Macular edema. A complication of diabetic retinopathy

Association Between Pentoxifylline Use and Diabetic Retinopathy in Patients with Type 2 Diabetes Mellitus and Chronic Kidney Disease: A Multi-Institutional Cohort Study

BACKGROUND

Pentoxifylline is administrated to improve the hemodynamics of patients with chronic kidney disease (CKD). Despite the improvement of capillary blood flow velocity in retina after pentoxifylline use, no evidence has been provided to prove the protective effect for diabetic retinopathy (DR). Therefore, this study aimed to assess the risk of DR in pentoxifylline users with CKD and diabetes mellitus (DM).

MATERIAL AND METHODS

In this retrospective cohort study, Chang Gung Research Database, which includes the data of patients with CKD and DM from 2003 to 2019, was used. Each calendar year was divided into 4 data units with 3 months each for every patient and every year during the follow-up. The ocular outcomes were new-onset DR, DR-related complications, and vitreoretinal interventions.

RESULTS

Total 56,439 patients without preexisting DR and 5,039 patients with preexisting DR were included in this study. Exposure to pentoxifylline was associated with elevated risk of new-onset DR (adjusted hazard ratio = 1.24, 95% confidence interval = 1.13-1.36) in patients without preexisting DR. Additionally, exposure to pentoxifylline was associated with elevated risk of DR-related complications and vitreoretinal interventions in patients with or without preexisting DR.

CONCLUSIONS

Exposure to pentoxifylline is associated with elevated risk of DR, regardless of whether patients have preexisting DR.

Evaluation of the effect of intravitreal injections on corneal epithelial, scleral and limbal region changes in diabetic retinopathy by AS-OCT

PURPOSE

The aim of the study is to evaluate the effects of diabetic retinopathy and intravitreal injections on the corneal, limbal and scleral areas.

METHODS

Patients with diabetes mellitus at different diagnosis and treatment levels were compared among themselves and with the control group in terms of corneal, limbal and scleral aspects with the help of anterior segment optical coherence tomography. In addition, clinical tests such as tear break-up time, Schirmer test-I and ocular surface disease index questionnaire were applied to the patients and the difference between the groups was investigated.

RESULTS

When the groups were examined in terms of BUT, SCH-I and OSDI, there was a statistically significant difference between control group and diabetic group(p < 0.05). In the limbal region, all measurements are higher than in patients with diabetic eye involvement. Thinning was detected in the scleral area with intravitreal injection (p < 0.05).

CONCLUSION

It should be known that DM may cause undesirable changes in the limbal region, and the importance of non-invasive detection with AS-OCT should not be forgotten. Since intravitreal injections for DME cause thinning of the sclera, it can cause various complications, and it may be recommended to change the quadrant in repetitive injection applications.

Non-Invasive Treatment of Early Diabetic Macular Edema by Multiwavelength Photobiomodulation with the Valeda Light Delivery System

Purpose

Diabetes is associated with ocular complications including diabetic macular edema (DME). Current therapies are invasive and include repeated intravitreal injections and laser therapy. Photobiomodulation (PBM) is a treatment (Tx) that utilizes selected wavelengths of light to induce cellular benefits including reduction of inflammation and edema. This single-center, open-label, post-hoc analysis explored the utility of multiwavelength PBM in subjects with DME.

Methods

Analysis included review of data from patients undergoing standard clinical care with an approved and marketed PBM medical device, the Valeda® Light Delivery System. Subjects with early-stage DME with good vision (Best-corrected visual acuity (BCVA) > 20/25, logMAR > 0.1) were evaluated in clinic and treated with one series of multiwavelength PBM (Tx delivered 3x/week over 3-4 weeks; total of 9 Tx sessions). Clinical, anatomical, and safety parameters were assessed in addition to subjective quality of life.

Results

A total of 30 eyes (19 subjects) were analyzed. Subjects were predominately male (68.4%) with a mean age of 56 ± 14 years. Reductions in central retinal thickness (CRT), resolution of intraretinal fluid (IRF) and improvement in diabetic retinopathy severity scale scores were observed following PBM treatment in select patients. Baseline BCVA remained stable over the follow-up observation period of 3 months post-PBM. Approximately 64% of patients reported subjective improvements in their ocular condition and decreased influence in everyday life. Detailed OCT evaluations confirmed no safety issues related to phototoxicity up to 16 months.

Conclusion

Early-stage DME subjects treated with Valeda multiwavelength PBM showed improvements in clinical and anatomical parameters. The Valeda multiwavelength PBM approach demonstrates a favorable safety profile with no signs of phototoxicity following an independent OCT review. PBM therapy may offer an alternative, non-invasive treatment strategy with a unique mechanism and modality for patients with early-stage DME.

Safety and effectiveness of the fluocinolone acetonide intravitreal implant (ILUVIEN): 3-year results from the European IRISS registry study

BACKGROUND

The ILUVIEN Registry Safety Study was a multicentre, open-label, non-randomised, observational, phase 4 study designed to assess the safety and effectiveness of the fluocinolone acetonide (FAc) implant in all indications in real-world practices in Europe.

METHODS

The study included data collected prospectively and retrospectively. Patients receiving FAc implants between 2013 and 2017 were included and monitored until the last patient reached ≥3 years of follow-up. Mean intraocular pressure (IOP) data over the course of the study, along with IOP events, use of IOP-lowering therapy, mean change in visual acuity (VA) and information on supplemental therapy use were analysed post-FAc implantation.

RESULTS

Six hundred and ninety-five eyes from 556 patients, with a mean±SD follow-up of 1150.5±357.36 days, were treated with a FAc implant. 96.7% of eyes had chronic diabetic macular oedema (cDMO). IOP lowering was achieved in 34.5% of eyes using topical agents and 4.3% by surgery. Seventy-three eyes (64.6% of 113 phakic) required cataract surgery during follow-up. Mean VA increased from a baseline of 52.2 letters to 57.1 letters at month 36, with improvement observed up to month 48. Supplementary therapies were given in 43.7% of eyes. When classified by length of cDMO less than or greater than the median duration those with a shorter history experienced greater VA gains than those with a longer history.

CONCLUSION

This study confirms the favourable, long-term benefit-to-risk profile of the FAc implant in eyes with cDMO, with an additional benefit in patients when this therapy is administered earlier.

Determinants of diabetic retinopathy in Ethiopia: A systematic review and meta-analysis

INTRODUCTION

Diabetic retinopathy (DR) is the primary retinal vascular complication of diabetes mellitus and a leading cause of visual impairment and blindness. It affects the global diabetic population. In Ethiopia, about one-fifth of diabetic patients were affected by DR, but there were inconsistent finding across studies about the determinants factors of DR. Therefore, we aimed to identify the risk factors for DR among diabetic patients.

METHODS

We have accessed previous studies through an electronic web-based search strategy using PubMed, Google (Scholar), the Web of Science, and the Cochrane Library with a combination of search terms. The quality of each included article was assessed using the Newcastle Ottawa Assessment Scale. All statistical analyses were carried out using Stata version 14 software. The odds ratios of risk factors were pooled using a fixed-effect meta-analysis model. Heterogeneity was assessed using the Cochrane Q statistics and I-Square (I2). Furthermore, publication bias was detected based on the graphic asymmetry test of the funnel plot and/or Egger's test (p< 0.05).

RESULTS

The search strategy retrieved 1285 articles. After the removal of duplicate articles, 249 articles remained. Following further screening, about 18 articles were assessed for eligibility, of which three articles were excluded because of reporting without the outcome of interest, poor quality, and not full text. Finally, fifteen studies were reviewed for the final analysis. Co-morbid hypertension (HTN) (AOR 2.04, 95%CI: 1.07, 3.89), poor glycemic control (AOR = 4.36, 95%CI: 1.47, 12.90), and duration of diabetes illness (AOR = 3.83, 95%CI: 1.17, 12.55) were found to be confirmed associated factors of diabetic retinopathy.

CONCLUSION

In this study, co-morbid HTN, poor glycemic control, and longer duration of diabetes illness were found to be the determinant factors of DR. Aggressive treatment of co-morbid HTN and blood glucose, and regular eye screening should be implemented to reduce the occurrence of DR.

TRIAL REGISTRATION

The review protocol was registered in the international prospective register of systematic reviews (PROSPERO) with registration number PROSPERO: CRD42023416724.

A deep learning nomogram of continuous glucose monitoring data for the risk prediction of diabetic retinopathy in type 2 diabetes

Continuous glucose monitoring (CGM) data analysis will provide a new perspective to analyze factors related to diabetic retinopathy (DR). However, the problem of visualizing CGM data and automatically predicting the incidence of DR from CGM is still controversial. Here, we explored the feasibility of using CGM profiles to predict DR in type 2 diabetes (T2D) by deep learning approach. This study fused deep learning with a regularized nomogram to construct a novel deep learning nomogram from CGM profiles to identify patients at high risk of DR. Specifically, a deep learning network was employed to mine the nonlinear relationship between CGM profiles and DR. Moreover, a novel nomogram combining CGM deep factors with basic information was established to score the patients' DR risk. This dataset consists of 788 patients belonging to two cohorts: 494 in the training cohort and 294 in the testing cohort. The area under the curve (AUC) values of our deep learning nomogram were 0.82 and 0.80 in the training cohort and testing cohort, respectively. By incorporating basic clinical factors, the deep learning nomogram achieved an AUC of 0.86 in the training cohort and 0.85 in the testing cohort. The calibration plot and decision curve showed that the deep learning nomogram had the potential for clinical application. This analysis method of CGM profiles can be extended to other diabetic complications by further investigation.

The 0.19-mg Fluocinolone Acetonide Intravitreal Implant Reduces Treatment Burden in Diabetic Macular Edema

PURPOSE

To assess treatment burden in patients with diabetic macular edema (DME) after the 0.19-mg fluocinolone acetonide (FAc) intravitreal implant (ILUVIEN).

DESIGN

Prospective and retrospective analyses of a 36-month, phase 4, open-label, observational study.

METHODS

Setting: Multicenter.

PATIENT POPULATION

Included patients had DME and previously received corticosteroid treatment without a clinically significant rise in intraocular pressure (IOP) (N = 202 eyes in 159 patients). Patients were not randomized.

OBSERVATION PROCEDURES

Prospective, observational treatment burden data were analyzed for their relationship to safety and functional efficacy outcomes across 36 months.

MAIN OUTCOME MEASURES

Outcomes included the mean number of yearly treatments, supplemental-free probability over time, best-corrected visual acuity, and monitoring of IOP-related events.

RESULTS

Over 36 months, the mean number of yearly treatments decreased from 3.5 before FAc to 1.7 after FAc; at 36 months, 68.3% of patients required 0 to 2 treatments per year. After FAc, the percentage of eyes requiring supplemental therapy decreased vs before FAc (P < .0001 for each). Through 36 months, 25% of FAc-treated eyes did not require supplemental treatment. At 36 months, mean best-corrected visual acuity increased by 4.5 letters vs a decline of 6.4 letters in the 36 months before FAc. IOP elevations >25 mm Hg occurred in 18.2% of eyes that did not receive supplemental treatment after FAc vs 27.2% of eyes that received supplemental treatments, which included additional intraocular steroids.

CONCLUSIONS

Over 36 months, the FAc implant is associated with improved visual outcomes and better disease control as measured by a significant reduction in yearly treatment burden in patients with DME.

Deep semi-supervised multiple instance learning with self-correction for DME classification from OCT images

Supervised deep learning has achieved prominent success in various diabetic macular edema (DME) recognition tasks from optical coherence tomography (OCT) volumetric images. A common problematic issue that frequently occurs in this field is the shortage of labeled data due to the expensive fine-grained annotations, which increases substantial difficulty in accurate analysis by supervised learning. The morphological changes in the retina caused by DME might be distributed sparsely in B-scan images of the OCT volume, and OCT data is often coarsely labeled at the volume level. Hence, the DME identification task can be formulated as a multiple instance classification problem that could be addressed by multiple instance learning (MIL) techniques. Nevertheless, none of previous studies utilize unlabeled data simultaneously to promote the classification accuracy, which is particularly significant for a high quality of analysis at the minimum annotation cost. To this end, we present a novel deep semi-supervised multiple instance learning framework to explore the feasibility of leveraging a small amount of coarsely labeled data and a large amount of unlabeled data to tackle this problem. Specifically, we come up with several modules to further improve the performance according to the availability and granularity of their labels. To warm up the training, we propagate the bag labels to the corresponding instances as the supervision of training, and propose a self-correction strategy to handle the label noise in the positive bags. This strategy is based on confidence-based pseudo-labeling with consistency regularization. The model uses its prediction to generate the pseudo-label for each weakly augmented input only if it is highly confident about the prediction, which is subsequently used to supervise the same input in a strongly augmented version. This learning scheme is also applicable to unlabeled data. To enhance the discrimination capability of the model, we introduce the Student-Teacher architecture and impose consistency constraints between two models. For demonstration, the proposed approach was evaluated on two large-scale DME OCT image datasets. Extensive results indicate that the proposed method improves DME classification with the incorporation of unlabeled data and outperforms competing MIL methods significantly, which confirm the feasibility of deep semi-supervised multiple instance learning at a low annotation cost.

Management of Patients with Diabetic Macular Edema Switched from Dexamethasone Intravitreal Implant to Fluocinolone Acetonide Intravitreal Implant

To assess anatomical and functional outcomes after switching from dexamethasone implant (DEXi) to fluocinolone acetonide implant (FAci) in 113 diabetic macular edema eyes, a multicentric retrospective observational study was conducted. Seventy-five eyes (73.5%) were switched 1−8 weeks after their last DEXi. The mean best-corrected visual acuity improved to 59.8 letters at month 4 and remained stable during the follow-up. The mean central macular thickness (CMT) significantly decreased during the follow-up, with a minimum of 320.9 μm at month 3. The baseline CMT was higher in eyes that received the last DEXi >8 weeks versus <8 weeks before the first FAci (p < 0.021). After FAci injection, additional treatments were needed in 37 (32.7%) eyes. A longer diabetes duration (p = 0.009), a longer time between the last DEXi and the first FAci (p = 0.035), and a high baseline CMT (p = 0.003) were risk factors for additional treatments. The mean intraocular pressure was <19 mmHg at all timepoints, with no difference between eyes receiving the last DEXi ≤8 weeks or >8 weeks before the switch. Switching from DEXi to FAci in DME is effective and safe. A short time between the last DEXi and the first FAci reduced CMT fluctuations and the need for early additional treatments.

A Cross-Sectional Study of Various Imaging and Biochemical Biomarkers in Patients with Diabetic Macular Edema in Different Stages of Diabetic Retinopathy

Purpose

To compare which imaging and biochemical biomarkers are associated with different stages of diabetic retinopathy (DR) in type 2 diabetes mellitus patients with diabetic macular edema (DME).

Patients and Methods

It was a cross-sectional, observational study that included 100 patients of DME with different stages of DR. Patients were divided into two groups: Group A – DME with non-proliferative diabetic retinopathy (NPDR) and Group B - DME with proliferative diabetic retinopathy (PDR). Group A was further subdivided into three subgroups: A (1) – DME with mild NPDR, A (2) – DME with moderate NPDR, and A (3) – DME with severe NPDR. The primary outcome measure was the association of imaging and biochemical biomarkers with different stages of DR in patients with DME.

Results

Out of 100 patients, Group A (1) had 1, Group A (2) 44, Group A (3) 29, and group: B had 29 patients. As Group A (1) had only one patient, we did not include it in the calculation. The overall mean age of the study population was 54.84+9.87 years, with a male preponderance (76%). The HbA1c levels, serum triglyceride level, serum cholesterol level, and microalbuminuria level showed no significant association with different stages of DR (P>0.05). Still, we found high serum urea levels (p=0.027) in Group B patients. The optical coherence tomography (OCT)-based imaging biomarkers – central subfield thickness (CST), cystoid macular edema (CME), subretinal fluid (SRF), and hyperreflective foci (HRF) – showed no significant association with various stages of DR. The presence of diffuse retinal thickness (DRT) (p=0.04) and the epiretinal membrane (ERM) (p=0.04) showed significant association with Group B patients.

Conclusion

The essential biochemical biomarkers such as serum urea levels and DRT and ERM may be considered an important imaging biomarker for the advanced stage of DR.

Diabetic Macular Edema Detection Using End-to-End Deep Fusion Model and Anatomical Landmark Visualization on an Edge Computing Device

Purpose

Diabetic macular edema (DME) is a common cause of vision impairment and blindness in patients with diabetes. However, vision loss can be prevented by regular eye examinations during primary care. This study aimed to design an artificial intelligence (AI) system to facilitate ophthalmology referrals by physicians.

Methods

We developed an end-to-end deep fusion model for DME classification and hard exudate (HE) detection. Based on the architecture of fusion model, we also applied a dual model which included an independent classifier and object detector to perform these two tasks separately. We used 35,001 annotated fundus images from three hospitals between 2007 and 2018 in Taiwan to create a private dataset. The Private dataset, Messidor-1 and Messidor-2 were used to assess the performance of the fusion model for DME classification and HE detection. A second object detector was trained to identify anatomical landmarks (optic disc and macula). We integrated the fusion model and the anatomical landmark detector, and evaluated their performance on an edge device, a device with limited compute resources.

Results

For DME classification of our private testing dataset, Messidor-1 and Messidor-2, the area under the receiver operating characteristic curve (AUC) for the fusion model had values of 98.1, 95.2, and 95.8%, the sensitivities were 96.4, 88.7, and 87.4%, the specificities were 90.1, 90.2, and 90.2%, and the accuracies were 90.8, 90.0, and 89.9%, respectively. In addition, the AUC was not significantly different for the fusion and dual models for the three datasets (p = 0.743, 0.942, and 0.114, respectively). For HE detection, the fusion model achieved a sensitivity of 79.5%, a specificity of 87.7%, and an accuracy of 86.3% using our private testing dataset. The sensitivity of the fusion model was higher than that of the dual model (p = 0.048). For optic disc and macula detection, the second object detector achieved accuracies of 98.4% (optic disc) and 99.3% (macula). The fusion model and the anatomical landmark detector can be deployed on a portable edge device.

Conclusion

This portable AI system exhibited excellent performance for the classification of DME, and the visualization of HE and anatomical locations. It facilitates interpretability and can serve as a clinical reference for physicians. Clinically, this system could be applied to diabetic eye screening to improve the interpretation of fundus imaging in patients with DME.

Efficacy and Safety of Intravitreal Fluocinolone Acetonide Implant for Chronic Diabetic Macular Edema Previously Treated in Real-Life Practice: The REALFAc Study

Diabetic macular edema (DME) is the main cause of visual impairment in diabetic patients and a chronic disease requiring long-term treatments. The fluocinolone acetonide (FAc) implant has recently been approved to treat DME in patients considered insufficiently responsive to available therapies. This study evaluates the functional and anatomical efficacy of the FAc implant in real-life practice. A total of 62 eyes with chronic DME were included and followed for a mean of 13.9 (+7.5) months. Previous treatment included at least anti-vascular endothelial growth factor (VEGF) in 83.9% of eyes, dexamethasone implant (DEX-I) in 100% of eyes, vitrectomy in 29.0% of eyes, and laser photocoagulation (either panretinal or focal photocoagulation) in 75.8% of eyes. The mean baseline best corrected visual acuity (BCVA) was 64.0 (+/−17.2) letters (median: 67.5 letters) with a mean DME duration of 60.3 (+/−30.6) months. The maximum BCVA gain occurred at 21 months with a mean gain of 5.0 (+/−12.7) letters. A total of 50.0% of eyes gained ≥5 letters during follow-up. Patients with lower BCVA at baseline had the lowest final BCVA (p < 0.001) but the highest BCVA gain (p = 0.02). The best overall improvement in mean central macular thickness (CMT) occurred at 18 months (p < 0.0001). The improvement in BCVA was inversely associated with the decrease in CMT and showed a decrease when CMT increased (DME recurrence). According to the history of vitrectomy, we did not find any significant difference in mean final BCVA (p = 0.1) and mean BCVA gain (p = 0.2) between eyes previously vitrectomized or not. A total of 23 eyes (37.1%) required additional treatment for DME, and 17.7% required an IOP-lowering procedure during follow-up. In conclusion, this real-life observational study demonstrated the efficacy and safety of the FAc implant in patients with chronic DME already treated with other available therapies.

Evaluation of the Effect of Garlic Tablet as a Complementary Treatment for Patients with Diabetic Retinopathy

PURPOSE

The aim of this study was to investigate the effectiveness of garlic (Allium sativum L.) tablets as a complimentary herbal medication in diabetic macular edema.

METHODS

A total of 91 diabetic participants (117 eyes) with central involved macular edema underwent a double-blind randomized trial. The patients used garlic tablets (500 mg) (2 tab/day) or placebo for 4 weeks and subsequently were examined by an expert ophthalmologist. Clinical manifestations including the best-corrected visual acuity (BCVA, logMAR), central macular thickness (CMT, μm), and intraocular pressure (IOP) were measured as the main outcomes.

RESULTS

BCVA was significantly improved by a 0.18 decrease in mean logMAR value in the garlic-treated patients in comparison with 0.06 in the control ones (P value = 0.027). CMT was decreased in both groups by a 102.99 μm decrease in the garlic group compared to 52.67 μm in the placebo group, albeit in a nonsignificant manner (P value: 0.094). IOP was decreased in the garlic group by 1.03 mmHg (P value: 0.024) and increased by 0.3 mmHg (P value: 0.468) in the placebo group.

CONCLUSION

Our trial suggests that garlic supplements can improve visual acuity, decrease the CMT and lower the IOP, and can be considered as an adjuvant treatment in patients with diabetic macular edema. Garlic was satisfactorily tolerated in diabetic patients, and no significant adverse effect interrupting the safety profile was observed.

Correlation of Volume of Macular Edema with Retinal Tomography Features in Diabetic Retinopathy Eyes

Optical coherence tomography (OCT) enables the detection of macular edema, a significant pathological outcome of diabetic retinopathy (DR). The aim of the study was to correlate edema volume with the severity of diabetic retinopathy and response to treatment with intravitreal injections (compared to baseline). Diabetic retinopathy (DR; n = 181) eyes were imaged with OCT (Heidelberg Engineering, Germany). They were grouped as responders (a decrease in thickness after intravitreal injection of Bevacizumab), non-responders (persistent edema or reduced decrease in thickness), recurrent (recurrence of edema after injection), and treatment naïve (no change in edema at follow-up without any injection). The post-treatment imaging of eyes was included for all groups, except for the treatment naïve group. All eyes underwent a 9 × 6 mm raster scan to measure the edema volume (EV). Central foveal thickness (CFT), central foveal volume (CFV), and total retinal volume (TRV) were obtained from the early treatment diabetic retinopathy study (ETDRS) map. The median EV increased with DR severity, with PDR having the greatest EV (4.01 mm³). This correlated positively with TRV (p < 0.001). Median CFV and CFT were the greatest in severe NPDR. Median EV was the greatest in the recurrent eyes (4.675 mm³) and lowest (1.6 mm³) in the treatment naïve group. Responders and non-responders groups had median values of 3.65 and 3.93 mm³, respectively. This trend was not observed with CFV, CFT, and TRV. A linear regression yielded threshold values of CFV (~0.3 mm³), CFT (~386 µm), and TRV (~9.06 mm³), above which EV may be detected by the current scanner. In this study, EV provided a better distinction between the response groups when compared to retinal tomography parameters. The EV increased with disease severity. Thus, EV can be a more precise parameter to identify subclinical edema and aid in better treatment planning.

Recommendations for the management of diabetic macular oedema with intravitreal dexamethasone implant: A national Delphi consensus study

PURPOSE

The intravitreal dexamethasone implant (DEX-I) is an alternative to anti-VEGF for the first-line treatment of diabetic macular oedema (DME). However, several questions remain regarding its routine use and its place in certain situations not always specified in current recommendations. A national consensus approach was, therefore, initiated by French retinal experts.

METHODS

An iterative Delphi consensus approach was used. A steering committee (SC) of seven experts analysed data from the literature to formulate statements divided into five key areas of treatment. These statements were submitted to the independent and anonymous electronic vote of 87 French retina experts among whom 39 expressed their opinion and therefore constituted the voting panel.

RESULTS

After two rounds of voting, 22 and 7 of 38 statements received a strong consensus and a good consensus, respectively. The consensus level was higher for statements regarding first-line indications and safety of DEX-I compared to those regarding efficacy assessment, reprocessing time or pathophysiological biomarkers. The panellists recommended the preferential use of DEX-I for patients with limited availability for multiple injections, those who needed to undergo cataract surgery or who had a recent cardiovascular history, and as a therapeutic alternative to anti-VEGF in patients with a history of vitrectomy, retinal serous detachment, hyper-reflective points or dry exudates in optical coherence tomography (OCT). However, some statements proposed by SC experts were not validated.

CONCLUSION

This study provides some key recommendations to clinicians treating diabetic macular oedema, which may be useful when using intravitreal dexamethasone implants in daily practice.

Diagnostic performance of deep-learning-based screening methods for diabetic retinopathy in primary care-A meta-analysis

Background

Diabetic retinopathy (DR) affects 10–24% of patients with diabetes mellitus type 1 or 2 in the primary care (PC) sector. As early detection is crucial for treatment, deep learning screening methods in PC setting could potentially aid in an accurate and timely diagnosis.

Purpose

The purpose of this meta-analysis was to determine the current state of knowledge regarding deep learning (DL) screening methods for DR in PC.

Data sources

A systematic literature search was conducted using Medline, Web of Science, and Scopus to identify suitable studies.

Study selection

Suitable studies were selected by two researchers independently. Studies assessing DL methods and the suitability of these screening systems (diagnostic parameters such as sensitivity and specificity, information on datasets and setting) in PC were selected. Excluded were studies focusing on lesions, applying conventional diagnostic imaging tools, conducted in secondary or tertiary care, and all publication types other than original research studies on human subjects.

Data extraction

The following data was extracted from included studies: authors, title, year of publication, objectives, participants, setting, type of intervention/method, reference standard, grading scale, outcome measures, dataset, risk of bias, and performance measures.

Data synthesis and conclusion

The summed sensitivity of all included studies was 87% and specificity was 90%. Given a prevalence of DR of 10% in patients with DM Type 2 in PC, the negative predictive value is 98% while the positive predictive value is 49%.

Limitations

Selected studies showed a high variation in sample size and quality and quantity of available data.

Recent trends in drug-delivery systems for the treatment of diabetic retinopathy and associated fibrosis

Diabetic retinopathy is a frequent microvascular complication of diabetes and a major cause of visual impairment. In advanced stages, the abnormal neovascularization can lead to fibrosis and subsequent tractional retinal detachment and blindness. The low bioavailability of the drugs at the target site imposed by the anatomic and physiologic barriers within the eye, requires long term treatments with frequent injections that often compromise patient's compliance and increase the risk of developing more complications. In recent years, much effort has been put towards the development of new drug delivery platforms aiming to enhance their permeation, to prolong their retention time at the target site and to provide a sustained release with reduced toxicity and improved efficacy. This review provides an overview of the etiology and pathophysiology of diabetic retinopathy and current treatments. It addresses the specific challenges associated to the different ocular delivery routes and provides a critical review of the most recent developments made in the drug delivery field.

COMPARISON OF INTRAVITREAL DEXAMETHASONE IMPLANT AND AFLIBERCEPT IN PATIENTS WITH TREATMENT-NAIVE DIABETIC MACULAR EDEMA WITH SEROUS RETINAL DETACHMENT

PURPOSE

To compare the efficacy and safety of intravitreal dexamethasone (DEX) implant versus aflibercept in patients with treatment-naive diabetic macular edema with inflammatory biomarkers.

METHODS

Ninety-eight eyes of 62 treatment-naive patients with diabetic macular edema with serous retinal detachment and hyperreflective foci were enrolled. Each patient was randomized to receive either aflibercept or DEX implant treatment. The treatment protocol included 3 monthly injections of 2 mg of aflibercept as a loading phase in the anti-vascular endothelial growth factor group and 0.7 mg of DEX implant in the DEX group and then pro re nata treatment. Primary outcome measures were mean changes in visual acuity and central retinal thickness at the end of the 12-month follow-up.

RESULTS

Forty-eight eyes of 29 patients were received DEX implant, and 50 eyes of 33 patients received the aflibercept injection. Mean central retinal thickness decreased from 615.2 µm at baseline to 297.7 µm at 12 months in the DEX group (P < 0.001) and from 576.5 µm to 367.4 µm in the aflibercept group (P < 0.001). Except for the first month, mean central retinal thickness reduction was significantly higher in the DEX group (P < 0.05, Mann-Whitney U Test). Visual acuity improved significantly at the end of the follow-ups (46.3-52.7 Early Treatment Diabetic Retinopathy Study letters in the DEX group and 47.5-56.8 Early Treatment Diabetic Retinopathy Study letters in the aflibercept group at 12 months, P < 0.001, paired-sample t-test). Adjusting by baseline values, the increase in mean visual acuity during the 12-month follow-ups favored the aflibercept group (P < 0.01), 25% of the DEX-treated eyes and 42% of the aflibercept treated eyes experienced 10 or more Early Treatment Diabetic Retinopathy Study letters visual gain (P: 0.058). The DEX group received significantly fewer (2.6 vs. 7.2) injections (P: 0.001).

CONCLUSION

It was observed that the both of DEX implant and aflibercept were effective and safe in treatment-naive diabetic macular edema patients with inflammatory phenotype. Anatomical results were found to be better in the DEX group, and functional results were found to be better in the aflibercept group. In pseudophakic eyes, the functional superiority of aflibercept ceased to exist, and the low number of injections in the DEX implant group was seen as an advantage.

Prediction of response to anti-vascular endothelial growth factor treatment in diabetic macular oedema using an optical coherence tomography-based machine learning method

PURPOSE

To predict the anti-vascular endothelial growth factor (VEGF) therapeutic response of diabetic macular oedema (DME) patients from optical coherence tomography (OCT) at the initiation stage of treatment using a machine learning-based self-explainable system.

METHODS

A total of 712 DME patients were included and classified into poor and good responder groups according to central macular thickness decrease after three consecutive injections. Machine learning models were constructed to make predictions based on related features extracted automatically using deep learning algorithms from OCT scans at baseline. Five-fold cross-validation was applied to optimize and evaluate the models. The model with the best performance was then compared with two ophthalmologists. Feature importance was further investigated, and a Wilcoxon rank-sum test was performed to assess the difference of a single feature between two groups.

RESULTS

Of 712 patients, 294 were poor responders and 418 were good responders. The best performance for the prediction task was achieved by random forest (RF), with sensitivity, specificity and area under the receiver operating characteristic curve of 0.900, 0.851 and 0.923. Ophthalmologist 1 and ophthalmologist 2 reached sensitivity of 0.775 and 0.750, and specificity of 0.716 and 0.821, respectively. The sum of hyperreflective dots was found to be the most relevant feature for prediction.

CONCLUSION

An RF classifier was constructed to predict the treatment response of anti-VEGF from OCT images of DME patients with high accuracy. The algorithm contributes to predicting treatment requirements in advance and provides an optimal individualized therapeutic regimen.

Detection rate of diabetic macular microaneurysms comparing dye-based angiography and optical coherence tomography angiography

Diabetic maculopathy (DM) is a microvascular dysfunction clinically characterized by microaneurysms (MA) leading to edema and central visual deprivation. This prospective explorative study investigated 27 eyes of 17 patients with DM by fluorescein/indocyanine green angiography (FA/ICGA; SPECTRALIS HRA-OCT, Heidelberg Engineering) and by swept source-optical coherence tomography angiography (SS-OCTA; DRI-OCT Triton Plus, Topcon) to identify clinically relevant MAs. The SS-OCTA cubes were split into the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) according to the automated segmentation. The images of all modalities were superimposed for alignment by an Early Treatment Diabetic Retinopathy Study grid overlay and compared to each other. In total, the mean number of MAs in FA was 33.4 ± 22 (standard deviation) (median 27.5 [q1:21.75;q3:38.25]), in ICGA 24.9 ± 16.9 (17.5 [14;35]), in the SCP 6.5 ± 3.7 (5.5 [3.75;9.25]) and in the DCP 18.1 ± 10.5 (18.5 [10.75;23.5]). Mixed effects models between ICGA and the DCP were borderline significant (p = 0.048; 95% confidence interval 0.21 to 13.49), whereas all other imaging methods differed significantly. Quantitative analysis of MAs in DM showed a plausible agreement between ICGA and the DCP in SS-OCTA. These findings contribute to the imaging methodology in DM.

Biologic Therapy and Treatment Options in Diabetic Retinopathy with Diabetic Macular Edema

Proliferative diabetic retinopathy and diabetic macular edema can be a potentially sightthreatening disease if not treated correctly. It is directly correlated to the duration of diabetes and how well managed the patients' diabetes is. In the last 15 years, the treatment of diabetic eye disease has taken a quantum leap in methodology due to the group of biological agents named antivascular endothelial growth factor (anti-VEGF). The introduction of the first biological agent has revolutionized the treatment, not only in diabetic eye disease but also across most inflammatory eye diseases, causing leakage of fluid from the blood vessels i.e., in age-related macular degeneration. The availability of these biological agents, despite their considerable costs, have significantly improved the outcomes measured in visual acuity compared to more traditional treatments of diabetic retinopathy in the form of sole laser treatment and glycemic control. The agents demonstrate a favorable safety profile, but if the rarest and most severe side effects occur, there is a potential total loss of vision. This review aims to make an overview of the current pharmaceutical therapeutic options in the treatment of diabetic macular edema. This includes laser therapy, intravitreal steroids, and a primary focus on intravitreal antivascular endothelial growth factors.

Vitrectomy with internal limiting membrane peeling versus nonsurgical treatment for diabetic macular edema with massive hard exudates

Purpose

To compare the anatomical and functional outcomes of severe diabetic macular edema (DME) with massive hard exudates managed by pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling or nonsurgical treatment.

Methods

We retrospectively reviewed 40 eyes with DME and massive hard exudates treated with either PPV with ILM peeling (vitrectomy group, 21 eyes) or nonsurgical treatment with anti-vascular endothelium growth factor (VEGF) and/or steroids (nonsurgical group, 19 eyes). Changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) and resolution of macular hard exudates were compared between the two groups.

Results

After treatment, CRT decreased steadily in the vitrectomy group but fluctuated in the nonsurgical group. Compared with eyes in the nonsurgical group, eyes in the vitrectomy group had better visual improvement (P < 0.05 at 6 and 12 months and the final visit) and greater decrease in CRT (P < 0.05 at 3 and 6 months and the final visit) after adjustment for baseline BCVA. Hard exudates resolved more rapidly in the vitrectomy group than in the nonsurgical group, with 94.1% versus 47.4% eyes showing significant absorption after 6 months of the treatment (P = 0.003). In the vitrectomy group, 62% eyes did not require any further injections for treating DME after the operation.

Conclusions

PPV with ILM peeling resulted in rapid resolution of hard exudates with significant anatomical and functional improvement in DME with massive hard exudates.

Cell Atlas of The Human Fovea and Peripheral Retina

Most irreversible blindness results from retinal disease. To advance our understanding of the etiology of blinding diseases, we used single-cell RNA-sequencing (scRNA-seq) to analyze the transcriptomes of ~85,000 cells from the fovea and peripheral retina of seven adult human donors. Utilizing computational methods, we identified 58 cell types within 6 classes: photoreceptor, horizontal, bipolar, amacrine, retinal ganglion and non-neuronal cells. Nearly all types are shared between the two retinal regions, but there are notable differences in gene expression and proportions between foveal and peripheral cohorts of shared types. We then used the human retinal atlas to map expression of 636 genes implicated as causes of or risk factors for blinding diseases. Many are expressed in striking cell class-, type-, or region-specific patterns. Finally, we compared gene expression signatures of cell types between human and the cynomolgus macaque monkey, Macaca fascicularis. We show that over 90% of human types correspond transcriptomically to those previously identified in macaque, and that expression of disease-related genes is largely conserved between the two species. These results validate the use of the macaque for modeling blinding disease, and provide a foundation for investigating molecular mechanisms underlying visual processing.

Fluocinolone acetonide (0.19 mg) intravitreal implant reduces treatment burden and improves practice resource utilisation for patients with diabetic macular oedema

Objective

Patients with diabetic macular oedema (DME) are known to have significantly greater medical treatment burden than patients with non-DME. Frequent injections and office visits can have a substantial impact on patient adherence and quality of life. This analysis assesses the impact of the 0.19 mg fluocinolone acetonide (FAc) implant (or injection) on treatment burden and practice resource utilisation in patients with DME.

Methods and analysis

This study is a single-centre retrospective chart review of 30 eyes (23 patients) that received a single FAc implant. Data was collected for a 12-month period pre-injection and post-injection of the FAc implant. Primary outcomes included the frequency of injections and ophthalmology office visits. Secondary outcomes included visual acuity (VA), intraocular pressure (IOP) and central subfield thickness (CSFT).

Results

The injection frequency significantly decreased from one injection every 2.6 months pre-injection to one injection every 8.8 months post-injection of the FAc implant (p<0.001). Sixty-three percent of the subjects did not require additional injections post-FAc implant. The mean number of ophthalmology office visits significantly decreased from 12.7 visits pre-FAc to 9.3 visits post-FAc implant (p<0.001). The mean VA (p=0.24) and CSFT (p=0.39) showed a mild numerical improvement that was not statistically significant. Thirty-seven percent of the eyes required additional IOP lowering drops. No eyes required incisional glaucoma surgeries.

Conclusions

The FAc implant significantly decreased the treatment burden and improved practice resource utilisation while maintaining or improving VA and CSFT. IOP events were mostly well-controlled with drops and no eyes required incisional glaucoma surgery.

Health Economic and Safety Considerations for Artificial Intelligence Applications in Diabetic Retinopathy Screening

Systematic screening for diabetic retinopathy (DR) has been widely recommended for early detection in patients with diabetes to address preventable vision loss. However, substantial manpower and financial resources are required to deploy opportunistic screening and transition to systematic DR screening programs. The advent of artificial intelligence (AI) technologies may improve access and reduce the financial burden for DR screening while maintaining comparable or enhanced clinical effectiveness. To deploy an AI-based DR screening program in a real-world setting, it is imperative that health economic assessment (HEA) and patient safety analyses are conducted to guide appropriate allocation of resources and design safe, reliable systems. Few studies published to date include these considerations when integrating AI-based solutions into DR screening programs. In this article, we provide an overview of the current state-of-the-art of AI technology (focusing on deep learning systems), followed by an appraisal of existing literature on the applications of AI in ophthalmology. We also discuss practical considerations that drive the development of a successful DR screening program, such as the implications of false-positive or false-negative results and image gradeability. Finally, we examine different plausible methods for HEA and safety analyses that can be used to assess concerns regarding AI-based screening.

Outcomes in diabetic macular edema switched directly or after a dexamethasone implant to a fluocinolone acetonide intravitreal implant following anti-VEGF treatment

AIMS

Fluocinolone acetonide (FAc) is an intravitreal corticosteroid implant approved for the second-line treatment of diabetic macular edema (DME). This study compared outcomes of patients with DME switched directly to an FAc implant, versus indirectly via dexamethasone, after anti-VEGF therapy failure.

METHODS

This is a retrospective, single-center chart review. Patients were assigned to Group A (switched to FAc after anti-VEGF) or Group B (switched to dexamethasone and then to FAc after > 4 months). Charts were reviewed for best-corrected visual acuity (BCVA), central macular thickness (CMT), intraocular pressure (IOP) and cataract development.

RESULTS

Forty-nine eyes were included. BCVA increased and CMT decreased with anti-VEGF (both groups), and dexamethasone (Group B only), but regressed after stopping treatment. With FAc, BCVA increased rapidly and significantly: increases were maintained up to 36 months (P < 0.001), except at 18 and 9 months in Groups A and B, respectively. Significant CMT reductions (P < 0.001) were evident after 3 months and maintained up to 36 months in both groups. IOP increase > 21 mmHg occurred in 14 patients (nine in Group A, five in Group B): all were sufficiently treated with IOP-lowering drops. Nineteen phakic eyes (73.1%) developed cataract: seven underwent phaco-emulsification (two in Group A, five in Group B).

CONCLUSIONS

Similar functional and anatomical improvements occurred in FAc-treated eyes, regardless of whether they first received dexamethasone or switched directly to FAc after anti-VEGF. Safety signals were consistent with corticosteroid class effects. Early switch to FAc could benefit patients who respond insufficiently to anti-VEGF.

Rapid Structural and Functional Improvements with the 0.19 mg Fluocinolone Acetonide Intravitreal Implant for Patients with DME and Low Visual Acuity: 6-Month Data from the UAE

Purpose

The 0.19 mg fluocinolone acetonide (FAc) intravitreal implant is approved in the United Arab Emirates (UAE) for treating diabetic macular edema (DME) in patients previously treated with a course of corticosteroids and that did not have a clinically significant rise in intraocular pressure (IOP). This ongoing study is assessing its effectiveness and safety in pseudophakic patients with DME in clinical practice from a single center in the UAE.

Methods

A retrospective, ongoing 6-month audit study (NCT03590587), in which 22 eyes from 22 patients were treated with a single FAc intravitreal implant after treatment with a prior course of corticosteroids. Outcomes assessed included mean changes in best-corrected visual acuity (BCVA), central macular thickness (CMT), and IOP. Six-month follow-up data are presented.

Results

After FAc implantation, mean BCVA improved rapidly, increasing by 25.4 ± 3.0 letters (mean±SEM) from baseline to Month 6 (p<0.0001). At 6 months, BCVA had improved by 15 letters or more in 91% of eyes (n=20/22). Mean CMT decreased by 267.0 ± 20.1 µm from baseline to Month 6 (p<0.0001). Over 85% of eyes (n=19/22) had a CMT less than 300 µm at 6 months. Mean IOP increased by 2.9 ± 0.7 mmHg from baseline to Month 6 (p<0.001). All eyes except 2 had an IOP of 21 mmHg or lower. At Month 6, five eyes (23%) needed IOP-lowering therapy.

Conclusion

Injection of the FAc intravitreal implant rapidly and significantly improved BCVA and CMT within 6 months. These rapid and significant improvements exceed those reported in other real-world studies. Safety signals were consistent with corticosteroid class effects. The FAc implant may be a useful treatment option for patients in the UAE, particularly those with sight threatening DME requiring rapid functional improvements.

A New Approach for Diabetic Macular Edema Treatment: review of clinical practice results with 0.19 mg fluocinolone acetonide intravitreal implant including vitrectomized eyes

PURPOSE OF REVIEW

Fluocinolone acetonide is a synthetic fluorinated glucocorticoid. It has selective and potent agonist properties by binding to the cytosolic glucocorticoid receptor with high affinity; it is devoid of mineralocorticoid activity. Two extended-release (i.e. lasting up to 3 years) drug delivery systems containing fluocinolone acetonide (FAc) have been approved by the FDA for intravitreal use: Retisert ® (Bausch&Lomb, New Jersey, USA) and Iluvien ® (Alimera Sciences, Atlanta, USA). The former contains 0.59 mg of FAc, which is approved for the treatment of chronic noninfectious posterior segment uveitis. The latter contains a dose of 0.19 mg of FAc and is approved for the treatment of diabetic macular edema and here we review the results published in the clinical literature relating to its use in the treatment of diabetic macular edema (DME).

RECENT FINDINGS

The 0.19 mg FAc implant (Iluvien®) is a new approved treatment approach for DME. It is a non-biodegradable implant that continuously releases a microdose of FAc into the vitreous cavity for up to three years. It is effective in chronic DME with the added value of decreasing the treatment burden of multiple intravitreal injections. Recently, clinical practice studies are reporting its efficacy and safety profile (intra-ocular pressure rise and cataract), as well as its use in clinical setting not included in clinical trial such as vitrectomized eyes.

SUMMARY

The FAc implant has demonstrated in clinical practice results that mirror the results of the clinical trials efficacy wise. Regarding its safety profile, cataract is a common complication, however, intra-ocular pressure rises may be lower than the ones reported in trials. The implant has shown effectiveness in vitrectomized eyes. An increasing evidence of real-world studies have supported utility of the implant in DME patients. It's extended-release format for up to 3 years benefits to the patient and carer as it means fewer injections and visits to the clinic.

Effect of Intravitreal Ranibizumab on Intraretinal Hard Exudates in Eyes with Diabetic Macular Edema

PURPOSE

To study the effect of monthly 0.3-mg intravitreal ranibizumab injections on intraretinal hard exudates (HEs) and correlate the effect with macular thickness in eyes with diabetic macular edema (DME).

DESIGN

Randomized, controlled trial.

METHODS

Twenty-four eyes of 24 subjects with DME were included in this institutional review board-approved, prospective longitudinal study. Subjects were randomly assigned to receive monthly intravitreal ranibizumab injections either until macular edema resolved or until both macular edema and HEs resolved. All subjects underwent spectral-domain optical coherence tomography imaging (Cirrus OCT), at baseline and monthly for 12 months. Mean HE area and mean macular thickness at baseline and month 12 were compared using a paired t test and correlated with Pearson analysis.

RESULTS

The average age of the 24 subjects was 65 (±8.55) years. There was a significant decrease (P = .001) in mean HE area from baseline (0.48 ± 0.43 mm²) to month 12 (0.17 ± 0.19 mm²). There was a significant increase (P < .001) in best-corrected visual acuity from a letter score of 63.38 (±7.92) at baseline to 76.38 (±8.93) at month 12. There was no additional vision benefit for continuing to treat with monthly injections for persistent HE in the absence of macular thickening.

CONCLUSION

In eyes with DME, monthly intravitreal ranibizumab injections resulted in significant reduction in intraretinal HEs that paralleled reductions in macular thickness and volume. Baseline foveal HEs were associated with worse vision outcomes, and continued treatment for persistent HEs in the absence of edema did not result in better vision.

Investigational plasma kallikrein inhibitors for the treatment of diabetic macular edema: an expert assessment

Introduction: Plasma kallikrein is a  mediator of vascular leakage and inflammation. Activation of plasma kallikrein can induce features of diabetic macular edema (DME) in preclinical models. Human vitreous shows elevated plasma kallikrein levels in patients with DME. Because of the incomplete response of some patients to anti-VEGF agents, and the treatment burden associated with frequent dosing, there is still considerable need for VEGF-independent targeted pathways.Areas covered: This review covers the role of plasma kallikrein in the pathogenesis of DME and the therapeutic potential of plasma kallikrein inhibitors. It discusses early clinical studies of plasma kallikrein pathway modulation for DME, which have been associated with some improvement in visual acuity but with limited improvement in macular edema. This review also highlights KVD001, which is furthest along the development pathway, THR-149, which has recently completed a phase 1 study, and oral agents under development.Expert opinion: Plasma kallikrein inhibitors have a potential role in the treatment of DME, with mixed functional/anatomic results in early clinical trials. Given the large unmet need in DME treatment, further studies are warranted.

Discontinuous to continuous therapy for persistent diabetic macular edema leads to reduction in treatment frequency

OBJECTIVE

To evaluate, in the setting of persistent diabetic macular edema, the impact that continuous fluocinolone acetonide delivery has on treatment burden, visual acuity, central retinal thickness, and intraocular pressure.

MATERIALS AND METHODS

A single-center, retrospective, cohort study of patients with persistent diabetic macular edema, previously treated with anti-vascular endothelial growth factor injections, dexamethasone implants, or focal laser, who were subsequently treated with fluocinolone acetonide was conducted. All retinal visits were analyzed prior to fluocinolone acetonide, until the most recent follow-up visit. Primary outcomes were pre- and post-fluocinolone acetonide changes in the best-corrected visual acuity and number of treatments required for diabetic macular edema. Secondary outcomes included changes in the central retinal thickness and intraocular pressure.

RESULTS

A total of 19 eyes with persistent diabetic macular edema were included and followed for a mean (SD) of 399.3 (222.9) days. Post-fluocinolone acetonide, the mean best-corrected visual acuity improved by 0.4 ETDRS letters for all eyes (p = 0.895) and the central retinal thickness decreased by 34.2 µm (p = 0.077). After fluocinolone acetonide, the number of treatments decreased from an average of one treatment every 2.7 months to one every 6 months (p = 0.009). Furthermore, post-fluocinolone acetonide, 10/19 eyes (52.6%) did not require additional treatment due to a dry macula, and those who did experienced a non-statistically significant reduction of treatments, from one every 2.6 months pre-fluocinolone acetonide, to one every 2.8 months post-fluocinolone acetonide (p = 0.622).

CONCLUSIONS

In the setting of persistent diabetic macular edema, fluocinolone acetonide significantly reduces the therapeutic burden, while maintaining best-corrected visual acuity and improving the central retinal thickness. In patient-centered discussions, judiciously employing fluocinolone acetonide should be performed to mitigate this therapeutic burden for patients.

[Ozurdex in the treatment of diabetic macular edema. When to prescribe?]

Retinal damage in diabetes is known to manifest in two main ways: diabetic retinopathy and diabetic macular edema. The most effective anti-inflammatory drugs today are glucocorticoids, a classic representative of which is dexamethasone. Two things that should be considered by ophthalmologists in the therapy of macular edema are the switching point to dexamethasone implant when the effectiveness of anti-vasoproliferative drugs is unsatisfactory, and the identification of the main predictors of diabetic macular edema that make glucocorticoids the drugs of first choice. The data from real clinical practice was used to develop the indications for intravitreal administration of a glucocorticoid as the therapy of first choice for diabetic macular edema. Glucocorticoids are prescribed to patients diagnosed with diabetic macular edema who has a history of acute cerebrovascular events, myocardial infarction or other cardiovascular and cerebrovascular diseases, as well as patients with a very high risk of a vascular catastrophe. Intravitreal glucocorticoids can be prescribed to patients who cannot follow the schedule of frequent visits and/or are not able to visit the hospital during the first 6 months after the administration of the drug. Considering the local character of its ophthalmic action, the method can be recommended for treating patients with pseudophakic eyes, persistent diabetic macular edema, or patients who underwent vitrectomy.

Tie-2/Angiopoietin pathway modulation as a therapeutic strategy for retinal disease

Introduction: The Tie-2/Angiopoietin pathway is a therapeutic target for the treatment of neovascular age-related macular degeneration (nAMD) and diabetic macular edema (DME). Activation of Tie-2 receptor via Ang-1 maintains vascular stability to limit exudation. Ang-2, a competitive antagonist to Ang-1, and VE-PTP, an endothelial-specific phosphatase, interfere with the Tie-2-Ang-1 axis, resulting in vascular leakage. Areas covered: Faricimab, a bispecific antibody that inhibits VEGF-A and Ang-2, is in phase 3 trials for nAMD and DME. Nesvacumab is an Ang-2 inhibitor; when coformulated with aflibercept, it failed to show benefit over aflibercept monotherapy in achieving visual gains in phase 2 studies of nAMD and DME. ARP-1536 is an intravitreally administered VE-PTP inhibitor undergoing preclinical studies. AKB-9778 is a subcutaneously administered VE-PTP inhibitor that, when combined with monthly ranibizumab, reduced DME more effectively than ranibizumab monotherapy in a phase 2 study. AKB-9778 monotherapy did not reduce diabetic retinopathy severity score compared to placebo. AXT107, currently in the preclinical phase, promotes conversion of Ang-2 into a Tie-2 agonist and blocks signaling through VEGFR2 and other receptor tyrosine-kinases. Expert opinion: Tie-2/Angiopoietin pathway modulators show promise to reduce treatment burden and improve visual outcomes in nAMD and DME, with potential to treat cases refractory to current treatment modalities.

Clinical Effectiveness of Intravitreal Fluocinolone Acetonide (FAc) (ILUVIEN™) in Patients with Diabetic Macular Oedema (DMO) Refractory to Prior Therapy: The Manchester Experience

INTRODUCTION

Diabetic macular oedema (DMO) remains a significant cause of sight loss in the UK. Despite macular laser and anti-VEGF agents, a large proportion of patients remain with persistent DMO. We present our results of using 0.19 mg fluocinolone acetonide (FAc) intravitreal implant in this cohort with up to 3 years of follow-up.

METHODS

This is a single-centre retrospective review of patients treated with FAc implant for refractory DMO. The primary efficacy end point was visual acuity and secondary efficacy end point was central retinal thickness (CRT) on OCT. A primary safety end point was a rise in IOP requiring treatment.

RESULTS

Twenty-one eyes were identified with an average follow-up of 27 months (6-36 months). Visual acuity change from baseline was - 0.1 ETDRS letters at year 1 (n = 13), 8.1 letters at year 2 (n = 13) and 10.7 letters at year 3 (n = 10). CRT improved by - 132.1 µm at year 1 (n = 15), - 172.8 µm at year 2 (n = 13) and - 157.8 µm at year 3 (n = 10). Five eyes (24%) required further anti-VEGF during follow-up and two (9.5%) required further focal laser. IOP rise requiring treatment was noted in eight eyes (38%). Seven were steroid induced. One was caused by rubeotic glaucoma. Six (75%) were managed medically and the remaining two also required surgery.

CONCLUSION

This data add to the limited real-world data on FAc in DMO with 3 years of follow-up. Vision and macular architectures both improved at varying rates over 3 years in patients with refractory DMO. IOP rise is a risk but, in the majority, it can be managed medically.

Retinal blood oxygen saturation and aqueous humour biomarkers in early diabetic retinopathy

PURPOSE

The aim of this study was to assess the relationship between retinal blood oxygen saturation (SO₂ ) and specific aqueous humour (AH) concentrations of proangiogenic biomarkers in diabetic patients with nonproliferative diabetic retinopathy (NPDR) and to compare them with those of matched control subjects.

METHODS

The sample comprised 14 participants with mild-to-moderate NPDR (69.1 ± 6.6 years) and 17 age-matched healthy controls (69.7 ± 6.3 years); all participants were previously scheduled for routine cataract extraction with intraocular lens implantation. Multiplex cytokine analyses of specific biomarkers, including vascular endothelial growth factor A (VEGF-A), angiopoietin2 (Ang2), epidermal growth factor (EGF), hepatocyte growth factor (HGF) and interleukin-8 (IL-8) were performed by BioPlex 200 system. Six non-invasive hyperspectral retinal images were acquired.

RESULTS

Mean SO₂ was significantly higher in both arterioles (94.4 ± 1.9 versus 93.0 ± 1.6) and venules (64.4 ± 5.6 versus 55.9 ± 4.8) of NPDR than in the healthy controls (p < 0.001). AH levels of HGF (p = 0.018), Ang2 (p = 0.005) and IL-8 (p = 0.034) were significantly higher, and EGF (p = 0.030) was significantly lower in NPDR subjects. The study demonstrated a correlation between venular retinal blood oxygen saturation and proangiogenic factors HGF (r = 0.558, p = 0.038), Ang2 (r = 0.556, p = 0.039) and EGF (r = -0.554, p = 0.040), but did not find any correlation for IL-8 (r = 0.330, p = 0.249) even though this biomarker was significantly higher in the diabetic group.

CONCLUSION

To our knowledge, the present study is the first report considering the association between SO₂ and AH concentrations of protein biomarkers in diabetic retinopathy. The biomarkers of interest have been shown to participate in cell death, which may explain higher oxygen saturation in NPDR.

Cross-Talk between Sirtuin 1 and the Proinflammatory Mediator High-Mobility Group Box-1 in the Regulation of Blood-Retinal Barrier Breakdown in Diabetic Retinopathy

Purpose: High-mobility group box-1 (HMGB1) mediates inflammation and breakdown of blood-retinal barrier (BRB) in diabetic retina. Sirtuin-1 (SIRT1) has protective effects against inflammation and oxidative stress. The aim of this study was to investigate the interaction between HMGB1 and SIRT1 in regulating BRB breakdown in diabetic retina. Methods: BRB breakdown was assessed in vivo with fluorescein isothiocyanate-conjugated dextran. Vitreous samples from 47 proliferative diabetic retinopathy (PDR) and 19 nondiabetic patients, and epiretinal membranes from 13 patients with PDR were studied by enzyme-linked immunosorbent assay and immunohistochemistry. Retinas from 4-week diabetic rats and from normal rats intravitreally injected with HMGB1 were studied by spectrophotometric assay, Western blot analysis, and RT-PCR. We also studied the effect of the HMGB1 inhibitor glycyrrhizin and the SIRT1 activator resveratrol on diabetes-induced biochemical changes in the retina. Results: HMGB1 levels in vitreous samples from PDR patients were significantly higher than in nondiabetic controls, whereas SIRT1 levels were significantly lower in vitreous samples from patients with inactive PDR than those in patients with active PDR and nondiabetic controls. In epiretinal membranes, SIRT1 was expressed in vascular endothelial cells and stromal cells. Diabetes and intravitreal injection of HMGB1 in normal rats downregulated SIRT1expression, whereas glycyrrhizin and resveratrol normalized diabetes-induced downregulation of SIRT1. Resveratrol significantly attenuated diabetes-induced downregulation of occludin and upregulation of HMGB1 and receptor for advanced glycation end products in the retina and breakdown of BRB. Conclusions: Our findings suggest that a functional link between SIRT1 and HMGB1 is involved in regulating of BRB breakdown in diabetic retina.

Intravitreal corticosteroid implant vs intravitreal ranibizumab for the treatment of macular edema: a meta-analysis of randomized controlled trials

PURPOSE

The purpose of this meta-analysis was to compare the efficacy and safety of corticosteroid implant and intravitreal ranibizumab for the treatment of macular edema (ME).

MATERIALS AND METHODS

PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were comprehensively searched for studies comparing dexamethasone implant with ranibizumab in patients with ME. Best-corrected visual acuity (BCVA), central subfield thickness (CST), and adverse events were extracted from the final eligible studies. RevMan 5.3 software was used to analyze the data, and the modified Jadad assessment tool was used to access the quality of outcomes.

RESULTS

Three randomized controlled trials (RCTs) were included in our analysis. The types of causes of ME include central retinal vein occlusion (CRVO), branch retinal vein occlusion (BRVO), and diabetic retinopathy (DR). The ranibizumab treatment group had significantly better BCVA compared with the corticosteroid treatment group (standard mean difference [SMD] -0.80; 95% CI -1.08, -0.53; P<0.00001). The ranibizumab treatment group also had higher CST reduction compared with the corticosteroid treatment group, and there was a significant difference (weighted mean difference [WMD] 167.58; 95% CI 125.21-209.95; P<0.00001). There was no significant difference in serious adverse effects between the two groups (SMD 1.67; 95% CI 0.69, 4.05; P=0.26). However, the use of corticosteroid implant had a higher risk of intraocular pressure (IOP) (OR 6.88; 95% CI 4.53-10.44; P<0.00001) elevation and cataract (OR 3.98; 95% CI 1.89-8.37; P=0.0003) than ranibizumab treatment and fewer injections.

CONCLUSIONS

Compared with ranibizumab, corticosteroid implant did not have greater improved BCVA, but corticosteroid implant had less CST reduction. The advantages of corticosteroids are fewer injections, while the advantages of ranibizumab include fewer side effects.

Intravitreal pro-inflammatory cytokines in non-obese diabetic mice: Modelling signs of diabetic retinopathy

Diabetic retinopathy is a vascular disease of the retina characterised by hyperglycaemic and inflammatory processes. Most animal models of diabetic retinopathy are hyperglycaemia-only models that do not account for the significant role that inflammation plays in the development of the disease. In the present study, we present data on the establishment of a new animal model of diabetic retinopathy that incorporates both hyperglycaemia and inflammation. We hypothesized that inflammation may trigger and worsen the development of diabetic retinopathy in a hyperglycaemic environment. Pro-inflammatory cytokines, IL-1β and TNF-α, were therefore injected into the vitreous of non-obese diabetic (NOD) mice. CD1 mice were used as same genetic background controls. Fundus and optical coherence tomography images were obtained before (day 0) as well as on days 2 and 7 after intravitreal cytokine injection to assess vessel dilation and beading, retinal and vitreous hyper-reflective foci and retinal thickness. Astrogliosis and microgliosis were assessed using immunohistochemistry. Results showed that intravitreal cytokines induced vessel dilation, beading, severe vitreous hyper-reflective foci, retinal oedema, increased astrogliosis and microglia upregulation in diabetic NOD mice. Intravitreal injection of inflammatory cytokines into the eyes of diabetic mice therefore appears to provide a new model of diabetic retinopathy that could be used for the study of disease progression and treatment strategies.

A meta-analysis of the effect of a dexamethasone intravitreal implant versus intravitreal anti-vascular endothelial growth factor treatment for diabetic macular edema

BACKGROUND

This meta-analysis evaluated the effectiveness and safety of dexamethasone (DEX) implant and intravitreal anti-vascular endothelial growth factor (VEGF) treatment for diabetic macular edema (DME).

METHODS

The PubMed, Embase, clinicaltrials.gov website and Cochrane Library databases were comprehensively searched for studies comparing DEX implant with anti-VEGF in patients with DME. Best-corrected visual acuity (BCVA), central subfield thickness (CST) and adverse events were extracted from the final eligible studies. Review Manager (RevMan) 5.3 for Mac was used to analyze the data and GRADE profiler were used to access the quality of outcomes.

RESULTS

Based on four randomized clinical trials assessing a total of 521 eyes, the DEX implant can achieve visual acuity improvement for DME at rates similar to those achieved via anti-VEGF treatment (mean difference [MD] = - 0.43, P = 0.35), with superior anatomic outcomes at 6 months (MD = - 86.71 μm, P = 0.02), while requiring fewer injections, in comparison to anti-VEGF treatment. Although the mean reduction in CST did not showed significant difference at 12 months (MD = - 33.77 μm, P = 0.21), the significant in BCVA from baseline to 12 months supported the anti-VEGF treatment (MD = - 3.26, P < 0.00001). No statistically significant differences in terms of the serious adverse events. However, use of the DEX implant has higher risk of intraocular pressure elevation and cataract than anti-VEGF treatment.

CONCLUSIONS

Compared with anti-VEGF, DEX implant improved anatomical outcomes significantly. However, this did not translate to improved visual acuity, which may be due to the progression of cataract. Therefore, the DEX implant may be recommended as a first chioce for select cases, such as for pseudophakic eyes, anti-VEGF-resistant eyes, or patients reluctant to receive intravitreal injections frequently.

Optical coherence tomography angiography

Optical coherence tomography (OCT) was one of the biggest advances in ophthalmic imaging. Building on that platform, OCT angiography (OCTA) provides depth resolved images of blood flow in the retina and choroid with levels of detail far exceeding that obtained with older forms of imaging. This new modality is challenging because of the need for new equipment and processing techniques, current limitations of imaging capability, and rapid advancements in both imaging and in our understanding of the imaging and applicable pathophysiology of the retina and choroid. These factors lead to a steep learning curve, even for those with a working understanding dye-based ocular angiography. All for a method of imaging that is a little more than 10 years old. This review begins with a historical account of the development of OCTA, and the methods used in OCTA, including signal processing, image generation, and display techniques. This forms the basis to understand what OCTA images show as well as how image artifacts arise. The anatomy and imaging of specific vascular layers of the eye are reviewed. The integration of OCTA in multimodal imaging in the evaluation of retinal vascular occlusive diseases, diabetic retinopathy, uveitis, inherited diseases, age-related macular degeneration, and disorders of the optic nerve is presented. OCTA is an exciting, disruptive technology. Its use is rapidly expanding in clinical practice as well as for research into the pathophysiology of diseases of the posterior pole.

Diabetic Macular Edema

Retinal edema is defined as any increase of water in retinal tissue resulting in an increase in its volume. This increase may be initially intracellular or extracellular. In the first case, there is cytotoxic edema. In the second, vasogenic edema, directly associated with an alteration of the blood-retinal barrier (BRB).

Retinal thickness can now be measured, using the retinal thickness analyser (RTA). Similarly, local breakdown of the BRB can now be mapped using the retinal leakage analyser (RLA). The application of these methods to diabetic macular edema has shown that both types of retinal retinopathy edema occur in the initial stages of diabetic retinal disease. These observations suggest a role for neuroprotective and vasoprotective agents in the management of diabetic retinal disease.