Characteristics of diabetic macular edema on optical coherence tomography may change over time or after treatment

Switching to an Intravitreal Dexamethasone Implant after Intravitreal Anti-VEGF Therapy for Diabetic Macular Edema: A Review

Among working-age people, diabetic retinopathy and diabetic macular edema are currently considered the main causes of blindness. Nowadays, intravitreal injections are widely acknowledged as a significant milestone in ophthalmology, especially for the treatment of several retinal diseases, including diabetic macular edema. In particular, anti-vascular endothelial growth factor (VEGF) agents are typically the first line of treatment; however, monthly injections are required, at least, during the loading dosage. Notably, an intravitreal 0.7 mg dexamethasone (DEX) implant (Ozurdex®, AbbVie Inc., North Chicago, IL, USA) is considered a legitimate substitute treatment for diabetic eyes that have not responded to anti-VEGF treatment. In fact, clinical trials and real-life studies have demonstrated the effectiveness and safety of an intravitreal DEX implant in treating such conditions over a period of three to six months. For this reason, wisely selecting diabetic patients might be crucial to decreasing the load of injections in clinics and hospitals. The purpose of this review is to analyze the available scientific literature to highlight the benefits, efficacy, and clinical criteria for choosing whether to switch from intravitreal anti-VEGF therapy to an intravitreal DEX implant in diabetic macular edema.

A quantitative evaluation of the effect of meals on macular thickness in diabetic patients with diabetic macular edema

PURPOSE

Central subfoveal thickness measurement is used in a large number of clinical trials to monitor the progression and treatment response of diabetic macular edema (DME) in patients of diabetic retinopathy (DR). Several studies have been carried out to investigate various factors affecting the central subfoveal thickness in order to minimize errors in the testing. We planned a study to investigate the effect of meals on central macular thickness (CMT) in patients with DME and compare that with nondiabetic patients.

METHODS

In this observational study, 50 patients of diabetes with DME and 50 normal controls were included. Macular thickness was measured after overnight fasting and 2 h postprandial for both the groups. Any changes in morphology and CMT were evaluated.

RESULTS

Each group had 22 females and 28 males with a mean age of 60.6 ± 6.6 in the diabetic group and of 49.66 ± 11.13 in the control group. Reduction in the CMT was noticed after the meals (mean: -9.78 ± 12.77 μm; P < 0.001) in those with DME as compared to the control group. This was more prominent in those who had intraretinal cystic spaces (17.14 ± 10.33 μm) and neurosensory detachment (66 µ). Patients with high blood sugar levels had higher CMT and a greater reduction in thickness was noticed in them postprandially (r = 0.414; P = 0.0028).

CONCLUSION

The CMT values in patients with DME are significantly affected by meals. Hence, an attempt should be made to measure CMT during the fasting state for more accurate results.

Real-World Evidence in the Management of Diabetic Macular Edema with Intravitreal Anti-VEGFs in Asia: A Systematic Literature Review

Purpose

To evaluate the visual outcomes and safety profile of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy in the treatment of diabetic macular edema (DME) in real-world studies in Asian countries.

Methods

A systematic review of electronic literature databases (Embase, Medline, and the Cochrane Library from January 1, 2010, to March 16, 2021) was conducted to identify observational studies that reported clinical and safety outcomes of anti-VEGF treatments for DME in Asia. We analyzed baseline patient characteristics, treatment patterns, mean number of injections, best-corrected visual acuity (BCVA), retinal thickness, and safety outcomes.

Results

Seventy-one studies were included in this review. Most studies reported treatment of DME with ranibizumab (n = 33), followed by aflibercept (n = 13), bevacizumab (n = 28), and conbercept (n = 9). At 12 months, the cumulative mean number of injections for ranibizumab, aflibercept, and conbercept was 5.2, 4.6, and 6, respectively. At the 12-month follow-up, the cumulative mean BCVA gain was 6.8 letters (ranibizumab), 4.6 letters (aflibercept), 4.9 letters (bevacizumab), and 8.3 letters (conbercept). The cumulative mean reduction in retinal thickness at 12 months was 116.9 μm (ranibizumab), 105.9 μm (aflibercept), 81.7 μm (bevacizumab), and 135.2 μm (conbercept). A strong positive correlation (r = 0.78) was observed between mean number of injections and change in BCVA at 12 months. A moderate positive correlation (r = 0.54) was observed between mean number of injections and mean reduction in retinal thickness at 12 months. A weak positive correlation was observed between baseline retinal thickness and visual acuity at 12 months. Baseline BCVA and mean number of injections were predictors of BCVA at 12 months.

Conclusion

All anti-VEGFs were effective in the treatment of DME in Asia. The data suggest that a greater number of anti-VEGF injections was associated with better improvement in BCVA and moderate reduction in retinal thickness at the 1-year follow-up.

Characteristics of macular morphology and microcirculation in diabetic macular edema patients with serous retinal detachment

BACKGROUND

To analyze and compare the characteristics of macular morphology and microcirculation in diabetic macular edema (DME) patients with and without macular serous retinal detachment (SRD).

METHODS

One hundred eyes in 81 patients diagnosed with the DME (the central macular thickness (CMT) of ≥ 300 μm) from March 2020 to November 2020 were selected. According to whether complicated with SRD, patients were divided into DME with SRD (60 eyes) and without SRD (40 eyes) groups. We analyzed the following parameters: CMT, central retinal thickness (CRT), subfoveal choroidal thickness (SFCT), number of hyperreflective foci (HF) in the complete retina, inner retina, outer retina, and subretinal space, the integrity of the ellipsoid zone (EZ) and external limiting membrane (ELM), the presence of disorganization of inner retinal layers (DRIL), foveal avascular zone (FAZ) area, and the vascular flow density of superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris.

RESULTS

(1) Compared to the group without SRD, the group with SRD had a greater CMT (P < 0.05) and a smaller CRT (P < 0.001); (2) The number of the HF in the complete retina, outer retina, and the subretinal space was larger in the group with SRD (P < 0.001); 3.The proportion of the EZ disruption (P < 0.05) and ELM disruption (P < 0.001) were higher in the group with SRD; 4. The SFCT (P < 0.05) and the vascular flow density of choriocapillaris (P < 0.05) were greater in the group with SRD; 5. There were no significant differences in the FAZ area and the vascular flow density of the DCP and SCP (P > 0.05); 6. The presence of the SRD was correlated with the integrity of the ELM, the number of HF in the complete retina, outer retina, and subretinal space (χ2 = 26.930, OR = 0.707, 0.263, 0.995, P < 0.001), as well as the SFCT (OR = 0.992, P < 0.05).

CONCLUSIONS

The results support the hypothesis that the presence of the ELM disruption, the larger number of the HF, and the thickening and hyperperfusion of the choroid may be involved in the pathogenesis of SRD in DME.

The Role of Intravitreal Corticosteroids in the Treatment of DME: Predictive OCT Biomarkers

This work aims to summarize predictive biomarkers to guide treatment choice in DME. Intravitreal anti-VEGF is considered the gold standard treatment for centers involving DME, while intravitreal steroid treatment has been established as a second-line treatment in DME. However, more than 1/3 of the patients do not adequately respond to anti-VEGF treatment despite up to 4-weekly injections. Not surprisingly, insufficient response to anti-VEGF therapy has been linked to low-normal VEGF levels in the serum and aqueous humor. These patients may well benefit from an early switch to intravitreal steroid treatment. In these patients, morphological biomarkers visible in OCT may predict treatment response and guide treatment decisions. Namely, the presence of a large amount of retinal and choroidal hyperreflective foci, disruption of the outer retinal layers and other signs of chronicity such as intraretinal cysts extending into the outer retina and a lower choroidal vascular index are all signs suggestive of a favorable treatment response of steroids compared to anti-VEGF. This paper summarizes predictive biomarkers in DME in order to assist individual treatment decisions in DME. These markers will help to identify DME patients who may benefit from primary dexamethasone treatment or an early switch.

Fluctuations in macular thickness in patients with diabetic macular oedema treated with anti-vascular endothelial growth factor agents

PURPOSE

To evaluate retinal thickness fluctuations in patients with diabetic macular oedema (DMO) treated with anti-vascular endothelial growth factor (anti-VEGF) injections.

METHODS

Visual acuity (VA) and central subfield thickness (CST) were collected at baseline, 3, 6, 9 and 12 months. Retinal thickness fluctuation was quantified by standard deviation (SD) of CST across 12 months. A mixed effects regression model evaluated the relationship between CST SD and VA at 12 months. Multiple linear regression analysis was performed to investigate predictors of CST SD.

RESULTS

Mean baseline and 12-month VAs were 63.5 ± 15.7 and 69.0 ± 13.8 Early Treatment of Diabetic Retinopathy Study (ETDRS) letters (change = +5.1 ± 16.1 letters, p < 0.001). Mean baseline and 12-month CSTs were 396.9 ± 109.7 and 337.7 ± 100.7 μm (change = -59.2 ± 114.8 μm, p < 0.001). Retinal thickness variability across the first 12 months was 59.4 ± 43.6 μm. Stratification of patient eyes by CST SD demonstrated 9.7 letters difference in 12-month VA between first and fourth quartiles. Significant predictors of CST SD include baseline CST, injection type, laser treatment, and DR stage.

CONCLUSIONS

Larger retinal thickness fluctuations are associated with poorer visual outcomes in eyes with DMO treated with anti-VEGF injections. Retinal thickness variability may be an important prognostic biomarker for DMO patients.

Change of Optical Coherence Tomography Morphology and Associated Structural Outcome in Diabetic Macular Edema after Ranibizumab Treatment

(1) Background: To investigate the correlation between therapeutic outcome and morphologic changes for diabetic macular edema (DME) after intravitreal injection of ranibizumab (IVIR). (2) Methods: This retrospective study included 228 eyes received IVIR for DME. Each participant was traced for two years after the initial IVIR, while the data of ophthalmic examination, optical coherence tomography (OCT) image, and systemic diseases were collected. The study population was categorized into different subgroups according to the existence of OCT morphologic change and the initial OCT morphologic pattern, including diffuse retinal thickening (DRT), cystoid macular edema (CME), serous retinal detachment (SRD), and vitreomacular interface abnormalities (VMIAs). The primary outcomes were the baseline best-corrected visual acuity (BCVA) and central macular thickness (CMT) during a two-year study period. The distribution of OCT morphologic change and its relation to primary outcome were analyzed. (3) Results: Comparing the 42 eyes (18.4%) with OCT morphological changes to another 186 eyes (81.6%) without such alteration, the former showed a poorer baseline BCVA (0.84 ± 0.39 vs. 0.71 ± 0.36, p = 0.035), worse final BCVA (0.99 ± 0.44 vs. 0.67 ± 0.30, p = 0.001), and thicker final CMT (354.21 ± 89.02 vs. 305.33 ± 83.05, p = 0.001). Moreover, the VMIA developed in 14.9% of all DME patients presenting the most common morphologic change among DRT, CME, and SRD. Besides, the presence of stroke was independently correlated to the morphologic change (adjusted odds ratio [aOR]: 6.381, 95% confidence interval (CI): 1.112–36.623, p = 0.038). (4) Conclusions: The change of OCT morphology in DME patients receiving IVIR was correlated to worse structural and visual outcome while the formation of VMIA most commonly occurred after initial treatment.

One-year outcomes of the treat-and-extend regimen using aflibercept for the treatment of diabetic macular edema

BACKGROUND

Optimal regimen using intravitreal aflibercept injections for diabetic macular edema (DME) in clinical practice remains to be elucidated. The purpose of this study is to evaluate a treat-and-extend (TAE) approach using intravitreal aflibercept in participants with center-involved DME.

METHODS

A 52-week open-label, prospective, multicenter, interventional study was conducted between August 2015 and November 2017 in Taiwan. Adults with diabetes mellitus and center-involved DME who have best-corrected visual acuity (BCVA) of 73 to 24 Early Treatment Diabetic Retinopathy Study letters and central retinal thickness (CRT) >300 μm were included. Participants received five monthly loading doses of 2 mg intravitreal aflibercept, followed by a TAE regimen with a four-week increment/decrement interval over 48 weeks; the maximum interval was 12 weeks. Main outcomes included changes in BCVA and CRT from baseline to week 52, additional anatomical outcomes, and treatment burden parameters.

RESULTS

Forty-five participants with mean (SD) age of 63.7 (8.3) years were analyzed. At baseline, mean (SD) BCVA and CRT were 58.3 (11.9) letters and 434.4 (116.8) μm, respectively. Changes from baseline in BCVA and CRT were +8.3 (9.3) letters and -138.2 (150.0) μm (both p < 0.001) at week 52, respectively. In addition, 22% (10/45) of patients gained ≥15 letters, 14% (6/44) of participants achieved ≥2-level improvement in diabetic retinopathy severity, and 51% (23/45) demonstrated dry retina at week 52 compared with 13% (6/45) at baseline. In total, 87% (39/45) of patients reached disease stability, entering TAE at week 20. Subsequently, 89% (40/45) of patients reached maximum interval at week 52. Mean (SD) number of injections was 7.7 (1.5) over a period of 52 weeks.

CONCLUSION

This straightforward and practical TAE regimen using intravitreal aflibercept injections resulted in favorable clinical outcomes with minimal treatment burden for DME at week 52.

Behavior of hyperreflective spots noted on optical coherence tomography following intravitreal therapy in diabetic macular edema: A systematic review and meta-analysis

Purpose:

Hyperreflective spots (HRS) are considered as spectral domain optical coherence tomography biomarkers in predicting response to intravitreal therapy (IVT) in diabetic macular edema (DME). We aimed to determine if there was a quantitative reduction in HRS following IVT in DME, if the response to antivascular endothelial growth factor (anti-VEGF) drugs was different from steroids, and if HRS-response was associated with improvement in visual acuity (VA) or reduction in central macular thickness (CMT).

Methods:

PubMed/MEDLINE, Scopus, ProQuest, CINAHL, Wiley online, and Web of Science were searched (between January 1, 2011 and July 1, 2020). Publication bias and heterogeneity were assessed. Meta-analysis was done using the random-effects model.

Results:

Totally, 1168 eyes from 19 studies were eligible for inclusion. IVT was associated with a reduction in quantitative HRS (z = -6.3, P < 0.0001). Studies, however, showed heterogeneity (I² = 93.2%). There was no difference between anti-VEGF and steroid therapies (P = 0.23). The evidence on predicting VA and CMT outcomes were limited by the number of analyzable studies, owing to the wide variation in individual study designs, and lack of randomized controlled trials.

Conclusion:

We could conclude that there is a definite reduction in quantitative HRS following either form of IVT. We highlight the lacunae in the existing literature on HRS in DME and propose goals for future studies to harness the advantage of this promising biomarker.

Optical Coherence Tomographic Patterns as Predictors of Structural Outcome After Intravitreal Ranibizumab in Diabetic Macula Edema

Background/Objectives

The purpose of this study was to present an association between the treatment response of diabetic macular edema (DME) to intravitreal ranibizumab (IVR) injections and different morphology patterns using spectral domain optical coherence tomography (SD-OCT).

Subjects/Methods

This retrospective study included 216 eyes of 142 subjects who received IVR for DME and were observed for at least 2 years. Medical charts and SD-OCT images of consecutive patients were reviewed at baseline, 1, 3, 6, 12, and 24 months after first IVR treatment. The OCT patterns were characterized as diffuse retinal thickening (DRT), cystoid macular edema (CME), serous retinal detachment (SRD), and vitreomacular interface abnormalities (VMIAs). All patients were classified into four groups based on the OCT findings.

Results

For a total of 216 eyes, 36 eyes were classified into the DRT group, 76 in the CME group, 42 in the SRD group, and 62 in the VMIA group. There were significant central macula thickness (CMT) improvements in all groups at the 1st month and the 2nd year, except for the DRT group at the 2nd year. Patients with OCT findings of hyperreflective dots (HRDs), metabolic parameters of hyperlipidemia, and coronary artery disease (CAD) had significantly less improvements in CMT at 2-year follow-up (P=0.029, 0.007, <0.001, respectively).

Conclusion

A trend toward decreased effectiveness after long-term IVR treatment was observed in the DRT group. Consistent IVR treatment could still achieve favorable improvement in the reduction of CMT in 2-year follow-up in the VMIA group. Different OCT patterns in DME may affect the therapeutic role of anti-VEGF agents and predict the structure outcome.

Intravitreal dexamethasone implant in naïve and previously treated patients with diabetic macular edema: a retrospective study

AIM

To assess the effect of the intravitreal dexamethasone implant (DEX) Ozurdex on the best corrected visual acuity (BCVA) and central retinal thickness (CRT) in patients with diabetic macular edema (DME).

METHODS

Totally 43 eyes (24 naïve and 19 previously treated) were included in the study. Retrospective and single-center study involved patients with a clinical diagnosed of DME, who received treatment with DEX implant and had a follow-up of at least 12mo. Primary endpoints included changes in BCVA and CRT.

RESULTS

At month 12, mean improvement in BCVA from baseline was 20.4±20.8 letters and 6.8±6.9 letters in naïve and previously treated patients, respectively (P=0.0132). The naïve patients achieved the BCVA improvement significantly faster (2.4±1.5mo) than the previously treated ones (3.5±2.4mo, P=0.0298; Mann-Whitney test). The proportion of eyes gaining ≥15 letters was 54.2% and 21.1% in the non-previously treated and previously treated groups, respectively (P=0.0293). CRT was significantly reduced from 484.0±119.8 and 487.5±159.9 µm to 272.0±39.2 and 233.5±65.7 µm in the naïve and previously treated patients, respectively; P<0.0001 each, respectively. The presence of subretinal fluid was significantly associated with the proportion of patients achieving a BCVA improvement ≥5 letters [HR (95%CI), 1.23 (1.04 to 1.45), P=0.0145]; ≥10 letters [HR (95%CI), 1.75 (1.10 to 2.77), P=0.0182]; and ≥15 letters [HR (95% CI), 2.04 (1.03 to 4.02), P=0.0407]. Naïve patients received less DEX implants throughout the study than the previously treated ones (1.8±0.6 vs 2.3±0.6, P=0.0172, respectively). Totally 9 patients (20.9%) have developed ocular hypertension, which was successfully controlled with topical hypotensive drugs. Of the 23 phakic eyes at baseline, 5 eyes (21.7%) either had new onset lens opacity or progression of an existing opacity during the study follow-up. Four of them (2 in the naïve group and 2 in the previously treated one) required cataract surgery at months 4, 6, 6, and 6, respectively.

CONCLUSION

The results obtained in this study may support the early use of DEX Ozurdex as first line therapy in naïve patients.

Intraocular pressure might play a role in the surgical management of patients with epiretinal membrane

PURPOSE

To investigate the prognostic factors and visual outcomes for patients with epiretinal membrane after pars plana vitrectomy and possible interactions between multiple factors.

METHODS

A retrospective chart review of adult patients with epiretinal membrane treated with pars plana vitrectomy performed by a single surgeon between February 1, 2015, and January 31, 2017 was conducted. The surgical procedures included standard 25-gauge vitrectomy with peeling of the epiretinal membrane and internal limiting membrane (ILM). Factors including age, sex, vision, intraocular pressure (IOP), lens status, and baseline optical coherence tomography angiography were analyzed to determine any association with visual outcomes. IOP and lens status were evaluated at every visit point and were used for analysis.

RESULTS

Visual changes after pars plana vitrectomy in patients with epiretinal membrane were significantly associated with time, lens status, baseline ellipsoid zone integrity, baseline vision, baseline parafoveal vessel density of superficial capillary plexus (SPVD), and IOP. Further investigation using Johnson-Neyman analysis revealed that vision improved over time, especially in pseudophakic eyes. High IOP at baseline or during follow-up was identified as a significant factor associated with limited visual improvement.

CONCLUSION

Our study showed that vision improved over time after vitrectomy for patients with epiretinal membrane. The surgical outcomes are more stable in pseudophakic eyes, and vision improved after cataract extraction in phakic eyes. IOP should be managed and monitored closely to optimize surgical and visual outcomes in patients.

δ Opioid Receptor Agonism Preserves the Retinal Pigmented Epithelial Cell Tight Junctions and Ameliorates the Retinopathy in Experimental Diabetes

Purpose

Outer blood retinal barrier breakdown is a neglected feature of diabetic retinopathy (DR). We demonstrated that the agonism of the δ opioid receptor (DOR) by epicatechin preserves the tight junction proteins in ARPE-19 cells under diabetic conditions. Presently, we aimed to evaluate the possible role of the DOR on the maintenance of tight junction of RPE layer and on the early markers of experimental DR.

Methods

DR markers and external retinal tight junction proteins were evaluated in CL57B diabetic mice submitted to intravitreous injection of short hairpin RNA (shRNA)-DOR (108 transducing units [TU]/mL) treated or not with DOR agonist (0.05 g/animal/d of epicatechin in drinking water) for 16 weeks. The presence of DOR in human retina from postmortem eyes from diabetic and nondiabetic donors were also performed.

Results

DOR is present in RPE layer and in neuro retina. The treatment with DOR agonist prevented the upregulation of the early markers of retinopathy (glial fibrillary acidic protein, VEGF) and the downregulation of pigment epithelium-derived factor, occludin, claudin-1, and zonula occludens-1 tight junction expressions. The silencing of DOR in retina of diabetic mice partially abolished the protective effects of epicatechin. In human retina specimens, DOR is present throughout the retina, similarly in nondiabetic and diabetic donors.

Conclusions

This set of experiments strongly indicates that the DOR agonism preserves RPE tight junctions and reduces the early markers of retinopathy in model of diabetes. These novel findings designate DOR as a potential therapeutic tool to treat DR with preservation of the RPE tight junction proteins.

Differentiation of Underlying Pathologies of Macular Edema Using Spectral Domain Optical Coherence Tomography (SD-OCT)

Purpose: To describe the morphological characteristics of macular edema (ME) of different origins using spectral domain optical coherence tomography (SD-OCT). Methods: This article summarizes and highlights key morphologic findings, based on published articles, describing the characteristic presentations of ME of different origins using SD-OCT. The following pathologies were included: uveitic macular edema, pseudophakic cystoid macular edema (PCME), diabetic macular edema (DME), macular edema secondary to central or branch retinal vein occlusion (CRVO/BRVO), microcystic macular edema (MME), ME associated with epiretinal membrane (ERM), and retinitis pigmentosa (RP). Conclusions: Macular edema of different origins show characteristic patterns that are often indicative of the underlying cause and pathology. Thus, trained algorithms may in the future be able to automatically differentiate underlying causes and support clinical diagnosis. Knowledge of different appearances support the clinical diagnosis and can lead to improved and more targeted treatment of ME.