Diabetic Retinopathy Clinical Research Network. A randomized trial comparing intravitreal triamcinolone acetonide and focal/grid photocoagulation for diabetic macular edema

The kallikrein-kinin system in diabetic retinopathy

Diabetic retinopathy (DR) is a major microvascular complication associated with type 1 and type 2 diabetes mellitus, which can lead to visual impairment and blindness. Current treatment strategies for DR are mostly limited to laser therapies, steroids, and anti-VEGF agents, which are often associated with unwanted side effects leading to further complications. Recent evidence suggests that kinins play a primary role in the development of DR through enhanced vascular permeability, leukocytes infiltration, and other inflammatory mechanisms. These deleterious effects are mediated by kinin B1 and B2 receptors, which are expressed in diabetic human and rodent retina. Importantly, kinin B1 receptor is virtually absent in sane tissue, yet it is induced and upregulated in diabetic retina. These peptides belong to the kallikrein-kinin system (KKS), which contains two separate and independent pathways of regulated serine proteases, namely plasma kallikrein (PK) and tissue kallikrein (TK) that are involved in the biosynthesis of bradykinin (BK) and kallidin (Lys-BK), respectively. Hence, ocular inhibition of kallikreins or antagonism of kinin receptors offers new therapeutic avenues in the treatment and management of DR. Herein, we present an overview of the principal features and known inflammatory mechanisms associated with DR along with the current therapeutic approaches and put special emphasis on the KKS as a new and promising therapeutic target due to its link with key pathways directly associated with the development of DR.

Effect of ranirestat, a new aldose reductase inhibitor, on diabetic retinopathy in SDT rats

PURPOSE

To evaluate the effect of ranirestat, a new aldose reductase inhibitor (ARI), on diabetic retinopathy (DR) in Spontaneously Diabetic Torii (SDT) rats.

METHODS

The animals were divided into six groups, normal Sprague-Dawley rats (n = 8), untreated SDT rats (n = 9), ranirestat-treated SDT rats (0.1, 1.0, and 10 mg/kg/day, n = 7, 8, and 6, resp.), and epalrestat-treated SDT rats (100 mg/kg/day, n = 7). Treated rats received oral ranirestat or epalrestat once daily for 40 weeks after the onset of diabetes. After the eyes were enucleated, the retinal thickness and the area of stained glial fibrillary acidic protein (GFAP) were measured.

RESULTS

The retinas in the untreated group were significantly thicker than those in the normal and ranirestat-treated (0.1, 1.0, and 10 mg/kg/day) groups. The immunostained area of GFAP in the untreated group was significantly larger than that in the normal and ranirestat-treated (1.0 and 10 mg/kg/day) groups. There were no significant differences between the untreated group and epalrestat-treated group in the retinal thickness and the area of stained GFAP.

CONCLUSION

Ranirestat reduced the retinal thickness and the area of stained GFAP in SDT rats and might suppress DR and have a neuroprotective effect on diabetic retinas.

Clinical trials on corticosteroids for diabetic macular edema

Diabetic macular edema (DME) is a common cause of visual impairment in diabetic patients. It is caused by an increase in the permeability of the perifoveal capillaries and a disruption of the blood retinal-barrier. The pathogenesis of DME is multifactorial. Several therapeutic modalities have been proposed for the treatment of DME. Corticosteroid treatments have emerged as an alternative therapy for persistent DME or refractory to conventional laser photocoagulation and other modalities, due to anti-inflammatory, anti-vascular endothelial growth factor and anti-proliferative effects. Many studies have demonstrated the beneficial therapeutic effect of corticosteroids with improvement to both retinal thickness and visual acuity in short-term on the treatment of DME. Peribulbar and intravitreal injections have been used to deliver steroids for DME with frequent injections due to the chronic and recurrent nature of the disease. Steroid-related side effects include elevated intraocular pressure, cataract, and injection related complications such as endophthalmitis, vitreous hemorrhage, and retinal detachment particularly with intravitreal steroid injections. In order to reduce the risks, complications and frequent dosing of intravitreal steroids, intravitreal implants have been developed recently to provide sustained release of corticosteroids and reduce repeated intravitreal injections for the management of DME.

Ranibizumab in diabetic macular edema

By 2050 the prevalence of diabetes will more than triple globally, dramatically increasing the societal and financial burden of this disease worldwide. As a consequence of this growth, it is anticipated that there will be a concurrent rise in the numbers of patients with diabetic macular edema (DME), already among the most common causes of severe vision loss worldwide. Recent available therapies for DME target the secreted cytokine, vascular endothelial growth factor (VEGF). This review focuses on the treatment of DME using the first humanized monoclonal antibody targeting VEGF that has been Food and Drug Administration-approved for the use in the eye, ranibizumab (Lucentis(®)).

Anti-vascular endothelial growth factor therapy for diabetic macular edema

Diabetes mellitus is a serious health problem that affects over 350 million individuals worldwide. Diabetic retinopathy (DR), which is the most common microvascular complication of diabetes, is the leading cause of new cases of blindness in working-aged adults. Diabetic macular edema (DME) is an advanced, vision-limiting complication of DR that affects nearly 30% of patients who have had diabetes for at least 20 years and is responsible for much of the vision loss due to DR. The historic standard of care for DME has been macular laser photocoagulation, which has been shown to stabilize vision and reduce the rate of further vision loss by 50%; however, macular laser leads to significant vision recovery in only 15% of treated patients. Mechanisms contributing to the microvascular damage in DR and DME include the direct toxic effects of hyperglycemia, sustained alterations in cell signaling pathways, and chronic microvascular inflammation with leukocyte-mediated injury. Chronic retinal microvascular damage results in elevation of intraocular levels of vascular endothelial growth factor A (VEGF), a potent, diffusible, endothelial-specific mitogen that mediates many important physiologic processes, including but not limited to the development and permeability of the vasculature. The identification of VEGF as an important pathophysiologic mediator of DME suggested that anti-VEGF therapy delivered to the eye might lead to improved visual outcomes in this disease. To date, four different inhibitors of VEGF, each administered by intraocular injection, have been tested in prospective, randomized phase II or phase III clinical trials in patients with DME. The results from these trials demonstrate that treatment with anti-VEGF agents results in substantially improved visual and anatomic outcomes compared with laser photocoagulation, and avoid the ocular side effects associated with laser treatment. Thus, anti-VEGF therapy has become the preferred treatment option for the management of DME in many patients.

Diabetic retinopathy: current concepts and emerging therapy

More Americans become blind each year from microvascular complications of diabetes than from any other cause. Several studies have indicated that tight glucose control and lifestyle modification can dramatically reduce the incidence and prevalence of diabetic retinopathy. Research over the past several years has yielded a tremendous increase in our knowledge of the pathogenesis of the damage to the retina that occurs in diabetes and has facilitated our ability to intervene and control the damage. New intravitreal medical therapies supported by government- and industry-supported research are gradually replacing standard laser photocoagulation for the treatment of all forms of retinopathy.

Green or yellow laser treatment for diabetic macular edema: exploratory assessment within the Diabetic Retinopathy Clinical Research Network

PURPOSE

Explore differences in green compared with yellow focal/grid laser treatment on functional and anatomical endpoints in eyes with diabetic macular edema.

METHODS

Data from two randomized clinical trials were evaluated for differences in visual acuity and optical coherence tomography parameters for eyes assigned to sham injection + prompt laser, ranibizumab + prompt laser, or prompt laser only: among subgroups of eyes treated exclusively and electively with either green or yellow laser.

RESULTS

In the sham injection + prompt laser group, the mean visual acuity letter score change for eyes receiving green and yellow laser treatment, respectively, was +2.4 ± 14 and +5.1 ± 13 at the 52-week visit (P = 0.06) and +2.4 ± 15 and +6.0 ± 13 at the 104-week visit (P = 0.13), with no corresponding evidence of differences in optical coherence tomography thickness. When comparing wavelength groups in the ranibizumab + prompt laser and prompt laser-only groups, meaningful differences in visual acuity and optical coherence tomography thickness were not detected at 1 year or 2 years.

CONCLUSION

A trend toward improved vision outcome with yellow laser observed in one trial was not corroborated by anatomical outcomes or by the other trial. In this study, without random assignment to different wavelengths controlling for bias and confounding, it is not possible to determine whether one wavelength is better than the other.

Automated detection of the foveal center improves SD-OCT measurements of central retinal thickness

BACKGROUND AND OBJECTIVE

To investigate the performance of an automated foveal center detection algorithm on spectral-domain optical coherence tomography (SD-OCT).

PATIENTS AND METHODS

Fifty normal eyes and 50 eyes with early stage dry age-related macular degeneration (AMD) were analyzed. The actual scan center (SC), automatically detected foveal center (AF), and manually identified foveal center (MF) were compared.

RESULTS

The mean of the radial distances was 89 ± 120 μm from MF to SC and 54 ± 41 μm from MF to AF for normal eyes and 179 ± 125 μm from SC to MF and 104 ± 62 μm from AF to MF for eyes with AMD. The differences were statistically significant (P < .001).

CONCLUSION

The automated algorithm designed to detect the foveal center was more accurate in detecting the foveal center than relying on the fixation target of the SD-OCT instrument.

Screening, prevention, and ambitious management of diabetic macular edema in patients with type 1 diabetes

Diabetic macular edema results from progressive retinopathy related to chronic hyperglycemic and inflammatory vascular damage. Loss of vision secondary to diabetic macular edema is the most common cause of vision loss in patients with diabetes. Blood glucose control remains the main means of preventing progression of retinopathy and macular edema. Recent advancements allowing more efficient mechanisms for screening patients and emerging treatments for macular edema have led to improved visual outcomes in this group of patients.

The evolving treatment options for diabetic macular edema

Diabetic retinopathy (DR) is the leading cause of vision loss in working-age adults, and diabetic macular edema (DME) is the most common cause of visual impairment in individuals with DR. This review focuses on the pathophysiology, previous treatment paradigms, and emerging treatment options in the management of DME.

A prospective randomized trial of intravitreal bevacizumab versus ranibizumab for the management of diabetic macular edema

PURPOSE

To compare visual acuity and spectral-domain optical coherence tomography (SDOCT) outcomes associated with intravitreal (IV) bevacizumab vs IV ranibizumab for the management of diabetic macular edema (DME).

DESIGN

Prospective randomized trial.

METHODS

Forty-eight patients (63 eyes) with center-involved DME were randomly assigned to receive 1.5 mg (0.06 cc) IV bevacizumab or 0.5 mg (0.05 cc) IV ranibizumab at baseline and monthly if central subfield thickness was greater than 275 μm.

RESULTS

Forty-five patients (60 eyes) completed 48 weeks of follow-up. At baseline, mean ± standard error best-corrected visual acuity (BCVA) (logMAR) was 0.60 (20/80) ± 0.05 in the IV bevacizumab group and 0.63 (20/85) ± 0.05 in the IV ranibizumab group. A significant improvement in mean BCVA was observed in both groups at all study visits (P < .05); this improvement was significantly greater in the IV ranibizumab group compared with the IV bevacizumab group at weeks 8 (P = .032) and 32 (P = .042). A significant reduction in mean central subfield thickness was observed in both groups at all study visits compared with baseline (P < .05), with no significant difference in the magnitude of macular thickness reduction between groups. The mean number of injections was significantly higher (P = .005) in the IV bevacizumab group (9.84) than in the IV ranibizumab group (7.67).

CONCLUSIONS

IV bevacizumab and IV ranibizumab are associated with similar effects on central subfield thickness in patients with DME through 1 year of follow-up. IV ranibizumab is associated with greater improvement in BCVA at some study visits, and the mean number of injections is higher in the IV bevacizumab group.

Microvascular complications and diabetic retinopathy: recent advances and future implications

Retinal microvascular alterations have been observed during diabetic retinopathy (DR) due to the retinal susceptibility towards subtle pathological alterations. Therefore, retinal microvascular pathology is essential to understand the nature of retinal degenerations during DR. In this review, the role of retinal microvasculature complications during progression of DR, along with recent efforts to normalize such alterations for better therapeutic outcome, will be underlined. In addition, current therapeutics and future directions for advancement of standard treatment for DR patients will be discussed.

Soluble mediators of diabetic macular edema: the diagnostic role of aqueous VEGF and cytokine levels in diabetic macular edema

Diabetic macular edema (DME) is a significant cause of vision loss and represents an important clinical and public health problem. It is characterized by breakdown of the blood retinal barrier with fluid accumulation in the sub-retinal and intra-retinal spaces. Although several hypotheses exist for the causes of diabetic macular edema, specific molecular mechanisms remain unclear. Current thinking includes the role of vascular endothelial growth factor (VEGF) and inflammatory cytokines in vascular permeability. We review studies showing a relationship between elevated aqueous VEGF, monocyte chemoattractant protein -1, interleukin 6, or interleukin 8 in association with DME and as predictors of DME. The presence of mediators in both the angiogenesis and inflammatory pathways data suggest a multifactorial model for the development of DME. Further studies targeting individual cytokine activity will be important to our understanding of the pathogenesis and treatment.

Intravitreal Corticosteroids in the Management of Diabetic Macular Edema

Diabetic macular edema (DME) remains an important worldwide cause of visual loss. Corticosteroids have a role in the treatment of some patients with advanced or recurrent DME. The best studied steroids for this indication are triamcinolone acetonide, dexamethasone, and fluocinolone acetonide. All steroids are associated with risks of cataract and intraocular pressure elevation. In addition, intravitreal injection of any medication is associated with risks of infectious endophthalmitis, which has led to the investigation of various extended-release steroid implants. At this time, no steroid is approved by the United States Food and Drug Administration (FDA) for the treatment of DME.

Assessment of the differences in pharmacokinetics and pharmacodynamics between four distinct formulations of triamcinolone acetonide

PURPOSE

To compare the durability of Kenalog, Trivaris, Triesence, and compounding pharmacy preservative-free triamcinolone acetonide in pigmented rabbits with syneretic vitreous using direct visualization, pharmacodynamics, and pharmacokinetics.

METHODS

Twenty-five Dutch-belted rabbits were used. Pharmacokinetic experiment: Rabbits were intravitreally injected with one of four 4-mg triamcinolone acetonide formulations. Wide-field imaging was serially performed to document residual drug mass. Pharmacodynamics experiment: Four triamcinolone acetonide groups and one control group received intravitreal recombinant human vascular endothelial growth factor 165 every 2 weeks and were followed with fluorescein angiography to assess vascular endothelial growth factor retinal vasculopathy as a measure of residual steroid effect. Particle size of the formulations was measured with Mastersizer 2000.

RESULTS

Remaining triamcinolone acetonide mass after 19 weeks: 12,091 ± 2,512 pixels for the Kenalog group, 1,307.36 ± 695.57 for Trivaris, 5577 ± 1477 for Triesence, and 1,535 ± 329 for compounded preservative-free triamcinolone acetonide. Kenalog suppressed recombinant human vascular endothelial growth factor-induced retinopathy more effectively than the other triamcinolone acetonide groups at Week 39, the final time point assessed. Particle size (90th percentile) was 47 μm for Kenalog, 26 μm for Triesence, and 22 μm for both compounded preservative-free triamcinolone acetonide and Trivaris.

CONCLUSION

Triamcinolone acetonide formulations do not have the same pharmacokinetics/pharmacodynamics. Kenalog has the longest vitreous visibility and durability. Particle size appears to correlate with efficacy and durability.

Fluocinolone acetonide intravitreal implant for the treatment of diabetic macular edema

Diabetic macular edema (DME) remains one of the leading causes of moderate to severe vision loss. Although laser photocoagulation was the standard of care for several years, few patients achieved significant improvements in visual acuity. As a result, several pharmacotherapies and surgeries have been investigated. The fluocinolone acetonide devices are one of the latest therapies considered for the treatment of DME. Despite bringing significant improvements in visual acuity, fluocinolone devices are associated with cataract formation, increased intraocular pressure (IOP), and surgery to lower IOP. Due to the risk of complications, fluocinolone acetonide devices should be considered only in cases refractive to first-line therapies. In this review, we evaluate current and emerging therapies for DME, with special emphasis on fluocinolone acetonide intravitreal devices.

Evolving strategies in the management of diabetic macular edema: clinical trials and current management

Diabetic macular edema (DME) is the leading cause of vision loss in the working-age population in developed countries. Management has traditionally consisted of focal/grid macular laser, according to the guidelines established by the Early Treatment of Diabetic Retinopathy Study. More recent prospective clinical trials examining the effect of intravitreal ranibizumab in the treatment of DME--most notably, READ-2, RESOLVE, RESTORE, RISE/RIDE, and DRCR.net protocol I--have demonstrated improved visual outcomes with pharmacologic targeting of vascular endothelial growth factor. Similar treatment benefits have also been noted in clinical trials evaluating intravitreal bevacizumab and aflibercept (Bolt and da Vinci, respectively). Intravitreal steroids, particularly in refractory cases, continue to have a limited role in the management of DME. In patients with symptomatic visual loss, the treatment paradigm for DME has shifted toward intravitreal pharmacotherapeutics, principally anti-vascular endothelial growth factor therapy, and this review examines the clinical trials leading to this change.

Dexamethasone intravitreal implant in combination with laser photocoagulation for the treatment of diffuse diabetic macular edema

PURPOSE

To evaluate Ozurdex (dexamethasone intravitreal implant [DEX implant]; Allergan, Inc, Irvine, CA) 0.7 mg combined with laser photocoagulation compared with laser alone for treatment of diffuse diabetic macular edema (DME).

DESIGN

Randomized, controlled, multicenter, double-masked, parallel-group, 12-month trial.

PARTICIPANTS

Two hundred fifty-three patients with retinal thickening and impaired vision resulting from diffuse DME in at least 1 eye (the study eye) were enrolled.

INTERVENTION

Patients were randomized to treatment in the study eye with DEX implant at baseline plus laser at month 1 (combination treatment; n = 126) or sham implant at baseline and laser at month 1 (laser alone; n = 127) and could receive up to 3 additional laser treatments and 1 additional DEX implant or sham treatment as needed.

MAIN OUTCOME MEASURES

The primary efficacy variable was the percentage of patients who had a 10-letter or more improvement in best-corrected visual acuity (BCVA) from baseline at month 12. Other key efficacy variables included the change in BCVA from baseline and the area of vessel leakage evaluated with fluorescein angiography. Safety variables included adverse events and intraocular pressure (IOP).

RESULTS

The percentage of patients who gained 10 letters or more in BCVA at month 12 did not differ between treatment groups, but the percentage of patients was significantly greater in the combination group at month 1 (P<0.001) and month 9 (P = 0.007). In patients with angiographically verified diffuse DME, the mean improvement in BCVA was significantly greater with DEX implant plus laser treatment than with laser treatment alone (up to 7.9 vs. 2.3 letters) at all time points through month 9 (P ≤ 0.013). Decreases in the area of diffuse vascular leakage measured angiographically were significantly larger with DEX implant plus laser treatment through month 12 (P ≤ 0.041). Increased IOP was more common with combination treatment. No surgeries for elevated IOP were required.

CONCLUSIONS

There was no significant between-group difference at month 12. However, significantly greater improvement in BCVA, as demonstrated by changes from baseline at various time points up to 9 months and across time based on the area under the curve analysis, occurred in patients with diffuse DME treated with DEX implant plus laser than in patients treated with laser alone.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Intravitreal bevacizumab plus grid laser photocoagulation or intravitreal bevacizumab or grid laser photocoagulation for diffuse diabetic macular edema: results of the Pan-american Collaborative Retina Study Group at 24 months

PURPOSE

To evaluate the anatomical and functional outcomes at 24 months in patients with diffuse diabetic macular edema treated with primary intravitreal bevacizumab (IVB) plus grid laser photocoagulation (GLP) or primary IVB alone or GLP alone.

METHODS

Retrospective, interventional, comparative, multicenter study. We included in this analysis 141 eyes of 120 patients with diffuse diabetic macular edema treated with primary IVB alone (Group A), 120 eyes of 94 patients with GLP therapy (Group B), and 157 eyes of 104 patients treated with IVB plus GLP (Group C).

RESULTS

In all 3 groups, the authors observed improvement of Early Treatment Diabetic Retinopathy Study best-corrected visual acuity from baseline to 24-month follow-up (P < 0.0001). The improvement rate in Group A was statistically significantly better than in Group B (analysis of variance, P = 0.013). The authors also found a decrease in central macular thickness in all groups from baseline to the 24-month follow-up (P < 0.0001). The comparison among 3 groups showed higher central macular thickness decrease in Group A than in Groups B and C (analysis of variance, P < 0.001).

CONCLUSION

The study provides evidence to support the use of primary IVB with or without GLP as treatment of diffuse diabetic macular edema. Primary IVB without GLP seems to be superior to GLP alone to provide stability or improvement in best-corrected visual acuity in patients with diffuse diabetic macular edema at 24 months.

Vitrectomy combined with intravitreal triamcinolone acetonide injection and macular laser photocoagulation for nontractional diabetic macular edema

Purpose

To evaluate the efficacy of vitrectomy combined with intravitreal injection of triamcinolone acetonide (IVTA) and macular laser photocoagulation for the treatment of nontractional diabetic macular edema (DME) refractory to anti-vascular endothelial growth factor (VEGF) therapy.

Methods

Twenty-eight eyes from 28 subjects who were diagnosed with nontractional DME refractory to three or more sequential anti-VEGF injections underwent sequential vitrectomy, IVTA, and macular laser photocoagulation. Changes in best-corrected visual acuity (BCVA) and central subfield thickness (CST) during the six months following vitrectomy were evaluated. Additionally, the CST and BCVA outcomes were compared with those of 26 eyes treated with the same triple therapy for nontractional DME refractory to conventional treatment, such as IVTA or macular laser photocoagulation, or both.

Results

The mean logarithm of the minimum angle of resolution BCVAs before and one, three, and six months after vitrectomy were 0.44 ± 0.15, 0.36 ± 0.18, 0.31 ± 0.14, and 0.34 ± 0.22, respectively. The mean CSTs were 433.3 ± 77.9, 329.9 ± 59.4, 307.2 ± 60.2, and 310.1 ± 80.1 microns, respectively. The values of both BCVA and CST at one, three, and six months were significantly improved from baseline (p < 0.05). The extent of CST reduction during the first month after triple therapy was greater in eyes refractory to conventional treatment than in eyes refractory to anti-VEGF (p = 0.012).

Conclusions

Vitrectomy combined with IVTA and macular laser photocoagulation had a beneficial effect on both anatomical and functional outcomes in eyes with nontractional DME refractory to anti-VEGF therapy.

Drug-induced uveitis

A number of medications have been associated with uveitis. This review highlights both well-established and recently reported systemic, topical, intraocular, and vaccine-associated causes of drug-induced uveitis, and assigns a quantitative score to each medication based upon criteria originally described by Naranjo and associates.

Personalized Medicine in Ophthalmology: From Pharmacogenetic Biomarkers to Therapeutic and Dosage Optimization

Rapid progress in genomics and nanotechnology continue to advance our approach to patient care, from diagnosis and prognosis, to targeting and personalization of therapeutics. However, the clinical application of molecular diagnostics in ophthalmology has been limited even though there have been demonstrations of disease risk and pharmacogenetic associations. There is a high clinical need for therapeutic personalization and dosage optimization in ophthalmology and may be the focus of individualized medicine in this specialty. In several retinal conditions, such as age-related macular degeneration, diabetic macular edema, retinal vein occlusion and pre-threshold retinopathy of prematurity, anti-vascular endothelial growth factor therapeutics have resulted in enhanced outcomes. In glaucoma, recent advances in cytoskeletal agents and prostaglandin molecules that affect outflow and remodel the trabecular meshwork have demonstrated improved intraocular pressure control. Application of recent developments in nanoemulsion and polymeric micelle for targeted delivery and drug release are models of dosage optimization, increasing efficacy and improving outcomes in these major eye diseases.

Current treatments in diabetic macular oedema: systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review is to appraise the evidence for the use of anti-VEGF drugs and steroids in diabetic macular oedema (DMO) as assessed by change in best corrected visual acuity (BCVA), central macular thickness and adverse events

DATA SOURCE

MEDLINE, EMBASE, Web of Science with Conference Proceedings and the Cochrane Library (inception to July 2012). Certain conference abstracts and drug regulatory web sites were also searched.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Randomised controlled trials were used to assess clinical effectiveness and observational trials were used for safety. Trials which assessed triamcinolone, dexamethasone, fluocinolone, bevacizumab, ranibizumab, pegaptanib or aflibercept in patients with DMO were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Risk of bias was assessed using the Cochrane risk of bias tool. Study results are narratively described and, where appropriate, data were pooled using random effects meta-analysis.

RESULTS

Anti-VEGF drugs are effective compared to both laser and placebo and seem to be more effective than steroids in improving BCVA. They have been shown to be safe in the short term but require frequent injections. Studies assessing steroids (triamcinolone, dexamethasone and fluocinolone) have reported mixed results when compared with laser or placebo. Steroids have been associated with increased incidence of cataracts and intraocular pressure rise but require fewer injections, especially when steroid implants are used.

LIMITATIONS

The quality of included studies varied considerably. Five of 14 meta-analyses had moderate or high statistical heterogeneity.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The anti-VEGFs ranibizumab and bevacizumab have consistently shown good clinical effectiveness without major unwanted side effects. Steroid results have been mixed and are usually associated with cataract formation and  intraocular pressure increase. Despite the current wider spectrum of treatments for DMO, only a small proportion of patients recover good vision (≥20/40), and thus the search for new therapies needs to continue.

Comparison of intravitreal bevacizumab, intravitreal triamcinolone acetonide, and macular grid augmentation in refractory diffuse diabetic macular edema: A prospective, randomized study

BACKGROUND

In spite of laser being the gold standard treatment for Diabetic Macular edema (DME), some patients do not respond to laser. Various treatment modalities are being tried in the management of refractory diffuse DME (DDME).

PURPOSE

To compare the efficacy of intravitreal bevacizumab (IVB), intravitreal triamcinolone acetonide (IVTA), and macular grid augmentation in the management of refractory DDME.

SETTINGS AND DESIGN

Prospective randomized study in a tertiary eye care center.

MATERIALS AND METHODS

SIXTY PATIENTS WITH REFRACTORY DDME WERE RANDOMLY ASSIGNED TO THREE GROUPS: Group 1 received IVB (1.25 mg/0.05 ml), Group 2 received IVTA (4 mg/0.1ml), and Group 3 underwent laser augmentation. Primary outcome measures were best corrected visual acuity (BCVA) and central macular thickness (CMT) at the end of 6 months.

STATISTICS

Analysis was performed using SPSS 14.0

RESULTS

Group 1 and 2 showed significant improvement in mean BCVA from 20/160 at baseline to 20/80 and from 20/125 to 20/63, respectively, at 6 months (P < 0.05). These groups also showed a significant reduction in the mean CMT from 457 ± 151 μ at baseline to 316 ± 136 μ and from 394 ± 61 μ to 261 ± 85 μ, respectively, at 6 months (P < 0.05). Group 3 showed only small improvement in mean BCVA from 20/100 to 20/80 (P = 1.0) while mean CMT increased from 358 ± 89 μ at baseline to 395 ± 127 μ at 6 months (P = 0.191). Eight (40%) eyes in Group 2 had intraocular pressure (IOP) rise and 10 (50%) eyes developed cataract.

CONCLUSIONS

Both IVB and IVTA may be effective in the treatment of refractory DDME compared with macular grid augmentation. IVTA may be associated with side effects such as IOP rise and cataract formation.

[Navigated focal retinal laser therapy using the NAVILAS® system for diabetic macula edema]

PURPOSE

The aim of this study was to investigate the accuracy of a navigated laser photocoagulator in clinically significant macular edema (CSME).

METHODS

Focal laser treatment for diabetic macular edema (DME) in 36 patients was digitally planned on fundus images and performed with navigation using NAVILAS® (OD-OS, Teltow, Germany). Treatment intensity was controlled visually during treatment so the laser spots applied were barely directly visible after treatment. Using color images (CI) and optical coherence tomography (OCT) 4,137 laser spots (mean 115 per eye) were analyzed at 1 month follow-up and accuracy of spot placement was determined.

RESULTS

In total 79% of laser spots were visible on CI of which 96% were within 100 µm of the planned target position. On an intention-to-treat (ITT) basis, 76% of the laser spots were placed and visible within the 100 µm target and OCT confirmed that laser effects were limited to the outer retina. The mean time for focal treatment was < 7 min (±3 min).

CONCLUSIONS

After NAVILAS treatment for DME a high percentage of laser effects could be visualized on post-treatment color images and the location showed high concordance with the preplanning target.

Diabetic macular edema: therapeutic options

Treatment for diabetic macular edema (DME) is continuously evolving with the advent of pharmacologic therapies. Focal laser photocoagulation remains the historical standard of care; however, a new wave of studies is rapidly emerging that shows the benefit of intravitreal antivascular endothelial growth factor medications and corticosteroids. The goal of this review is to compare the various treatment options for DME, and include data from the most recent clinical trials of therapies for this complex condition.

Short-term results of intravitreal dexamethasone implant (OZURDEX(®)) in treatment of recalcitrant diabetic macular edema: A case series

Context:

Dexamethasone Posterior-Segment Drug Delivery System is a novel, biodegradable, sustained-release drug delivery system (OZURDEX^®) for treatment of macular edema following retinal vein occlusion and posterior uveitis. However, its potential role in management of diabetic macular edema has not been reported yet.

Aim:

The aim was to evaluate the safety and efficacy of (OZURDEX^®) in patients with recalcitrant diabetic macular edema (DME).

Setting and Design:

A retrospective, interventional case series from a tertiary eye care center in India is presented. Inclusion criteria comprised patients presenting with recalcitrant DME, 3 or more months after one or more treatments of macular laser photocoagulation and/or intravitreal anti-vascular endothelial growth factor (VEGF) injections. Exclusion criteria included history of corticosteroid-responsive intraocular pressure (IOP) rise, cataract extraction, or other intraocular surgery within 3 months. The main outcome measure was visual acuity at 1 and 4 months after OZURDEX^® injection. Secondary outcome measures included change in central macular thickness on Optical coherence tomography (OCT) and changes in IOP following intravitreal OZURDEX^® implant. Of 18 eyes (17 patients) with recalcitrant diabetic macular edema that underwent OZURDEX^® implant, three eyes (two patients) had follow-up of more than 3 months post-injection.

Results:

Mean age of patients was 56 years. Mean duration of diabetes mellitus was 16.6 years. Systemic control of DM was good as assessed by FBS/PPBS and HbA1c. The pre-operative mean central macular thickness was 744.3 μm and improved to 144 and 570 μm at months 1 and 4, respectively. Preoperative mean BCVA was 0.6 logMAR units and improved to 0.3 and 0.46 logMAR units at month 1 and 4, respectively. The mean follow-up was 4.3 months (range 4-5 months).

Conclusion:

OZURDEX^® appears efficacious in management of recalcitrant diabetic macular edema. The results of the ongoing POSURDEX^® study will elaborate these effects better.

Diabetic macular edema: current and emerging therapies

Diabetic macular edema is a leading cause of vision impairment among people within the working- age population. This review discusses the pathogenesis of diabetic macular edema and the treatment options currently available for the treatment of diabetic macular edema, including for focal/grid photocoagulation, intravitreal corticosteroids and intravitreal anti-vascular endothelial growth factor agents. The biologic rationale for novel therapeutic agents, many of which are currently being evaluated in clinical trials, also is reviewed.

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.

Diabetic macular edema: new trends in management

The treatment of diabetic macular edema may be evolving from a laser ablative approach into a pharmacotherapeutic approach. The exponential growth that has occurred over the past decade in the retinal pharmacotherapy field has led to the development of several pharmacotherapies for retinal vascular diseases such as diabetic macular edema. Many of these agents, in the form of intravitreal injections or sustained delivery devices, have already undergone clinical trial testing for safety and efficacy and many others are currently being similarly evaluated. Some of these agents have proven to be more efficacious than traditional laser therapy, and it is possible that traditional laser therapy for diabetic macular edema may be abandoned altogether in the near future, especially with the introduction of the micropulse laser. However, more research and experience is still needed in order to determine the best treatment agent or combination of therapeutic modalities, as well as the best treatment regimen for a given patient. In this article, we briefly review the major new developments in the field of diabetic macular edema treatment. In addition, we touch on some of the promising forthcoming therapies.

Acute effect of pure oxygen breathing on diabetic macular edema

Purpose. A small-scale pilot study of the pathophysiology of diabetic macular edema (DME) was made by assessing concomitant changes in macular volume (MV), mean arterial blood pressure (MABP), intraocular pressure (IOP), retinal artery diameter (RAD), and retinal vein diameter (RVD) in response to 120 minutes of pure oxygen breathing.
Methods. Eleven eyes of 11 patients with DME were examined at baseline and while breathing pure oxygen for 120 minutes followed by 120 minutes of breathing atmospheric air. Macular volume was determined by optical coherence tomography, retinal trunk vessel diameters by fundus photography, intraocular pressure by pulse-air tonometry, and arterial blood pressure by sphygmomanometry.
Results. After initiation of pure oxygen breathing, reductions of 2.6% in RAD (p=0.04) and 11.5% reduction in RVD (p<0.001) were observed while MABP increased by 5.2 mmHg. After resumption of atmospheric air breathing, RAD and RVD rapidly returned to baseline values whereas MABP remained 2.3 mmHg higher than baseline (p=0.04). Macular volume was found to be reduced by 1.2% compared to baseline (p=0.04) at 120 minutes after cessation of pure oxygen breathing and resumption of atmospheric air breathing. 
Conclusion. These results indicate that the vasomotor response of the retinal arteries alone cannot explain the delayed reduction in macular volume after short course of pure oxygen breathing.

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.

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.

Two-wavelength fundus autofluorescence and macular pigment optical density imaging in diabetic macular oedema

PURPOSE

To evaluate the application of 488 and 514 nm fundus autofluorescence (FAF) and macular pigment optical density (MPOD) imaging in diabetic macular oedema (DMO) and to demonstrate the typical imaging features.

PATIENTS AND METHODS

A hundred and twenty-five eyes of 71 consecutive patients with diabetic retinopathy who underwent examination at a specialist university clinic employing a modified Heidelberg Retina Angiograph, using two different light sources of 488 and 514 nm wavelength, were retrospectively reviewed. MPOD images were calculated using modified Heidelberg Eye Explorer software. All images were evaluated by two independent masked graders. Features from FAF and MPOD images were correlated with optical coherence tomography (OCT) imaging findings and inter-grader variability, sensitivity and specificity were calculated using OCT as reference.

RESULTS

Sixty-seven eyes had DMO on OCT. The inter-grader variability was 0.84 for 488 nm FAF, 0.63 for 514 nm FAF and 0.79 for MPOD imaging. Sensitivity and specificity for detection of DMO were 80.6 and 89.7% for 488 nm FAF; 55.2 and 94.8% for 514 nm FAF; and 80.6 and 91.4% for MPOD imaging. In 488 nm FAF and MPOD imaging, DMO was better visualised in comparison with 514 nm FAF imaging, P<0.01. MPOD revealed displacement of macular pigment by intraretinal cysts.

CONCLUSION

MPOD imaging, and particularly its combination with 488 nm and 514 nm FAF, provides a valuable addition to OCT in the evaluation of DMO and is clinically useful in rapid en-face assessment of the central macula.

Management of retinal vascular diseases: a patient-centric approach

Retinal vascular diseases are a leading cause of blindness in the Western world. Advancement in the clinical management of these diseases has been fast-paced, with new treatments becoming available as well as license extensions of existing treatments. Vascular endothelial growth factor (VEGF) has been implicated in certain retinal vascular diseases, including wet age-related macular degeneration (AMD), diabetic macular oedema (DMO), and retinal vein occlusion (RVO). Treatment of wet AMD and visual impairment due to either DMO or macular oedema secondary to RVO with an anti-VEGF on an as needed basis, rather than a fixed schedule, allows an individualised treatment approach; providing treatment when patients are most likely to benefit from it, while minimising the number of unnecessary intravitreal injections. Thus, an individualised treatment regimen reduces the chances of over-treatment and under-treatment, optimising both the risk/benefit profile of the treatment and the efficient use of NHS resource. Streamlining of treatment for patients with wet AMD and visual impairment due to either DMO or macular oedema secondary to RVO, by using one treatment with similar posology across all three diseases, may help to minimise burden of clinic capacity and complexity and hence optimise patient outcomes. Informed treatment decisions and efficient clinic throughput are important for optimal patient outcomes in the fast-changing field of retinal vascular diseases.

Association of outer retinal layer morphology with visual acuity in patients with retinal vein occlusion: SCORE Study Report 13

PURPOSE

To assess associations between visual acuity (VA) and the status of the photoreceptor inner segment-outer segment (IS-OS) junction in a subset of patients in the Standard Care vs COrticosteroid for REtinal Vein Occlusion (SCORE) Study.

METHODOLOGY

High-resolution time domain optical coherence tomography (OCT) scans of study eyes from a single site participating in the SCORE Study were evaluated. Integrity of the IS-OS junction in the central subfield was evaluated using a three-step scale: absent, abnormal or normal. Associations of the IS-OS status with ETDRS VA letter score and center point thickness (CPT) were investigated.

RESULTS

Baseline OCTs of 42 eyes were evaluated. The IS-OS junction was absent in 30 (71%) and abnormal in 12 (29%). At month 12, the IS-OS junction was absent in 18 (43%), abnormal in 12 (28%), and normal in 12 (28%) eyes. At baseline, IS-OS status was significantly associated with CPT, but not with VA. At month 12, IS-OS status was significantly associated with CPT and VA, that is, absent or abnormal IS-OS was associated with increased CPT and worse VA. Change in IS-OS status was not associated with change in CPT (P=0.8). Worsening of IS-OS status was associated with loss of VA and improvement in IS-OS status to normal was associated with gain in VA (P=0.03).

CONCLUSION

In this data set with long-term follow-up of OCTs as part of the SCORE Study, there is a correlation between change in IS-OS status and VA. This supports further evaluation of outer retinal morphology in larger data sets.

New approaches for the treatment of diabetic macular oedema: recommendations by an expert panel

The current standard therapy for patients with diabetic macular oedema (DME)--focal/grid laser photocoagulation--usually does not improve impaired vision, and many patients lose vision despite laser therapy. Recent approval of ranibizumab by the European Medicines Agency to treat visual impairment due to DME fulfils the previously unmet medical need for a treatment that can improve visual acuity (VA) in these patients. We reviewed 1- and 2-year clinical trial findings for ranibizumab used as treatment for DME to formulate evidence-based treatment recommendations in the context of this new therapy. DME with or without visual impairment should be considered for treatment when it fulfils the Early Treatment Diabetic Retinopathy Study (ETDRS) criteria for clinically significant oedema. For DME with centre involvement and associated vision loss due to DME, monthly ranibizumab monotherapy with treatment interruption and re-initiation based on VA stability is recommended. Laser therapy based on ETDRS guidelines is recommended for other forms of clinically significant DME without centre involvement or when no vision loss has occurred, despite centre involvement. Because these recommendations are based on randomised controlled trials of 1-2 years duration, guidance may need updating as long-term ranibizumab data become available and as additional therapeutic agents are assessed in clinical trials.

Optical coherence tomography in the diagnosis and management of diabetic macular edema: time-domain versus spectral-domain

Optical coherence tomography (OCT) is an important imaging modality in the setting of diabetic macular edema (DME). Its use allows more precise evaluation of retinal pathology in DME, including retinal thickness and edema, vitreomacular interface abnormalities, subretinal fluid, and foveal microstructural changes. Additional advantages include its ability to quantitatively monitor response to treatment of DME by laser, intravitreal pharmacotherapies, and vitreoretinal surgery. OCT measurements are now used in all major clinical studies of DME treatment as critical endpoints. This article presents a review of both time-domain and spectral-domain OCT in the diagnosis and management of DME. The authors discuss the various parameters evaluated by the OCT systems and provide an evidence-based evaluation of their accuracy, significance, reliability, and limitations. As the capability of OCT continues to advance, it appears that its use will play an increasingly important role in the understanding, evaluation, and treatment of DME.

Clinical development of new treatments for diabetic macular oedema

The benchmark treatment for diabetic macular oedema, the major cause of visual impairment in patients with diabetes mellitus, has traditionally been laser photocoagulation; however, as laser treatment does not always improve vision or even prevent further loss in many cases, several new pharmacotherapies that are injected into the vitreous for diabetic macular oedema have been successfully trialled over the past decade. Others are currently being evaluated. The two major classes of these drugs are steroids and vascular endothelial growth factor antagonists. In this article we briefly review the major clinical studies recently conducted in this field.

Combination therapy for diabetic macular edema

Diabetic macular edema is a main reason for visual loss in diabetic patients. Until recent years, macular laser photocoagulation was the only available therapy. The awareness that inflammation is an important factor in the pathogenetic process of DME gave reason for intravitreal treatment with corticosteroids. The introduction of anti-VEGF drugs brought a revolutionary change in the treatment of DME. This paper will review the important clinical trials with an emphasis on combination therapies.

Emerging pharmacotherapies for diabetic macular edema

Diabetic macular edema (DME) remains an important cause of visual loss in patients with diabetes mellitus. Although photocoagulation and intensive control of systemic metabolic factors have been reported to achieve improved outcomes in large randomized clinical trials (RCTs), some patients with DME continue to lose vision despite treatment. Pharmacotherapies for DME include locally and systemically administered agents. We review several agents that have been studied for the treatment of DME.

Intravitreal diclofenac versus intravitreal triamcinolone acetonide in the treatment of diabetic macular edema

PURPOSE

To compare the efficacy and safety of intravitreal diclofenac versus intravitreal triamcinolone acetonide in the treatment of diabetic macular edema.

METHODS

Thirty-two eyes with diffuse diabetic macular edema were randomly allocated to intravitreal injection of 4 mg/0.1 mL of triamcinolone (Group 1: N = 16) or 500 μg/0.1 mL of diclofenac (Group 2: N = 16). Preoperative and postoperative visual acuity, intraocular pressure, and central macular thickness were recorded and compared between the 2 groups up to 12 weeks.

RESULTS

Both groups showed statistically significant reduction in central macular thickness (triamcinolone: P = 0.02 and diclofenac: P = 0.01), without statistically significant difference between the 2 groups. Visual improvement was significant only in triamcinolone group (P = 0.05). However, the 2 groups showed no statistically significant difference in mean visual acuity or mean line improvement. Transient elevation of intraocular pressure occurred in 12.5% of the triamcinolone group. Diclofenac group showed statistically significant reduced intraocular pressure (P = 0.02).

CONCLUSION

Intravitreal diclofenac is effective in the treatment of diffuse diabetic macular edema up to 12 weeks. Intravitreal triamcinolone and diclofenac appear to have comparable therapeutic effects on retinal thickness. The degree of visual improvement is higher with triamcinolone.

Ranibizumab for diabetic macular edema: results from 2 phase III randomized trials: RISE and RIDE

PURPOSE

To evaluate the efficacy and safety of intravitreal ranibizumab in diabetic macular edema (DME) patients.

DESIGN

Two parallel, methodologically identical, phase III, multicenter, double-masked, sham injection-controlled, randomized studies.

PARTICIPANTS

Adults with vision loss from DME (best-corrected visual acuity [BCVA], 20/40-20/320 Snellen equivalent) and central subfield thickness ≥275 μm on time-domain optical coherence tomography (OCT).

INTERVENTION

Monthly intravitreal ranibizumab (0.5 or 0.3 mg) or sham injections. Macular laser was available per-protocol-specified criteria.

MAIN OUTCOME MEASURES

Proportion of patients gaining ≥15 letters in BCVA from baseline at 24 months.

RESULTS

In RISE (NCT00473330), 377 patients were randomized (127 to sham, 125 to 0.3 mg, 125 to 0.5 mg). At 24 months, 18.1% of sham patients gained ≥15 letters versus 44.8% of 0.3-mg (P<0.0001; difference vs sham adjusted for randomization stratification factors, 24.3%; 95% confidence interval [CI], 13.8-34.8) and 39.2% of 0.5-mg ranibizumab patients (P<0.001; adjusted difference, 20.9%; 95% CI, 10.7-31.1). In RIDE (NCT00473382), 382 patients were randomized (130 to sham, 125 to 0.3 mg, 127 to 0.5 mg). Significantly more ranibizumab-treated patients gained ≥15 letters: 12.3% of sham patients versus 33.6% of 0.3-mg patients (P<0.0001; adjusted difference, 20.8%; 95% CI, 11.4-30.2) and 45.7% of 0.5-mg ranibizumab patients (P<0.0001; adjusted difference, 33.3%; 95% CI, 23.8-42.8). Significant improvements in macular edema were noted on OCT, and retinopathy was less likely to worsen and more likely to improve in ranibizumab-treated patients. Ranibizumab-treated patients underwent significantly fewer macular laser procedures (mean of 1.8 and 1.6 laser procedures over 24 months in the sham groups vs 0.3-0.8 in ranibizumab groups). Ocular safety was consistent with prior ranibizumab studies; endophthalmitis occurred in 4 ranibizumab patients. The total incidence of deaths from vascular or unknown causes, nonfatal myocardial infarctions, and nonfatal cerebrovascular accidents, which are possible effects from systemic vascular endothelial growth factor inhibition, was 4.9% to 5.5% of sham patients and 2.4% to 8.8% of ranibizumab patients.

CONCLUSIONS

Ranibizumab rapidly and sustainably improved vision, reduced the risk of further vision loss, and improved macular edema in patients with DME, with low rates of ocular and nonocular harm.