Diabetic Macular Edema: Pathophysiology and Novel Therapeutic Targets

DETECTION OF MORPHOLOGIC PATTERNS OF DIABETIC MACULAR EDEMA USING A DEEP LEARNING APPROACH BASED ON OPTICAL COHERENCE TOMOGRAPHY IMAGES

PURPOSE

To develop a deep learning (DL) model to detect morphologic patterns of diabetic macular edema (DME) based on optical coherence tomography (OCT) images.

METHODS

In the training set, 12,365 OCT images were extracted from a public data set and an ophthalmic center. A total of 656 OCT images were extracted from another ophthalmic center for external validation. The presence or absence of three OCT patterns of DME, including diffused retinal thickening, cystoid macular edema, and serous retinal detachment, was labeled with 1 or 0, respectively. A DL model was trained to detect three OCT patterns of DME. The occlusion test was applied for the visualization of the DL model.

RESULTS

Applying 5-fold cross-validation method in internal validation, the area under the receiver operating characteristic curve for the detection of three OCT patterns (i.e., diffused retinal thickening, cystoid macular edema, and serous retinal detachment) was 0.971, 0.974, and 0.994, respectively, with an accuracy of 93.0%, 95.1%, and 98.8%, respectively, a sensitivity of 93.5%, 94.5%, and 96.7%, respectively, and a specificity of 92.3%, 95.6%, and 99.3%, respectively. In external validation, the area under the receiver operating characteristic curve was 0.970, 0.997, and 0.997, respectively, with an accuracy of 90.2%, 95.4%, and 95.9%, respectively, a sensitivity of 80.1%, 93.4%, and 94.9%, respectively, and a specificity of 97.6%, 97.2%, and 96.5%, respectively. The occlusion test showed that the DL model could successfully identify the pathologic regions most critical for detection.

CONCLUSION

Our DL model demonstrated high accuracy and transparency in the detection of OCT patterns of DME. These results emphasized the potential of artificial intelligence in assisting clinical decision-making processes in patients with DME.

Short-Term Outcomes of Refractory Diabetic Macular Edema Switch From Ranibizumab to Dexamethasone Implant and the Influential Factors: A Retrospective Real World Experience

Introduction: To evaluate the effectiveness and safety of intravitreal dexamethasone (DEX) implants in refractory diabetic macular edema (DME) treated by intravitreal ranibizumab.

Materials and Methods: We retrospectively analyzed DME patients who received DEX implant treatment after being refractory to at least 3 monthly intravitreal ranibizumab injections. The main outcomes were best-corrected visual acuity (BCVA), central retinal thickness (CRT), and intraocular pressure (IOP).

Results: Twenty-nine eyes of 26 patients who had previously received an average of 8.1 ± 4.4 ranibizumab injections were included. Patients received between one and three DEX implants during 12.4 ± 7.4 months of follow-up. The mean final CRT significantly decreased from 384.4 ± 114.4 μm at baseline to 323.9 ± 77.7 μm (p = 0.0249). The mean final BCVA was 51.4 ± 21.3 letters, which was not significant compared to baseline (44.9 ± 30.2 letters, p = 0.1149). Mean IOP did not increase significantly. All patients tolerated the treatment well without serious adverse events. Higher baseline CRT and worse BCVA correlated with better therapeutic responses.

Conclusion: Switching to DEX implant is feasible and safe for treating patients of DME refractory to intravitreal ranibizumab in real world. Further larger-scale or multicenter studies would be conducted to explore different DEX treatment strategies for DME, such as first-line or early switch therapy, for better BCVA improvement.

Treatment choices for diabetic macular oedema: a guideline for when to consider an intravitreal corticosteroid, including adaptations for the COVID-19 era

First-line treatment of centrally involved diabetic macular oedema (CI-DMO) is often with an anti-vascular endothelial growth factor (anti-VEGF) agent. Although this can provide efficacy in the majority of eyes, a sizeable proportion do not respond sufficiently and many continue to receive anti-VEGF therapy after it may be optimal. This imposes a treatment burden on both patients and clinicians and, most importantly of all, can be sight threatening. Changing treatment to an intravitreal corticosteroid implant at the appropriate time may help optimise patient outcomes and reduce injection frequency, thereby reducing treatment burden. Eight retina specialists convened to discuss how to ensure eyes with CI-DMO receiving intravitreal anti-VEGF therapy are evaluated for a potential change to intravitreal corticosteroid therapy at the most effective time in their treatment journey. They concluded that clear criteria on when to consider changing treatment would be helpful and so developed a consensus guideline covering key decision points such as when and how to assess response to anti-VEGF therapy, when to consider a change to corticosteroid therapy and when and how to assess the response to corticosteroid therapy. The guideline was developed before the COVID-19 pandemic but, with the additional challenges arising from this including even greater pressure on clinic capacity, it is more important than ever to reconsider current working practices and adopt changes to improve patient care while also easing pressure on clinic capacity, reducing hospital visits and maintaining patient safety. This publication therefore also includes suggestions for adapting the guidelines in the COVID-19 era.

Visual Function for Driving in Diabetic Macular Edema and Retinal Vein Occlusion Post-Stabilization with Anti-Vascular Endothelial Growth Factor

Purpose

What is the level of visual function in patients with diabetic macular edema (DME) and retinal vein occlusion (RVO) post-stabilization with anti-vascular endothelial growth factor?

Patients and Methods

This observational non-controlled single center study evaluated visual function in two patient populations with macular edema 25 with diabetic macular edema and 25 with retinal vein occlusion treated following standard protocol of anti-VEGF therapy post- stabilization.

Results

A total of 68 eyes from 50 patients were analyzed including 18 bilateral and 7 unilateral diabetic macular edema, 14 patients with central and 11 with branch retinal vein occlusion. The mean age was 69± 11 years and 64% were male. In the RVO group: LogMAR BCVA was 0.12±0.13 compared to the unaffected eye 0.04±0.05 (P=<0.01), contrast sensitivity in the treated eye was 1.69±0.21 log units compared to 1.84± 0.15 log units in the unaffected eye (p=<0.01), the ganglion cell volume was 0.88± 0.15 mm³ in the treated eye compared to 1.04± 0.1 mm³ in the unaffected eye (P=<0.01). In the diabetic macular edema group: LogMAR BCVA was 0.17±0.13, contrast sensitivity in the treated eye was 1.16±0.21 log units compared to the normal population 1.92±0.8 log units (p=<0.01), the ganglion cell volume was 0.94± 0.14 mm³ in the treated eye compared to 1.03± 0.12 mm³ in the normal population (P=<0.001). In both groups a majority of treated eyes retained visual acuity ≥+0.4 LogMAR (diabetic macular edema 95%, RVO 96%) however contrast sensitivity was more than two standard deviations below the normal population mean in a majority of treated eyes in both groups (diabetic macular edema 88% RVO 64%).

Conclusion

Impairment in contrast sensitivity in both groups could impact activities of daily living including driving and should prompt questions about how we advise patients regarding their level of function and the potential limitations/restrictions that should be placed on such activities.

Patterns of ellipsoid zone change associated with visual outcome for diabetic macular oedema

Clinical relevance: Optical coherence tomography biomarkers are dynamic and possibly change over time. The dynamic biomarkers may better predict improvement of final vision than those at baseline for diabetic macular oedema after treatment.Background: To investigate predictors for ellipsoid zone (EZ) dynamics and the association with visual acuity after treatment for diabetic macular oedemaMethods: A total of 135 eyes from 135 patients with anti-vascular endothelial growth factor treatment for diabetic macular oedema were retrospectively enrolled in this study. EZ status was evaluated by optical coherence tomography at baseline, 1, 3, 6, and 12 months post-operatively. Macular perfusion status was analysed by fluorescein angiography. Duration of EZ disruption was quantified by giving scores from 0 to 5 based on the sum of visits with evidence of EZ disruption. Linear regression models were used to predict factors for scores of EZ disruption. Binary logistic regression was used to predict various EZ biomarkers for final visual acuity improvement.Results: Thirty of 87 eyes (34.4%) with intact EZ at baseline developed subsequent EZ disruption. For those with EZ disruption at baseline, 17 of 48 (35.4%) patients had restoration of disrupted EZ over time. Non-perfused macula was associated with both earlier development of EZ disruption and poor restoration (p < 0.001 and p = 0.011, respectively). Non-perfused macula, absence of epiretinal membrane, and EZ disruption at baseline predicted higher EZ scores (p < 0.001, p = 0.022 and p < 0.001, respectively). Higher EZ scores (p = 0.016), but not baseline EZ disruption (p = 0.56), were less likely to have improvement of final vision 5 letters or more.Conclusion: Macular perfusion status played an independent role in EZ dynamics. Duration of EZ disruption could be more predictive than baseline status for improvement of vision over 12 months.

Involvement of Cytokines in the Pathogenesis of Diabetic Macular Edema

Diabetic macular edema (DME) is a critical complication of diabetic retinopathy, a condition that arises from the breakdown of the blood–retinal barrier and the consequent increase in vascular permeability. Over the years, attempts have been made to treat DME by various approaches, including laser photocoagulation, steroid triamcinolone acetonide, and vitrectomy. However, treatment was unsatisfactory until research identified vascular endothelial growth factor (VEGF) as a factor in the pathogenesis of DME. Intraocular anti-VEGF agents show good efficacy in DME. Nevertheless, in some patients the condition recurs or becomes resistant to treatment, suggesting that other factors may be involved. Because inflammation and retinal hypoxia are seen in DME, research has examined the potential role of cytokines and other inflammatory mediators. In this review, we provide an overview of this research and describe feedback mechanisms that may represent a target for novel treatments.

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.

Citicoline in Ophthalmological Neurodegenerative Disease: A Comprehensive Review

Cytidine 5'-diphosphocholine has been widely studied in systemic neurodegenerative diseases, like Alzheimer's disease, Parkinson's disease, and brain ischemia. The rationale for the use of citicoline in ophthalmological neurodegenerative diseases, including glaucoma, anterior ischemic optic neuropathy, and diabetic retinopathy, is founded on its multifactorial mechanism of action and the involvement in several metabolic pathways, including phospholipid homeostasis, mitochondrial dynamics, as well as cholinergic and dopaminergic transmission, all being involved in the complexity of the visual transmission. This narrative review is aimed at reporting both pre-clinical data regarding the involvement of citicoline in such metabolic pathways (including new insights about its role in the intracellular proteostasis through an interaction with the proteasome) and its effects on clinical psychophysical, electrophysiological, and morphological outcomes following its use in ophthalmological neurodegenerative diseases (including the results of the most recent prospective randomized clinical trials).

Systemic contribution of inflammatory mediators to the severity of diabetic and uveitic macular edema

PURPOSE

To assess whether serum cytokine and growth factor levels are associated with diabetic macular edema (DME) and uveitic macular edema (UME) objective severity.

METHODS

Cross-sectional observational study of 81 patients (1 eye/patient) with DME (n=48) and UME (n=33). Macular edema (ME) was defined upon central macular thickness (CMT) ≥ 300 μm on spectral domain optical coherence tomography (OCT). Serum samples were obtained from peripheral blood and IL-1β, IL-6, IL-8, IL-10, MCP-1, TNF-α, and VEGF levels were determined by Luminex analysis. Main outcome measure was the correlation between mediators' levels and CMT and macular volume (MV) on OCT for ME cases.

RESULTS

In DME, IL-6 levels were found to significantly correlate with MV (r=0.324; p=0.028) whereas in UME, IL-8 was significantly associated with both CMT (r=0.401; p=0.021) and MV (r=0.391; p=0.024). IL-8 independently correlated with CMT (ß=177.2; p=0.033) and MV (ß=3.17; p=0.008) in UME multivariate model.

CONCLUSION

Peripheral blood IL-6 and IL-8 levels could play a role in the severity of DME and UME, respectively. IL-8 even seems to be independently associated with CMT and MV in UME cases. Such systemic implications could enforce DME and UME personalized diagnostic and therapeutic approaches.

Serous business: Delineating the broad spectrum of diseases with subretinal fluid in the macula

A wide range of ocular diseases can present with serous subretinal fluid in the macula and therefore clinically mimic central serous chorioretinopathy (CSC). In this manuscript, we categorise the diseases and conditions that are part of the differential diagnosis into 12 main pathogenic subgroups: neovascular diseases, vitelliform lesions, inflammatory diseases, ocular tumours, haematological malignancies, paraneoplastic syndromes, genetic diseases, ocular developmental anomalies, medication-related conditions and toxicity-related diseases, rhegmatogenous retinal detachment and tractional retinal detachment, retinal vascular diseases, and miscellaneous diseases. In addition, we describe 2 new clinical pictures associated with macular subretinal fluid accumulation, namely serous maculopathy with absence of retinal pigment epithelium (SMARPE) and serous maculopathy due to aspecific choroidopathy (SMACH). Differentiating between these various diseases and CSC can be challenging, and obtaining the correct diagnosis can have immediate therapeutic and prognostic consequences. Here, we describe the key differential diagnostic features of each disease within this clinical spectrum, including representative case examples. Moreover, we discuss the pathogenesis of each disease in order to facilitate the differentiation from typical CSC.

Diabetic maculopathy: multicolour and SD-OCT versus fundus photography

Objective

The English Diabetic Eye Screening (DES) programme recommends patients with M1 diabetic maculopathy to be referred to hospital eye services. DES uses flash fundus photography as the reference standard for maculopathy grading. We compared multicolour versus non-stereoscopic fundus photography at identifying M1 maculopathy, with spectral domain optical coherence tomography (SD-OCT) identifying macular thickening.

Methods and analysis

This cross-sectional study included 345 patients with R1M1 referred from DES and reviewed in secondary care with fundus photographs, multicolour and SD-OCT. Maculopathy was graded based on DES exudate criteria on both multicolour and fundus photography in a blind fashion by two independent graders. Macular thickness was ascertained on SD-OCT.

Results

Intergrader agreement on grading maculopathy using fundus photography (Cohen's κ=0.91) and multicolour (Cohen's κ=0.82) was 'almost perfect'. Agreement between fundus photography and multicolour on grading maculopathy (Cohen's κ=0.76) was 'substantial'. Compared with fundus photography, multicolour had sensitivity of 87% (95% CI 81% to 93%) and specificity of 90% (95% CI 87% to 94%) in detecting M1 maculopathy. SD-OCT identified 84 eyes with macular thickening, 47 of which were graded as M0 by fundus photography. 5 eyes with exudates and severe macular oedema requiring urgent intervention were also missed on fundus photography but not on multicolour. Multicolour, when complemented by SD-OCT, did not miss any clinically significant macular oedema.

Conclusion

Multicolour integrates synergistically in a single platform with SD-OCT providing effective monitoring of M1 diabetic maculopathy. The need for fundus photography is eliminated by multicolour/SD-OCT in dedicated R1M1 virtual clinics not requiring parallel diabetic retinopathy grading.

A dynamic nomogram for predicting diabetic macular edema in type 2 diabetes patients based on plasma cytokines

OBJECTIVE

This study investigated changes of plasma cytokines and aimed to build a dynamic nomogram for diabetic macular edema (DME) in type 2 diabetes mellitus (T2DM).

METHODS

In a pilot cohort, plasma samples were selected from 9 T2DM patients and 9 DME patients to screen for cytokine differences. The screening cytokines were then validated by enzyme-linked immunoassay in a cohort, which contained 100 DME (DME group) and 100 T2DM patients without DME (T2DM group). A dynamic nomogram for predicting DME was developed, based on the plasma cytokines.

RESULTS

In the pilot cohort, 11 plasma cytokines were significantly increased in the DME group. In the validation cohort, platelet-derived growth factor (PDGF)-BB, tissue inhibitors of metalloproteinase (TIMP)-1, angiopoietin (ANG-1), and vascular endothelial cell growth factor receptor (VEGFR)-2 were confirmed to be significantly elevated in the DME group. The dynamic nomogram demonstrated good calibration and discrimination, with an area under the receiver operating characteristic curve (AUC) of 0.88. In the test set, sensitivity, specificity, and AUC were 73.3%, 80.0%, and 0.84, respectively.

CONCLUSION

Plasma cytokines were closely associated with DME. A novel dynamic monogram including ANG-1, PDGF-BB, TIMP-1, and VEGFR2 was a novel tool for predicting DME.

Association Between First- and Third-Month Responses to Intravitreal Ranibizumab for Diabetic Macular Edema

Purpose:

This work examines the relationship between first- and third-month anatomical and visual response with antivascular endothelial growth factor for diabetic macular edema.

Methods:

We prospectively evaluated 58 eyes with center-involved diabetic macular edema. Response was categorized upon the anatomical status after 3 monthly doses based on the reduction of central macular thickness (CMT) from baseline (≥20% or not). Correlation analysis between the anatomical response status, gained letters, optical coherence tomography morphological features, and other baseline characteristics were obtained.

Results:

Twenty-five eyes (43.1%) achieved an anatomical reduction of ≥20% at the third month. Those with a reduction of ≥20% of CMT had subretinal fluid ( P < .01), lower hemoglobin A1c values ( P < .01), lower proportion of intraretinal cysts ( P < .01), a greater anatomical reduction, and visual improvement at the first month of treatment. Multiple logistic regression analysis, showed that the change of CMT after the first injection was an independent predictor for the anatomical reduction of ≥20% after the loading phase ( P < .05). Best corrected visual acuity gain after the first dose showed a significant association with an improvement of ≥10 letters after the loading phase ( P < .05), but not for macular thickness reduction.

Conclusions:

First month anatomical reduction was associated with the anatomical response at 3 months ( P = .042) after monthly ranibizumab therapy. Visual improvement at the first month was predictive only for the visual outcome after the 3 monthly doses ( P = .032).

Diabetic vascular hyperpermeability: optical coherence tomography angiography and functional loss assessments of relationships among retinal vasculature changes

Our study assessed the influence of vascular permeability on vascular flow density (FD)-correlated retinal sensitivity (RS) in DR. In this cross-sectional, prospective, consecutive study, RS in the extrafoveal macula of DR patient was measured by microperimetry. FD was measured in the total, superficial, and deep capillary plexus layers (TCP, SCP, and DCP) by optical coherence tomography angiography. All measurement points were classified into four categories according to intensity of fluorescein leakage and FD, and the RS reduction was compared. A stratified analysis by retinal thickness (RT) was also performed. Fourteen eyes (14 patients) were enrolled. FDs at 207 RS measurement points were analyzable. For TCP, SCP and DCP, the leakage did not decrease RS at points where FD was maintained. The greater the leakage, the smaller the RS reduction at points with low FD in TCP (P = .020). Points with high leakage showed a significant smaller RS reduction than points with low leakage (P = .001 for TCP, P = .040 for SCP, and P = .046 for DCP) only in areas with low RT and low FD. Our results suggested that vascular hyperpermeability may inhibit the RS reduction in the non-edematous ischemic diabetic retina.

The effect of intravitreal anti-vascular endothelial growth factor injections on corneal endothelium in patients with diabetic macular oedema

PURPOSE

To evaluate the characteristics of corneal parameters in patients with diabetic macular oedema (DME) treated with intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections.

METHODS

Participants in this study were 36 patients with DME, treated with either intravitreal ranibizumab (n = 16) or aflibercept (n = 20). All participants underwent best-corrected visual acuity (BCVA) measurement, optical coherence tomography and non-contact specular microscopy to evaluate corneal endothelium parameters (endothelial cell density-ECD, hexagonality, coefficient of variation of the cell size and central corneal thickness-CCT), at baseline and at months 6 and 12 after the first intravitreal injection. Comparisons between baseline and months 6 and 12 were performed.

RESULTS

There was no statistically significant difference regarding ECD, hexagonality, coefficient of variation of the cell size and CCT at month 6 and 12 post initial injection compared to baseline in patients with DME. BCVA improved significantly at month 6 and 12 compared to baseline (p < 0.001 for both comparisons). Central retinal thickness was significantly reduced at month 6 and 12 compared to baseline (p < 0.001 for both comparisons).

CONCLUSION

Intravitreal anti-VEGF injections in patients with DME were found not to affect corneal parameters, namely ECD, hexagonality, coefficient of variation of the cell size and CCT at the long-term follow-up of 12 months.

Aqueous Cytokine Expression and Higher Order OCT Biomarkers: Assessment of the Anatomic-Biologic Bridge in the IMAGINE DME Study

PURPOSE

To identify biomarkers for predicting response to anti-vascular endothelial growth factor (VEGF) therapy in diabetic macular edema (DME) and evaluate any links between cytokine expression and optical coherence tomography (OCT) phenotype.

DESIGN

The IMAGINE is a post hoc image analysis and cytokine expression assessment of the Efficacy & Safety Trial of Intravitreal Injections Combined With PRP for CSME Secondary to Diabetes Mellitus (DAVE) randomized clinical trial.

METHODS

Subjects were categorized as anatomical responders or nonresponders, and within the responder group as rebounders and non-rebounders based on quantitative, longitudinal OCT criteria. Retinal layer and fluid features were extracted using an OCT machine-learning augmented segmentation platform. Responders were further sub-classified by rapidity of response. Aqueous concentrations of 54 cytokines were measured at multiple timepoints. Expression was compared between responder groups and correlated with OCT imaging biomarkers.

RESULTS

Of the 24 eyes studied, 79% were anatomical responders with 38% super responders, 17% early responders, and 25% slow responders. Twenty-one percent were nonresponders. Super responders had increased baseline vascular endothelial growth factor (VEGF) (880.0 pg/mL vs 245.4 pg/mL; P = .012) and decreased monocyte chemotactic protein-1 (MCP-1) (513.3 pg/mL vs 809.5 pg/mL; P = .0.042) concentrations compared with nonresponders. Interleukin-6 (-24.9 pg/mL vs 442.8 pg/mL; P = .032) concentrations increased among nonresponders during therapy. VEGF concentrations correlated with central subfield thickness (r = 0.49; P = .01). Panmacular retinal volume correlated with increased interleuckin-6 (r = 0.47; P = .02) and decreased MCP-1 (r = -0.45; P = .03). Matrix metallopeptidase-1 correlated with subretinal fluid volume (r = 0.50; P = .01).

CONCLUSIONS

OCT imaging biomarkers correlated with both intraocular cytokines and responsiveness to anti-VEGF therapy, which indicated a possible link to underlying pathways and their relevance to DME prognosis. Baseline concentrations of VEGF and MCP-1 are associated with anatomic response to anti-VEGF therapy.

Retinal applications of swept source optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA)

The advent of optical coherence tomography (OCT) revolutionized both clinical assessment and research of vitreoretinal conditions. Since then, extraordinary advances have been made in this imaging technology, including the relatively recent development of swept-source OCT (SS-OCT). SS-OCT enables a fast scan rate and utilizes a tunable swept laser, thus enabling the incorporation of longer wavelengths than conventional spectral-domain devices. These features enable imaging of larger areas with reduced motion artifact, and a better visualization of the choroidal vasculature, respectively. Building on the principles of OCT, swept-source OCT has also been applied to OCT angiography (SS-OCTA), thus enabling a non-invasive in depth-resolved imaging of the retinal and choroidal microvasculature. Despite their advantages, the widespread use of SS-OCT and SS-OCTA remains relatively limited. In this review, we summarize the technical details, advantages and limitations of SS-OCT and SS-OCTA, with a particular emphasis on their relevance for the study of retinal conditions. Additionally, we comprehensively review relevant studies performed to date to the study of retinal health and disease, and highlight current gaps in knowledge and opportunities to take advantage of swept source technology to improve our current understanding of many medical and surgical chorioretinal conditions. We anticipate that SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift to more widespread adoption of new imaging technology to clinical practice.

Factors Affecting a Short-Term Response to Anti-VEGF Therapy in Diabetic Macular Edema

Diabetic macular edema (DME) is a common cause of visual impairment in patients with diabetes. Although intravitreal anti-vascular endothelial growth factor (VEGF) injections were efficacious in clinical trials, several patients exhibited a poor response. This study aimed to compare clinical features between patients who were susceptible to intravitreal anti-VEGF injections for DME and those who were not. A single-center, retrospective study of 102 such patients was conducted (123 eyes; mean ± standard deviation age, 63.4 ± 10.8 years; 57.8% males). Systemic and ocular data, assessed at baseline and after a month, were compared between good (>20% decrease in central macular thickness (CMT)) and poor (≤20% decrease in CMT) responders using the Mann-Whitney U test/Fisher's exact test. Eighty-one eyes (65.9%) were good responders. The glycosylated hemoglobin level was higher (p = 0.011) in poor (7.5% ± 0.94%) than in good (7.04% ± 1.19%) responders. The foveal avascular zone was larger (p = 0.0003) in poor (0.67 ± 0.33 μm²) than in good (0.47 ± 0.23 μm²) responders. The number of microaneurysms in the pericapillary network was higher (p = 0.0007) in poor (2.7 ± 2.2) than in good (1.4 ± 2.0) responders. Baseline glycemic control and macular ischemia may be associated with the short-term response to intravitreal anti-VEGF injections.

Machine Learning Approach for Intraocular Disease Prediction Based on Aqueous Humor Immune Mediator Profiles

PURPOSE

Various immune mediators have crucial roles in the pathogenesis of intraocular diseases. Machine learning can be used to automatically select and weigh various predictors to develop models maximizing predictive power. However, these techniques have not yet been applied extensively in studies focused on intraocular diseases. We evaluated whether 5 machine learning algorithms applied to the data of immune-mediator levels in aqueous humor can predict the actual diagnoses of 17 selected intraocular diseases and identified which immune mediators drive the predictive power of a machine learning model.

DESIGN

Cross-sectional study.

PARTICIPANTS

Five hundred twelve eyes with diagnoses from among 17 intraocular diseases.

METHODS

Aqueous humor samples were collected, and the concentrations of 28 immune mediators were determined using a cytometric bead array. Each immune mediator was ranked according to its importance using 5 machine learning algorithms. Stratified k-fold cross-validation was used in evaluation of algorithms with the dataset divided into training and test datasets.

MAIN OUTCOME MEASURES

The algorithms were evaluated in terms of precision, recall, accuracy, F-score, area under the receiver operating characteristic curve, area under the precision-recall curve, and mean decrease in Gini index.

RESULTS

Among the 5 machine learning models, random forest (RF) yielded the highest classification accuracy in multiclass differentiation of 17 intraocular diseases. The RF prediction models for vitreoretinal lymphoma, acute retinal necrosis, endophthalmitis, rhegmatogenous retinal detachment, and primary open-angle glaucoma achieved the highest classification accuracy, precision, and recall. Random forest recognized vitreoretinal lymphoma, acute retinal necrosis, endophthalmitis, rhegmatogenous retinal detachment, and primary open-angle glaucoma with the top 5 F-scores. The 3 highest-ranking relevant immune mediators were interleukin (IL)-10, interferon-γ-inducible protein (IP)-10, and angiogenin for prediction of vitreoretinal lymphoma; monokine induced by interferon γ, interferon γ, and IP-10 for acute retinal necrosis; and IL-6, granulocyte colony-stimulating factor, and IL-8 for endophthalmitis.

CONCLUSIONS

Random forest algorithms based on 28 immune mediators in aqueous humor successfully predicted the diagnosis of vitreoretinal lymphoma, acute retinal necrosis, and endophthalmitis. Overall, the findings of the present study contribute to increased knowledge on new biomarkers that potentially can facilitate diagnosis of intraocular diseases in the future.

Non-invasive multimodal imaging of Diabetic Retinopathy: A survey on treatment methods and Nanotheranostics

Diabetes Retinopathy (DR) is one of the most prominent microvascular complications of diabetes. It is one of the pre-eminent causes for vision impairment followed by blindness among the working-age population worldwide. The de facto cause for DR remains challenging, despite several efforts made to unveil the mechanism underlying the pathology of DR. There is quite less availability of the low cost pre-emptive theranostic imaging tools in terms of in-depth resolution, due to the multiple factors involved in the etiology of DR. This review work comprehensively explores the various reports and research works on all perspectives of diabetic retinopathy (DR), and its mechanism. It also discusses various advanced non-destructive imaging modalities, current, and future treatment approaches. Further, the application of various nanoparticle-based drug delivery strategies used for the treatment of DR are also discussed. In a nutshell, the present review work bolsters the pursuit of the development of an advanced non-invasive optical imaging modal with a nano-theranostic approach for the future diagnosis and treatment of DR and its associated ocular complications.

Foveal Eversion: A Possible Biomarker of Persistent Diabetic Macular Edema

Introduction

We aimed to evaluate the impact of foveal eversion on treatment response and persistent diabetic macular edema (DME).

Methods

The study was designed as interventional and prospective. DME eyes were treated with ranibizumab and/or dexamethasone (DEX) implants, or with fluocinolone acetonide (FAc) implants. FAc-treated eyes were eventually retreated by additional ranibizumab injections. Main outcome measure was the relationship between foveal eversion and both clinical outcome and persistent DME.

Results

Sixty-eight DME eyes (68 patients) treated by anti-VEGF/DEX and 50 FAc-treated eyes (50 patients) were recruited. The follow-up was 16 ± 3 months. The anti-VEGF/DEX group and FAc-treated group were statistically matched for age, sex, DME duration and previous number of injections (p > 0.05). Both groups experienced statistically significant improvements of both BCVA and central macular thickness (p < 0.01) at the end of the follow-up. Persistent DME was shown by 46% of anti-VEGF/DEX eyes and 42% of FAc-treated eyes. Foveal eversion was found in 50% of anti-VEGF/DEX eyes and in 44% of FAc-treated eyes. Its presence was associated with worse anatomical and visual outcome and higher persistence of DME in both groups (p < 0.01) and with higher retreatment percentages in FAc-treated eyes (p < 0.01).

Conclusion

Foveal eversion is associated with worse clinical and morphological outcomes in DME.

Dilated retinal large vessels and capillaries associated with diabetic macular edema and photoreceptor loss respectively

PURPOSE

Previously, we measured retinal large vessels and capillaries separately on optical coherence tomography angiography (OCTA). In the present study, we aim to evaluate the role of these parameters in association to diabetic macular edema (DME) and ellipsoid zone disruption (EZD).

METHODS

In this cross-sectional study, 54 eyes from 31 patients (10 females, 31 Asians) with severe non-proliferative diabetic retinopathy (25 eyes) or proliferative diabetic retinopathy (PDR, 29 eyes) were enrolled. All eyes underwent 3 × 3 mm OCTA scans centered on the fovea. Perfusion density (PD), vessel length density (VLD), and vessel diameter index (VDI) were calculated for retinal large vessels and superficial capillaries separately. Other OCTA findings included suspended scattering particles in motion (SSPiM), number of microaneurysms (MA) in all retinal layers, and the area of foveal avascular zone (FAZ) of superficial capillary plexus. DME and EZD were evaluated on B-scans. Both univariate and multivariate analysis were performed.

RESULTS

Of the 54 study eyes, 31 (57%) had DME and 21 (40%) had EZD. Multivariate regression model showed that PDR (β = 27.8, 95% confidence interval (CI): 2.7-282.8, p = 0.005), more MA (β = 2.5, 95% CI: 1.3-4.5, p = 0.003), and increased VDI of larger vessels (β = 1.9, 95% CI: 1.0-3.5, p = 0.047) were risk factors for DME. As for EZD, presence of SSPiM (β = 5.5, 95% CI: 1.2-26.1, p = 0.032) and increased VDI of capillaries (β = 3.9, 95% CI: 1.1-13.8, p = 0.034) were risk factors.

CONCLUSIONS

In eyes with diabetic retinopathy, dilation of retinal larger vessels was associated with macular edema, while dilation of retinal capillaries was associated with ellipsoid zone disruption.

Real-World Efficacy and Safety of Fluocinolone Acetonide Implant for Diabetic Macular Edema: A Systematic Review

To assess real-world outcomes of fluocinolone acetonide (FAc) implant in treating diabetic macular edema (DME), a systematic literature review was conducted on PubMed in order to identify publications assessing the efficacy and safety of the FAc implant in DME in daily practice. Case reports and randomized controlled trials were excluded. Twenty-two observational real-world studies analyzing a total of 1880 eyes were included. Mean peak visual gain was +8.7 letters (11.3 months post-FAc injection) and was greater for lower baseline best corrected visual acuity (BCVA) and for more recent DME. Mean central retinal thickness (CRT) decreased 34.3% from baseline. 77.0% of the analyzed studies reported both BCVA improvement of at least five letters and a CRT decrease by 20% or more. Rescue therapy was needed more frequently when FAc was administered for chronic DME. FAc-induced ocular hypertension was reported in 20.1% of patients but only 0.6% needed surgery. Cataract extraction was performed in 43.2% of phakic patients. Adequate patient selection is essential for optimal FAc response and better safety profile. Currently positioned as second- or third-line treatment in the management algorithm, FAc implant decreases treatment burden and provides better letter gain when administered for more recent DME.

Automatic prediction of treatment outcomes in patients with diabetic macular edema using ensemble machine learning

Background

This study aimed to predict the treatment outcomes in patients with diabetic macular edema (DME) after 3 monthly anti-vascular endothelial growth factor (VEGF) injections using machine learning (ML) based on pretreatment optical coherence tomography (OCT) images and clinical variables.

Methods

An ensemble ML system consisting of four deep learning (DL) models and five classical machine learning (CML) models was developed to predict the posttreatment central foveal thickness (CFT) and the best-corrected visual acuity (BCVA). A total of 363 OCT images and 7,587 clinical data records from 363 eyes were included in the training set (304 eyes) and external validation set (59 eyes). The DL models were trained using the OCT images, and the CML models were trained using the OCT images features and clinical variables. The predictive posttreatment CFT and BCVA values were compared with true outcomes obtained from the medical records.

Results

For CFT prediction, the mean absolute error (MAE), root mean square error (RMSE), and R² of the best-performing model in the training set was 66.59, 93.73, and 0.71, respectively, with an area under receiver operating characteristic curve (AUC) of 0.90 for distinguishing the eyes with good anatomical response. The MAE, RMSE, and R² was 68.08, 97.63, and 0.74, respectively, with an AUC of 0.94 in the external validation set. For BCVA prediction, the MAE, RMSE, and R² of the best-performing model in the training set was 0.19, 0.29, and 0.60, respectively, with an AUC of 0.80 for distinguishing eyes with a good functional response. The external validation achieved a MAE, RMSE, and R² of 0.13, 0.20, and 0.68, respectively, with an AUC of 0.81.

Conclusions

Our ensemble ML system accurately predicted posttreatment CFT and BCVA after anti-VEGF injections in DME patients, and can be used to prospectively assess the efficacy of anti-VEGF therapy in DME patients.

Correlation between Imaging Morphological Findings and Laboratory Biomarkers in Patients with Diabetic Macular Edema

PURPOSE

To investigate the potential association between peripheral blood biomarkers and morphological characteristics of retinal imaging in patients with diabetic macular edema (DME).

METHODS

Participants in this cross-sectional study were 36 consecutive patients (36 eyes) with treatment-naïve DME, who underwent spectral domain-optical coherence tomography (SD-OCT), fundus photography, and fundus fluorescein angiography (FFA). In addition, peripheral blood samples were taken to evaluate full blood count and biochemical parameters. Correlation between imaging characteristics and laboratory parameters was examined.

RESULTS

Eyes with central subfield thickness greater than 405 μm presented significantly higher neutrophils/lymphocytes (p = 0.043) and higher lipoprotein (a) compared to eyes with CST < 405 μm (p = 0.003). Presence of hyperreflective foci on SD-OCT was associated with significantly higher white blood cell count (p = 0.028). Ellipsoid zone disruption was associated with significantly lower hematocrit (p = 0.012), hemoglobin (p = 0.009), and red blood cell count (p = 0.026), as well as with higher lipoprotein (a) (p = 0.015). Macular ischemia on FFA was associated with significantly higher monocytes (p = 0.027) and monocytes/HDL (p = 0.019). No significant associations were found between laboratory parameters and subretinal fluid, intraretinal fluid, exudates, cysts, disorganization of inner retinal layers, epiretinal membrane, and external limiting membrane condition.

CONCLUSION

Specific imaging morphological characteristics were found to be associated with laboratory parameters in patients with DME. These findings may shed light on the pathophysiology of DME and its correlation with the development of specific clinical signs.

Vessel Density Changes on Optical Coherence Tomography Angiography after Vascular Endothelial Growth Factor Inhibitor Treatment for Diabetic Macular Edema

Objectives

To evaluate the changes in macular vessel density after treatment with vascular endothelial growth factor (VEGF) inhibitors in center-involving diabetic macular edema (DME) and to compare these changes between anatomical responders and non-responders.

Materials and Methods

This retrospective study included 22 eyes with center-involving DME. All eyes had 3 consecutive administrations of VEGF inhibitors. Optical coherence tomography (OCT) and OCT angiography (OCTA) of the macula with manual adjustment of segmentation lines were performed at baseline and after treatment. Vessel density in the central and parafoveal regions of the superficial and deep capillary plexus (SCP/DCP) were measured at baseline and after treatment. Vessel density and changes therein were compared between anatomical responders and non-responders as defined by changes in central subfield thickness (CST).

Results

Overall, there were no significant differences in vessel density in the central and parafoveal regions of the SCP and DCP after treatment compared to baseline. After categorization by anatomical response, 12 eyes were responders (CST decreased by 173.7±47.7 μm) and 10 eyes were non-responders (CST increased by 20.8±38.9 μm) (p<0.0001). There were no corresponding significant differences between responders and non-responders in SCP and DCP vessel density or changes therein after treatment.

Conclusion

There were no significant changes in macular vessel density after the early stages of VEGF inhibitor treatment for DME, and there was no relationship with the anatomical response. The effect of VEGF inhibitors in DME treatment may not be related to increasing vessel density.

The Effect of Anti-Vascular Endothelial Growth Factor on Retinal Microvascular Changes in Diabetic Macular Edema Using Swept-Source Optical Coherence Tomography Angiography

Purpose

This study evaluates the effect of anti-vascular endothelial growth factor (anti-VEGF) therapy on microaneurysm changes and foveal avascular zone (FAZ) using optical coherence tomography angiography (OCTA) in patients with diabetic macular edema (DME).

Design

Prospective observational study.

Materials and Methods

This study involved patients with DME undergoing anti-VEGF treatment (aflibercept, ranibizumab, and bevacizumab). Macula OCTA images were obtained before (visit 0) and 1 month after (visit 1) anti-VEGF injection. Microaneurysm counts were performed, and the FAZ was evaluated in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). The differences in microaneurysms, FAZ, and clinical correlations were analyzed.

Results

A total of 152 eyes were analyzed. The patients' mean age was 59 years. Bevacizumab was used in 69.7%, ranibizumab in 15.1%, and aflibercept in 15.1%. There was a significant reduction in the FAZ in the SCP and DCP between visits 0 and 1. All anti-VEGF medications reduced the number of microaneurysms (p<0.01). After treatment, changes in the FAZ in SCP and DCP corresponded with changes in visual acuity (p<0.01).

Conclusion

Microaneurysms as detected by OCTA might serve as a biomarker for a clinical response to anti-VEGF treatment in the short term. The FAZ might also predict visual acuity improvement after anti-VEGF injection.

Trial Registration

Thai Clinical Trials Registry (TCTR20161010005).

Interdigitation and Ellipsoid Zones Disruption Correlate with Visual Outcomes among Treatment-Naive Patients with Diabetic Macular Edema

INTRODUCTION

We have recently shown that defects in interdigitation and ellipsoid zones (IZ and EZ) can predict response to anti-VEGF therapy in a small group of treatment-naive diabetic macular edema (DME) patients. The aim of the current study is to further evaluate this association in a larger study group of patients over a longer follow-up time.

METHODS

Thirty eyes of 30 treatment-naive DME patients were analyzed in this retrospective study. The integrity of foveal IZ and EZ was evaluated using optical coherence tomography at the diagnosis of DME and following anti-VEGF injections. The defect size was correlated with best-corrected visual acuity (BCVA) and central macular thickness (CMT).

RESULTS

The mean patients' age at baseline was 63.0 ± 10.0 years. Patients underwent 3.9 ± 2.9 anti-VEGF injections for a mean of 9.1 ± 4.8 months. Following treatment, the mean Snellen visual acuity (VA) improved from 20/52 to 20/44 (p = 0.05), CMT decreased from 432.5 ± 141.4 μm to 375.2 ± 121.4 µm (p = 0.05) and IZ/EZ defect size decreased from 259.83 ± 375.94 µm to 65.34 ± 143.97 µm (p = 0.001). In patients with no IZ/EZ defects at baseline, the mean Snellen VA was better when compared to those with IZ/EZ defects (20/36 vs. 20/70, p = 0.031). The number of eyes with IZ/EZ defects decreased from 17 (57%) at baseline to 6 (20%) at end of follow-up (p < 0.01). BCVA gain correlated with IZ/EZ defect size reduction (r = 0.41, p = 0.02) but not with improvement in CMT (r = 0.28, p = 0.121).

CONCLUSIONS

IZ/EZ defect size correlated not only with baseline BCVA but also predicted the change in BCVA after anti-VEGF treatment. Possible future automatic measurement of IZ/EZ defect size might prove helpful for the evaluation of treatment response.

Effects of Long-Term DME Control With 0.2 µg/Day Fluocinolone Acetonide Implant on Quality of Life: An Exploratory Analysis From the FAME Trial

BACKGROUND AND OBJECTIVE

Exploratory investigation of the effect of diabetic macular edema (DME) control with the 0.2 µg/day fluocinolone acetonide (FAc) intravitreal implant on quality of life (QOL) outcomes.

PATIENTS AND METHODS

Post-hoc analysis of patients from the FAME study who received the FAc implant and had answered the National Eye Institute Visual Function Questionnaire 25 (NEI-VFQ-25) at baseline and Year 3 (N = 324). Patients were divided into quartiles (area under the curve [AUC]-central subfield thickness [CST]/day; n = 81/quartile). NEIVFQ-25 and best-corrected visual acuity (BCVA) changes were analyzed per quartile during a period of 3 years.

RESULTS

NEI-VFQ-25 scores were significantly higher in patients with low AUC-CST/day (Quartiles 1 [P < .001] and 2 [P = .004]). Increases in NEIVFQ-25 subscale scores correlated with AUC-CST/day quartiles. BCVA significantly improved in patients with the lowest AUC-CST/day (Quartiles 1 and 2 [P < .001]).

CONCLUSION

There was a positive and sustained correlation between the long-term control of DME and patient-reported QOL outcomes for up to 3 years following a single FAc implant in patients with controlled DME. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:658-667.].

The cells involved in the pathological process of diabetic retinopathy

Diabetic retinopathy(DR) is an expanding global health problem, the exact mechanism of which has not yet been clarified clearly, new insights into retinal physiology indicate that diabetes-induced retinal dysfunction may be viewed as an impairment of the retinal neurovascular unit, including retinal ganglion cells, glial cells, endothelial cells, pericytes, and retinal pigment epithelium. Different retinal cells have unique structure and functions, while the interactions among which are less known. Cells are the basic unit of organism structure and function, their impairment could lead to abnormal physiological functions and even organ disorder. Considering the body is multi-dimension and the complexity of DR, one point or a single type of cell can't be used to illustrate the mechanism of occurrence and development of DR. In this review, we provided a systematic and comprehensive elaboration of the cells that are involved in the process of DR. We underlined the importance of considering the neurovascular unit, not just retinal vascular and neural cells, in understanding the pathophysiology of DR. Our studies provided a better understanding of the pathological process in DR and provide a theoretical basis for further research.

Dysregulation of the NLRP3 Inflammasome in Diabetic Retinopathy and Potential Therapeutic Targets

Diabetic Retinopathy (DR) is an insidious neurovascular disorder secondary to chronic glycemic dysregulation in elderly diabetic patients. In the later stages of DR, the disease manifests as fluid infiltrating the macula, culminating in the leading cause of irreversible visual impairment in working age adults. With the current mainstay treatments preoccupied with slowing down the progression of DR, this presents an unsustainable solution from both an economic and quality of life perspective. Although the exact mechanisms by which hyperglycemia leads to retinal tissue insult are unknown, the evidence suggests that chronic low-grade inflammation in diabetic eye is in part driving the constellation of symptoms present in DR. Of the innate immune system within the eye, the NLR Family Pyrin Domain Containing 3 Inflammasome (NLRP3) has been identified in retinal cells as a causal factor in the pathogenesis of DR. Multiple pathways appear to be present in the diabetic eye that instigate prolonged activation of the NLRP3 which subsequently exerts its deleterious effects by upregulating the release of Interleukin-1Beta and Interleukin-18. In this review, we highlight the current understanding of the pathophysiology of DR, the dysregulation of the NLRP3 secondary to hyperglycemic stress in retinal cells, and novel therapeutic targets to alleviate overactivation of the inflammasome.

Inflammatory cytokines, oxidative and antioxidative stress levels in patients with diabetic macular edema and hyperreflective spots

PURPOSE

To determine the levels of serum oxidative, antioxidative markers and inflammatory cytokines in patients diagnosed with diabetic macular edema (DME) whose hyperreflective spots (HRS) were detected by optical coherence tomography (OCT).

METHODS

In this prospective cross-sectional clinical study included a total of 88 patients; 31 patients (group-1) with DME and HRS detected by OCT, 29 patients (group-2) with DME without HRS, and 28 patients (group-3) diagnosed with diabetes mellitus (DM) without any diabetic retinopathy findings. The main outcomes were best-corrected visual acuity (BCVA), CMT (central macular thickness), CMV (central macular volume), TMV (total macular volume), CT (choroidal thickness), serum TAS (total antioxidant status), TOS (total oxidant status), VEGF (vascular endothelial growth factor), FGF (fibroblast growth factor) and IL-1b levels. OCT parameters and biochemical measurements were compared statistically between the three groups.

RESULTS

A total of 88 patients (43 females (48.9%) and 45 males (51.1%)) were included in the study. The mean age was 56.29 ± 9.23 years. There was no difference between the three groups in age-and-sex. In group-1 and 2, BCVA(LogMAR) was statistically higher than group 3. CMT, CMV, TMV, TAS, TOS, VEGF and FGF were significantly higher in group-1 than in group-3. CMT, CMV, TMV, VEGF and FGF were significantly higher in group-2 than group 3. TOS and VEGF were significantly higher in group-1 than group-2.

CONCLUSIONS

This study demonstrates that in patients with DME and HRS, TOS and VEGF levels were higher than those without HRS. Hence, hyperreflective spots may be an inflammatory biomarker.

Intravitreal ranibizumab alone or in combination with panretinal photocoagulation for the treatment of proliferative diabetic retinopathy with coexistent macular edema: long-term outcomes of a prospective study

AIMS

To compare intravitreal ranibizumab as monotherapy or in combination with panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PDR) and coexistent diabetic macular edema (DME) in a long-term follow-up of 24 months.

METHODS

Participants in this prospective study were 47 patients with PDR and concurrent DME, who were randomized at baseline into two groups: (i) the "ranibizumab alone" group (n = 23), which was treated with at least 3 intravitreal ranibizumab injections as a loading phase, and (ii) the "combination" group (n = 24), which was treated with PRP and at least 3 intravitreal ranibizumab injections. Thereafter, all patients were followed up at a pro re nata (PRN) basis, with regular monthly monitoring for 24 months. At each visit, best corrected visual acuity (BCVA) and spectral domain-optical coherence tomography were performed, while regression of neovascularization was also recorded.

RESULTS

The "combination" group had better control of neovascularization and less events of vitreous hemorrhage than ranibizumab alone through the 2 years. BCVA did not differ significantly between the two groups at months 12 and 24 of the follow-up. The "ranibizumab" alone group presented greater reduction in central retinal thickness at month 12, which did not reach significance at month 24 compared to "combination" group. Greater number of injections was needed in the monotherapy group (mean 14 injections) compared to "combination" group (mean 11 injections) through month 24.

CONCLUSIONS

Both intravitreal ranibizumab alone or in combination with PRP could be used effectively for the treatment of PDR and coexistent DME. Even though there was no difference in BCVA and CRT at the 24-month follow-up between the two groups, the combination group presented greater regression of neovascularization with less injections.

Subthreshold Micropulse Laser in Diabetic Macular Edema: 1-Year Improvement in OCT/OCT-Angiography Biomarkers

Purpose

The aim of this study was to evaluate 1-year quantitative changes in specific inflammatory parameters on optical coherence tomography (OCT) / optical coherence tomography angiography (OCTA) in diabetic macular edema (DME) treated with subthreshold micropulse laser (SMPL).

Methods

Thirty-seven patients / eyes with previously treatment-naïve DME treated with SMPL were prospectively evaluated at 3, 6, and 12 months. Fifteen fellow eyes with only microaneurysms (MAS) not eligible for treatment were controls. Evaluated OCT / OCTA parameters included: central macular thickness (CMT); hyper-reflective retinal spots (HRS); disorganization of inner retinal layers (DRILs); MA in the superficial / deep capillary plexuses (SCP/DCP); cysts in the area at the SCP / DCP; and macular perfusion parameters (MATLAB, version 2017b).

Results

In the treated group, mean best corrected visual acuity (BCVA) progressively increased from 69.4 ± 12.0 to 76.0 ± 9.1 Early Treatment Diabetic Retinopathy Study (ETDRS) letters (P < 0.001) at 12 months; HRS decreased from baseline (80.75 ± 20.41) at 3 (73.81 ± 17.1, P = 0.002), 6 (69.16 ± 16.48, P < 0.0001), and 12 months (66.29 ± 18.53, P < 0.0001). MA decreased at 3 months in the DCP (P = 0.015), at 6 and 12 months in both plexuses (P ≤ 0.0007). BCVA, HRS, and MA remained stable in the controls during all follow-ups. DRIL was present in 18 of 37 patients at baseline and progressively decreased from 557.0 ± 238.7 to 387.1 ± 282.1 μm (P = 0.01). The area of cyst decreased both in the SCP (P = 0.03) and the DCP (P = 0.02). CMT and perfusion parameters did not change.

Conclusions

SMPL reduced the number of HRS (sign of activated microglia cells in the retina), MA, DRIL extension, and the area of cysts. Further studies are needed to confirm these preliminary data on the anti-inflammatory effect of SMPL, and to explore the mechanism of action.

Translational Relevance

The follow-up of OCT/OCTA noninvasive biomarkers offers a unique insight in the mechanism of laser action, suggesting an anti-inflammatory effect of SMPL.

Optical Coherence Tomography Biomarkers of Inflammation in Diabetic Macular Edema Treated by Fluocinolone Acetonide Intravitreal Drug-Delivery System Implant

Introduction

The fluocinolone acetonide (FAc) intravitreal drug-delivery system implant is a recent, second-line, intravitreal drug for the management of diabetic macular edema (DME). FAc acts against DME with a major anti-inflammatory effect. Despite the already proved efficacy, a number of patients still show persistent DME and require anti-VEGF retreatment. The main aim of the present study was to assess the relationship between quantitative biomarkers of inflammation and both DME recovery and the need for additional anti-VEGF in eyes treated by FAc implant.

Methods

The study was designed as prospective and interventional with 1 year of follow-up. We analyzed structural optical coherence tomography (OCT) quantitative biomarkers of inflammation, namely choroidal hyperreflective foci (HF) and the choroidal vascularity index (CVI), and we assessed the relationship with other clinically relevant biomarkers and the outcome achieved after 1 year. Moreover, we stratified DME eyes in good and poor responders to FAc implant to highlight clinically relevant differences.

Results

Our study included 50 eyes (50 patients) treated by FAc implant. We found significant best-corrected visual acuity (BCVA) and central macular thickness (CMT) improvements after 1 year. Good responders started with worse visual acuity and higher CMT than poor responders, but gained letters significantly at the end of the follow-up, whereas poor responders showed stable BCVA values. Good responders were characterized by significantly higher choroidal HF and lower CVI than poor responders. Poor responders required significantly higher additional anti-VEGF treatments.

Conclusions

Quantitative structural OCT biomarkers of inflammation allowed distinguishing different inflammatory profiles of DME. The inflammatory component helped to categorize DME eyes in good and poor responders to FAc implant.

[The role of internal limiting membrane peeling in the treatment of diabetic macular edema]

Analysis of the current understanding of the role of internal limiting membrane in the pathogenesis of diabetic macular edema and the feasibility of its surgical removal is based on data from domestic and international literature on pathogenesis, clinical manifestations, outcomes of multicenter studies of treatment and prognosis of this disease. The advantages and disadvantages of both peeling and preservation of the inner limiting membrane are described. The limitations and inconsistencies of data provided by the authors of each theory requires more complete functional studies in the pre- and postoperative periods, increasing the selection of patients, modifying the criteria for inclusion in groups, and microscopic examination of removed membranes. Thus, this issue requires further study due to the ambiguity of the conclusions and the lack of comparative data on the long-term prospects of each of the methods.

Bradykinin 1 Receptor Antagonist BI1026706 Does Not Reduce Central Retinal Thickness in Center-Involved Diabetic Macular Edema

Purpose

The bradykinin 1 receptor may be important in inflammatory retinal vascular leakage in diabetic macular edema. BI 1026706 is an antagonist of bradykinin 1 receptor that has demonstrated efficacy in preclinical studies. Boehringer Ingelheim trial 1320.22 (NCT02732951) was a randomized, double-blind, placebo-controlled study. The pharmacodynamics, safety, and tolerability of oral BI 1026706 for 12 weeks were evaluated in patients with type 1 or type 2 diabetes mellitus and mild visual impairment owing to center-involved diabetic macular edema.

Methods

Patients (n = 105) were randomized to receive either oral BI 1026706 100 mg twice daily (morning and evening) or placebo for 12 weeks. The primary end point of the study was week 12 change from baseline in central subfield foveal thickness (CSFT) by spectral domain optical coherence tomography. Additional end points included absolute CSFT values, safety, and pharmacokinetics.

Results

After 12 weeks of treatment, there was no meaningful change from baseline in the adjusted mean CSFT in either treatment group (BI 1026706, 10.3 µm; placebo, –6.2 µm; adjusted mean treatment difference, 16.5 µm [95% confidence interval, –16.2 to 49.1]). There were also no differences in best-corrected visual acuity outcomes between treatment groups. Most reported adverse events were of mild or moderate intensity, and were balanced between treatment groups.

Conclusions

BI 1026706 was not superior to placebo in CSFT week-12 change from baseline. Therefore, BI 1026706 does not reduce CSFT, a morphologic sign of diabetic macular edema.

Translational Relevance

Kinin-kallikrein inhibition effects may not be apparent over 12 weeks for bradykinin 1 receptor inhibition alone.

Emerging corticosteroid delivery platforms for treatment of diabetic macular edema

INTRODUCTION

Diabetic macular edema (DME) is a leading cause of vision impairment. Low-grade inflammation is thought to play a critical role in its pathogenesis. Although vascular endothelial growth factor inhibitors are used first-line, not all eyes with DME respond optimally and may respond better to corticosteroids. Currently corticosteroids for DME are given intravitreally and require regular monitoring. There is an unmet need for longer lasting therapies and/or effective noninvasive therapies such as those given via oral or topical routes.

AREAS COVERED

This review discusses emerging corticosteroid delivery platforms for DME treatment. A literature search of investigational novel therapeutic steroid delivery platform in DME was conducted. Results are presented from preclinical, phase 1,2 & 3 clinical trials of various drug delivery systems using new technologies such as Solubilizing Nanoparticle technology, Mucus Penetrating Particles technology and Particle Replication In Non-wetting Templates. These new platforms aim to deliver corticosteroids effectively via topical, episcleral, subtenon, oral, and intravitreal routes.

EXPERT OPINION

These novel drug delivery platforms have the potential to lead to noninvasive or minimally invasive therapies and may overcome the shortcomings of current pharmacotherapy. However, larger comparative trials are needed for these agents to be added to the current armamentarium in DME management.

A potential novel therapeutic target in diabetic retinopathy: a chemokine receptor (CCR2/CCR5) inhibitor reduces retinal vascular leakage in an animal model

PURPOSE

We have previously shown that the chemokine CCL2 plays an important role in monocyte trafficking into the retina and alteration of the BRB in an animal model of diabetic retinopathy. In this study, we examined the effect of pharmacologically targeting the chemokine pathway to reduce the increased retinal vascular permeability in this model.

METHODS

C57BL/6 J mice were made diabetic using streptozotocin. After 4 months of diabetes, mice (n = 10) were treated by intraperitoneal injections of TAK-779 (dual CCR2/CCR5 inhibitor) (30 mg/kg) daily for 2 weeks. Retinal vascular permeability and protein expression were done using western blot. The SDF-1 levels were measured by ELISA. Immune cell infiltration in the retinas was measured using flow cytometry.

RESULTS

The dual inhibitor significantly decreased retinal vascular permeability in diabetic animals. There was a significant reduction in macrophage/microglia infiltration in the retinas of treated animals. Levels of SDF-1 and ICAM-1 were significantly reduced and the tight junction protein ZO-1 level was increased, and phospho-VE-Cad was significantly reduced with drug treatment.

CONCLUSIONS

A chemokine receptor inhibitor (CCR2/CCR5) can reduce retinal vascular permeability in diabetic animals. Targeting the chemokine pathway pharmacologically may be used as a novel therapeutic strategy in management of diabetic macular edema.

Risk factors for ocular hypertension after intravitreal dexamethasone implantation in diabetic macular edema

We designed a retrospective observational study to identify factors associated with ocular hypertension [OHTN, defined as intraocular pressure (IOP) > 25 mmHg] after intravitreal dexamethasone (IVD) implantation in diabetic macular edema (DME) patients. We measured IOP monthly after placement of an IVD implant, and identified the trend of IOP, incidence of OHTN, and its associated systemic or ocular factors. On average, IOP was highest at 2 months after IVD implantation. Of 84 DME patients who received an IVD implant, 3 (3.57%) presented with an IOP ≥ 25 mmHg at 1 month after implantation, 6 (7.14%) at 2 months, and 2 (2.38%) at 3 months. Compared with the non-OHTN group, the OHTN group had significantly shorter axial lengths and were younger. Logistic regression analysis revealed that axial length < 23.00 mm and age < 57 years were associated with OHTN occurrence. Patients whose IOP was elevated > 30% or ≥ 20 mmHg at 1 month post-implantation, subsequently developed OHTN with statistical significance. In conclusion, shorter axial length and younger age were associated with OHTN occurrence after IVD implantation. Additionally, identifying levels or trends in IOP at 1 month after the IVD procedure may be helpful in predicting subsequent OHTN occurrence.

THREE-YEAR OUTCOMES IN A RANDOMIZED SINGLE-BLIND CONTROLLED TRIAL OF INTRAVITREAL RANIBIZUMAB AND ORAL SUPPLEMENTATION WITH DOCOSAHEXAENOIC ACID AND ANTIOXIDANTS FOR DIABETIC MACULAR EDEMA

The decrease in macular thickness observed at 24 months was maintained at Month 36 in patients with diabetic macular edema treated with a combination of intravitreal ranibizumab and oral supplementation with high-dose docosahexaenoic acid and antioxidants.

Purpose:

To report 3-year results of a randomized single-blind controlled trial of intravitreal ranibizumab combined with oral docosahexaenoic acid (DHA) supplementation versus ranibizumab alone in patients with diabetic macular edema.

Methods:

There were 26 patients (31 eyes) in the DHA group and 29 (38 eyes) in the control group. Ranibizumab (0.5 mg) was administered monthly for the first 4 months followed by a pro re nata (PRN) regimen. In the experimental group, patients received oral DHA supplementation (1,050 mg/day) (Brudyretina 1.5 g).

Results:

At 36 months, mean decrease of central subfield macular thickness was higher in the DHA-supplementation group than in controls (275 ± 50 μm vs. 310 ± 97 μm) with significant differences at Months 25, 30, 33, and 34. Between-group differences in best-corrected visual acuity were not found, but the percentages of ETRDS gains >5 and >10 letters were higher in the DHA-supplementation group. Differences serum HbA1c, plasma total antioxidant capacity values, erythrocyte DHA content, and serum IL-6 levels were all significant in favor of the DHA-supplementation group.

Conclusion:

The addition of a high-rich DHA dietary supplement to intravitreal ranibizumab was effective to achieve better sustained improvement of central subfield macular thickness outcomes after 3 years of follow-up as compared with intravitreal ranibizumab alone.

Ranibizumab versus aflibercept for diabetic macular edema: 18-month results of a comparative, prospective, randomized study and multivariate analysis of visual outcome predictors

PURPOSE

The purpose of this study was to compare the anatomical and functional outcomes of ranibizumab versus aflibercept for the treatment of diabetic macular edema (DME) in a long-term follow-up.

METHODS

Participants in this prospective study were 112 treatment naïve patients with DME, who received treatment with either intravitreal ranibizumab (n = 54) or aflibercept (n = 58). The demographic data, the best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT) characteristics were evaluated at baseline and at month 1, 2, 3, 6, 12, and 18 post treatment, while factors affecting visual outcome were determined using multivariate analysis.

RESULTS

At month 18, the mean BCVA of ranibizumab-treated eyes increased 7.9 letters compared to 6.9 letters for eyes receiving aflibercept, with greater number of injections in ranibizumab group (9.2 ± 2.3 vs. 7.6 ± 2.1 injections in the ranibizumab and aflibercept group respectively, p = 0.0002). The difference in letters between the two groups was not statistically significant, nor the difference in central subfield thickness at month 18. Factors associated with poorer BCVA were found to be increasing age, HbA1c ≥7.5%, increasing central retinal thickness and disrupted ellipsoid zone.

CONCLUSIONS

Ranibizumab and aflibercept presented similar anatomical and functional outcomes in 18-month follow-up in patients with DME. It is important to determine factors, affecting VA, so as to provide individualized treatment.

PHACOEMULSIFICATION CATARACT SURGERY WITH PROPHYLACTIC INTRAVITREAL BEVACIZUMAB FOR PATIENTS WITH COEXISTING DIABETIC RETINOPATHY: A Meta-Analysis

PURPOSE

To evaluate the clinical effectiveness of intravitreal bevacizumab (IVB) injection combined with cataract surgery in the treatment of patients with cataract and coexisting diabetic retinopathy (DR).

METHODS

Pertinent comparative studies were identified through systemic searches of PubMed, EMBASE, and the Cochrane Controlled Trials Register up to March 1, 2016. Outcome measures included corrected distance vision acuity, central macular thickness, and progression of DR and maculopathy. A meta-analysis was performed using RevMan (Cochrane Collaboration, Oxford, United Kingdom).

RESULTS

Six studies describing a total of 283 eyes were identified. The meta-analysis results showed that corrected distance vision acuity measured at 1 month and 3 months after cataract surgery was significantly better in the IVB groups than in the control groups (P < 0.00001 and P = 0.01), whereas the corrected distance vision acuity at 6 months did not vary significantly between the 2 groups (P = 0.24). Similarly, the central macular thickness at 1, 3, and 6 months after surgery was significantly thinner in the IVB groups than in the control groups (P = 0.01, P = 0.0004, and P = 0.01, respectively). At 6 months, the progression of postoperative DR and maculopathy occurred more frequently in the control group than in the IVB group (P = 0.0001 and P < 0.0001, respectively).

CONCLUSION

Our meta-analysis indicates that cataract surgery combined with IVB seems to be an effective treatment in patients with coexisting DR in the short term (up to 6 months). More randomized, prospective, and large-sample-sized trials are needed to evaluate the long-term effects of IVB at the time of cataract surgery in patients with DR.

Hyperreflective foci in diabetic macular edema with serous retinal detachment: association with dyslipidemia

AIMS

Hyperreflective foci (HF), detected in the retina of diabetic patients, suggest the presence of microglial activation and migration, while controversies still remain for the origin of HF to be precursors of hard exudates. We investigated the presence of HF and their association with dyslipidemia in serous retinal detachment (SRD)-type diabetic macular edema (DME).

METHODS

Forty-two eyes in 42 patients with diabetic retinopathy (DR) and 22 eyes in 22 patients with branch retinal vascular occlusion (BRVO) showing macular edema were included in this study. The medical records and OCT findings were retrospectively reviewed in patients with SRD-type DME and compared with those with BRVO. The mean number of HF, the mean choroidal thickness, and lipid profiles were analyzed and compared between groups.

RESULTS

The mean number of HF was significantly higher in DR group compared to BRVO group. Significant correlation of HF was noted with triglycerides (r = 0.523, P = 0.002). Triglycerides were significantly associated with HF by linear regression (β = 0.012, 95% CI 0.001-0.024, P = 0.034) and remained significantly associated by multiple linear regression (β = 0.014, 95% CI 0.003-0.025, P = 0.014).

CONCLUSIONS

HF on OCT of DME patients could be indicative of activated microglia. HF are associated with dyslipidemia, especially high triglycerides, suggesting inflammatory reaction from dyslipidemia in diabetic retina.

Persistent or Recurrent Diabetic Macular Edema After Fluocinolone Acetonide 0.19 mg Implant: Risk Factors and Management

PURPOSE

To investigate baseline characteristics of patients undergoing additional antivascular endothelial growth factor (VEGF) injections for residual or recurrent diabetic macular edema (DME) in the first year after 0.19-mg fluocinolone acetonide (FAc) implant.

DESIGN

Prospective cohort study.

METHODS

Ninety-four eyes of 66 patients received an FAc implant. Eyes with persistent or recurrent DME were managed with pro re nata anti-VEGF agents. Demographic data and medical history were collected at baseline. Best-corrected visual acuity and central macular thickness were measured every 2 months. The 3 outcomes explored were 1) the risk factors for administration of additional anti-VEGF agents, 2) the interval from FAc to first anti-VEGF injection; and 3) the number of anti-VEGF doses required to maintain regression of DME.

RESULTS

Eighteen eyes (19.1%) of 13 patients received 1.3 ± 0.6 anti-VEGF injections. These eyes had significantly thicker central macular thickness at baseline and over the entire follow-up period (P < .001); best-corrected visual acuity was similar at every time point to eyes that were not receiving extra DME treatments. Eyes without preexistent panretinal photocoagulation (PRP) had a higher risk to undergo supplemental treatments (hazard ratio 1.5 [95% confidence interval 1.1-2.5, P = .03). The interval between FAc implant and the first anti-VEGF had a significant linear positive relationship with the number of dexamethasone implants before FAc implant (P = .002, R² = 0.47). No association was found between baseline factors and the number of injections given.

CONCLUSION

Anti-VEGF agents are efficient treatment to maintain visual acuity in residual/recurrent DME after FAc. Patients with higher baseline central macular thickness and with no previous central macular thickness are more likely to require additional treatments to control DME.

Ocular hypertension and severe intraocular pressure elevation after posterior subtenon injection of triamcinolone acetonide for various diseases

AIM

To evaluate and compare the incidences of ocular hypertension and severe intraocular pressure (IOP) elevation after posterior subtenon injection of triamcinolone acetonide (PSTA) for various diseases.

METHODS

Totally 179 eyes that had received PSTA for diabetic macular edema (n=108), pseudophakic cystoid macular edema (n=20), branch retinal vein occlusion (n=16), central retinal vein occlusion (CRVO, n=14), choroidal neovascularization (n=14) or noninfectious uveitis (n=7) were retrospectively enrolled. The primary outcomes included ocular hypertension defined as an IOP>21 mm Hg, and severe IOP elevation defined as a rise of 10 mm Hg or more in IOP compared with baseline. Cox regression models were used to analyze the hazard ratios (HRs) among different diseases.

RESULTS

After PSTA, the mean IOPs from month 1 to month 6 all significantly increased (P<0.05). Ocular hypertension occurred in 30.7% of eyes (median time: 8wk), and severe IOP elevation occurred in 16.2% of eyes (median time: 9wk). Patients receiving PSTA for CRVO or uveitis had a significantly higher risk for ocular hypertension (HR=3.049, P=0.004 for CRVO; HR=5.464, P=0.019 for uveitis) and severe IOP elevation (HR=2.913, P=0.034 for CRVO; HR=7.650, P=0.009 for uveitis).

CONCLUSION

IOP significantly increases within 6mo after PSTA, with the onset of ocular hypertension happening mostly at 2 to 3mo. Patients of CRVO or noninfectious uveitis have a higher risk of ocular hypertension or severe IOP elevation after PSTA and should be monitored for IOP more carefully.