Role of Inflammation in Classification of Diabetic Macular Edema by Optical Coherence Tomography

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

PURPOSE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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).

Effect of diabetic macular oedema on serum iron status indicators

CLINICAL RELEVANCE

The role of subclinical inflammation in the pathophysiology of diabetic macular oedema (DME), which is known to be quite complex, is of much interest. Serum ferritin level, which is an indicator of body iron stores, is both an inflammatory marker for various neurodegenerative diseases and an important indicator in the evaluation of iron-induced oxidative stress.

BACKGROUND

Iron metabolism indicators play a role in the formation and development of diabetic retinopathy, which is known to be associated with subclinical inflammation, and may also play a role in the pathogenesis of DME. The aim of this study was to investigate the role of serum iron metabolism markers in the pathogenesis of DME.

MATERIALS AND METHODS

The files of all nonproliferative diabetic retinopathy (NPDR) patients who were scheduled for the first intravitreal injection for DME in the eye clinic between January 2019 and January 2020 were reviewed retrospectively. By examining the files of all diabetes mellitus patients who attended the outpatient eye clinic on the same dates, those without retinopathy and those with NPDR but not DME were recorded. All results, including a comprehensive ophthalmological examination, laboratory data of fasting blood tests, and an internal medicine outpatient examination were collected for analysis.

RESULTS

Of the 157 participants, 44 were NPDR patients with oedema, 50 were NPDR patients without oedema, and 63 were patients without retinopathy. There was a significant difference between the groups in respect of creatinine, high-density lipoprotein, mean corpuscular volume, serum iron and ferritin, total iron binding capacity and transferrin saturation (p < 0.050). Ferritin values were found to be significantly higher in patients with macular oedema. Other iron status markers were found to be significantly lower (p < 0.050).

CONCLUSION

Evaluation of serum iron status indicators in the routine follow-up of diabetic patients may be of diagnostic and/or prognostic benefit in terms of DME.

The Anatomic and Functional Outcomes of Ozurdex-Aided Vitrectomy in Proliferative Diabetic Retinopathy

Purpose

To investigate the 3-months outcomes of patients who underwent intraoperative intravitreal injection of Ozurdex for proliferative diabetic retinopathy (PDR).

Methods

This is a prospective randomized controlled clinical trial (ChiCTR2100043399). Seventy-one patients with PDR who had indications for surgery without intravitreal injection history within 3 months preoperatively were enrolled. Patients were randomly divided into three groups based on the medicine injected intraoperatively: Ozurdex, Conbercept, and Control group. The primary outcome is the best-corrected visual acuity (BCVA) within 3 months postoperatively. The secondary outcomes include the intraocular pressure (IOP), mean sensitivity, central retinal thickness and vessels perfusion.

Results

The BCVA and the mean sensitivity improved in the three groups (F = 130.8, P < 0.0001; F = 34.18, P < 0.0001), but there was no statistical difference among the three groups (F = 0.858, P = 0.552; F = 0.964, P = 0.452). The IOP was no significant differences among the three groups within 3 months postoperatively (F = 0.881, P = 0.533). Compared with the other two groups, central retinal thickness (CRT) and outer retinal layer (ORL) thickness decreased significantly in patients of the Ozurdex group (F = 3.037, P = 0.008; F = 2.626, P = 0.018), especially in the diabetic macular edema (DME) patients (F = 2.761, P = 0.0164; F = 2.572, P = 0.0240). In macular region, superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP) perfusion were not shown statistical difference at 3 months postoperatively in the all three groups compared with 1 day postoperatively (P > 0.05).

Conclusion

Compared with the other two groups, anatomical outcomes was improved significantly in Ozurdex group for DR patients. Ozurdex may help to improve the visual acuity and visual sensitivity, and there is no significant difference in the change of IOP and microvascular improvement.

Clinical Trial Registration

This trial is registered with the Chinese Clinical Trial Registry (http://www.chictr.org.cn, registration number ChiCTR2100043399).

Clinical and optical coherence tomography biomarkers as prognostic factors in dexamethasone intravitreal implant for diabetic macular edema

PURPOSE

Aim of the study was to evaluate the efficacy of dexamethasone (DEX) 0.7 mg intravitreal implant in patients with diabetic macular edema (DME) and serous retinal detachment (SRD), and to study the prognostic factors on a follow up of 12 months.

METHODS

Forty eyes of twenty- six patients with centre involving DME and SRD, who underwent DEX implant, were enrolled. Best-corrected visual acuity (BCVA), Swept source OCT imaging and intraocular pressure were evaluated. Central macular thickness (CMT), vitreomacular adhesion (VMA), disorganization of retinal inner layers (DRILs), hyperreflective dots (HRD), SRD and ellipsoid zone (EZ) disruption were included in the analysis at baseline and 12 months after implant.

RESULTS

According to our parametric analysis, at 12 months, BVCA improvement from 48.6 ± 23.4 letters to 53.3 ± 24.5 letters was statistically significant (p = 0.04), CMT decreased from 460 ± 99.52 μm to 322.9 ± 117 μm. The presence at baseline of VMA (p = 0.01), EZ disruption (p = 0.03) and DRILs (p = 0.04), were associated with poor BCVA improvement at the end of follow-up.

CONCLUSION

In conclusion, OCT biomarkers can be considered significant prognostic factors for treatment outcome in patients with DME undergoing DEX intravitreal implant.

Optical Coherence Tomography Angiography as a Diagnostic Tool for Diabetic Retinopathy

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes mellitus, leading to visual impairment if left untreated. This review discusses the use of optical coherence tomography angiography (OCTA) as a diagnostic tool for the early detection and management of DR. OCTA is a fast, non-invasive, non-contact test that enables the detailed visualisation of the macular microvasculature in different plexuses. OCTA offers several advantages over fundus fluorescein angiography (FFA), notably offering quantitative data. OCTA is not without limitations, including the requirement for careful interpretation of artefacts and the limited region of interest that can be captured currently. We explore how OCTA has been instrumental in detecting early microvascular changes that precede clinical signs of DR. We also discuss the application of OCTA in the diagnosis and management of various stages of DR, including non-proliferative diabetic retinopathy (NPDR), proliferative diabetic retinopathy (PDR), diabetic macular oedema (DMO), diabetic macular ischaemia (DMI), and pre-diabetes. Finally, we discuss the future role of OCTA and how it may be used to enhance the clinical outcomes of DR.

Exploring the Impact of Glycemic Control on Diabetic Retinopathy: Emerging Models and Prognostic Implications

This review addresses the complexities of type 1 diabetes (T1D) and its associated complications, with a particular focus on diabetic retinopathy (DR). This review outlines the progression from non-proliferative to proliferative diabetic retinopathy and diabetic macular edema, highlighting the role of dysglycemia in the pathogenesis of these conditions. A significant portion of this review is devoted to technological advances in diabetes management, particularly the use of hybrid closed-loop systems (HCLSs) and to the potential of open-source HCLSs, which could be easily adapted to different patients' needs using big data analytics and machine learning. Personalized HCLS algorithms that integrate factors such as patient lifestyle, dietary habits, and hormonal variations are highlighted as critical to reducing the incidence of diabetes-related complications and improving patient outcomes.

Optical coherence tomography in the management of diabetic macular oedema

Diabetic macular oedema (DMO) is the major cause of visual impairment in people with diabetes. Optical coherence tomography (OCT) is now the most widely used modality to assess presence and severity of DMO. DMO is currently broadly classified based on the involvement to the central 1 mm of the macula into non-centre or centre involved DMO (CI-DMO) and DMO can occur with or without visual acuity (VA) loss. This classification forms the basis of management strategies of DMO. Despite years of research on quantitative and qualitative DMO related features assessed by OCT, these do not fully inform physicians of the prognosis and severity of DMO relative to visual function. Having said that, recent research on novel OCT biomarkers development and re-defined classification of DMO show better correlation with visual function and treatment response. This review summarises the current evidence of the association of OCT biomarkers in DMO management and its potential clinical importance in predicting VA and anatomical treatment response. The review also discusses some future directions in this field, such as the use of artificial intelligence to quantify and monitor OCT biomarkers and retinal fluid and identify phenotypes of DMO, and the need for standardisation and classification of OCT biomarkers to use in future clinical trials and clinical practice settings as prognostic markers and secondary treatment outcome measures in the management of DMO.

Optical coherence tomography angiography analysis of choroidal microvasculature in various forms of diabetic macular edema

INTRODUCTION

Optical coherence tomography angiography (OCTA) research in diabetic macular edema (DME) has focused on the retinal microvasculature with little attention to the choroid. The goal of this study was to analyze the association between quantitative choroidal OCTA parameters and various forms of DME observed on optical coherence tomography.

METHODS

We conducted a retrospective study of 61 eyes of 53 patients with DME. DME was classified as early or advanced, and as sponge-like diffuse retinal thickening (DRT), cystoid macular edema (CME) or serous retinal detachment (SRD). Quantitative OCTA parameters (vessel density [VD] in the superficial capillary plexus [SCP], middle capillary plexus [MCP], deep capillary plexus [DCP] and choriocapillaris [CC]) were recorded.

RESULTS

The VD in the CC and SCP was significantly higher in patients with early DME compared to patients with advanced DME (P value<0.01). CC VD was lower in subjects with SRD compared to DRT and CME (P value<0.001). Moreover, it was lower in CME compared to DRT (P value<0.05). No statistical differences were found between VD in the MCP and DCP (P value>0.05). Furthermore, CC VD was lower in patients with increased retinal thickness, disruption of the ellipsoid zone (EZ) or external limiting membrane (ELM), and disorganization of the inner retinal layers (DRIL) (P value<0.05).

CONCLUSION

CC ischemia plays an important role in the pathogenesis of DME. We demonstrated a decrease in CC VD in patients with severe DME, SRD, retinal thickening, EZ and/or ELM disruption and DRIL.

Evaluation of changes in epivascular glia before and after intravitreal dexamethasone implant: An OCT pilot study

PURPOSE

To detect changes in epivascular glia (EVG) in diabetic retinopathy after intravitreal dexamethasone implant using en face optical coherence tomography (enface OCT) and OCT angiography (OCTA) and to correlate improvements in functional and structural features.

METHODS

A total of 38 eyes of 38 patients were enroled in this prospective study. They were divided into two different study groups: the first group including 20 eyes with diabetic retinopathy type 1 complicated by macular oedema and the control group including 18 eyes from 18 healthy age-matched patients. The main outcome measures were: (i) differences at baseline in the foveal avascuar zone (FAZ) area in the study group versus control; (ii) the presence of epivascular glia in the study group versus control, (iii) differences at baseline between foveal macular thickness versus control; (iv) changes in foveal macular thickness, FAZ and epivascular glia in the study group before and after intravitreal dexamethasone implant.

RESULTS

At baseline FAZ area detected at OCTA was larger in the study group than in the control group, and epivascular glia was only detected in the study group. Three months after intravitreal injection of dexamethasone implant in the study group the best corrected visual acuity (BCVA) improved and central macular tickness reduced (P<0.0001). No significant differences were found in FAZ area while epivascular glia disappeared in 80% of the patients after treatment.

CONCLUSIONS

Glia activation due to retinal inflammation in diabetic retinopathy (DR) can be detected on en face-OCT as epivascular glia. Intravitreal dexamethasone (DEX) implant improves both the anatomical and functional condition in the presence of these signs.

Immune Fingerprint in Diabetes: Ocular Surface and Retinal Inflammation

Diabetes is a prevalent global health issue associated with significant morbidity and mortality. Diabetic retinopathy (DR) is a well-known inflammatory, neurovascular complication of diabetes and a leading cause of preventable blindness in developed countries among working-age adults. However, the ocular surface components of diabetic eyes are also at risk of damage due to uncontrolled diabetes, which is often overlooked. Inflammatory changes in the corneas of diabetic patients indicate that inflammation plays a significant role in diabetic complications, much like in DR. The eye's immune privilege restricts immune and inflammatory responses, and the cornea and retina have a complex network of innate immune cells that maintain immune homeostasis. Nevertheless, low-grade inflammation in diabetes contributes to immune dysregulation. This article aims to provide an overview and discussion of how diabetes affects the ocular immune system's main components, immune-competent cells, and inflammatory mediators. By understanding these effects, potential interventions and treatments may be developed to improve the ocular health of diabetic patients.

Efficacy and Safety of Brolucizumab, Aflibercept, and Ranibizumab for the Treatment of Patients with Visual Impairment Due to Diabetic Macular Oedema: A Systematic Review and Network Meta-Analysis

INTRODUCTION

Key clinical guidelines recommend anti-vascular endothelial growth factor (VEGF) therapy as first-line treatment for visual impairment due to diabetic macular oedema (DMO). A systematic literature review (SLR) and network meta-analysis (NMA) were conducted comparing the relative efficacy of the anti-VEGF brolucizumab with a focused network of the most relevant comparator dosing regimens approved in countries other than the USA (aflibercept, ranibizumab). The safety and tolerability of brolucizumab were also assessed.

METHODS

A broad SLR was conducted to identify randomised controlled trials to ensure all relevant potential comparators were captured. Identified studies were refined to those appropriate for inclusion in the NMA. A Bayesian NMA was conducted comparing brolucizumab 6 mg (every 12 [Q12W]/every 8 weeks [Q8W]) with relevant aflibercept 2 mg and ranibizumab 0.5 mg regimens.

RESULTS

Fourteen studies were included in the NMA. At 1-year follow-up, the various aflibercept 2 mg and ranibizumab 0.5 mg regimens were mostly comparable with brolucizumab 6 mg Q12W/Q8W across key visual and anatomical outcomes, except brolucizumab 6 mg was favoured over ranibizumab 0.5 mg every 4 weeks (Q4W) for the change from baseline (CFB) in best-corrected visual acuity (BCVA), and BCVA loss/gain of pre-specified numbers of letters, and over ranibizumab 0.5 mg pro re nata for CFB in diabetic retinopathy severity scale, and retinal thickness. At year 2, where data were available, brolucizumab 6 mg showed similar results across efficacy outcomes versus all other anti-VEGFs. In most cases, discontinuation rates (all cause, and due to adverse events [AE]) and serious and overall rates of AEs excluding ocular inflammatory events were similar (in unpooled and pooled-treatment analyses) versus comparators.

CONCLUSION

Brolucizumab 6 mg Q12W/Q8W was comparable or superior to aflibercept 2 mg and ranibizumab 0.5 mg regimens for various visual and anatomical efficacy outcomes and discontinuation rates.

Three Major Causes of Metabolic Retinal Degenerations and Three Ways to Avoid Them

An imbalance of homeostasis in the retina leads to neuron loss and this eventually results in a deterioration of vision. If the stress threshold is exceeded, different protective/survival mechanisms are activated. Numerous key molecular actors contribute to prevalent metabolically induced retinal diseases-the three major challenges are age-related alterations, diabetic retinopathy and glaucoma. These diseases have complex dysregulation of glucose-, lipid-, amino acid or purine metabolism. In this review, we summarize current knowledge on possible ways of preventing or circumventing retinal degeneration by available methods. We intend to provide a unified background, common prevention and treatment rationale for these disorders and identify the mechanisms through which these actions protect the retina. We suggest a role for herbal medicines, internal neuroprotective substances and synthetic drugs targeting four processes: parainflammation and/or glial cell activation, ischemia and related reactive oxygen species and vascular endothelial growth factor accumulation, apoptosis and/or autophagy of nerve cells and an elevation of ocular perfusion pressure and/or intraocular pressure. We conclude that in order to achieve substantial preventive or therapeutic effects, at least two of the mentioned pathways should be targeted synergistically. A repositioning of some drugs is considered to use them for the cure of the other related conditions.

Efficacy and safety profile of intravitreal dexamethasone implant versus antivascular endothelial growth factor treatment in diabetic macular edema: a systematic review and meta-analysis

To better understand the efficacy of intravitreal dexamethasone implant (Ozurdex) versus antivascular endothelial growth factor (anti-VEGF) treatment in patients with diabetic macular edema (DME). A systematic review and meta-analysis. The study included randomized control trials (RCTs) and non-randomized control trials (Non-RCTs) before December 2021 that compare the efficacy of Ozurdex-related therapyand anti-VEGF therapy. We searched PubMed, Cochrane Library, and EMBASE. The quality of the included studies was assessed carefully. 30 studies were included. Regarding BCVA change, the overall result revealed no significant differences between Ozurdex and anti-VEGF therapies in patients with nonresistant DME, but Ozurdex group had significantly more VA improvement than anti-VEGF therapies in patients with resistant DME (MD 0.12, 95% CI 0.02-0.21). In terms of central retinal thickness (CRT) decrease, there was a significant difference between Ozurdex therapy and anti-VEGF therapy in patients with nonresistant DME (MD 48.10, 95% CI 19.06-77.13) and resistant DME (MD 65.37, 95% CI 3.62-127.13). Overall, Ozurdex therapy resulted in significantly greater VA improvement and CRT decrease than anti-VEGF therapy in resistant DME patients. Ozurdex therapy was not inferior to anti-VEGF therapy in patients with nonresistant DME.

Mid-term safety and effectiveness of macular peeling one month after intravitreal dexamethasone implant for tractional diabetic macular edema

Macular peeling combined or followed by intravitreal dexamethasone implant (DEX-i) was recommended as an efficacy approach for tractional diabetic macular edema (tDME). Knowing the synergistic effect of cataract surgery and DEX-i one month earlier in eyes with DME, we compared Epiretinal Membrane/Inner Limiting Membrane (ERM/ILM) peeling preceded by DEX-i one month before versus ERM/ILM peeling alone for the treatment of tDME. A retrospective study on patients affected by tDME who underwent ERM/ILM peeling one month after DEX-i (n = 11; Group A) or ERM/ILM peeling alone (n = 10; Group B) was performed. Longitudinal comparison of best-correct visual acuity (BCVA), central retinal thickness (CRT), and intraocular pressure (IOP) between the time of surgery (T₀) and each time point (months 1,3,5,6) within and among the groups were assessed. To evaluate the repeated measurements of BCVA, CRT, and IOP, a linear mixed-effects model was used. In Group A, DEX-i significantly improved mean BCVA and CRT (P < 0.001) just after 1 month (T₀). After ERM/ILM peeling, mean BCVA and CRT significantly improved from month 1 in Group A and month 3 in Group B. Mixed model revealed a significant difference in BCVA (P ≤ 0.0001) and CRT (P ≤ 0.02) at different time-points among the groups with better results in Group A. Neither complications nor uncontrolled IOP increase was detected. ERM/ILM peeling confirmed its effectiveness in treating tDME. DEX-i performed one month before surgery seemed to be a safe approach and ensured a greater and faster recovery considering functional and tomographic parameters.

Classification of Retinal Diseases in Optical Coherence Tomography Images Using Artificial Intelligence and Firefly Algorithm

In recent years, the number of studies for the automatic diagnosis of biomedical diseases has increased. Many of these studies have used Deep Learning, which gives extremely good results but requires a vast amount of data and computing load. If the processor is of insufficient quality, this takes time and places an excessive load on the processor. On the other hand, Machine Learning is faster than Deep Learning and does not have a much-needed computing load, but it does not provide as high an accuracy value as Deep Learning. Therefore, our goal is to develop a hybrid system that provides a high accuracy value, while requiring a smaller computing load and less time to diagnose biomedical diseases such as the retinal diseases we chose for this study. For this purpose, first, retinal layer extraction was conducted through image preprocessing. Then, traditional feature extractors were combined with pre-trained Deep Learning feature extractors. To select the best features, we used the Firefly algorithm. In the end, multiple binary classifications were conducted instead of multiclass classification with Machine Learning classifiers. Two public datasets were used in this study. The first dataset had a mean accuracy of 0.957, and the second dataset had a mean accuracy of 0.954.

OCT and OCT Angiography Update: Clinical Application to Age-Related Macular Degeneration, Central Serous Chorioretinopathy, Macular Telangiectasia, and Diabetic Retinopathy

Similar to ultrasound adapting soundwaves to depict the inner structures and tissues, optical coherence tomography (OCT) utilizes low coherence light waves to assess characteristics in the eye. Compared to the previous gold standard diagnostic imaging fluorescein angiography, OCT is a noninvasive imaging modality that generates images of ocular tissues at a rapid speed. Two commonly used iterations of OCT include spectral-domain (SD) and swept-source (SS). Each comes with different wavelengths and tissue penetration capacities. OCT angiography (OCTA) is a functional extension of the OCT. It generates a large number of pixels to capture the tissue and underlying blood flow. This allows OCTA to measure ischemia and demarcation of the vasculature in a wide range of conditions. This review focused on the study of four commonly encountered diseases involving the retina including age-related macular degeneration (AMD), diabetic retinopathy (DR), central serous chorioretinopathy (CSC), and macular telangiectasia (MacTel). Modern imaging techniques including SD-OCT, TD-OCT, SS-OCT, and OCTA assist with understanding the disease pathogenesis and natural history of disease progression, in addition to routine diagnosis and management in the clinical setting. Finally, this review compares each imaging technique's limitations and potential refinements.

The Role of Inflammation and Therapeutic Concepts in Diabetic Retinopathy-A Short Review

Diabetic retinopathy (DR) as a microangiopathy is the most common complication in patients with diabetes mellitus (DM) and remains the leading cause of blindness among adult population. DM in its complicated pathomechanism relates to chronic hyperglycemia, hypoinsulinemia, dyslipidemia and hypertension-all these components in molecular pathways maintain oxidative stress, formation of advanced glycation end-products, microvascular changes, inflammation, and retinal neurodegeneration as one of the key players in diabetes-associated retinal perturbations. In this current review, we discuss the natural history of DR with special emphasis on ongoing inflammation and the key role of vascular endothelial growth factor (VEGF). Additionally, we provide an overview of the principles of diabetic retinopathy treatments, i.e., in laser therapy, anti-VEGF and steroid options.

Aucubin protects against retinal ganglion cell injury in diabetic rats via inhibition of the p38MAPK pathway

OBJECTIVE

To explore the role of aucubin in regard to injured retinal ganglion cells (RGCs) in diabetic rats and its mechanism.

METHODS

A rat model of diabetes mellitus was created by single intraperitoneal injection of 55 mg/kg of streptozotocin. Rats were treated with intraperitoneal injection of 1, 5, and 10 mg/kg aucubin or 5 μg/kg p38MAPK inhibitor SB203580, once a day, for 28 consecutive days. Body weight, blood glucose, morphological changes, count and apoptosis of RGCs, p38MAPK signaling pathway, apoptosis-related proteins, oxidative stress indices, and inflammatory factors were observed and compared among the groups.

RESULTS

Aucubin and SB203580 reduced the abnormality of the photoreceptor layer, bipolar cell layer and RGCs. Aucubin significantly reduced body weight, fasting blood glucose, RGC apoptosis rate, p38MAPK protein phosphorylation level, protein expression of Caspase 3 and Bax, vascular endothelial growth factors (interleukin-1β, intercellular adhesion molecule-1 and tumor necrosis factor-α) and malondialdehyde levels, and increased RGC count and protein expression of Bcl-2 and Bcl-2/Bax (P < 0.05).

CONCLUSION

Aucubin can protect RGCs in diabetic rats, inhibit RGC apoptosis, and reduce oxidative stress and inflammatory response, and 10 mg/kg aucubin showed optimal efficacy. The mechanism may be related to the inhibition of the p38MAPK signaling pathway.

Diabetic Patients With Rosacea Increase the Risks of Diabetic Macular Edema, Dry Eye Disease, Glaucoma, and Cataract

PURPOSE

Inflammation plays a role in diabetic eye diseases, but the association between rosacea and eye diseases in patients with diabetes remains unknown.

DESIGN

This retrospective cohort study used claims data from the National Health Insurance Research Database in Taiwan to investigate the association between rosacea and eye diseases in patients with diabetes.

MATERIALS AND METHODS

Taiwanese patients diagnosed as having diabetes mellitus between January 1, 1997, and December 31, 2013, and using any hypoglycemic agents were included and divided into rosacea and nonrosacea groups. After applying 1:20 sex and age matching and exclusion criteria, 1:4 propensity score matching (PSM) was conducted to balance the covariate distribution between the groups. The risk of time-to-event outcome between rosacea and nonrosacea groups in the PSM cohort was compared using the Fine and Gray subdistribution hazard model.

RESULTS

A total of 4096 patients with rosacea and 16,384 patients without rosacea were included in the analysis. During a mean follow-up period of 5 years, diabetic patients with rosacea had significantly higher risks of diabetic macular edema [subdistribution hazard ratio (SHR): 1.31, 95% confidence interval (CI): 1.05-1.63], glaucoma with medical treatment (SHR: 1.11, 95% CI: 1.01-1.21), dry eye disease (SHR: 1.55, 95% CI: 1.38-1.75), and cataract surgery (SHR: 1.13, 95% CI: 1.02-1.25) compared with diabetic patients without rosacea. A cumulative incidence analysis performed up to 14 years after the index date revealed that the risks of developing ocular diseases consistently increased over time. No significant differences in diabetic retinopathy, age-related macular degeneration, retinal vascular occlusion, ischemic optic neuropathy, optic neuritis, uveitis, or retinal detachment were identified according to rosacea diagnosis. However, we observed significant associations between rosacea and psoriasis, irritable bowel syndrome, anxiety, and major depressive disorder among patients with diabetes.

CONCLUSIONS

Rosacea is associated with diabetic macular edema, glaucoma, dry eye disease, and cataract development in diabetic patients, as well as increased risks of psoriasis, irritable bowel syndrome, anxiety, and depression in diabetic patients.

Inflammation in diabetic retinopathy: possible roles in pathogenesis and potential implications for therapy

Diabetic retinopathy, characterized as a microangiopathy and neurodegenerative disease, is the leading cause of visual impairment in diabetic patients. Many clinical features observed in diabetic retinopathy, such as capillary occlusion, acellular capillaries and retinal non-perfusion, aggregate retinal ischemia and represent relatively late events in diabetic retinopathy. In fact, retinal microvascular injury is an early event in diabetic retinopathy involving multiple biochemical alterations, and is manifested by changes to the retinal neurovascular unit and its cellular components. Currently, intravitreal anti-vascular endothelial growth factor therapy is the first-line treatment for diabetic macular edema, and benefits the patient by decreasing the edema and improving visual acuity. However, a significant proportion of patients respond poorly to anti-vascular endothelial growth factor treatments, indicating that factors other than vascular endothelial growth factor are involved in the pathogenesis of diabetic macular edema. Accumulating evidence confirms that low-grade inflammation plays a critical role in the pathogenesis and development of diabetic retinopathy as multiple inflammatory factors, such as interleukin-1β, monocyte chemotactic protein-1 and tumor necrosis factor -α, are increased in the vitreous and retina of diabetic retinopathy patients. These inflammatory factors, together with growth factors such as vascular endothelial growth factor, contribute to blood-retinal barrier breakdown, vascular damage and neuroinflammation, as well as pathological angiogenesis in diabetic retinopathy, complicated by diabetic macular edema and proliferative diabetic retinopathy. In addition, retinal cell types including microglia, Müller glia, astrocytes, retinal pigment epithelial cells, and others are activated, to secrete inflammatory mediators, aggravating cell apoptosis and subsequent vascular leakage. New therapies, targeting these inflammatory molecules or related signaling pathways, have the potential to inhibit retinal inflammation and prevent diabetic retinopathy progression. Here, we review the relevant literature to date, summarize the inflammatory mechanisms underlying the pathogenesis of diabetic retinopathy, and propose inflammation-based treatments for diabetic retinopathy and diabetic macular edema.

OCT-Based Biomarkers are Associated with Systemic Inflammation in Patients with Treatment-Naïve Diabetic Macular Edema

INTRODUCTION

Diabetic macular edema (DME) is one of the major sight-threatening complications of diabetic retinopathy, which is associated with retinal inflammation. However, it is still unknown whether DME is associated with systemic inflammation. The study aimed to investigate the association between systemic inflammatory and optical coherence tomography (OCT) biomarkers in patients with treatment-naïve center-involving diabetic macular edema (DME) and to further explore the role of systemic inflammation in DME.

METHODS

Medical records including clinical characteristics and ophthalmic examinations were collected from patients with treatment-naïve center-involving DME. Systemic inflammation markers including systemic immune-inflammatory index (SII), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) were calculated. OCT biomarkers, including intraretinal cyst (IRC) size, disorganization of retinal inner layers (DRIL), external limiting membrane (ELM)/ellipsoid zone (EZ) integrity, retinal hyperreflective foci (HRF), subretinal fluid (SRF) and vitreomacular (VM) status were evaluated manually. Correlation analysis and multivariable linear regression models were used to investigate the relationship between systemic inflammatory markers and OCT biomarkers.

RESULTS

A total of 82 patients with treatment-naïve center-involving DME were included. The number of HRF on OCT was correlated with SII, NLR, and PLR and positively associated with SII (p < 0.001) in both univariate and multivariate linear regression analyses. The differences remained largely the same during subgroup analysis controlling DM duration, SRF, and ELM/EZ integrity. No significant association was observed between other OCT biomarkers and blood inflammatory markers.

CONCLUSION

Retinal HRF in diabetic macular edema is associated with blood inflammatory markers, which supports the theory of HRF's inflammatory nature and emphasizes the important role of inflammation in DME. SII may be a potential marker for DME treatment decisions.

Diabetic Macular Edema Treatment: Laser Photocoagulation Versus anti-VEGF Drugs

Abstract: Objective: The present study was aimed to compare best-corrected vision and central macular thickness for macular edema in diabetes (DME) after utilizing laser, Avastin, and Lucentis. Methods: A retrospective randomized cross-sectional study was conducted at Alfaisal Eye Center, Khartoum. Best-corrected vision and central macular thickness (CMT) were assessed by Snellen's chart and Heidelberg optical coherence tomography OCT, respectively. Results: In this study, a total of 252 records of DME-treated patients with laser applications, Avastin, and Lucentis were enrolled, their mean age was 57 ± 5.22 yrs. A significant enhancement in best-corrected vision and CMT of studied groups with laser applications, Avastin, and Lucentis was obtained (P= 0.000) with no differences between treated groups (p= 0.445 and 0,479), respectively. Non-significant differences in variable measurements related to gender or age (p = 0.117, 0.781), respectively. CMT of females (260 ± 48 μm) was thinner than males (306 ± 74 μm) after treatment (P = 0.000). Conclusion: laser applications, Avastin, and Lucentis improved best-corrected vision and reduced central macular thickness significantly with no clear differences between studied groups. Age or gender have a non-significant impact on dependent variables. Females gained thinner results compared to males after treatment.  

Prediction of anti-VEGF efficacy in diabetic macular oedema using intraocular cytokines and macular optical coherence tomography

PURPOSE

In eyes with diabetic macular oedema (DME), aqueous humour (AH) cytokine levels before and after anti-vascular endothelial growth factor (VEGF) treatment were compared and correlated with optical coherence tomography structural parameters.

METHODS

This prospective study included 56 control patients with cataracts and 83 patients with DME manifesting as diffuse retinal thickening (DRT), cystoid macular oedema and serous retinal detachment (SRD). AH samples were obtained before intravitreal injection of anti-VEGF or cataract surgery. VEGF, interleukin (IL)-6, IL-8, IL-10, interferon-inducible protein 10 (IP-10) and monocyte chemotactic protein 1 (MCP-1) levels were measured by multiplex bead assay. AH cytokine levels, central macular thickness (CMT), number of hyper-reflective foci (HF), continuity of external limiting membrane and ellipsoid zone (EZ) and best-corrected visual acuity were evaluated.

RESULTS

In SRD, IL-6 and MCP-1 levels and HF were increased (all p < 0.05) compared to DRT. At baseline, the number of HF was correlated with VEGF, IL-6, IL-8, IP-10 and MCP-1 (all p < 0.05). Eyes sensitive to anti-VEGF treatment had high baseline levels of VEGF, MCP-1, HF and many EZ disruptions (all p < 0.05). DME patients with normal VEGF levels but with high levels of IL-8, IP-10 and MCP-1 (all p < 0.05) had little change in CMT after anti-VEGF treatment (p = 0.678).

CONCLUSIONS

AH concentrations of some inflammatory cytokines in DME were differentially expressed among the three DME morphologies. HF was associated with VEGF and other inflammatory cytokine levels. Multiple HF at baseline predicted a significant decrease in CMT, and eyes with normal VEGF but increased inflammatory cytokines may be insensitive to anti-VEGF treatment.

Putative Biomarkers in Tears for Diabetic Retinopathy Diagnosis

Purpose

Tear fluid biomarkers may offer a non-invasive strategy for detecting diabetic patients with increased risk of developing diabetic retinopathy (DR) or increased disease progression, thus helping both improving diagnostic accuracy and understanding the pathophysiology of the disease. Here, we assessed the tear fluid of nondiabetic individuals, diabetic patients with no DR, and diabetic patients with nonproliferative DR (NPDR) or with proliferative DR (PDR) to find putative biomarkers for the diagnosis and staging of DR.

Methods

Tear fluid samples were collected using Schirmer test strips from a cohort with 12 controls and 54 Type 2 Diabetes (T2D) patients, and then analyzed using mass spectrometry (MS)-based shotgun proteomics and bead-based multiplex assay. Tear fluid-derived small extracellular vesicles (EVs) were analyzed by transmission electron microscopy, Western Blotting, and nano tracking.

Results

Proteomics analysis revealed that among the 682 reliably quantified proteins in tear fluid, 42 and 26 were differentially expressed in NPDR and PDR, respectively, comparing to the control group. Data are available via ProteomeXchange with identifier PXD033101. By multicomparison analyses, we also found significant changes in 32 proteins. Gene ontology (GO) annotations showed that most of these proteins are associated with oxidative stress and small EVs. Indeed, we also found that tear fluid is particularly enriched in small EVs. T2D patients with NPDR have higher IL-2/-5/-18, TNF, MMP-2/-3/-9 concentrations than the controls. In the PDR group, IL-5/-18 and MMP-3/-9 concentrations were significantly higher, whereas IL-13 was lower, compared to the controls.

Conclusions

Overall, the results show alterations in tear fluid proteins profile in diabetic patients with retinopathy. Promising candidate biomarkers identified need to be validated in a large sample cohort.

Deep Learning Algorithm-Based MRI Image in the Diagnosis of Diabetic Macular Edema

This study investigates the value of magnetic resonance imaging (MRI) based on a deep learning algorithm in the diagnosis of diabetic macular edema (DME) patients. A total of 96 patients with DME were randomly divided into the experimental group (N  = 48) and the control group (N  = 48). A deep learning 3D convolutional neural network (3D-CNN) algorithm for MRI images of patients with DME was designed. The application value of this algorithm was comprehensively evaluated by MRI image segmentation Dice value, sensitivity, specificity, and other indicators and diagnostic accuracy. The results showed that the quality of MRI images processed by the 3D-CNN algorithm based on deep learning was significantly improved, and the Dice value, sensitivity, and specificity index data were significantly better than those of the traditional CNN algorithm (P < 0.05). In addition, the diagnostic accuracy of MRI images processed by this algorithm was 93.78 ± 5.32%, which was significantly better than the diagnostic accuracy of 64.25 ± 10.24% of traditional MRI images in the control group (P < 0.05). In summary, the 3D-CNN algorithm based on deep learning can significantly improve the accuracy and sensitivity of MRI image recognition and segmentation in patients with DME, can significantly improve the diagnostic accuracy of MRI in patients with DME, and has a good clinical application value.

Retinal and Choroidal Vascular Perfusion and Thickness Measurement in Diabetic Retinopathy Patients by the Swept-Source Optical Coherence Tomography Angiography

Purpose

To observe the changes in retinal and choroidal microstructures in patients with different stages of diabetic retinopathy (DR) and to evaluate the vascular perfusion of retina and choroid retinal thickness, retinal and choroidal vessel density by the swept-source optical coherence tomography angiography (SS-OCTA).

Methods

Subjects were divided into three groups: healthy control group (30 cases, 51 eyes), non-proliferative diabetic retinopathy (NPDR, 42 cases, 71 eyes) and proliferative diabetic retinopathy (PDR, 31 cases, 53 eyes). The area of the foveal avascular zone (FAZ), retinal and choroidal vascular perfusion, and the deep vascular complexes, including the intermediate capillary plexus (ICP) and deep capillary plexus (DCP) within the radius of 3, 6, 9, and 12 mm around the fovea were measured by SS-OCTA.

Results

Compared with the healthy control group, DR patients presented significantly increased fovea avascular area, while vessel density (VD) in the ICP and DCP, vascular perfusion rate, and the retinal thickness were considerably decreased. There were significant differences in the retinal thickness, ICP, and DCP vessel densities between the control and NPDR groups, or control and PDR groups, or PDR and NPDR groups. The deep vascular perfusion rate also significantly differed between the control and PDR groups, but there was no significant difference between the PDR and NPDR groups. The choroidal perfusion exhibited significant differences across different areas and amongst the three groups. Furthermore, the choroidal thickness showed a significant difference between the PDR and NPDR groups.

Conclusion

Our results showed significant differences in the area of the avascular fovea and the VD of deep vascular complexes between DR patients and healthy control subjects. Moreover, there were significant differences in retinal VD, especially in the deep-retinalregions, choroidal perfusion, and the volume of large vessel choroid in DR patients with different degrees of disease severity. Notably, SS-OCTA provided in-depth information for detecting the potential VD damage in DR patients caused by a multitudeof factors.

Overview of global publications on machine learning in diabetic retinopathy from 2011 to 2021: Bibliometric analysis

PURPOSE

To comprehensively analyze and discuss the publications on machine learning (ML) in diabetic retinopathy (DR) following a bibliometric approach.

METHODS

The global publications on ML in DR from 2011 to 2021 were retrieved from the Web of Science Core Collection (WoSCC) database. We analyzed the publication and citation trend over time and identified highly-cited articles, prolific countries, institutions, journals and the most relevant research domains. VOSviewer and Wordcloud are used to visualize the mainstream research topics and evolution of subtopics in the form of co-occurrence maps of keywords.

RESULTS

By analyzing a total of 1147 relevant publications, this study found a rapid increase in the number of annual publications, with an average growth rate of 42.68%. India and China were the most productive countries. IEEE Access was the most productive journal in this field. In addition, some notable common points were found in the highly-cited articles. The keywords analysis showed that "diabetic retinopathy", "classification", and "fundus images" were the most frequent keywords for the entire period, as automatic diagnosis of DR was always the mainstream topic in the relevant field. The evolution of keywords highlighted some breakthroughs, including "deep learning" and "optical coherence tomography", indicating the advance in technologies and changes in the research attention.

CONCLUSIONS

As new research topics have emerged and evolved, studies are becoming increasingly diverse and extensive. Multiple modalities of medical data, new ML techniques and constantly optimized algorithms are the future trends in this multidisciplinary field.

Aqueous Level of ANGPTL4 Correlates with the OCTA Metrics of Diabetic Macular Edema in NPDR

PURPOSE

To investigate the aqueous levels of angiogenic factors in nonproliferative diabetic retinopathy (NPDR) patients with diabetic macular edema (DME) and to ascertain their association with optical coherence tomography angiography (OCTA) metrics.

METHODS

This study enrolled 21 NPDR eyes with DME (NPDR/DME+), 17 NPDR eyes without DME (NPDR/DME-), and 16 diabetic eyes without retinopathy (DWR). Luminex bead-based multiplex array was used to measure the levels of 25 cytokines. OCTA system with a scan area of 3 × 3 mm was used to measure retinal thickness (RT), retinal volume (RV), superficial vessel density (SVD), deep vessel density (DVD), foveal avascular zone (FAZ) area, perimeter and acircularity index.

RESULTS

The levels of ANGPTL4 were significantly different among the three groups (P < 0.05), in which NPDR/DME+ group had the highest level and NPDR/DME- group had a higher level than the DWR group (all, P < 0.0167). OCTA examination showed that, compared with DWR and NPDR/DME- group, RT and RV increased and the whole/parafoveal DVD decreased in NPDR/DME+ group (all, P < 0.05). Meanwhile, NPDR/DME- group had lower parafoveal DVD than the DWR group (P < 0.05). Correlation analysis showed that the levels of ANGPTL4 were positively correlated with foveal/parafoveal RT and RV and negatively correlated with whole/parafoveal DVD in NPDR patients (all, P < 0.05). As the influencing factor of RT, RV, and DVD, every additional 10³ pg/ml of ANGPTL4 was associated with an increase in foveal and parafoveal RT of 4.299 μm and 3.598 μm, respectively. Every additional 10⁶ pg/ml of ANGPTL4 was associated with an increase in foveal and parafoveal RV of 3.371 mm³ and 17.705 mm³, respectively. Every additional 10⁴ pg/ml of ANGPTL4 was associated with a decrease in whole and parafoveal DVD of 1.705% and 1.799%, respectively.

CONCLUSIONS

The level of ANGPTL4 in aqueous humor of NPDR patients with DME was significantly increased and ANGPTL4 might predict RT, RV, and parafoveal DVD of DME in NPDR patients.

Targeting Plasma Kallikrein With a Novel Bicyclic Peptide Inhibitor (THR-149) Reduces Retinal Thickening in a Diabetic Rat Model

Purpose

To investigate the effect of plasma kallikrein (PKal)-inhibition by THR-149 on preventing key pathologies associated with diabetic macular edema (DME) in a rat model.

Methods

Following streptozotocin-induced diabetes, THR-149 or its vehicle was administered in the rat via either a single intravitreal injection or three consecutive intravitreal injections (with a 1-week interval; both, 12.5 µg/eye). At 4 weeks post-diabetes, the effect of all groups was compared by histological analysis of Iba1-positive retinal inflammatory cells, inflammatory cytokines, vimentin-positive Müller cells, inwardly rectifying potassium and water homeostasis-related channels (Kir4.1 and AQP4, respectively), vascular leakage (fluorescein isothiocyanate-labeled bovine serum albumin), and retinal thickness.

Results

Single or repeated THR-149 injections resulted in reduced inflammation, as depicted by decreasing numbers and activation state of immune cells and IL-6 cytokine levels in the diabetic retina. The processes of reactive gliosis, vessel leakage, and retinal thickening were only significantly reduced after multiple THR-149 administrations. Individual retinal layer analysis showed that repeated THR-149 injections significantly decreased diabetes-induced thickening of the inner plexiform, inner nuclear, outer nuclear, and photoreceptor layers. At the glial-vascular interface, reduced Kir4.1-channel levels in the diabetic retina were restored to control non-diabetic levels in the presence of THR-149. In contrast, little or no effect of THR-149 was observed on the AQP4-channel levels.

Conclusions

These data demonstrate that repeated THR-149 administration reduces several DME-related key pathologies such as retinal thickening and neuropil disruption in the diabetic rat. These observations indicate that modulation of the PKal pathway using THR-149 has clinical potential to treat patients with DME.

Joint segmentation of multi-class hyper-reflective foci in retinal optical coherence tomography images

Hyper-reflective foci (HRF) refers to the spot-shaped, block-shaped areas with characteristics of high local contrast and high reflectivity, which is mostly observed in retinal optical coherence tomography (OCT) images of patients with fundus diseases. HRF mainly appears hard exudates (HE) and microglia (MG) clinically. Accurate segmentation of HE and MG is essential to alleviate the harm in retinal diseases. However, it is still a challenge to segment HE and MG simultaneously due to similar pathological features, various shapes and location distribution, blurred boundaries, and small morphology dimensions. To tackle these problems, in this paper, we propose a novel global information fusion and dual decoder collaboration-based network (GD-Net), which can segment HE and MG in OCT images jointly. Specifically, to suppress the interference of similar pathological features, a novel global information fusion (GIF) module is proposed, which can aggregate the global semantic information efficiently. To further improve the segmentation performance, we design a dual decoder collaborative workspace (DDCW) to comprehensively utilize the semantic correlation between HE and MG while enhancing the mutual influence on them by feedback alternately. To further optimize GD-Net, we explore a joint loss function which integrates pixel-level with image-level. The dataset of this study comes from patients diagnosed with diabetic macular edema at the department of ophthalmology, University Medical Center Groningen, the Netherlands. Experimental results show that our proposed method performs better than other state-of-the-art methods, which suggests the effectiveness of the proposed method and provides research ideas for medical applications.

Algorithm for Detection and Quantification of Hyperreflective Dots on Optical Coherence Tomography in Diabetic Macular Edema

Purpose: To develop an algorithm to detect and quantify hyperreflective dots (HRDs) on optical coherence tomography (OCT) in patients with diabetic macular edema (DME).

Materials and Methods: Twenty OCTs (each OCT contains 128 b scans) from 20 patients diagnosed with DME were included in this study. Two types of HRDs, hard exudates and small HRDs (hypothesized to be activated microglia), were identified and labeled independently by two raters. An algorithm using deep learning technology was developed based on input (in total 2,560 OCT b scans) of manual labeling and differentiation of HRDs from rater 1. 4-fold cross-validation was used to train and validate the algorithm. Dice coefficient, intraclass coefficient (ICC), correlation coefficient, and Bland–Altman plot were used to evaluate agreement of the output parameters between two methods (either between two raters or between one rater and proposed algorithm).

Results: The Dice coefficients of total HRDs, hard exudates, and small HRDs area of the algorithm were 0.70 ± 0.10, 0.72 ± 0.11, and 0.46 ± 0.06, respectively. The correlations between rater 1 and proposed algorithm (range: 0.95–0.99, all p < 0.001) were stronger than the correlations between the two raters (range: 0.84–0.96, all p < 0.001) for all parameters. The ICCs were higher for all the parameters between rater 1 and proposed algorithm (range: 0.972–0.997) than those between the two raters (range: 0.860–0.953).

Conclusions: Our proposed algorithm is a good tool to detect and quantify HRDs and can provide objective and repeatable information of OCT for DME patients in clinical practice and studies.

Malfunction of outer retinal barrier and choroid in the occurrence and progression of diabetic macular edema

Diabetic macular edema (DME) is the most common cause of vision loss in diabetic retinopathy, affecting 1 in 15 patients with diabetes mellitus (DM). The disruption of the inner blood-retina barrier (BRB) has been largely investigated and attributed the primary role in the pathogenesis and progression in DME, but there is increasing evidence regarding the role of outer BRB, separating the RPE from the underlying choriocapillaris, in the occurrence and evolution of DME. The development of novel imaging technologies has led to major improvement in the field of in vivo structural analysis of the macula allowing us to delve deeper into the pathogenesis of DME and expanding our vision regarding this condition. In this review we gathered the results of studies that investigated specific outer BRB optical coherence tomography parameters in patients with DM with the aim to outline the current status of its role in the pathogenesis and progression of DME and identify new research pathways contributing to the advancement of knowledge in the understanding of this condition.

En face image-based classification of diabetic macular edema using swept source optical coherence tomography

This retrospective study was performed to classify diabetic macular edema (DME) based on the localization and area of the fluid and to investigate the relationship of the classification with visual acuity (VA). The fluid was visualized using en face optical coherence tomography (OCT) images constructed using swept-source OCT. A total of 128 eyes with DME were included. The retina was segmented into: Segment 1, mainly comprising the inner nuclear layer and outer plexiform layer, including Henle’s fiber layer; and Segment 2, mainly comprising the outer nuclear layer. DME was classified as: foveal cystoid space at Segment 1 and no fluid at Segment 2 (n = 24), parafoveal cystoid space at Segment 1 and no fluid at Segment 2 (n = 25), parafoveal cystoid space at Segment 1 and diffuse fluid at Segment 2 (n = 16), diffuse fluid at both segments (n = 37), and diffuse fluid at both segments with subretinal fluid (n = 26). Eyes with diffuse fluid at Segment 2 showed significantly poorer VA, higher ellipsoid zone disruption rates, and greater central subfield thickness than did those without fluid at Segment 2 (P < 0.001 for all). These results indicate the importance of the localization and area of the fluid for VA in DME.

Evaluation of morphological characteristics of diabetic macular edema in patients with non-proliferative versus proliferative diabetic retinopathy: a spectral-domain optical coherence tomography study

PURPOSE

To evaluate the morphological characteristics in patients with diabetic macular edema (DME), either with co-existent non-proliferative diabetic retinopathy (NPDR) or with PDR.

METHODS

Retrospective study includes 138 treatment naïve patients with DME, either with NPDR (n = 96) or in combination with PDR (n = 42). All patients underwent best corrected visual acuity (BCVA) measurement, spectral domain-optical coherence tomography (SD-OCT) and fluorescein angiography, while demographic characteristics were also recorded. Specific clinical and morphological characteristics were analyzed and compared between the two groups.

RESULTS

Patients with DME and PDR presented higher central retinal thickness and mixed type of edema, with predominantly cystoid component and large cysts, extending in the foveal, peri- and para-foveal area, compared to patients with DME and NPDR. The presence of non-perfusion areas in patients with DME and PDR led to additional ellipsoid zone and external limiting membrane disruption in a higher percentage, accompanied with worse visual acuity compared to patients with DME and NPDR. Patients with DME and PDR had also higher vitreomacular traction percentage and higher HbA1c levels than those with DME and NPDR.

CONCLUSION

Variations in morphological characteristics of DME on SD-OCT existed between patients with NPDR and those with PDR. These differences may explain the alterations in visual acuity and prognosis.

Optical Coherence Tomography Predictors of Favorable Functional Response in Naïve Diabetic Macular Edema Eyes Treated with Dexamethasone Implants as a First-Line Agent

Purpose

To evaluate efficacy and safety of intravitreal dexamethasone 0.7 mg implant in treatment-naïve DME patients and to assess the utility of OCT structural biomarkers as predictors of functional response after treatment.

Methods

Thirty-nine eyes of 39 diabetic patients with center involving DME were enrolled. Best-corrected visual acuity (BCVA) and SS-OCT (DRI SS-OCT Triton, Topcon, Japan) to evaluate central retinal thickness (CRT), serous retinal detachment (SRD), intraretinal cysts (IRC), number of hyper-reflective spots (HRS), integrity of the ellipsoid zone (EZ), disorganization of the inner retinal layers (DRIL), vitreomacular adhesion (VMA), vitreomacular traction (VMT), and posterior vitreous detachment (PVD) were evaluated at baseline and at 3, 6, and 12 months after treatment. Multiple logistic analysis was performed to evaluate the possible OCT biomarker as predictive factors for final visual acuity improvement at the end of treatment.

Results

At 12 months after treatment, the mean BCVA improved from 51.6 ± 17.5 to 56.9 ± 17.3 ETDRS letters (p=0.03). Furthermore, there were statistically significant changes in CRT, IRC, HRS, and SRD. Nineteen patients presented a  >10-letters improvement in BCVA; the presence of SRD at baseline was a predictor of good functional treatment response at 12 months (OR 2.1; 95% C.I. 1.2–4.9; p=0.001) as well as the presence of EZ integrity preoperatively (OR 1.3; 95% C.I. 0.5–2.4; p=0.001) and the absence of vitreoretinal interface alteration (OR 1.1; 95% C.I. 0.3–2.3; p=0.02). No significant changes in the IOP and lens status were observed throughout the follow-up period.

Conclusion

This study empathized the importance of structural biomarkers as predictors of favorable response and confirmed the efficacy and safety of intravitreal dexamethasone implant in treatment-naïve DME patients showing a better functional response in the presence of SRD integrity of EZ and absence of vitreoretinal alterations.

Saudi Arabia Guidelines for diabetic macular edema: A consensus of the Saudi Retina Group

Diabetes mellitus (DM) and its complications are major public health burdens in Saudi Arabia. The prevalence of diabetic retinopathy (DR) is 19.7% and the prevalence of diabetic macular edema (DME) is 5.7% in Saudi Arabia. Diabetic macular edema is a vision-threatening complication of DR and a major cause of vision loss worldwide. Ocular treatments include retinal laser photocoagulation, anti-vascular endothelial growth factor (anti-VEGF) agents, intravitreal corticosteroids, and vitreoretinal surgery when necessary. The present consensus was developed as a part of the Saudi Retina Group's efforts to generate Saudi guidelines and consensus for the management of DME, including recommendations for its diagnosis, treatment, and best practice. The experts' panel stipulates that the treatment algorithm should be categorized according to the presence of central macula involvement. In patients with no central macular involvement, laser photocoagulation is recommended as the first-line option. Patients with central macular involvement and no recent history of cardiovascular (CVS) or cerebrovascular disorders can be offered anti-VEGF agents as the first-line option. In the case of non-responders (defined as an improvement of <20% in optical coherence tomography or a gain of fewer than 5 letters in vision), switching to another anti-VEGF agent or steroids should be considered after 3 injections. Within the class of steroids, dexamethasone implants are recommended as the first choice. In patients with a recent history of CVS events, the use of anti-VEGF agents is not recommended, regardless of their lens status. The experts' panel recommends that a future study be conducted to provide a cut-off point for early switching to steroid implants in pseudo-phakic eyes.

Bone Morphogenetic Protein-2 Induces Non-Canonical Inflammatory and Oxidative Pathways in Human Retinal Endothelial Cells

The mechanisms of diabetic retinopathy (DR), are not yet fully understood. We previously demonstrated an upregulation of retinal bone morphogenetic protein-2 (BMP2) in experimental diabetes and in retinas of diabetic human subjects. The purpose of current study was to investigate the role of non-canonical inflammatory pathway in BMP2-induced retinal endothelial cell (REC) barrier dysfunction. For this purpose, we used RT-PCR and western blotting to evaluate the levels of BMP2 signaling components (BMP2, BMP4, BMP receptors), VEGF, phosphorylated p38 MAPK and NFκB, and oxidative stress markers in cultured human retinal endothelial cells (HRECs) subjected to BMP2 (50ng/ml) for up to 24 h. Also, effect of high glucose (HG, 30mM D-glucose) on the expression of BMP2 and its downstream genes was examined in HRECs. H2-DCF is a fluorogenic dye that measures the levels of cellular reactive oxygen species (ROS) was used to measure the pro-oxidative effect of BMP2. Moreover, we evaluated the effect of inhibiting p38 and VEGF signaling on BMP2-induced HRECs barrier dysfunction by measuring the trans-endothelial cell electrical resistance (TER) using electric cell-substrate impedance sensing (ECIS). We also tested the effect of HG on the integrity of HRECs barrier in the presence or absence of inhibitors of BMP2 signaling. Our data reveals that BMP2 and high glucose upregulates BMP components of the BMP signaling pathway (SMAD effectors, BMP receptors, and TGFβ ligand itself) and induces phosphorylation of p38 MAPK and NFκB with nuclear translocation of NFκB. Inhibition of p38 or NFκB attenuated BMP2-induced VEGF expression and barrier dysfunction in HRECs. Also, inhibition of VEGFR2 attenuated BMP2-induced barrier dysfunction. Moreover, BMP2 induces generation of ROS and endothelial nitric oxide synthase (eNOS) expression and activity in HRECs. Finally, HG upregulated BMP2 and its downstream genes (SMAD, BMP4, ALKs, and TGF-β) in HRECs and BMP2 inhibitors attenuated HG-induced HRECs barrier dysfunction. Our results suggest that in addition to the regular canonical SMAD signaling BMP2 induces non-canonical inflammatory pathway in HRECs via activation of p38/NFκB pathway that causes the upregulation of VEGF and the disruption of HRECs. Inhibition of BMP2 signaling is a potential therapeutic intervention to preserve endothelial cell barrier function in DR.

Retinal biomarkers for Alzheimer's disease and vascular cognitive impairment and dementia (VCID): implication for early diagnosis and prognosis

Cognitive impairment and dementia are major medical, social, and economic public health issues worldwide with significant implications for life quality in older adults. The leading causes are Alzheimer's disease (AD) and vascular cognitive impairment/dementia (VCID). In both conditions, pathological alterations of the cerebral microcirculation play a critical pathogenic role. Currently, the main pathological biomarkers of AD-β-amyloid peptide and hyperphosphorylated tau proteins-are detected either through cerebrospinal fluid (CSF) or PET examination. Nevertheless, given that they are invasive and expensive procedures, their availability is limited. Being part of the central nervous system, the retina offers a unique and easy method to study both neurodegenerative disorders and cerebral small vessel diseases in vivo. Over the past few decades, a number of novel approaches in retinal imaging have been developed that may allow physicians and researchers to gain insights into the genesis and progression of cerebromicrovascular pathologies. Optical coherence tomography (OCT), OCT angiography, fundus photography, and dynamic vessel analyzer (DVA) are new imaging methods providing quantitative assessment of retinal structural and vascular indicators-such as thickness of the inner retinal layers, retinal vessel density, foveal avascular zone area, tortuosity and fractal dimension of retinal vessels, and microvascular dysfunction-for cognitive impairment and dementia. Should further studies need to be conducted, these retinal alterations may prove to be useful biomarkers for screening and monitoring dementia progression in clinical routine. In this review, we seek to highlight recent findings and current knowledge regarding the application of retinal biomarkers in dementia assessment.

New Insights into Diabetic and Vision-Threatening Retinopathy: Importance of Plasma Long Pentraxine 3 and Taurine Levels

PURPOSE

To investigate diabetic retinopathy (DR), plasma long pentraxin-3 (PTX-3) and taurine levels, and systemic factors in patients with type 2 diabetes mellitus (DM).

MATERIALS AND METHODS

Patients with type 2 DM were categorized based on the presence of DR and maculopathy. Retinal findings (retinopathy, maculopathy, flame-shaped hemorrhage, intraretinal microvascular abnormalities, neovascularization of the optic disc, neovascularization elsewhere, and soft exudate); laboratory findings (fasting blood glucose, glycosylated hemoglobin [HbA1c], Taurine, PTX-3); systolic blood pressure (SBP) and diastolic blood pressure (DBP) were analyzed.

RESULTS

In this study, 39 patients with a mean age of 59.5 ± 8.1 years were included. The mean taurine level was significantly lower (p = .025) and HbA1c values were significantly higher (p = .0001) in patients with and without DR, respectively. In patients with varying severity of DR, a significant difference in the plasma taurine level was found (p = .0001). The mean PTX-3 level decreased with the severity of retinopathy; however, there was no significant difference in levels among the grading groups (p = .732). Taurine and PTX-3 levels were significantly lower in patients with maculopathy (p = .001 and p = .022, respectively) and significantly higher in patients with grade 0 maculopathy than in those with grade 1, 2, or 3 maculopathy (p = .023, p = .01, and p = .01, respectively). Patients with flame-shaped hemorrhage had significantly lower PTX-3 levels (p = .009) and higher SBP and DBP levels (p = .003, p = .023) than those without the hemorrhage.

CONCLUSIONS

No significant relation between PTX-3 level and severity of DR was found. HbA1c, taurine, and PTX-3 levels in patients with vision-threatening DR symptoms were significantly different from those without these symptoms. Management of systemic blood pressure and glycemic control is mandatory in the follow-up of DR, and increasing the plasma taurine levels can prevent vision loss.