Efficacy of Ozurdex implant in recalcitrant diabetic macular edema—a single-center experience

A Review on Diabetic Retinopathy

Diabetic retinopathy is a well-recognised microvascular complication of diabetes and is among the leading cause of blindness all over the world. Over the last decade, there have been advances in the diagnosis of diabetic retinopathy and diabetic macular edema. At the same time, newer therapies for the management of diabetic retinopathy have evolved. As a result of these advances, a decline in severe vision loss due to diabetes has been witnessed in some developing countries. However, there is a steady increase in the number of people affected with diabetes, and is expected to rise further in the coming years. Therefore, it is prudent to identify diabetic retinopathy, and timely intervention is needed to decrease the burden of severe vision loss. An effort has been made to review all the existing knowledge regarding diabetic retinopathy in this article and summarize the present treatment options for diabetic retinopathy.

Intravitreal Dexamethasone Implant (IDI) Alone and Combined with Navigated 577 nm Subthreshold Micropulse Laser (SML) for Diabetic Macular Oedema

Background: The anatomical and functional changes after intravitreal dexamethasone implant (IDI) alone and combined with navigated subthreshold micropulse laser (NSML) in diabetic macular oedema (DMO) were compared. Methods: Patients with a clinically confirmed diagnosis of non-proliferative diabetic retinopathy (NPDR) and DMO were enrolled in this prospective study and were randomly assigned to two different treatment groups: thirty patients were treated with IDI (IDI group), and the other 30 patients received IDI combined with NSML treatment (combined IDI/NSML group). All patients during a 6-month follow-up underwent best corrected visual acuity (BCVA) evaluation and spectral domain optical coherence tomography (SD OCT). The main outcome measures were: BCVA, central macular thickness (CMT); (3) choroidal vascularity index (CVI), subfoveal choroidal thickness (SCHT); and time to retreatment between IDI at baseline and the second implant in both groups. Results: BCVA, CMT, and SCHT significantly decreased starting from the 1-month follow-up and CVI from 3 months in both groups. The between-group differences were significantly different from 1-month follow-up for BCVA, from 5-month follow-up for CMT and SCHT, and from 4-month follow-up for CVI. The Needed to Treat analysis indicated that six patients would have to be treated with SML after IDI in order for just one person to receive a benefit. Conclusions: the combined treatment showed good anatomical and functional outcomes for the treatment of DMO. In addition, IDI/SML seems to reduce injection frequency over time, improving patients’ quality of life and reducing the socio-economic burden.

Real-Life Efficacy, Safety, and Use of Dexamethasone Intravitreal Implant in Posterior Segment Inflammation Due to Non-infectious Uveitis (LOUVRE 2 Study)

Introduction

To evaluate real-life efficacy, safety, and treatment patterns with the dexamethasone intravitreal implant (DEX) in posterior segment inflammation due to non-infectious uveitis (treatment-naïve or not) in French clinics.

Methods

In this prospective, multicenter, observational, non-comparative, post-reimbursement study, consecutive patients with posterior segment inflammation due to non-infectious uveitis were enrolled and evaluated at baseline (day 0). Those who received DEX on day 0 were re-evaluated at months 2, 6, and 18. Retreatment with DEX and/or alternative therapies was allowed during follow-up. Primary outcome: patients (%) with at least a 15-letter gain in best corrected visual acuity (BCVA) at 2 months. Secondary outcomes included patients (%) with at least 15-letter BCVA gains at 6 and 18 months; mean BCVA change from baseline at 2, 6, and 18 months; and patients (%) retreated, mean central retinal thickness (CRT), and adverse events (AEs) at all post-baseline visits.

Results

Ninety-seven of 245 enrolled patients with posterior segment inflammation due to non-infectious uveitis (80% previously treated) and disease duration of 5 years (average) received DEX on day 0 and were included in efficacy analyses. At month 2 (n = 91), 20.5% of patients (95% CI 12.0–28.9) gained at least 15 letters from a baseline mean of 60.9 letters; the mean gain was 6.2 letters (95% CI 3.5–8.9). At month 6, 50.0% (n = 38/76) of patients did not receive alternative treatment or DEX retreatment, mostly because inflammation had sufficiently subsided (n = 27/38, 71.1%). Although early study termination prevented efficacy analysis at 18 months (n = 12), CRT reductions persisted throughout follow-up. From baseline to month 18, 21/245 (8.6%) patients had DEX-related AEs; 17/245 (6.9%) had ocular hypertension (most common AE).

Conclusion

LOUVRE 2 confirms DEX efficacy on visual acuity and CRT in predominantly DEX-pretreated patients with relatively old/stabilized uveitis. DEX tolerability was consistent with known/published data, confirming treatment benefits in posterior segment inflammation due to non-infectious uveitis.

ClinicalTrials.gov Identifier

NCT02951975.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40123-022-00525-8.

Updates on the Current Treatments for Diabetic Retinopathy and Possibility of Future Oral Therapy

Diabetic retinopathy (DR) is a complication of diabetes and one of the leading causes of vision loss worldwide. Despite extensive efforts to reduce visual impairment, the prevalence of DR is still increasing. The initial pathophysiology of DR includes damage to vascular endothelial cells and loss of pericytes. Ensuing hypoxic responses trigger the expression of vascular endothelial growth factor (VEGF) and other pro-angiogenic factors. At present, the most effective treatment for DR and diabetic macular edema (DME) is the control of blood glucose levels. More advanced cases require laser, anti-VEGF therapy, steroid, and vitrectomy. Pan-retinal photocoagulation for non-proliferative diabetic retinopathy (NPDR) is well established and has demonstrated promising outcomes for preventing the progressive stage of DR. Furthermore, the efficacy of laser therapies such as grid and subthreshold diode laser micropulse photocoagulation (SDM) for DME has been reported. Vitrectomy has been performed for vitreous hemorrhage and tractional retinal detachment for patients with PDR. In addition, anti-VEGF treatment has been widely used for DME, and recently its potential to prevent the progression of PDR has been remarked. Even with these treatments, many patients with DR lose their vision and suffer from potential side effects. Thus, we need alternative treatments to address these limitations. In recent years, the relationship between DR, lipid metabolism, and inflammation has been featured. Research in diabetic animal models points to peroxisome proliferator-activated receptor alpha (PPARα) activation in cellular metabolism and inflammation by oral fenofibrate and/or pemafibrate as a promising target for DR. In this paper, we review the status of existing therapies, summarize PPARα activation therapies for DR, and discuss their potentials as promising DR treatments.

Anti-VEGF-Resistant Retinal Diseases: A Review of the Latest Treatment Options

Anti-vascular endothelial growth factor (anti-VEGF) therapy currently plays a central role in the treatment of numerous retinal diseases, most notably exudative age-related macular degeneration (eAMD), diabetic retinopathy and retinal vein occlusions. While offering significant functional and anatomic benefits in most patients, there exists a subset of 15–40% of eyes that fail to respond or only partially respond. For these cases, various treatment options have been explored with a range of outcomes. These options include steroid injections, laser treatment (both thermal therapy for retinal vascular diseases and photodynamic therapy for eAMD), abbreviated anti-VEGF treatment intervals, switching anti-VEGF agents and topical medications. In this article, we review the effectiveness of these treatment options along with a discussion of the current research into future directions for anti-VEGF-resistant eyes.

Differential response to intravitreal dexamethasone implant in naïve and previously treated diabetic macular edema eyes

Background

To identify different response patterns to intravitreal dexamethasone implants (IDI) in naïve and previously treated (PT) diabetic macular edema (DME) eyes in a real-life setting.

Methods

342 IDI injections (203 DME eyes) were included. Number of IDI injections, percentage (%) of eyes with 1, 2, 3 and ≥ 4 injections, time to reinjections, visual acuity (VA), intraocular pressure (IOP) and central retinal thickness (CRT) were evaluated for naïve and PT DME eyes over 24 months.

Results

Mean number of injections was significantly lower in naïve vs PT DME eyes (1.40 ± 0.9 vs 1.82 ± 0.9, p < 0.001). The percentage of eyes receiving 1 injection was significantly higher in naïve vs PT DME eyes (76.1 vs 47.7), (p < 0.001). However, it was significantly lower for 2 (16.4 vs 29.4), or 3 injections (1.4 vs 17.6) (both p < 0.001), with no differences in eyes receiving ≥4 injections (5.9 vs 5.1 respectively, p = 0.80). Mean time to reinjection was not significantly different between both groups for the second, third and fourth injection (9.6 ± 4.0 vs 10.0 ± 5.5, p = 0.75, 13.2 ± 4.0 vs 16.0 ± 3.5, p = 0.21 and 21.7 ± 3.8 vs 19.7 ± 5.8, p = 0.55). VA scores were consistently better in naïve vs PT DME eyes at all studied timepoints, with no significant differences in CRT reduction or adverse effect rates.

Conclusion

Naïve DME eyes received lower number of IDI injections and showed better VA levels than PT DME eyes for 24 months in a real-world setting. This data supports the IDI use in early DME stages and provide further evidence of better IDI response when used as first-line therapy.

The effects of intravitreal injections on intraocular pressure and retinal nerve fiber layer: a systematic review and meta-analysis

The number of eye diseases treated with intravitreal injections is increasing. Obviously, an injection of fluid into the eye results in an increase of intraocular pressure (IOP), the main risk factor for glaucoma. However, the effect of these repeated IOP increases on the eye is unclear. Therefore, we performed a systematic review with meta-analyses. PubMed, Embase and Clinical Trials Registries were searched for articles investigating the relationship between intravitreal injections (anti-vascular endothelial growth factor [anti-VEGF] or steroids) and either IOP, retinal nerve fiber layer (RNFL)-thickness and glaucoma. Multiple meta-analyses were performed, combining data on intravitreal injection of anti-VEGF medication and dexamethasone implants. A total of 74 articles were eligible for meta-analyses. The short-term effect of an intravitreal injection of anti-VEGF showed a statistically significant increase in IOP. One day after injection of anti-VEGF, however, IOP was significantly lower than baseline. The long-term time-intervals showed no significant difference in IOP. After intravitreal injection of a dexamethasone implant, IOP was significantly higher than baseline 1 month post-injection. RNFL-thickness was significantly reduced 6 and 12 months post-injection of anti-VEGF, as well as at end of follow up. Caution is advised when using intravitreal medication, especially when treating patients with advanced glaucoma; in these cases, prophylactic IOP-lowering medication may be considered.

Dexamethasone Implant in Patients with Diabetic Macular Edema Resistant to Anti-VEGF Therapy

Objectives:

To investigate the efficacy of single dose intravitreal dexamethasone implant in patients with diabetic macular edema (DME) resistant to anti-VEGF therapy.

Materials and Methods:

Twenty eyes of 14 patients (8 male, 6 female; mean age, 65±5.7 years) with DME resistant to intravitreal ranibizumab injections were studied. A single intravitreal dexamethasone implant was injected into each eye and patients were followed up for 6 months. Response to therapy was assessed monthly by measuring intraocular pressure (IOP), best-corrected visual acuity (BCVA), and central foveal thickness (CFT).

Results:

Baseline (before injection) IOP was 14.9±2.7 mmHg and did not change significantly in the six months following injection. Baseline BCVA was 1.04±0.35 LogMAR and improved to 0.86±0.31 at month 1 without statistical significance (p=0.056). CFT was significantly lower in all monthly measurements compared to its baseline value of 682.2±229.2 μm. During the follow-up period, endophthalmitis, significant cataract, or rhegmatogenous retinal detachment were not detected.

Conclusion:

Intravitreal dexamethasone implant injection is associated with significant CFT reduction for up to six months without causing any complications. Although BCVA did not improve in parallel with the CFT reduction, intravitreal dexamethasone implant should be considered as an effective and safe treatment option in the management of DME patients resistant to anti-VEGF injections.

Factors Influencing Intravitreal Bevacizumab and Triamcinolone Treatment in Patients with Diabetic Macular Edema

PURPOSE

To evaluate factors associated with response to intravitreal bevacizumab (IVB) and intravitreal triamcinolone acetonide (IVTA) in diabetic macular edema (DME).

METHODS

Ninety-one eyes of 88 patients diagnosed with DME were enrolled in this retrospective chart review. Group 1 included eyes that showed good response to IVB. Group 2 included eyes that did not respond to IVB but responded to IVTA. Group 3 included eyes that responded to neither. Clinical factors, HbA1c, and optical coherence tomography (OCT) findings including patterns of macular edema were compared among the 3 groups.

RESULTS

A total of 44, 27, and 20 eyes were included in groups 1, 2, and 3, respectively. HbA1c was higher in group 3 than in the other groups. Proportion of full (combination of all patterns) type edema was higher in group 3 than in the other 2 groups. In group 1, the proportion of sponge-like diffuse retinal thickening type was higher and cystoid macular edema type was lower than in the other groups.

CONCLUSIONS

The degree of diabetic control and morphologic subtypes with OCT should be considered to better predict the prognosis after treatment in DME.

Long-term efficacy and safety profile of multiple injections of intravitreal dexamethasone implant to manage diabetic macular edema: A systematic review of real-world studies

INTRODUCTION

Systematic review of real-world studies about repeated dexamethasone intravitreal implant (DEXi) 0.7 mg in diabetic macular edema management, in order to identify the effective window of time occurring between injections, the critical evaluation of efficacy of the treatment, and the relative long-term safety in the real life setting.

METHODS

Literature databases such as PubMed, SCOPUS, and EMBASE were used to identify reports including DEX implant injections.

RESULTS

Twenty-one peer-reviewed publications were identified. DEX implants retreatment was considered on a pro re nata (PRN) basis at any time or starting from month three or four. About 1/3 of the eyes were retreated before six months from first injection (range 0-86.7%). Mean retreatment average time was 5.3 ± 0.9 months, with an estimated average of 1.3 injections each six months. There was no statistical correlation between average retreatment time and incidence of adverse events or other variables investigated. Limited safety issues related to implants number have been found, suggesting an overall good tolerance of long-term DEXi.

CONCLUSIONS

Comprehensive evaluation of real-world data suggests an average DEXi duration close to five months, following a PRN treatment strategy, including about 1/3 of patients. Repeated DEXi administration revealed an acceptable long-term efficacy/safety ratio.

Pharmacological Management of Diabetic Macular Edema in Real-Life Observational Studies

OBJECTIVES OF THE STUDY

of observational studies concerning the pharmacological management of diabetic macular edema (DME).

METHODS

A literature review was conducted using the PubMed database on 1 February 2018 to identify studies evaluating the efficacy of anti-VEGF and dexamethasone (DEX) implants for DME. Studies with more than 10 patients and follow-up of more than 6 months were selected. Analyses were carried out on the overall population and on subgroups defined according to baseline visual acuity (BVA) and the patients' naïve or non-naïve status.

RESULTS

Thirty-two studies evaluating the efficacy of anti-VEGF and 31 studies evaluating the efficacy of DEX-implants were retained, concerning 6,842 and 1,703 eyes, respectively. A mean gain of +4.7 letters for a mean of 5.8 injections (mean follow-up: 15.6 months) and +9.6 letters for a mean of 1.6 injections (10.3 months) was found in the anti-VEGF and DEX-implant studies, respectively. Final VA appears to be similar for both treatment (62 letters for anti-VEGF, 61.2 letters for DEX-implant), and BVA appears lower for DEX-implant, which may partially explain the greater visual gain. The DEX-implant studies show greater gains in VA compared to the anti-VEGF studies, especially for higher BVA. Indeed, mean gains for the subgroups of patients with BVA<50 letters, 5060 letters are +4.3, +5.8, and +3.1 letters, respectively, in the anti-VEGF studies and +10.5, +9.3, and +8.8 letters, respectively, in the DEX-implant studies. Regarding the patient's initial status, only naïve status appears to confer the best functional response in DEX-implant studies.

CONCLUSION

Observational studies investigating DEX-implant report clinically similar final VA when compared to anti-VEGF, but superior visual gains in real-life practice. This latter difference could be due to the better BVA, but also to the fact that less injections were administered in the anti-VEGF observational studies than in the interventional studies.

Radiation retinopathy treated successfully with aflibercept

Aflibercept (aflibercept) is a novel anti-vascular endothelial growth factor drug indicated for wet age-related macular degeneration and macular oedema secondary to retinal vein occlusion and diabetic macular oedema. While only newly introduced on the market, it is growing in popularity and over 5.5 million doses have been prescribed worldwide. Due to its versatile mechanism, it is indicated for numerous eye pathologies, and in particular, has been adapted to treat various types of retinopathy. To our knowledge, this is the first case report of solely using aflibercept to treat cystoid macular oedema in radiation retinopathy.

Concurrent injection of dexamethasone intravitreal implant and anti-angiogenic agent in patients with macular edema: A retrospective cohort study

To evaluate the safety and efficiency in macular edema patients who concurrently received a single injection of a dexamethasone intravitreal implant (DEX, 0.7 mg) and ranibizumab (2.3 mg).A retrospective cohort study was conducted, and medical records from 2012 to 2016 were reviewed. Patients who received concurrent DEX and ranibizumab injections with a follow-up period of at least 3 months were enrolled in the study group. An age and gender-matched group received ranibizumab injections and was designated the control group. The best-corrected visual acuity (BCVA), central macular thickness (CMT) and intraocular pressure (IOP) were included in the analysis. Steroid-induced ocular hypertension (SIOH) is defined as either an elevation of more than 10 mmHg from baseline or a single IOP measurement of more than 30 mmHg.A total of 26 patients were enrolled in the current study with 13 patients in each group. Both the BCVA (P = .04) and CMT (P < .01) achieved significant improvement after the follow-up period in the study group. The IOP increased after the injection but no significant elevation was observed throughout the follow-up period in the study group (P = .15). For SIOH, 1 patient in the study group had an elevated IOP of 10 mmHg (7.7%) at 2 postoperative months, and no single IOP measurement of more than 30 mmHg was obtained. Five patients (38.5%) in the study group received medical treatment that successfully retarded their IOP elevation, and no individuals required surgical management. In the control group, there were no significant fluctuations concerning BCVA, CMT, and IOP, and no ocular hypertension was observed. According to the inter-group analysis, the CMT and BCVA recovered more significantly in the study group than in the control group.Concurrent injection of DEX and ranibizumab is a preliminary method that shows effectiveness in treating ME. Furthermore, safety is also guaranteed, with moderate levels of severity and transient IOP elevation being observed. A future large-scale study is necessary to evaluate the long-term effects and safety of this combined treatment.

REAL-LIFE STUDY IN DIABETIC MACULAR EDEMA TREATED WITH DEXAMETHASONE IMPLANT: The Reldex Study

PURPOSE

To evaluate the efficacy and safety of intravitreal implant of dexamethasone (Ozurdex) in diabetic macular edema in real-life practice.

METHODS

In this bicentric retrospective study, the authors reviewed 128 eyes of 89 patients. Main outcome measures included changes in best-corrected visual acuity, central macular thickness, time to retreatment, and incidence of adverse effects. Linear mixed-effects models were used to study changes in best-corrected visual acuity and central macular thickness over the 3-year follow-up.

RESULTS

Best-corrected visual acuity increased by a mean of 3.6 letters at Month 2 (P = 0.005), 4.2 letters at Month 12 (P = 0.006), 5.3 at Month 24 (P = 0.007), and 9.5 letters at Month 36 (P = 0.023). The proportion of eyes achieving at least a 15-letter improvement from baseline was 25.4% at Month 36. Central macular thickness decreased from 451 μm to 289 μm at Month 2 (P < 0.001), 370 μm at Month 12 (P < 0.001), 377 μm at Month 24 (P = 0.004), and 280 μm at Month 36 (P = 0.001). A mean of 3.6 injections were administered over the 3-year follow-up. Ten percent of eyes developed a transient increase in intraocular pressure (IOP ≥ 25 mmHg), and cataract was removed from 47% of phakic eyes.

CONCLUSION

This large case series study showed favorable 3-year outcomes when using Ozurdex to treat diabetic macular edema. Intravitreal Ozurdex provides substantial long-term benefits in the treatment of diabetic macular edema in real-life.

Efficacy of the Intravitreal Sustained-Release Dexamethasone Implant for Diabetic Macular Edema Refractory to Anti-Vascular Endothelial Growth Factor Therapy: Meta-Analysis and Clinical Implications

BACKGROUND AND OBJECTIVE

To assess the effect on best-corrected visual acuity (BCVA) and efficacy of the intravitreal sustained-release 0.7 mg dexamethasone implant (Ozurdex; Allergan, Irvine, CA) in patients with recalcitrant diabetic macular edema (DME).

PATIENTS AND METHODS

Meta-analysis utilizing the MOOSE framework and a random effects model. Studies included adults undergoing treatment with Ozurdex for DME. The methodologic quality of each study was assessed using the MINORS and the Cochrane Collaboration Risk of Bias for randomized studies.

RESULTS

A total of 3,859 patients among 15 studies were included in the final analysis. The mean difference in BCVA was a gain of four lines or 20 Early Treatment of Diabetic Retinopathy Study letters with Ozurdex at a mean follow-up period of 6 months.

CONCLUSIONS

Treatment with Ozurdex is associated with significant mean improvement in visual acuity. Clinicians should have a multimodality approach to treating DME and be aware of this treatment option in those who have a suboptimal response to anti-VEGF therapy. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:160-166.].

Contralateral eye-to-eye comparison of intravitreal ranibizumab and a sustained-release dexamethasone intravitreal implant in recalcitrant diabetic macular edema

Objective

To compare the effects of intravitreal ranibizumab (RZB) or dexamethasone (DEX) intravitreal implant in cases of recalcitrant diabetic macular edema (DME).

Methods

Retrospective, interventional study examining patients with symmetric bilateral, center-involved DME recalcitrant to treatment with RZB, who received DEX in one eye while the contralateral eye continued to receive RZB every 4–5 weeks for a study period of 3 months.

Results

Eleven patients (22 eyes) were included: mean logarithm of the minimal angle of resolution (logMAR) visual acuity (VA) for the DEX arm improved from 0.415 (standard deviation [SD] ±0.16) to 0.261 (SD ±0.18) at final evaluation, and mean central macular thickness (CMT) improved from 461 µm (SD ±156) to 356 µm (SD ±110; net decrease: 105 µm, P=0.01). Mean logMAR VA for the RZB arm improved from 0.394 (SD ±0.31) to 0.269 (SD ±0.19) at final evaluation. Mean CMT improved from 421 µm (SD ±147) to 373 µm (SD ±129; net decrease: 48 µm, P=0.26).

Conclusion

A subset of recalcitrant DME patients demonstrated significant CMT reduction and VA improvement after a single DEX injection.

Outcomes of vitrectomy, membranectomy and internal limiting membrane peeling in patients with refractory diabetic macular edema and non-tractional epiretinal membrane

Purpose

To evaluate the efficacy of vitrectomy, membranectomy, and internal limiting membrane (ILM) peeling on macular thickness and best corrected visual acuity (BCVA) in patients with refractory diffuse diabetic macular edema (DME) and non-tractional epiretinal membrane (NT-ERM).

Methods

This prospective interventional case series included eyes with refractory DME (central subfield macular thickness [CSMT] > 300 μm) after at least two intravitreal injections of bevacizumab (IVB) and one intravitreal injection of triamcinolone (IVT), and accompanying NT-ERM. Complete ophthalmic examination, baseline spectral domain optical coherence tomography (SD-OCT), and fluorescein angiography (FA) were performed prior to 23 gauge pars plana vitrectomy with membranectomy and internal limiting membrane (ILM) peeling. Postoperative evaluation was done with clinical examination and SD-OCT. Linear mix model analysis was used to study postoperative results.

Results

Twelve eyes from 11 patients (5 males) with a mean age of 60.33 ± 9.01 (range 46–73 years) were included. The mean follow-up time was 13.5 ± 4.48 months (range 4–20 months). A significant reduction in CSMT was found (from 559 ± 89 μm to 354 ± 76 μm; P = 0.001), with a non-significant BCVA change (from 0.84 ± 0.32 logMAR to 0.72 ± 0.2 logMAR; P = 0.967). There was no significant correlation between CSMT and BCVA (partial correlation = −0.115, P = 0.445) and also between estimated mean CSMT change per month and estimated mean BCVA change per month (r = 0.337, P = 0.283).

Conclusion

In this series, our results did not show that vitrectomy, membranectomy, and ILM peeling result in significant improvement of BCVA in eyes with refractory DME and non-tractional ERM in spite of central macular thickness reduction.

Diabetic macular oedema: pathophysiology, management challenges and treatment resistance

Diabetic macular oedema (DMO) is the leading cause of vision loss in patients living with diabetes. DMO results from hyperglycaemia-induced activation of pathways that lead to oxidative stress and release of cytokines, impairing the inner and outer blood-retinal barriers. Improved understanding of the pathophysiological mechanisms leading to DMO have led to the development of effective therapies, including vitreoretinal surgery, laser photocoagulation, intravitreal anti-vascular endothelial growth factor drugs and corticosteroids. Advances in imaging, including fluorescein angiography and optical coherence tomography, have also enhanced diagnosis and management of the condition. Despite these advances, there remain patients who do not respond completely to therapy, reflecting the complex pathophysiology of DMO. These patients may be considered treatment-resistant. In this review, we summarise the pathophysiology of DMO, as well as the available treatments and their mechanism of action. Additionally, we focus on treatment-resistant disease and review the literature on potential options for managing this complication of diabetes.

Efficacy and Safety of a Dexamethasone Implant in Patients with Diabetic Macular Edema at Tertiary Centers in Korea

Purpose. To evaluate the real-world efficacy and safety of the dexamethasone implant (DEX implant) in patients with diabetic macular edema (DME). Methods. Retrospective, multicenter, and noncomparative study of DME patients who were treated with at least one DEX implant. A total of 186 eyes from 165 patients were included. Best-corrected visual acuity (BCVA), central retinal thickness (CRT), complications, and number of retreatments were collected. Data at baseline and monthly for 6 months were analyzed. Results. The average baseline BCVA and CRT were 0.60 LogMAR and 491.6 μm, respectively. The mean BCVA improved until 3 months and then decreased up to 6 months of follow-up (0.53, 0.49, and 0.55 LogMAR at 1, 3, and 6 months; p = 0.001, <0.001, and 0.044, resp.). The change of mean CRT was similar to BCVA (345.0, 357.7, and 412.5 μm at 1, 3, and 6 months, p < 0.001, <0.001, and <0.001, resp.). 91 eyes (48.9%) received additional treatment with anti-VEGF or DEX implant. The average treatment-free interval was 4.4 months. In group analyses, the DEX implant was more effective in pseudophakic eyes, DME with subretinal fluid (SRF), or diffuse type. Conclusions. Intravitreal dexamethasone implants are an effective treatment for patients with DME, most notably in pseudophakic eyes, DME with SRF, or diffuse type. A half of these patients require additional treatment within 6 months.