosphorylated AKT (p-AKT) were quantified by Western blot (WB). The retinal pigment epithelium (RPE) cells were cultured and classified into five groups as follows: normal glucose group (NG group), high glucose group (HG group), high glucose + QJDH pill group (HG + QJDH group), high glucose + inhibitor group (HG + LY294002 group), and high glucose + inhibitor + QJDH pill group (HG + LY294002 + QJDH group). Cell viability and apoptosis were detected via Cell Counting Kit-8 (CCK8) and then analyzed by flow cytometry.

RESULTS

In vivo experiments revealed that the QJDH pill effectively reduced blood glucose, symptoms of increased water intake, elevated urination, increased food intake and decreased body mass in DR mice. QJDH pill also slowed the development of a series of fundus imaging signs, such as retinal microangiomas, tortuous dilatation of blood vessels, decreased vascular density, and thinning of retinal thickness, downregulated IL-6, IL-17, TNF-α, and VEGF levels in peripheral blood, and inhibited retinal cell apoptosis by activating the PI3K/AKT signaling pathway. Moreover, in vitro experiments showed that high glucose environment inhibited RPE cell viability and activated RPE cell apoptosis pathway. In contrast, lyophilized powder of QJDH pill increased RPE cell viability, protected RPE cells from high glucose-induced damage, and decreased apoptosis of RPE cells by activating the pi3k pathway.

CONCLUSION

QJDH pill induces hypoglycemic, anti-inflammatory effects, anti-VEGF and anti-retinal cell apoptosis by activating PI3K/AKT signaling pathway, and thus can protect the retina and slow the DR progression.

Changes in peripapillary microvasculature in patients with type 2 diabetes patients: effect of systemic hypertension

To determine the effect of hypertension (HTN) on the peripapillary microvasculature in type 2 diabetes mellitus (T2DM) patients without diabetic retinopathy (DR). The patients were classified into three groups: the control group (group 1), T2DM group (group 2), and both T2DM and HTN group (group 3). Peripapillary vessel density (VD) was compared using analysis of covariance and linear regression analysis was performed to identify the factors affecting the peripapillary VD. A total of 286 eyes were enrolled: 124 in group 1, 111 in group 2, and 51 in group 3. The peripapillary VDs for the full area were 18.3 ± 0.6, 17.8 ± 1.0, and 17.3 ± 1.2 mm-1 in group 1, group 2, and group 3, respectively, which were significantly different after adjustment for age and best-corrected visual acuity (P < 0.001). In post hoc analyses, group 1 versus group 2 (P < 0.001), group 1 versus group 3 (P < 0.001), and group 2 versus group 3 (P = 0.001) showed significant differences. In linear regression analysis, HTN (B =  - 0.352, P = 0.043) and peripapillary retinal nerve fiber layer (pRNFL) thickness (B = 0.045, P < 0.001) were significantly associated with peripapillary VD in T2DM patients. Peripapillary VD in T2DM patients without clinical DR were lower compared to normal controls, and they were more decreased when HTN was comorbid. The combination of ischemic damage by high blood pressure and impairment of the neurovascular unit by hyperglycemia would result in more severe deterioration of peripapillary microvasculature, and this impairment could be also reflected by pRNFL thinning.

Association between HSP-Specific T-Cell Counts and Retinal Nerve Fiber Layer Thickness in Patients with Primary Open-Angle Glaucoma

Objective

Previous laboratory reports implicate heat shock protein (HSP)-specific T-cell responses in glaucoma pathogenesis; here, we aimed to provide direct clinical evidence by correlating systemic HSP-specific T-cell levels with glaucoma severity in patients with primary open-angle glaucoma (POAG).

Design

Cross-sectional case-control study.

Subjects

Thirty-two adult patients with POAG and 38 controls underwent blood draw and optic nerve imaging.

Methods

Peripheral blood monocytes (PBMC) were stimulated in culture with HSP27, α-crystallin, a member of the small HSP family, or HSP60. Both interferon-γ (IFN-γ)+ CD4+ T helper type 1 cells (Th1) and transforming growth factor-β1 (TGF-β1)+ CD4+ regulatory T cells (Treg) were quantified by flow cytometry and presented as a percentage of total PBMC counts. Relevant cytokines were measured using enzyme-linked immunosorbent assays. Retinal nerve fiber layer thickness (RNFLT) was measured with OCT. Pearson's correlation (r) was used to assess correlations.

Main Outcome Measures

Correlations of HSP-specific T-cell counts, and serum levels of corresponding cytokine levels with RNFLT.

Results

Patients with POAG (visual field mean deviation, -4.7 ± 4.0 dB) and controls were similar in age, gender, and body mass index. Moreover, 46.9% of POAG and 60.0% of control subjects had prior cataract surgery (P = 0.48). Although no significant difference in total nonstimulated CD4+ Th1 or Treg cells was detected, patients with POAG exhibited significantly higher frequencies of Th1 cells specific for HSP27, α-crystallin, or HSP60 than controls (7.3 ± 7.9% vs. 2.6 ± 2.0%, P = 0.004; 5.8 ± 2.7% vs. 1.8 ± 1.3%, P < 0.001; 13.2 ± 13.3 vs. 4.3 ± 5.2, P = 0.01; respectively), but similar Treg specific for the same HSPs compared with controls (P ≥ 0.10 for all). Concordantly, the serum levels of IFN-γ were higher in POAG than in controls (36.2 ± 12.1 pg/ml vs. 10.0 ± 4.3 pg/ml; P < 0.001), but TGF-β1 levels did not differ. Average RNFLT of both eyes negatively correlated with HSP27- and α-crystallin-specific Th1 cell counts, and IFN-γ levels in all subjects after adjusting for age (partial correlation coefficient r = -0.31, P = 0.03; r = -0.52, p = 0.002; r = -0.72, P < 0.001, respectively).

Conclusions

Higher levels of HSP-specific Th1 cells are associated with thinner RNFLT in patients with POAG and control subjects. The significant inverse relationship between systemic HSP-specific Th1 cell count and RNFLT supports the role of these T cells in glaucomatous neurodegeneration.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Retinal and choroidal microvascular characterization and density changes in different stages of diabetic retinopathy eyes

Background

The purpose of this study was to evaluate the changes in fundus vascular density and micromorphological structure of all vascular plexuses during the different stages of diabetic retinopathy (DR), and the correlation between fundus blood flow and the DR severity.

Methods

This observational cross-sectional study was conducted of 50 eyes with different stages of DR, 25 diabetes mellitus (DM) patients without clinical signs of DR and 41 healthy eyes. The foveal avascular zone (FAZ), vessel density of superficial capillary plexus (SCP), and deep retinal capillary plexus (DCP) were acquired by RTVue XR Avanti OCTA device. The perfusion density (PD), skeleton vessel density (SVD) was manually calculated using ImageJ. The area under receiver operating characteristic (ROC) curve was used to determine the diagnostic value of OCTA parameters in distinguishing DR and healthy eyes.

Results

The choroidal VD were significantly higher in the healthy group than in the DM without DR, NPDR, and PDR groups (p < 0.001). The mean retinal parafovea VD, PD, and retinal SVD were higher in healthy and DM without DR eyes compared with NPDR and DR eyes in all vascular layers (p < 0.001). The parafoveal VD of SCP, and DCP decreased, and FAZ area increased with the exacerbation of DR. The OCTA parameters, including FAZ area, parafovea VD, PD, and SVD in all vascular layers showed significant correlation with DR severity (all p < 0.001). ROC curves of OCTA parameters (FAZ area, retinal parafovea VD, retinal PD, and SVD in all vascular layers) for had high sensitivity and specificity in distinguishing DR versus healthy eyes.

Conclusion

The choroidal parafovea VD, retinal parafovea VD, retinal PD, and SVD in the two plexuses decreased, and retinal FAZ area increased significantly with worsening DR. VD, PD, and SVD might be potential early biomarkers indicating the progression of DR before appearance of clinically PDR in patients with DM. In this study, OCTA parameters had high sensitivity and specificity in distinguishing DR and healthy eyes.

Assessment of Parafoveal Diabetic Macular Ischemia on Optical Coherence Tomography Angiography Images to Predict Diabetic Retinal Disease Progression and Visual Acuity Deterioration

Importance

The presence of diabetic macular ischemia (DMI) on optical coherence tomography angiography (OCTA) images predicts diabetic retinal disease progression and visual acuity (VA) deterioration, suggesting an OCTA-based DMI evaluation can further enhance diabetic retinopathy (DR) management.

Objective

To investigate whether an automated binary DMI algorithm using OCTA images provides prognostic value on DR progression, diabetic macular edema (DME) development, and VA deterioration in a cohort of patients with diabetes.

Design, Setting, and Participants

In this cohort study, DMI assessment of superficial capillary plexus and deep capillary plexus OCTA images was performed by a previously developed deep learning algorithm. The presence of DMI was defined as images exhibiting disruption of fovea avascular zone with or without additional areas of capillary loss, while absence of DMI was defined as images presented with intact fovea avascular zone outline and normal distribution of vasculature. Patients with diabetes were recruited starting in July 2015 and were followed up for at least 4 years. Cox proportional hazards models were used to evaluate the association of the presence of DMI with DR progression, DME development, and VA deterioration. Analysis took place between June and December 2022.

Main Outcomes and Measures

DR progression, DME development, and VA deterioration.

Results

A total of 321 eyes from 178 patients were included for analysis (85 [47.75%] female; mean [SD] age, 63.39 [11.04] years). Over a median (IQR) follow-up of 50.41 (48.16-56.48) months, 105 eyes (32.71%) had DR progression, 33 eyes (10.28%) developed DME, and 68 eyes (21.18%) had VA deterioration. Presence of superficial capillary plexus-DMI (hazard ratio [HR], 2.69; 95% CI, 1.64-4.43; P < .001) and deep capillary plexus-DMI (HR, 3.21; 95% CI, 1.94-5.30; P < .001) at baseline were significantly associated with DR progression, whereas presence of deep capillary plexus-DMI was also associated with DME development (HR, 4.60; 95% CI, 1.15-8.20; P = .003) and VA deterioration (HR, 2.12; 95% CI, 1.01-5.22; P = .04) after adjusting for age, duration of diabetes, fasting glucose, glycated hemoglobin, mean arterial blood pressure, DR severity, ganglion cell-inner plexiform layer thickness, axial length, and smoking at baseline.

Conclusions and Relevance

In this study, the presence of DMI on OCTA images demonstrates prognostic value for DR progression, DME development, and VA deterioration.

Retinal OCTA Image Segmentation Based on Global Contrastive Learning

The automatic segmentation of retinal vessels is of great significance for the analysis and diagnosis of retinal related diseases. However, the imbalanced data in retinal vascular images remain a great challenge. Current image segmentation methods based on deep learning almost always focus on local information in a single image while ignoring the global information of the entire dataset. To solve the problem of data imbalance in optical coherence tomography angiography (OCTA) datasets, this paper proposes a medical image segmentation method (contrastive OCTA segmentation net, COSNet) based on global contrastive learning. First, the feature extraction module extracts the features of OCTA image input and maps them to the segment head and the multilayer perceptron (MLP) head, respectively. Second, a contrastive learning module saves the pixel queue and pixel embedding of each category in the feature map into the memory bank, generates sample pairs through a mixed sampling strategy to construct a new contrastive loss function, and forces the network to learn local information and global information simultaneously. Finally, the segmented image is fine tuned to restore positional information of deep vessels. The experimental results show the proposed method can improve the accuracy (ACC), the area under the curve (AUC), and other evaluation indexes of image segmentation compared with the existing methods. This method could accomplish segmentation tasks in imbalanced data and extend to other segmentation tasks.

Characteristics and Classification of Choroidal Caverns in Patients with Various Retinal and Chorioretinal Diseases

PURPOSE

To investigate the features of choroidal caverns in diverse retinal diseases with swept-source optical coherence tomography (SS-OCT).

METHODS

Subjects with normal eyes, retinitis pigmentosa (RP), wet age-related macular degeneration (wAMD), acute central serous chorioretinopathy (CSC), or chronic CSC were enrolled. The characteristics of choroidal caverns were evaluated with SS-OCT. The prevalence of choroidal caverns in retinal diseases and the correlations between the number, width and depth of choroidal caverns with the thickness of choroid were analyzed.

RESULTS

Among 315 eyes of 220 subjects, choroidal caverns were found in 110 eyes (34.9%). Choroidal caverns were divided into two categories based on their location and size. Type I was small and usually lobulated, presented in the choroidal capillary and Sattler's layers. Type II was larger, usually isolated, and presented in the Sattler's and Haller's layers. The prevalence of type I in subjects with normal eyes, RP, wAMD, acute CSC, or chronic CSC was 17.4%, 19.6%, 1.6%, 32.8%, and 85.2%, respectively, while that of type II was 0%, 0%, 21.3%, 13.8%, and 53.7%, respectively. The number, width, and thickness of type II choroidal caverns correlated positively with macular choroidal thickness.

CONCLUSIONS

Choroidal caverns could be divided into two categories. Type II choroidal caverns appeared associated with the pachychoroid spectrum and RPE atrophic diseases.