Intravitreal triamcinolone acetonide injection for treatment of refractory diabetic macular edema: a systematic review

The Treatment of Diabetic Retinal Edema with Intravitreal Steroids: How and When

Diabetic macular edema (DME) is a common complication of diabetes mellitus and a leading cause of visual impairment worldwide. It is defined as the diabetes-related accumulation of fluid, proteins, and lipids, with retinal thickening, within the macular area. DME affects a significant proportion of individuals with diabetes, with the prevalence increasing with disease duration and severity. It is estimated that approximately 25-30% of diabetic patients will develop DME during their lifetime. Poor glycemic control, hypertension, hyperlipidemia, diabetes duration, and genetic predisposition are recognized as risk factors for the development and progression of DME. Although the exact pathophysiology is still not completely understood, it has been demonstrated that chronic hyperglycemia triggers a cascade of biochemical processes, including increased oxidative stress, inflammation, activation of vascular endothelial growth factor (VEGF), cellular dysfunction, and apoptosis, with breakdown of the blood-retinal barriers and fluid accumulation within the macular area. Early diagnosis and appropriate management of DME are crucial for improving visual outcomes. Although the control of systemic risk factors still remains the most important strategy in DME treatment, intravitreal pharmacotherapy with anti-VEGF molecules or steroids is currently considered the first-line approach in DME patients, whereas macular laser photocoagulation and pars plana vitrectomy may be useful in selected cases. Available intravitreal steroids, including triamcinolone acetonide injections and dexamethasone and fluocinolone acetonide implants, exert their therapeutic effect by reducing inflammation, inhibiting VEGF expression, stabilizing the blood-retinal barrier and thus reducing vascular permeability. They have been demonstrated to be effective in reducing macular edema and improving visual outcomes in DME patients but are associated with a high risk of intraocular pressure elevation and cataract development, so their use requires an accurate patient selection. This manuscript aims to provide a comprehensive overview of the pathology, epidemiology, risk factors, physiopathology, clinical features, treatment mechanisms of actions, treatment options, prognosis, and ongoing clinical studies related to the treatment of DME, with particular consideration of intravitreal steroids therapy.

Subthreshold micropulse diode laser treatment in diabetic macular edema: biological impact, therapeutic effects, and safety

PURPOSE

To introduce the treatment of diabetic macular edema (DME) with subthreshold micropulse diode laser (SMPL), to summarize the biological impact, therapeutic effects, and safety of this treatment, and to discuss the response to DME when SMPL is combined with anti-vascular endothelial growth factor (anti-VEGF) or steroid.

METHODS

The literature search was performed on the PubMed database, with a selection of English-language articles published from 2000 to 2023 with the following combinations of search terms: diabetes macular (o) edema, micropulse laser or subthreshold micropulse laser, anti-vascular endothelial growth factor, and steroid.

RESULTS

SMPL is a popular, invisible retinal laser phototherapy that is inexpensive, safe, and effective in the treatment of DME. It can selectively target the retinal pigment epithelium, reduce the expression of pro-inflammatory factors, promote the absorption of macular edema, and exert a similar and lasting clinical effect to traditional lasers. No significant difference was found in the therapeutic effects of SMPL between different wavelengths. However, HbA1c level and pretreatment central macular thickness (CMT) may affect the therapeutic outcomes of SMPL.

CONCLUSION

SMPL has a slow onset and produces lasting clinical effects similar to conventional photocoagulation. It has been reported that SMPL combined with the intravitreal anti-VEGF injection can significantly reduce the number of injections without influencing the therapeutic effect, which is essential for clinical applications and research. Although 577 nm SMPL is widely used clinically, there are no standardized protocols for SMPL. Additionally, some important problems regarding the treatment of SMPL require further discussion and exploration.

The ideal treatment timing for diabetic retinopathy: the molecular pathological mechanisms underlying early-stage diabetic retinopathy are a matter of concern

Diabetic retinopathy (DR) is a prevalent complication of diabetes, significantly impacting patients' quality of life due to vision loss. No pharmacological therapies are currently approved for DR, excepted the drugs to treat diabetic macular edema such as the anti-VEGF agents or steroids administered by intraocular route. Advancements in research have highlighted the crucial role of early intervention in DR for halting or delaying disease progression. This holds immense significance in enhancing patients' quality of life and alleviating the societal burden associated with medical care costs. The non-proliferative stage represents the early phase of DR. In comparison to the proliferative stage, pathological changes primarily manifest as microangiomas and hemorrhages, while at the cellular level, there is a loss of pericytes, neuronal cell death, and disruption of components and functionality within the retinal neuronal vascular unit encompassing pericytes and neurons. Both neurodegenerative and microvascular abnormalities manifest in the early stages of DR. Therefore, our focus lies on the non-proliferative stage of DR and we have initially summarized the mechanisms involved in its development, including pathways such as polyols, that revolve around the pathological changes occurring during this early stage. We also integrate cutting-edge mechanisms, including leukocyte adhesion, neutrophil extracellular traps, multiple RNA regulation, microorganisms, cell death (ferroptosis and pyroptosis), and other related mechanisms. The current status of drug therapy for early-stage DR is also discussed to provide insights for the development of pharmaceutical interventions targeting the early treatment of DR.

Anti-VEGF combined with ocular corticosteroids therapy versus anti-VEGF monotherapy for diabetic macular edema focusing on drugs injection times and confounding factors of pseudophakic eyes: A systematic review and meta-analysis

PURPOSE

To assess the effectiveness and safety of combining intravitreal endothelial growth factor inhibitor (anti-VEGF) and ocular corticosteroids for diabetic macular edema (DME).

METHODS

Articles concentrating on the efficacy and safety of combining anti-VEGF and ocular corticosteroids therapy for DME versus anti-VEGF monotherapy was screened systematically. Meta-analysis was conducted on the basis of a protocol registered in the PROSPERO (CRD42023408338) and performed on the extracted continuous variables and dichotomous variables. The outcome was expressed as weighted mean difference (MD) and risk ratio (RR).

RESULTS

Add up to 21 studies including 1468 eyes were enrolled in this study. The MD for best-corrected visual acuity (BCVA) improvement at 1/3/6/12-month between the combination therapy group and monotherapy group were 2.56 (95% CI [0.43, 4.70]), 2.46 (95% CI [-0.40, 5.32]), - 1.76 (95% CI [-3.18, -0.34]), - 1.94 (95% CI [-3.87, 0.00]), respectively. The MD for central retinal thickness (CMT) reduction at 1/3/6/12-month between two groups were - 66.27 (95% CI [-101.08, -31.47]), - 33.62 (95% CI [-57.55, -9.70]), - 4.54 (95% CI [-16.84, 7.76]), - 26.67 (95% CI [-41.52, -11.82]), respectively. Additionally, the combination group had higher relative risk of high intraocular pressure and cataract progression events.

CONCLUSIONS

Anti-VEGF combined with ocular corticosteroids had a significant advantage over anti-VEGF monotherapy within 3 months of DME treatment, which reached the maximum with increasing anti-VEGF injection times to 3. However, with the prolongation of the treatment cycle, the effect of combined therapy after 6 months was no better than monotherapy, and the side effects of combined therapy were more severe.

The evolving therapeutic landscape of diabetic retinopathy

INTRODUCTION

Diabetic retinopathy (DR) is a leading cause of blindness worldwide. Recent decades have seen rapid progress in the management of diabetic eye disease, evolving from pituitary ablation to photocoagulation and intravitreal pharmacotherapy. The advent of effective intravitreal drugs inhibiting vascular endothelial growth factor (VEGF) marked a new era in DR therapy. Sustained innovation has since produced several promising biologics targeting angiogenesis, inflammation, oxidative stress, and neurodegeneration.

AREAS COVERED

This review surveys traditional, contemporary, and emerging therapeutics for DR, with an emphasis on anti-VEGF therapies, receptor tyrosine kinase inhibitors, angiopoietin-Tie2 pathway inhibitors, integrin pathway inhibitors, gene therapy 'biofactory' approaches, and novel systemic therapies. Some of these investigational therapies are being delivered intravitreally via sustained release technologies for extended durability. Other investigational agents are being delivered non-invasively via topical and systemic routes. These strategies hold promise for early and long-lasting treatment of DR.

EXPERT OPINION

The evolving therapeutic landscape of DR is rapidly expanding our toolkit for the effective and durable treatment of blinding eye disease. However, further research is required to validate the efficacy of novel therapeutics and characterize real world outcomes.

A pilot study of viscoelastic agent to prevent recurrent vitreous hemorrhage after vitrectomy for proliferative diabetic retinopathy

BACKGROUND

To evaluate the possibilty of preventing recurrent vitreous hemorrhage (RVH) after vitrectomy in proliferative diabetic retinopathy (PDR) patients with unabsorbed vitreous hemorrhage (VH) by intravitreal injection of viscoelastic agent (VA) at the end of the surgery and compared its effect with triamcinolone acetonide (TA).

METHODS

This was a pilot prospective, observational study. PDR patients with VH who underwent vitrectomy were assigned to 3 groups according to the tamponade applicated at the end of the surgery, including VA group (intravitreally injected 1 ml VA if the retina was prone to bleed during the operation), TA group (intravitreally injected 2 mg TA when there was much exudates), or balanced salt solution (BSS) group (no tamponade). Then postoperative follow-up was performed routinely until 6 months after surgery. The primary outcome was the incidence of RVH, secondary outcome were the best-corrected visual acuity (BCVA) and introcular pressure (IOP). Cataract formation and other complication were also assessed.

RESULTS

A total of 68 eyes, from 68 patients, were included. 18,18,32 eyes were enrolled in the VA group, TA group and BSS group, respectively. The integral incidence of RVH after vitrectomy was 5.6%, 5.6% and 12.5% respectively (P = 0.602). There was no early RVH in VA or TA group, whereas 3 early RVHs were identified in BSS group, however there was no significant difference (P = 0.171). Every group had one late RVH case. In all groups, final BCVA showed significant improvement compared to baseline. BCVA at any postoperative visit showed no significant differences among 3 groups. Mean IOP was higher 1 week after surgery in VA group compared with the other groups; however, in other times the differences were not significant. No cataract formation and other complication was noted in 3 groups.

CONCLUSION

Intravitreal injection of VA or TA at the end of vitrectomy for PDR patients with unabsorbed VH tend to reduce the incidence of early RVH after vitrectomy similarly. As VA was preferred to applicate in the eyes that were prone to bleed, intravitreal injection of VA at the end of vitrectomy might be a promising method for preventing RVH in PDR patients.

Optical Coherence Tomography Reflectivity in Foveal Cysts: A Novel Biomarker for Early-Response Prediction of Diabetic Macular Edema Treated with Dexamethasone

This study investigated spectral-domain optical coherence tomography (OCT) biomarkers to predict short-term anatomical improvement for diabetic macular edema (DME) after dexamethasone (DEX) injection in intravitreal anti-vascular endothelial growth factor (anti-VEGF) non-responders. This retrospective comparative study included 31 eyes of 31 patients with DME unresponsive to anti-VEGF, divided into better and lesser responder groups. OCT prior to DEX injection was used to evaluate the morphological features including optical density (ODN) and optical density ratio (ODR) of the outer nuclear layer (ONL) cysts. Correlations between baseline OCT parameters and mean central macular thickness (CMT) changes at 1 month were analyzed. There were no between-group differences in age, sex, number of previous anti-VEGF injections, duration of diabetes, or HbA1c level. However, ODN and ODR values in ONL cysts were lower in the better responder group (p = 0.020 and p < 0.001, respectively). ODN and ODR showed negative correlations with CMT changes (R = −0.546, p = 0.002 and R = −0.436, p = 0.014, respectively). Higher OCT reflectivity in the foveal cystoid space was associated with a lesser decrease in CMT after DEX injection in anti-VEGF non-responders, suggesting the usefulness of this parameter in predicting short-term CMT responses after DEX injection.

Intravitreal corticosteroids for diabetic macular edema: a network meta-analysis of randomized controlled trials

BACKGROUND

To evaluate the efficacy and safety of different intravitreal corticosteroids for treating diabetic macular edema (DME).

METHODS

Four databases were systematically searched for randomized controlled trials comparing different intravitreal corticosteroids for treating DME. The primary outcome was the change in best-corrected visual acuity (BCVA) within 6 months after the first injection (short-term BCVA). Secondary outcomes were the change in BCVA over 1 year (long-term BCVA) and changes in central macular thickness (CMT) and intraocular pressure (IOP) within 6 months after the first injection. Network meta-analysis was performed to aggregate the results from the individual studies.

RESULTS

Nineteen trials involving 2839 eyes were included. Intravitreal triamcinolone acetonide (TA) injections (≥ 8 mg and 4-8 mg), fluocinolone acetonide (FA) implants (0.5 µg/day) and dexamethasone (DEX) implants (700 µg) improved short-term BCVA (mean changes in logMAR [95% confidence interval] - 0.27 [- 0.40, - 0.15]; - 0.12 [- 0.18, - 0.06]; - 0.10 [- 0.21, - 0.01]; and - 0.06 [- 0.11, - 0.01]). Intravitreal TA injections (4 mg, multiple times), FA implants (0.5 µg/day and 0.2 µg/day), and DEX implants (350 µg) improved long-term BCVA (mean changes in logMAR [95% confidence interval] - 0.11 [- 0.21, - 0.02]; - 0.09 [- 0.15, - 0.03]; - 0.09 [- 0.14, - 0.02]; and - 0.04 [- 0.07, - 0.01]). All intravitreal corticosteroids reduced CMT, and different dosages of TA did not show significant differences in increasing IOP.

CONCLUSIONS

Intravitreal corticosteroids effectively improved BCVA in DME patients, with higher dosages showing greater efficacies. TA was not inferior to FA or DEX and may be considered a low-cost alternative choice for DME patients. The long-term efficacy and safety of different corticosteroids deserve further investigation. Trial registration Prospectively registered: PROSPERO, CRD42020219870.

Kinins and Their Receptors as Potential Therapeutic Targets in Retinal Pathologies

The kallikrein-kinin system (KKS) contributes to retinal inflammation and neovascularization, notably in diabetic retinopathy (DR) and neovascular age-related macular degeneration (AMD). Bradykinin type 1 (B1R) and type 2 (B2R) receptors are G-protein-coupled receptors that sense and mediate the effects of kinins. While B2R is constitutively expressed and regulates a plethora of physiological processes, B1R is almost undetectable under physiological conditions and contributes to pathological inflammation. Several KKS components (kininogens, tissue and plasma kallikreins, and kinin receptors) are overexpressed in human and animal models of retinal diseases, and their inhibition, particularly B1R, reduces inflammation and pathological neovascularization. In this review, we provide an overview of the KKS with emphasis on kinin receptors in the healthy retina and their detrimental roles in DR and AMD. We highlight the crosstalk between the KKS and the renin–angiotensin system (RAS), which is known to be detrimental in ocular pathologies. Targeting the KKS, particularly the B1R, is a promising therapy in retinal diseases, and B1R may represent an effector of the detrimental effects of RAS (Ang II-AT1R).

Intravitreal bevacizumab versus intravitreal triamcinolone for diabetic macular edema-Systematic review, meta-analysis and meta-regression

Background

The most frequent cause of vision loss from diabetic retinopathy is diabetic macular edema (DME). Earlier clinical trials tried to examine the role of intravitreal triamcinolone (IVT) and intravitreal bevacizumab (IVB) in DME; they either qualified IVT over IVB or IVB over IVT or did not exhibit a significant difference.

Objective

This paper aims to compare the efficacy and safety of IVB versus IVT alone or combined IVB+IVT in the treatment of DME.

Methods

We systematically searched PubMed, CENTRAL, Scopus, Embase, Science Direct, OVID, and Web of Science for randomized controlled trials of IVB versus IVT alone or combined IVB+IVT and IVT versus the combined IVB+IVT in DME patients.

Results

A total of 1243 eyes of 17 trials were included in our meta-analysis and regression. Repeated injections of IVB were superior at improving VA comparing with those of IVT at 12, 24, 48-weeks, and IVB+IVT at 12, 24, 48-weeks. Single injections were comparable across the three arms regarding BCVA improvement. CMT reductions were also comparable across the three arms. Meanwhile, the overall safety regarding intraocular pressure and intraocular hypertension significantly favored the IVB group. Improvement in VA was best modified with CMT reduction from 480 um to 320um. This association was significant at 12-weeks in the three arms and persisted till 24-weeks and 48-weeks exclusively in the IVB group.

Conclusions and relevance

Our analysis reveals that repeated successive injections associate with better BCVA compared to single injection. Current evidence affirms that IVB is superior to IVT and IVB+IVT at improving BCVA, comparable at reducing CMT, and presents a better safety profile in the treatment of DME.

Effects of Switching from Anti-VEGF Treatment to Triamcinolone Acetonide in Eyes with Refractory Macular Edema Associated with Diabetic Retinopathy or Retinal Vein Occlusion

Purpose

To evaluate the efficacy of switching from intravitreal antivascular endothelial growth factor (VEGF) agents to triamcinolone acetonide (TA) in eyes with diabetic macular edema (DME) or with retinal vein occlusion-associated macular edema (RVO-ME) on the resolution of the macular edema (ME).

Methods

The medical records of 11 eyes of 11 patients with DME and 9 eyes of 9 patients with RVO-ME whose MEs were refractory to anti-VEGF treatment were reviewed. The central retinal thickness (CRT), best-corrected visual acuity (BCVA), intraocular pressure (IOP), and the mean interval of the recurrences were measured during the anti-VEGF treatment and after switching to the TA injections.

Results

Switching to TA injections significantly increased the mean interval for recurrences from 9.2 ± 2.7 weeks to 22.3 ± 12.9 weeks in eyes with DME (P = 0.006). In eyes with RVO-ME, the mean period of recurrence was 12.3 ± 5.6 weeks before and 11.6 ± 4.4 weeks after the switch (P = 0.44). The mean interval for recurrence was extended to more than 8 weeks in 7 of 11 eyes with DME, but none of the eyes with RVO-ME had a prolongation of more than 4 weeks. An elevation of the IOP was observed in 3 of the 20 eyes after the TA injection.

Conclusions

These findings indicate that switching to TA injections can be a good option for DME eyes refractory to anti-VEGF injections but not for the RVO-ME eyes.

An evidence map of clinical practice guideline recommendations and quality on diabetic retinopathy

To present an evidence map for explicating research trends and gaps, we systematically review clinical practice guidelines (CPGs) on diabetic retinopathy (DR) and assess the quality of CPGs and consistency of recommendations. A literature search was performed in PubMed, Embase, Web of Science, CPG databases, and website of diabetes society to include the CPGs. The basic information, methodological quality, and reporting quality of CPGs, recommendations for DR were exacted by the Excel 2013. Methodological and reporting quality of DR CPGs were evaluated by AGREE II instrument and RIGHT checklist. The bubble plot format of evidence map was made by Excel 2013. Nineteen CPGs proved eligible, which included eight DR CPGs and 11 comprehensive diabetic CPGs. The identified CPGs were of mixed quality and they scored poorly in the rigor of development, applicability domains by AGREE II. Field two (background) had the highest reporting rate (86.31%) and field five (review and quality assurance) obtained the lowest reporting rate (31.58%) among the seven domains of RIGHT checklist. According to the recommendations of CPGs, there were three inconsistencies in the screening of DR, and CPGs recommendations for treatment were consistent on the whole. At the same time, recommendations for laser therapy were not accurate. Some recommendations were not specific and clear in some DR CPGs. This evidence map could collect and evaluate the characteristics of published CPGs, add to our knowledge and promote the development of trustworthy CPGs for DR.

Emerging drugs for the treatment of diabetic retinopathy

INTRODUCTION

Diabetic retinopathy (DR) is one of the main pathological features of the diabetes mellitus spectrum. It is estimated that in 2020 about 4 million people worldwide suffered from blindness or visual impairment caused by DR. Many patients cannot access treatment, mostly because of high costs, while others discontinue it prematurely due to the high number of intravitreal administrations required, or the occurrence of ocular complications, or discomfort in quality of life.

AREAS COVERED

The aims of this paper are to summarize the current understanding of the pathogenesis and treatment of diabetic retinopathy, focus on the most promising new approaches to treatment that are being evaluated in clinical trials, and outline the potential financial impact of new drugs in future markets.

EXPERT OPINION

Slow-release systems with steroids, anti-VEGF or sunitinib are promising. Oral imatinib would avoid the ocular complications of intravitreal drugs. Brolucizumab and abicipar pegol may be superior to aflibercept and ranibizumab with the advantage of less frequent administrations. Faricimab, active on Tie-2 receptors, is being evaluated in two phase 3 clinical trials. Further knowledge of the efficacy and safety of these drugs is necessary before their final approval for the treatment of diabetic retinopathy.

The Evolving Treatment of Diabetic Retinopathy

Purpose

To review the current therapeutic options for the management of diabetic retinopathy (DR) and diabetic macular edema (DME) and examine the evidence for integration of laser and pharmacotherapy.

Methods

A review of the PubMed database was performed using the search terms diabetic retinopathy, diabetic macular edema, neovascularization, laser photocoagulation, intravitreal injection, vascular endothelial growth factor (VEGF), vitrectomy, pars plana vitreous surgery, antiangiogenic therapy. With additional cross-referencing, this yielded 835 publications of which 301 were selected based on content and relevance.

Results

Many recent studies have evaluated the pharmacological, laser and surgical therapeutic strategies for the treatment and prevention of DR and DME. Several newer diagnostic systems such as optical coherence tomography (OCT), microperimetry, and multifocal electroretinography (mfERG) are also assisting in further refinements in the staging and classification of DR and DME. Pharmacological therapies for both DR and DME include both systemic and ocular agents. Systemic agents that promote intensive glycemic control, control of dyslipidemia and antagonists of the renin-angiotensin system demonstrate beneficial effects for both DR and DME. Ocular therapies include anti-VEGF agents, corticosteroids and nonsteroidal anti-inflammatory drugs. Laser therapy, both as panretinal and focal or grid applications continue to be employed in management of DR and DME. Refinements in laser devices have yielded more tissue-sparing (subthreshold) modes in which many of the benefits of conventional continuous wave (CW) lasers can be obtained without the adverse side effects. Recent attempts to lessen the burden of anti-VEGF injections by integrating laser therapy have met with mixed results. Increasingly, vitreoretinal surgical techniques are employed for less advanced stages of DR and DME. The development and use of smaller gauge instrumentation and advanced anesthesia agents have been associated with a trend toward earlier surgical intervention for diabetic retinopathy. Several novel drug delivery strategies are currently being examined with the goal of decreasing the therapeutic burden of monthly intravitreal injections. These fall into one of the five categories: non-biodegradable polymeric drug delivery systems, biodegradable polymeric drug delivery systems, nanoparticle-based drug delivery systems, ocular injection devices and with sustained release refillable devices. At present, there remains no one single strategy for the management of the particular stages of DR and DME as there are many options that have not been rigorously tested through large, randomized, controlled clinical trials.

Conclusion

Pharmacotherapy, both ocular and systemic, will be the primary mode of intervention in the management of DR and DME in many cases when cost and treatment burden are less constrained. Conventional laser therapy has become a secondary intervention in these instances, but remains a first-line option when cost and treatment burden are more constrained. Results with subthreshold laser appear promising but will require more rigorous study to establish its role as adjunctive therapy. Evidence to support an optimal integration of the various treatment options is lacking. Central to the widespread adoption of any therapeutic regimen for DR and DME is substantiation of safety, efficacy, and cost-effectiveness by a body of sound clinical trials.

The effects of intravitreal triamcinolone acetonide in diabetic macular edema refractory to anti-VEGF treatment

PURPOSE

To investigate the efficacy and safety of primary intravitreal triamcinolone acetonide (IVTA) in eyes affected by diabetic macular edema (DME) refractory to anti-vascular endothelial growth factor (VEGF) therapy.

STUDY DESIGN

Retrospective observational study METHODS: The medical records of patients who attended our clinic from March 2013 to September 2018 with refractory macular were reviewed. We included the patients who were injected at least one IVTA and completed 6 months of observation. Best-corrected Snellen visual acuity (VA), central macular thickness (CMT), intraocular pressure (IOP), and adverse events (AEs) were examined at baseline and at 1 month, 2 months, 3 months, and 6 months.

RESULTS

Sixty-four eyes of 54 subjects were included. The mean VA was improved significantly at all time points compared to pre-treatment (P < 0.0001), with the greatest mean improvement at 1 month (0.3 logMAR). The reduction in mean CMT was also significant at all follow-up examinations compared to baseline (P < 0.0001), with the greatest decrease at 1 month (113.68 ± 53.78 μm). A poorer VA before injection was a factor that influenced visual gain 1 month post treatment (0.247 logMAR units/unit increase in baseline VA, P = 0.006). The most common AE associated with IVTA treatment was elevated IOP (11 eyes), observed significantly more often after IVTA injections containing a preservative (25.8%) than after those that were preservative-free (9.1%) (P = 0.033).

CONCLUSION

IVTA injection can be an alternative steroid treatment for DME refractory to anti-VEGF therapy.

Treatment of Diabetic Macular Edema

PURPOSE OF REVIEW

Diabetes mellitus is a global epidemic which is growing in prevalence, and diabetic macular edema (DME) is a leading cause of visual impairment among patients affected by this disease. Our objective is to review current and upcoming therapeutic approaches to DME.

RECENT FINDINGS

Once considered the gold standard in treatment of DME, focal/grid laser is now reserved mostly for non-center-involving DME, while anti-vascular endothelial growth factor (anti-VEGF) therapy has become the first-line treatment. However, suboptimal responders to anti-VEGF and the burden of frequent injections have stimulated the development of novel approaches. Corticosteroids can be effective in treating DME, but adverse effects such as intraocular pressure elevation and cataract formation must be considered. Emerging therapeutics and drug delivery systems in the pipeline offer exciting potential solutions to this vision-threatening disease. Multiple types of therapeutics targeting various pathways implicated in the pathogenesis of DME may help lessen the global burden of vision loss from diabetes.

Periocular injection of candesartan-PLGA microparticles inhibits laser-induced experimental choroidal neovascularization

Purpose

Microparticle technology enables local administration of medication. The purpose of this study was to examine the inhibitory effect of locally administered candesartan (CAN)-encapsulated microparticles on experimental choroidal neovascularization (CNV).

Methods

Laser photocoagulation was used to induce CNV in Brown Norway rats. The rats were pretreated with subconjunctival injections of CAN (5.0 mg/eye) or phosphate buffer saline for 3 days before photocoagulation. The volume of CNV was evaluated 7 days after laser injury using the lectin staining technique. The infiltration of macrophages within the CNV lesion was determined using immunofluorescent staining with an anti-CD68 antibody. mRNA levels of MCP-1, IL1-β and VEGF in the retinal pigment epithelium/choroid complex were determined using quantitative PCR (q-PCR).

Results

CNV volume was significantly suppressed by the treatment with CAN compared with that in vehicle-treated eyes (P<0.05, two-tailed Student’s t-test). Subconjunctival injections of CAN decreased the numbers of CD68⁺ cells in the CNV lesion. The increased mRNA levels of MCP-1, IL1-β, and VEGF induced by photocoagulation was significantly suppressed following the local administration of CAN (P<0.05, two-tailed Student’s t-test).

Conclusion

Local administration of CAN inhibited experimentally induced CNV possibly through anti-inflammatory effects.

Safety of high-dose intravitreal triamcinolone acetonide as low-cost alternative to anti-vascular endothelial growth factor agents in lower-middle-income countries

Purpose

The purpose of this study was to evaluate the safety of high-dose intravitreal triamcinolone acetonide (IVTA) as affordable low-cost alternative to anti-vascular endothelial growth factor (anti-vascular endothelial growth factor [anti-VEGF] agents) in lower-middle-income countries.

Patients and methods

This was a retrospective interventional non-comparative case series. The study recruited patients who received 20 mg IVTA for treating various retinal and optic nerve diseases over the past 5 years. Main outcome measure was assessment of complications secondary to high-dose IVTA. The crosstabs procedure was used to display the interaction between the variables tested. The ANOVA test was used to analyze the differences among group means.

Results

The study included 207 eyes of 168 patients. The main indication for high-dose IVTA were diabetic macular edema 64%, and macular edema secondary to retinal vein occlusion 19%. The mean follow-up period post-injection was 22 months. Mean number of injections was 1.3. Cataract developed in 54% of eyes. Glaucoma developed in 18.5% of eyes. Glaucoma surgery for intractable glaucoma attributed to high-dose IVTA was needed in 1% of eyes. Endophthalmitis and retinal detachment developed in one patient each.

Conclusion

High-dose IVTA is a safe and cost-effective alternative to anti-VEGF agents. Cataract formation and intraocular pressure rise do not pose major adverse effects when weighed against the risk of vision loss due to inability to afford anti-VEGF treatment.

Short-Term Results of Intravitreal Triamcinolone Acetonide Combined with Cataract Surgery for Diabetic Macular Edema in Japan: In the Era of Anti-Vascular Endothelial Growth Factor Therapy

PURPOSE

To evaluate the effectiveness of an intravitreal triamcinolone acetonide injection (IVTA) combined with cataract surgery for diabetic macular edema (DME) resistant to anti-vascular endothelial growth factor (anti-VEGF) therapy.

PROCEDURE

IVTA combined with cataract surgery was performed on 29 eyes of patients with DME (aged 70.5 ± 6.2 years) who were refractive to anti-VEGF treatments. The visual acuity, central retinal thickness (CRT), and the central retinal sensitivity were assessed at 1, 4, 12, and 24 weeks after the treatment.

RESULTS

The visual acuity improved significantly from 0.49 ± 0.30 logMAR units to 0.35 ± 0.33 logMAR units at 24 weeks after the treatment (p < 0.05; repeated ANOVA). The CRT decreased significantly from 435.1 ± 112.3 μm to 350.8 ± 123.3 μm at 12 weeks after the treatment (p < 0.05). The retinal sensitivity threshold also improved significantly from 18.2 ± 4.3 dB to 20.4 ± 3.8 dB at 4 weeks after the treatment (p < 0.05).

CONCLUSIONS

IVTA combined with cataract surgery is effective for successful treatment of eyes with DME refractive to anti-VEGF therapy.

Current Advances in Pharmacotherapy and Technology for Diabetic Retinopathy: A Systematic Review

Diabetic retinopathy (DR) is classically defined by its vascular lesions and damage in the neurons of the retina. The cellular and clinical elements of DR have many features of chronic inflammation. Understanding the individual cell-specific inflammatory changes in the retina may lead to novel therapeutic approaches to prevent vision loss. The systematic use of available pharmacotherapy has been reported as a useful adjunct tool to laser photocoagulation, a gold standard therapy for DR. Direct injections or intravitreal anti-inflammatory and antiangiogenesis agents are widely used pharmacotherapy to effectively treat DR and diabetic macular edema (DME). However, their effectiveness is short term, and the delivery system is often associated with adverse effects, such as cataract and increased intraocular pressure. Further, systemic agents (particularly hypoglycemic, hypolipidemic, and antihypertensive agents) and plants-based drugs have also provided promising treatment in the progression of DR. Recently, advancements in pluripotent stem cells technology enable restoration of retinal functionalities after transplantation of these cells into animals with retinal degeneration. This review paper summarizes the developments in the current and potential pharmacotherapy and therapeutic technology of DR. Literature search was done on online databases, PubMed, Google Scholar, clinitrials.gov, and browsing through individual ophthalmology journals and leading pharmaceutical company websites.

Intravitreal triamcinolone acetate for radiation maculopathy recalcitrant to high-dose intravitreal bevacizumab

BACKGROUND/AIMS

To evaluate the effect of adjuvant intravitreal triamcinolone acetonide (ITA) for radiation maculopathy (RM) recalcitrant to high-dose bevacizumab in patients with choroidal melanoma after plaque radiotherapy.

METHODS

Eight eyes of eight patients with RM secondary to plaque radiotherapy for choroidal melanoma, recalcitrant to high-dose bevacizumab (3.0 mg) were retrospectively evaluated. Intravitreal injections of ITA (4 mg/0.1 mL) were performed at 4-week to 16-week intervals as an adjunct to continued bevacizumab therapy. Change in central foveal thickness (CFT) as measured by optical coherence tomography and change in visual acuity (VA) were the main outcome measures.

RESULTS

At the time of diagnosis of choroidal melanoma, VA was 20/20 to 20/50 in 88% (n=7) and 20/60 to 20/200 in 12% (n=1). The mean radiation dose to the fovea was 81 Gy (median 75.2 Gy; range: 22.72-132.8 Gy). The mean onset to RM was 25 months after plaque therapy (median 25 months; range 12-44 months). At the time of initiation of ITA, VA was 20/20 to 20/50 in 38% (3/8), and 20/60 to 20/200 in 62% (5/8). After initiation of ITA, VA was stable or improved in 100% of patients (n=8) at 3 months, 88% at 6 months, 88% at 9 months and 75% at 12 months. Mean CFT was 417 µm at ITA initiation, 339 µm at 1 month, 355 µm at 6 months, 339 µm at 9 months and 359 µm at 1 year.

CONCLUSION

Intravitreal triamcinolone can be added to preserve vision and decrease macular oedema in patients with RM recalcitrant to high-dose anti-vascular endothelial growth factor agents.

Gene therapy for diabetic retinopathy: Are we ready to make the leap from bench to bedside?

Diabetic retinopathy (DR), a chronic and progressive complication of diabetes mellitus, is a sight-threatening disease characterized in the early stages by neuronal and vascular dysfunction in the retina, and later by neovascularization that further damages vision. A major contributor to the pathology is excess production of vascular endothelial growth factor (VEGF), a growth factor that induces formation of new blood vessels and increases permeability of existing vessels. Despite the recent availability of effective treatments for the disease, including laser photocoagulation and therapeutic VEGF antibodies, DR remains a significant cause of vision loss worldwide. Existing anti-VEGF agents, though generally effective, are limited by their short therapeutic half-lives, necessitating frequent intravitreal injections and the risk of attendant adverse events. Management of DR with gene therapies has been proposed for several years, and pre-clinical studies have yielded enticing findings. Gene therapy holds several advantages over conventional treatments for DR, such as a longer duration of therapeutic effect, simpler administration, the ability to intervene at an earlier stage of the disease, and potentially fewer side-effects. In this review, we summarize the current understanding of the pathophysiology of DR and provide an overview of research into DR gene therapies. We also examine current barriers to the clinical application of gene therapy for DR and evaluate future prospects for this approach.

Clearance of autophagy-associated dying retinal pigment epithelial cells - a possible source for inflammation in age-related macular degeneration

Retinal pigment epithelial (RPE) cells can undergo different forms of cell death, including autophagy-associated cell death during age-related macular degeneration (AMD). Failure of macrophages or dendritic cells (DCs) to engulf the different dying cells in the retina may result in the accumulation of debris and progression of AMD. ARPE-19 and primary human RPE cells undergo autophagy-associated cell death upon serum depletion and oxidative stress induced by hydrogen peroxide (H₂O₂). Autophagy was revealed by elevated light-chain-3 II (LC3-II) expression and electron microscopy, while autophagic flux was confirmed by blocking the autophago-lysosomal fusion using chloroquine (CQ) in these cells. The autophagy-associated dying RPE cells were engulfed by human macrophages, DCs and living RPE cells in an increasing and time-dependent manner. Inhibition of autophagy by 3-methyladenine (3-MA) decreased the engulfment of the autophagy-associated dying cells by macrophages, whereas sorting out the GFP-LC3-positive/autophagic cell population or treatment by the glucocorticoid triamcinolone (TC) enhanced it. Increased amounts of IL-6 and IL-8 were released when autophagy-associated dying RPEs were engulfed by macrophages. Our data suggest that cells undergoing autophagy-associated cell death engage in clearance mechanisms guided by professional and non-professional phagocytes, which is accompanied by inflammation as part of an in vitro modeling of AMD pathogenesis.

Effect of Posterior Subtenon Triamcinolone Acetonide Injection on Diabetic Macular Edema Refractory to Intravitreal Bevacizumab Injection

Purpose

To evaluate the effects of posterior subtenon triamcinolone acetonide injection on refractory diabetic macular edema (DME) after intravitreal bevacizumab (IVB) injection failure.

Methods

Patients with DME and central subfield thickness (CST) >300 µm who did not respond to IVB injections were retrospectively included. Specifically, we enrolled patients who were diagnosed with refractory DME and who experienced an increase in CST after 1 to 2 IVB injections or no decrease after ≥3 consecutive IVB injections. One clinician injected 20 mg of triamcinolone acetonide into the posterior subtenon space. All patients received ophthalmic examinations at baseline and at 2, 4, and 6 months post-baseline. Examinations included Snellen visual acuity, intraocular pressure, and spectral-domain optical coherence tomography.

Results

Forty eyes of 34 patients were included. The average baseline CST was 476 µm. The average CST decreased to 368 µm at 2 months, 374 µm at 4 months, and 427 µm at 6 months (p < 0.001 for all results, Wilcoxon signed-rank test). The average intraocular pressure increased from 15.50 to 16.92 mmHg at 2 months but decreased to 16.30 mmHg at 4 months and 15.65 mmHg at 6 months. Logarithm of the minimum angle of resolution visual acuity improved from 0.56 to 0.50 at 2 months (p = 0.023), 0.50 at 4 months (p = 0.083), and 0.48 at 6 months (p = 0.133, Wilcoxon signed-rank test). No complications were detected.

Conclusions

Posterior subtenon triamcinolone acetonide is an effective and safe treatment for reducing CST in DME refractory to IVB.

New treatments for diabetic macular edema

This work comprehensively reviews the latest treatment options for diabetic macular edema (DME) used in its management and presents further work on the topic. Diabetic retinopathy is an important and increasingly prevalent cause of preventable blindness worldwide. To meet this increasing burden there has recently been a proliferation of pharmacological therapies being used in clinical practice. A variety of medical treatment options now exist for DME. These include non-steroidal anti-inflammatory drugs such as nepafenac, as well as intravitreal steroids like triamcinolone (kenalog). Long-term results up to 7 years after commencing treatment are presented for triamcinolone. Studies are reviewed on the use of dexamethasone (ozurdex) and fluocinolone (Retisert and Iluvien implants) including the FAME studies. A variety of anti-vascular endothelial growth factor (anti-VEGF) agents used in DME are considered in detail including ranibizumab (lucentis) and the RESTORE, RIDE, RISE and Diabetic Retinopathy Clinical Research Network (DRCR.net) studies. Bevacizumab (avastin) and pegaptinib (macugen) are also considered. The use of aflibercept (eylea) is reviewed including the significance of the DA VINCI, VISTA-DME, VIVID-DME and the DRCR.net studies which have recently suggested potentially greater efficacy when treating DME for aflibercept in patients with more severely reduced visual acuity at baseline. Evidence for the anti-VEGF agent bevasiranib is also considered. Studies of anti-tumour necrosis factor agents like infliximab are reviewed. So are studies of other agents targeting inflammation including minocycline, rapamycin (sirolimus) and protein kinase C inhibitors such as midostaurin and ruboxistaurin. The protein kinase C β inhibitor Diabetic Macular Edema Study is considered. Other agents which have been suggested for DME are discussed including cyclo-oxygenase-2 inhibitors like celecoxib, phospholipase A2 inhibitors, recombinant erythropoietin, and monoclonal anti-interleukin antibodies such as canakinumab. The management of DME in a variety of clinical scenarios is also discussed - in newly diagnosed DME, refractory DME including after macular laser, and postoperatively after intraocular surgery. Results of long-term intravitreal triamcinolone for DME administered up to seven years after commencing treatment are considered in the context of the niche roles available for such agents in modern management of DME. This is alongside more widely used treatments available to the practitioner such as anti-VEGF agents like aflibercept (Eylea) and ranibizumab (Lucentis) which at present are the mainstay of pharmacological treatment of DME.

Complications of intravitreal injections in patients with diabetes

Intravitreal injections for the treatment of retinal disorders and intraocular infection have become a common ophthalmic procedure, and injections of anti-vascular endothelial growth factor agents or steroids are frequently performed for the treatment of diabetic macular edema or other diabetic vascular pathology. Diabetic patients may be at higher risk of adverse events than non-diabetic individuals given frequent systemic co-morbidities, such as cardiovascular and renal disease, susceptibility to infection, and unique ocular pathology that includes fibrovascular proliferation. Fortunately, many associated complications, including endophthalmitis, are related to the injection procedure and can therefore be circumvented by careful attention to injection techniques. This review highlights the safety profile of intravitreal injections in patients with diabetes. Although diabetic patients may theoretically be at higher risk than non-diabetic patients for complications, a comprehensive review of the literature does not demonstrate substantial increased risk of intravitreal injections in patients with diabetes.

Intravitreal controlled release of dexamethasone from engineered microparticles of porous silicon dioxide

Dexamethasone is a glucocorticoid that is widely used in the ophthalmic arena. The recent FDA approved dexamethasone implant can provide a three month efficacy but with high rate of drug related cataract and high intraocular pressure (IOP). It seems that higher steroid in aqueous humor and around lens may be associated with these complications based on clinical fact that higher IOP was observed with intravitreal triamcinolone acetonide (TA) than with subtenon TA. We hypothesize that placing a sustained dexamethasone release system near back of the eye through a fine needle can maximize efficacy while mitigate higher rate of IOP rise and cataract. To develop a sustained intravitreal dexamethasone delivery system, porous silicon dioxide (pSiO2) microparticles were fabricated and functionalized with amines as well as carboxyl groups. Dexamethasone was conjugated to pSiO2 through the Steglich Esterification Reaction between hydroxyl of dexamethasone and carboxyl groups on the pSiO2. The drug loading was confirmed by Fourier transform infrared spectroscopy (FTIR) and loading efficiency was quantitated using thermogravimetric analysis (TGA). In vitro release was conducted for three months and dexamethasone was confirmed in the released samples using liquid chromatography-tandem mass spectrometry (LC/MS/MS). A pilot ocular safety and determination of vitreous drug level was performed in rabbit eyes. The drug loading study demonstrated that loading efficiency was from 5.96% to 10.77% depending on the loading reaction time, being higher with longer loading reaction time before reaching saturation around 7 days. In vitro drug release study revealed that dexamethasone release from pSiO2 particles was sustainable for over 90 days and was 80 days longer than free dexamethasone or infiltration-loaded pSiO2 particle formulation in the same setting. Pilot in vivo study demonstrated no sign of ocular adverse reaction in rabbit eyes following a single 3 mg intravitreal injection and free drug level at 2-week was 107.23 ± 10.54 ng/mL that is well above the therapeutic level but only around 20% level of dexamethasone released from OZURDEX(®) (dexamethasone intravitreal implant) in a rabbit eye model. In conclusion, dexamethasone is able to covalently load to the pSiO2 particles and provide sustained drug release for at least 3 months in vitro. Intravitreal injection of these particles were well tolerated in rabbit eyes and free drug level in vitreous at 2-week was well above the therapeutic level.

Subtenon Vs Intravitreal Triamcinolone injection in Diabetic Macular Edema, A prospective study in Chinese population

Objective: Purpose of this study was to validate that Subtenon (SB) Triamcinolone (TA) injection is an alternative to Intravitreal (IV) Triamcinolone (TA) injection for the treatment of diabetic macular edema (DME).

Methods: Forty eyes were selected having DME due to type 1 or type 2 diabetes. All the patients were treated with photocoagulation. IVTA was administered in one eye and SBTA in following eye of same patient. Improvement in visual acuity, macular edema and intraocular pressure was assessed before treatment and on 2^nd, 4^th, 8^th and 12^th week after treatment.

Results: After administration of IVTA, MVA was reduced from baseline value (0.805 ± 0.069Log/MAR) to (0.577 ± 0.091 Log/MAR, p<.001) at the end of treatment. Similar results were observed after SBTA administration. MVA was reduced from (0.814 ± 0.082Log/MAR) to (0.49 ± 0.080 Log/MAR, p<.001) at 12^th week. After IVTA injection Central macular thickness was significantly reduced to (246.8 ± 25 µm, p<0.001) from (390.5 ± 17 µm). There were no significant (p=0.51) difference in both eyes receiving different routes of same treatment. After SBTA injection CMT was significantly reduced to lower values (241.5 ± 27 µm, p<0.001) from (394.4 ± 21 µm). Intraocular pressure after IVTA administration was high (2.32 ± 0.72 mm/Hg, p=0.04) as compared to baseline (1.82 ± 0.94 mm/Hg). Similar pattern was also seen after SBTA administration but to significant extent. Elevation of IoP was observed in both eyes.

Conclusion: Subtenon Triamcinolone injection is an alternative to Intravitreal Triamcinolone Injection for Diabetic Macular Edema.

Evolving strategies in the management of diabetic retinopathy

Diabetic retinopathy (DR), the most common long-term complication of diabetes mellitus, remains one of the leading causes of blindness worldwide. Tight glycemic and blood pressure control has been shown to significantly decrease the risk of development as well as the progression of retinopathy and represents the cornerstone of medical management of DR. The two most threatening complications of DR are diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR). Focal/grid photocoagulation and panretinal photocoagulation are standard treatments for both DME and PDR, respectively. Focal/grid photocoagulation is a better treatment than intravitreal triamcinolone acetonide in eyes with DME. Currently, most experts consider combination focal/grid laser therapy and pharmacotherapy with intravitreal antivascular endothelial growth factor agents in patients with center-involving DME. Combination therapy reduces the frequency of injections needed to control edema. Vitrectomy with removal of the posterior hyaloid seems to be effective in eyes with persistent diffuse DME, particularly in eyes with associated vitreomacular traction. Emerging therapies include fenofibrate, ruboxistaurin, renin-angiotensin system blockers, peroxisome proliferator-activated receptor gamma agonists, pharmacologic vitreolysis, and islet cell transplantation.

Intravitreal steroids for the treatment of retinal diseases

Diabetic macular edema (DME), pseudophakic cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO), and uveitis are ocular conditions related to severe visual impairment worldwide. Corticosteroids have been widely used in the treatment of these retinal diseases, due to their well-known antiangiogenic, antiedematous, and anti-inflammatory properties. Intravitreal steroids have emerged as novel and essential tools in the ophthalmologist's armamentarium, allowing for maximization of drug efficacy and limited risk of systemic side effects. Recent advances in ocular drug delivery methods led to the development of intraocular implants, which help to provide prolonged treatment with controlled drug release. Moreover, they may add some potential advantages over traditional intraocular injections by delivering certain rates of drug directly to the site of action, amplifying the drug's half-life, contributing in the minimization of peak plasma levels of the drug, and avoiding the side effects associated with repeated intravitreal injections. The purpose of this review is to provide an update on the use of intravitreal steroids as a treatment option for a variety of retinal diseases and to review the current literature considering their properties, safety, and adverse events.

Cost-effectiveness of treatment of diabetic macular edema

BACKGROUND

Macular edema is the most common cause of vision loss among patients with diabetes.

OBJECTIVE

To determine the cost-effectiveness of different treatments of diabetic macular edema (DME).

DESIGN

Markov model.

DATA SOURCES

Published literature and expert opinion.

TARGET POPULATION

Patients with clinically significant DME.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

Laser treatment, intraocular injections of triamcinolone or a vascular endothelial growth factor (VEGF) inhibitor, or a combination of both.

OUTCOME MEASURES

Discounted costs, gains in quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs).

RESULTS OF BASE-CASE ANALYSIS

All treatments except laser monotherapy substantially reduced costs, and all treatments except triamcinolone monotherapy increased QALYs. Laser treatment plus a VEGF inhibitor achieved the greatest benefit, gaining 0.56 QALYs at a cost of $6975 for an ICER of $12 410 per QALY compared with laser treatment plus triamcinolone. Monotherapy with a VEGF inhibitor achieved similar outcomes to combination therapy with laser treatment plus a VEGF inhibitor. Laser monotherapy and triamcinolone monotherapy were less effective and more costly than combination therapy.

RESULTS OF SENSITIVITY ANALYSIS

VEGF inhibitor monotherapy was sometimes preferred over laser treatment plus a VEGF inhibitor, depending on the reduction in quality of life with loss of visual acuity. When the VEGF inhibitor bevacizumab was as effective as ranibizumab, it was preferable because of its lower cost.

LIMITATION

Long-term outcome data for treated and untreated diseases are limited.

CONCLUSION

The most effective treatment of DME is VEGF inhibitor injections with or without laser treatment. This therapy compares favorably with cost-effective interventions for other conditions.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

The effect of ocular pigmentation on transscleral delivery of triamcinolone acetonide

PURPOSE

To determine the capacity and kinetics of the binding between triamcinolone acetonide (TA) and the ocular pigment for a better understanding of the transscleral delivery.

METHODS

In the in vitro study, natural melanin (sepia officinalis, Sigma-Aldrich) was incubated at 37°C with different concentrations of TA and the binding capacity/binding affinity was measured. The TA releasing profile from the melanin was also studied through repeated incubation of TA-melanin in fresh phosphate-buffed saline. In the ex vivo study, the effect of the choroidal pigment on the trans sclera/choroid permeability of TA was investigated through Franz-type vertical diffusion cells using both a TA suspension and a saturated TA solution.

RESULTS

The amount of TA bound to melanin increases with the increase of the TA concentration and with an increase in the incubation time. A Scatchard analysis revealed that the maximum number of moles of TA bound to melanin is predicted to be 22.43 nmol/mg, with a binding affinity of K=2.4×10(-5) nM(-1). TA released from a pigment showed a fast phase within the first 24 h and a slow phase thereafter. About 40% of the bound TA released in the first day and 73.94% of accumulative release was observed after 5 days. The TA suspension showed more TA penetration through the scleral-choroid complex than the saturated solution (P=0.0104). The apparent permeability coefficients for the suspension across the sclera-choroid of pigmented and albino rabbits are 7.48±1.53×10(-6) cm/s and 10.78±2.49×10(-6) cm/s, respectively.

CONCLUSIONS

TA can bind to and release from the ocular pigment, which may extend the TA ocular half-life and therapeutic duration when TA is delivered through a subtenon injection. A further in vivo study is warranted to validate the findings and to quantitate the magnitude of the difference between pigmented and albino animals.

Systemic factors influence the prognosis of diabetic macular edema after pars plana vitrectomy with internal limiting membrane peeling

PURPOSE/AIMS

To evaluate the prognostic factors for the best corrected visual acuity (BCVA) and central subfield macular thickness (CSMT) after vitrectomy with internal limiting membrane (ILM) peeling for diabetic macular edema.

MATERIALS AND METHODS

A total of 44 eyes of 35 patients who had undergone vitrectomy with ILM peeling between March 2008 and September 2009 were examined. The relationships between preoperative systemic or ocular factors and BCVA or CSMT were evaluated before and at 6 months after the surgical procedure.

RESULTS

Mean logarithm of the minimum angle of resolution improved from 0.74 ± 0.35 (mean ± SD) preoperatively to 0.55 ± 0.4 at 6 months postoperatively (p = 0.001). There was a significant improvement of the CSMT from 482 ± 116 μm before the operation to 355 ± 126 μm 6 months after the operation (p < 0.0001). The preoperative CSMT was significantly thicker with ischemic disease (p = 0.0016). Preoperative BCVA was significantly lower when subfoveal hard exudate was present (p = 0.0005). At the 6-month follow-up, CSMT was significantly thicker when there was a higher glycosylated hemoglobin (p = 0.008). BCVA at the 6-month follow-up was significantly lower in the group without any diabetes treatment history (p = 0.0075) prior to the diagnosis of diabetic retinopathy.

CONCLUSIONS

While BCVA and CSMT were associated with ocular factors before surgery, they were associated with glycemic control postoperatively. Glycemic control may be important for retinal thickness after ocular surgery.

Intravitreal triamcinolone versus intravitreal bevacizumab for diabetic macular edema: a meta-analysis

AIM

To compare the efficacy of the sole intravitreal triamcinolone (IVT) versus intravitreal bevacizumab (IVB) alone or IVB combined with IVT in the treatment of diabetic macular edema (DME).

METHODS

Pertinent publications were identified through systematic searches of database and manually searching. Methodological quality of the literatures was valuated according to the Jadad Score. RevMan 5.1.0 was used to do the meta-analysis. Heterogeneity was determined and sensitivity was conducted.

RESULTS

Six studies were ultimately included in the meta-analysis. The results of our analysis showed IVT had a statistically significant improvement in vision over the IVB at 1 month and 3 months (P<0.01). However, the reduction was not significant regarding central macular thickness (CMT) during the earlier (1 month and 3 months) follow-up period (P=0.12, P=0.41, respectively). At later visit (6 months), IVT had a significant decrease in CMT when compared to IVB (P<0.01) while no significant improvement in visual acuity (VA) was observed (P=0.14). The incidence of intraocular hypertension was 13/102 in IVT group during follow-up period while 0/103 in IVB group. The difference was significant (P<0.01). With regards to IVT versus IVB combined with IVT, there were no significant differences in CMT at 1 month (P=0.86) and 3 months (P=0.06). The incidence of intraocular hypertension was 6/67 in IVT group during follow-up period while 4/66 in IVB+IVT group. But the difference was not significant (P=0.53).

CONCLUSION

Current evidence shows IVT is superior in improving VA at earlier follow-up (1 month and 3 months) and in reducing CMT at later follow-up (6 months) for DME. At other time, it is in favor of IVT treatment but there are no statistically significances. However, IVT has the side-effect of ocular hypertension. There is no adequate evidence of the benefit adding IVB to IVT in contrast to IVT alone.

Green-light fundus autofluorescence in diabetic macular edema

AIM

To evaluate the role of central green-light fundus autofluorescence (FAF) in diabetic macular edema (DME).

METHODS

A consecutive series of 92 study eyes with diabetic retinopathy were included. Out of those, 51 diabetic eyes had DME and were compared to 41 diabetic eyes without DME. In all subjects, green-light FAF images were obtained, quantified and classified into various FAF patterns. Cross-sectional optical coherence tomography (OCT) scans were obtained for evaluation of Inner/Outer segment (IS/OS) layer integrity, measurements of central RPE-IS/OS layer thickness as well as classification of DME into various subtypes.

RESULTS

Mean central green-light FAF intensity of eyes with DME (1.289±0.140)log did not significantly differ from diabetic patients without DME (1.317±0.137)log. Most classifiable FAF patterns were seen in patients with cystoid DME. Mean central retinal thickness (CRT) of all study eyes with DME was (501.9±112.4)µm compared to (328.2±27.0)µm in diabetic patients without DME. Patients with DME had significantly more disrupted photoreceptor IS/OS layers than diabetic patients without DME (28/51 vs 5/41, P<0.001). Mean RPE-IS/OS thickness of patients with DME (60.7±14.1)µm was significantly (P<0.001) lower than in diabetic eyes without DME (73.5±9.4)µm. Correlation analys1s revealed non-significant correlations of green-light FAF intensity and OCT parameters in all subtypes of DME.

CONCLUSION

Our results indicate a poor correlation of central green-light FAF intensity with CRT, IS/OS layer integrity or RPE-IS/OS layer thickness in diabetic patients with or without DME and its various subtypes. Thus, central green-light FAF is not suitable for detection of retinal thickening in DME.

Pathophysiology and treatment of diabetic retinopathy

In the past years, the management of diabetic retinopathy (DR) relied primarily on a good systemic control of diabetes mellitus, and as soon as the severity of the vascular lesions required further treatment, laser photocoagulation or vitreoretinal surgery was done to the patient. Currently, even if the intensive metabolic control is still mandatory, a variety of different clinical strategies could be offered to the patient. The recent advances in understanding the complex pathophysiology of DR allowed the physician to identify many cell types involved in the pathogenesis of DR and thus to develop new treatment approaches. Vasoactive and proinflammatory molecules, such as vascular endothelial growth factor (VEGF), play a key role in this multifactorial disease. Current properly designed trials, evaluating agents targeting VEGF or other mediators, showed benefits in the management of DR, especially when metabolic control is lacking. Other agents, directing to the processes of vasopermeability and angiogenesis, are under investigations, giving more hope in the future management of this still sight-threatening disease.

Systemic factors influence the prognosis of diabetic macular edema after pars plana vitrectomy with internal limiting membrane peeling

BACKGROUND

To evaluate the prognostic factors for the best-corrected visual acuity (BCVA) and foveal average retinal thickness after vitrectomy with internal limiting membrane (ILM) peeling for diabetic macular edema.

DESIGN

Retrospective, single-center study.

PARTICIPANTS

This study involved 31 eyes of 27 patients who had undergone vitrectomy with ILM peeling between January 2005 and March 2008.

METHODS

Relationships between preoperative systemic or ocular factors and BCVA or foveal average retinal thickness before and 6 months after the operation were evaluated.

MAIN OUTCOME MEASURES

BCVA and foveal average retinal thickness before and 6 months after the operation.

RESULTS

The mean logarithm of the minimum angle of resolution improved from 0.84 ± 0.64 (mean ± standard deviation) preoperatively to 0.64 ± 0.38 six months postoperatively (p = 0.393). Foveal average retinal thickness significantly improved from 473 ± 146 µm preoperatively to 318 ± 108 µm 6 months after the operation (p < 0.0001). Preoperative foveal average retinal thickness was significantly thicker with cardiovascular disease or cerebral infarction (p = 0.0019) or cystoid macular edema (p = 0.0028), while preoperative BCVA was significantly lower when an epiretinal membrane (p = 0.042) was present. Foveal average retinal thickness at the 6-month follow-up was significantly thicker when patients had a higher body mass index (p = 0.0088), were not on dialysis (p = 0.012), or did not have proliferative diabetic retinopathy (p = 0.013). BCVA at the 6-month follow-up was significantly lower in the group with no history of diabetes treatment until diabetic retinopathy was found (p = 0.023) and in patients with a higher preoperative glycosylated hemoglobin (p = 0.033).

CONCLUSIONS

Preoperatively, BCVA and foveal average retinal thickness were primarily associated with ocular factors, while they were strongly associated with systemic factors, postoperatively. Ocular factor improvements may be related to the surgical procedure.

Change in macular thickness in a case of refractory diabetic macular edema with dexamethasone intravitreal implant in comparison to intravitreal bevacizumab: a case report

We report on the significant improvement of central macular thickness in a case of clinically significant macular edema after dexamethasone 0.7 mg sustained-release intravitreal implant (Ozurdex®; Allergan, Inc, Irvine, CA, USA). Patient presented to us with persistent clinically significant macular edema (CSME) in both eyes. Right eye received dexamethasone implant and left eye received two intravitreal bevacizumab injections 1.25 mg/0.05 mL (Avastin®; Genentech Inc., South San Francisco, CA, USA) with an interval of four weeks. After six weeks of follow-up, dexamethasone implant in the right eye showed normal macular thickness whereas persistent macular edema (ME) was found even after second intravitreal bevacizumab injection in the left eye.

Current epidemiology of diabetic retinopathy and diabetic macular edema

With increasing global prevalence of diabetes, diabetic retinopathy (DR) is set to be the principle cause of vision impairment in many countries. DR affects a third of people with diabetes and the prevalence increases with duration of diabetes, hyperglycemia, and hypertension-the major risk factors for the onset and progression of DR. There are now increasing data on the epidemiology of diabetic macular edema (DME), an advanced complication of DR, with studies suggesting DME may affect up to 7 % of people with diabetes. The risk factors for DME are largely similar to DR, but dyslipidemia appears to play a more significant role. Early detection of DR and DME through screening programs and appropriate referral for therapy is important to preserve vision in individuals with diabetes. Future research is necessary to better understand the potential role of other risk factors such as apolipoproteins and genetic predisposition to shape public health programs.

Corticosteroid use for diabetic macular edema: old fad or new trend?

Diabetic retinopathy is the leading cause of blindness in working age individuals in developed countries. Most cases of diabetes related vision loss result from breakdown of the blood-retinal barrier with resultant diabetic macular edema (DME). For over 30 years, laser photocoagulation has been the standard therapy for DME, but most eyes do not experience significant improvements in visual acuity. Intravitreal injections of drugs that inhibit the action of vascular endothelial growth factor (VEGF) lead to gains in vision, but can be expensive and need to be repeated frequently. In addition to VEGF-mediated breakdown of the blood-retinal barrier, recent evidence suggests that inflammation plays an important role in the development of DME. Recognizing this, physicians have injected steroids into the vitreous and developers have created sustained release implants. Intravitreal injections of triamcinolone acetonide lead to rapid resolution of macular edema and significant short-term improvements in visual acuity, but unfortunately, visual acuities diminish when treatment is continued through 2 years. However, intravitreal triamcinolone remains an attractive treatment option for eyes that are pseudophakic, scheduled to undergo cataract surgery, resistant to laser photocoagulation, or require urgent panretinal photocoagulation for proliferative retinopathy. In controlled trials, intraocular implants that slowly release dexamethasone and fluocinolone show promise in reducing macular edema and improving visual acuity. The high incidences of drug related cataracts and glaucoma, however, require that corticosteroids be used cautiously and that patients be selected carefully. The increasing number of patients with DME, the burgeoning cost of medical care and the continuing development of intravitreal steroids suggest that the use of these agents will likely increase in coming years.

Intravitreal versus subtenon triamcinolone acetonide injection for diabetic macular edema: a systematic review and meta-analysis

OBJECTIVE

To compare the efficacy of intravitreal (IV) triamcinolone acetonide (IVTA) versus subtenon (ST) triamcinolone acetonide (STTA) injection for the treatment of diabetic macular edema (DME).

METHODS

Searches for randomized clinical trials published between 1 January 1950 and 15 March 2011 were conducted using PubMed, MEDLINE, EMBASE, and the Cochrane Library included in the present meta-analysis are five randomized controlled trials, each with a minimum follow-up of 3 mo. All included studies evaluated the efficacy of TA for the treatment of refractory DME, and compared IVTA with STTA by measuring visual acuity (VA), central macular thickness (CMT), and intraocular pressure (IOP).

RESULTS

One mo post-injection, treatment with IVTA had significantly improved VA (MD, -0.14 logMAR; 95% CI = -0.16 to -0.13) and reduced CMT (MD = -174.02 μm; 95% CI = -249.97 to -98.08) compared with STTA. At 3 mo post-injection, treatment with IVTA had significantly improved VA (MD = -0.07 logMAR; 95% CI = -0.09 to -0.05) and reduced CMT (MD = -119.46 μm; 95% CI = -176.55 to -62.36) compared with STTA. The benefits of either treatment were no longer significant at 6 mo, and patients had to be retreated. Compared with STTA, IVTA injections produced no difference in IOPs at 1 mo, higher IOPs at 3 mo, and lower IOP values at 6 months

CONCLUSIONS

Within 3 mo, IVTA is more effective than is STTA in improving VA and reducing CMT in patients with refractory DME. However, the benefits of either regimen were no longer evident at 6 mo.

Intraocular corticosteroids for posterior segment disease: 2012 update

INTRODUCTION

Diabetic macular edema (DME), cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO) and uveitis are responsible for severe visual impairment worldwide. In some patients with these conditions, treatment with intraocular corticosteroids may be beneficial. Although off-label use of these agents has occurred for many years, novel agents including preservative-free and sustained-release intravitreal implants are currently being studied in clinical trials (CTs).

AREAS COVERED

This paper reviews the use of CTs for vitreoretinal (VR) diseases including choroidal neovascularization, CME, DME, RVO and posterior uveitis. It also discusses the use of corticosteroids for treating VR disease, including dexamethasone, fluocinolone acetonide, intravitreal implants and triamcinolone acetonide.

EXPERT OPINION

Used alone, intravitreal corticosteroids may benefit disorders such as DME, RVO and uveitis compared with standard therapy. Cases of exudative AMD non-responsive to standard treatment may benefit from combination therapy, including usage of intravitreal corticosteroid injections. Intraoperative use of these agents may aid visualization of retinal structures. Sustained-release intraocular implants have been approved for posterior uveitis and RVO associated with macular edema. In spite of this, most intraocular corticosteroids have a limited duration of action along with significant side effects, including cataract and glaucoma. Currently, intravitreal corticosteroid usage for DME is considered off-label.

Acetylation of retinal histones in diabetes increases inflammatory proteins: effects of minocycline and manipulation of histone acetyltransferase (HAT) and histone deacetylase (HDAC)

Histone acetylation was significantly increased in retinas from diabetic rats, and this acetylation was inhibited in diabetics treated with minocycline, a drug known to inhibit early diabetic retinopathy in animals. Histone acetylation and expression of inflammatory proteins that have been implicated in the pathogenesis of diabetic retinopathy were increased likewise in cultured retinal Müller glia grown in a diabetes-like concentration of glucose. Both the acetylation and induction of the inflammatory proteins in elevated glucose levels were significantly inhibited by inhibitors of histone acetyltransferase (garcinol and antisense against the histone acetylase, p300) or activators of histone deacetylase (theophylline and resveratrol) and were increased by the histone deacetylase inhibitor, suberolylanilide hydroxamic acid. We conclude that hyperglycemia causes acetylation of retinal histones (and probably other proteins) and that the acetylation contributes to the hyperglycemia-induced up-regulation of proinflammatory proteins and thereby to the development of diabetic retinopathy.

Pharmacokinetic study of vitreous and serum concentrations of triamcinolone acetonide after posterior sub-tenon's injection

PURPOSE

To compare a theoretical pharmacokinetic model of triamcinolone acetonide after posterior sub-Tenon's injection with experimental serum and undiluted vitreous triamcinolone acetonide concentrations obtained during pars plana vitrectomy.

DESIGN

Clinical-practice, prospective, interventional case series study.

METHODS

This study compared computer-modeled triamcinolone acetonide diffusion after posterior sub-Tenon's injection with triamcinolone acetonide levels in experimental undiluted vitreous and serum samples from 57 patients undergoing vitrectomy assessed via mass spectrometry and high-pressure liquid chromatography. At least 5 pairs of samples were collected at each of 7 time points (1 day, 3 days, and 1, 2, 3, 4, and 8 weeks) after triamcinolone acetonide injection, with 6 controls without injection. Cortisol levels were measured in 31 sets of samples.

RESULTS

The theoretical model predicted that triamcinolone acetonide levels in systemic blood, vitreous, and choroidal extracellular matrix would plateau after 3 days at 15 ng/mL, 227 ng/mL and 2230 ng/mL, respectively. Experimental vitreous levels of triamcinolone peaked at 111 ng/mL at day 1, then reached a plateau in the range 15 to 25 ng/mL, while serum triamcinolone levels peaked at day 3 near 35 ng/mL and plateaued near 2 to 8 ng/mL. Serum triamcinolone and cortisol levels were inversely correlated (Spearman -0.42, P = .02).

CONCLUSIONS

The theoretical model predicts efficient delivery of triamcinolone acetonide from the posterior sub-Tenon's space to the extracellular choroidal matrix. The experimental findings demonstrate low levels of serum triamcinolone that alter systemic cortisol levels and higher vitreous levels lasting at least 1 month. Both assessments support trans-scleral delivery of posterior sub-Tenon's triamcinolone.