Diabetic macular edema: pathogenesis and treatment

The REVEAL Study: Ranibizumab Monotherapy or Combined with Laser versus Laser Monotherapy in Asian Patients with Diabetic Macular Edema

OBJECTIVE

The primary study hypothesis was that ranibizumab 0.5 mg monotherapy or combined with laser is superior to laser monotherapy based on mean average change in best-corrected visual acuity (BCVA) over 12 months in Asian patients with visual impairment resulting from diabetic macular edema (DME).

DESIGN

A 12-month, randomized, double-masked, multicenter, laser-controlled, phase III study.

PARTICIPANTS

Three hundred ninety-six patients aged ≥18 years, with type 1 or 2 diabetes mellitus, BCVA of 78-39 Early Treatment Diabetic Retinopathy Study (ETDRS) letters, and visual impairment resulting from DME.

METHODS

Patients were randomized to ranibizumab + sham laser (n = 133), ranibizumab + active laser (n = 132), or sham injection + active laser (n = 131). Ranibizumab/sham injections were administered on day 1 and continued monthly. As of month 3, monthly injections were continued if stable vision was not reached. Treatment was reinitiated if BCVA decreased because of DME progression. Active/sham laser was administered on day 1 and thereafter according to ETDRS guidelines.

MAIN OUTCOME MEASURES

Average change in BCVA from baseline to months 1 through 12, central retinal subfield thickness (CRST), and safety over 12 months.

RESULTS

Ranibizumab monotherapy or combined with laser was superior to laser in improving mean average change in BCVA from baseline to months 1 through 12 (+5.9 and +5.7 vs +1.4 letters). At month 12, greater proportion of patients gained ≥15 letters with ranibizumab and ranibizumab + laser compared with laser (18.8% and 17.8% vs 7.8%). Mean CRST reduced significantly from baseline to month 12 with ranibizumab (-134.6 μm) and ranibizumab + laser (-171.8 μm) versus laser (-57.2 μm). Patients received a mean of 7.8 and 7.0 ranibizumab injections in the ranibizumab and ranibizumab + laser arms, respectively, and 1.5-1.9 active laser across treatment arms over 12 months. Conjunctival hemorrhage was the most common ocular, whereas nasopharyngitis and hypertension were the most common nonocular adverse events. Ranibizumab was not associated with any cases of cerebrovascular hemorrhage and cerebrovascular ischemia. No death related to study treatment was reported.

CONCLUSIONS

Ranibizumab monotherapy or combined with laser showed superior BCVA improvements over laser treatment alone in Asian patients with visual impairment resulting from DME. No new ocular or nonocular safety findings were observed and treatment was well tolerated over 12 months.

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.

A novel intravitreal fluocinolone acetonide implant (Iluvien(®)) in the treatment of patients with chronic diabetic macular edema that is insufficiently responsive to other medical treatment options: a case series

Background

Iluvien^® is a novel, nonbiodegradable, sustained-release drug delivery system (0.2 μg/d fluocinolone acetonide [FAc]) indicated in Europe for the treatment of vision impairment associated with chronic diabetic macular edema (DME), considered insufficiently responsive to available therapies.

Objective

To evaluate the safety and efficacy of 190-μg FAc implant in patients with chronic DME refractory to other medical treatment options in a clinical setting.

Methods

Retrospective registry data were collected by using standard case report forms (CRFs). Prior to intravitreal injection of the FAc implant, all patients were treated either with a vascular endothelial growth factor (VEGF) antagonist and/or a steroid (triamcinolone, dexamethasone implant). Patients were excluded from receiving FAc if they had a known history of elevated intraocular pressure (IOP) following corticosteroid therapy, glaucoma, ocular hypertension, or any contraindications cited in the summary of product characteristics. Best-corrected visual acuity (BCVA) was the main study parameter. Central fovea thickness (CFT) and IOP were measured concurrently. These parameters were recorded prior to and after the injection of the 190-μg FAc implant (between 1 week and 9 months). Injections were performed between May 2013 and March 2014.

Results

Fifteen eyes from ten patients were treated. Thirteen eyes (nine patients) were pseudophakic, and seven eyes (five patients) were vitrectomized prior to receiving therapy. BCVA improved in eleven eyes (73.3%), remained unchanged in two eyes (13.3%), and decreased slightly in two eyes (13.3%) at the last follow-up visit versus baseline levels. IOP increased in two patients and was controlled using fixed-combination of IOP-lowering eyedrops or sectorial cyclocryotherapy (n=1).

Conclusion

The 190-μg FAc implant was efficacious and showed a favorable benefit-to-risk profile in the patient population with chronic DME of this case series that were refractory to other therapies. The longer-term efficacy and safety in a real-life setting is still being assessed in this center. FAc may offer an important treatment option for patients with chronic DME refractory to other treatment options.

Topical nepafenec in eyes with noncentral diabetic macular edema

PURPOSE

To evaluate the effect of a topical, nonsteroidal antiinflammatory drug, nepafenac 0.1%, in eyes with noncentral diabetic macular edema.

METHODS

Multicenter, double-masked randomized trial. Individuals with good visual acuity and noncentral-involved diabetic macular edema were randomly assigned to nepafenac 0.1% (N = 61) or placebo (nepafenac vehicle, N = 64) 3 times a day for 12 months. The primary outcome was mean change in optical coherence tomography retinal volume at 12 months.

RESULTS

Mean baseline retinal volume was 7.8 mm. At 12 months, in the nepafenac and placebo groups respectively, mean change in retinal volume was -0.03 mm and -0.02 mm (treatment group difference: -0.02, 95% confidence interval: -0.27 to 0.23, P = 0.89). Central-involved diabetic macular edema was present in 7 eyes (11%) and 9 eyes (14%) at the 12-month visit (P = 0.79), respectively. No differences in visual acuity outcomes were identified. One study participant developed a corneal melt after using nepafenac in the nonstudy eye, which had a history of severe dry eye. No additional safety concerns were evident.

CONCLUSION

In eyes with noncentral diabetic macular edema and good visual acuity, topical nepafenac 0.1% 3 times daily for 1 year likely does not have a meaningful effect on optical coherence tomography-measured retinal thickness.

Distribution of intraretinal exudates in diabetic macular edema during anti-vascular endothelial growth factor therapy observed by spectral domain optical coherence tomography and fundus photography

PURPOSE

To evaluate changes in the distribution and morphology of intraretinal microexudates and hard exudates (HEs) during intravitreal anti-vascular endothelial growth factor therapy in patients with persistent diabetic macular edema.

METHODS

Twenty-four patients with persistent diabetic macular edema after photocoagulation were investigated in this prospective cohort study. Each eye was assigned to a loading dose of three anti-vascular endothelial growth factor treatments at monthly intervals. Additional single treatments were performed if diabetic macular edema persisted or recurred. Intraretinal exudates were analyzed over 6 months using spectral domain optical coherence tomography (SD-OCT) and fundus photography.

RESULTS

Before treatment, microexudates were detected by SD-OCT as hyperreflective foci in 24 eyes, whereas HEs were seen in 22 eyes. During therapy, HE increased significantly in number and size. This was accompanied by accumulation of microexudates in the outer retina. Enlargement of hyperreflective structures in SD-OCT was accompanied by enlargement of HE at corresponding fundus locations. A rapid reduction in diabetic macular edema was seen in all patients, but to varying degrees. Patients with hemoglobin A1c levels <7% and serum cholesterol <200 mg/dL formed fewer HEs and featured more edema reduction and visual acuity gain.

CONCLUSION

Diabetic macular edema reduction during intravitreal anti-vascular endothelial growth factor therapy was accompanied by dynamic rearrangement of intraretinal exudates at corresponding locations in fundus photography and SD-OCT. Intraretinal aggregates of microexudates detectable as hyperreflective foci by SD-OCT may compose and precede HE before they become clinically visible.

Diabetic retinopathy - ocular complications of diabetes mellitus

In industrialized nations diabetic retinopathy is the most frequent microvascular complication of diabetes mellitus and the most common cause of blindness in the working-age population. In the next 15 years, the number of patients suffering from diabetes mellitus is expected to increase significantly. By the year 2030, about 440 million people in the age-group 20-79 years are estimated to be suffering from diabetes mellitus worldwide (prevalence 7.7%), while in 2010 there were 285 million people with diabetes mellitus (prevalence 6.4%). This accounts for an increase in patients with diabetes in industrialized nations by 20% and in developing countries by 69% until the year 2030. Due to the expected rise in diabetic patients, the need for ophthalmic care of patients (i.e., exams and treatments) will also increase and represents a challenge for eye-care providers. Development of optimized screening programs, which respect available resources of the ophthalmic infrastructure, will become even more important. Main reasons for loss of vision in patients with diabetes mellitus are diabetic macular edema and proliferative diabetic retinopathy. Incidence or progression of these potentially blinding complications can be greatly reduced by adequate control of blood glucose and blood pressure levels. Additionally, regular ophthalmic exams are mandatory for detecting ocular complications and initiating treatments such as laser photocoagulation in case of clinical significant diabetic macular edema or early proliferative diabetic retinopathy. In this way, the risk of blindness can considerably be reduced. In advanced stages of diabetic retinopathy, pars-plana vitrectomy is performed to treat vitreous hemorrhage and tractional retinal detachment. In recent years, the advent of intravitreal medication has improved therapeutic options for patients with advanced diabetic macular edema.

Diabetes and retinal vascular dysfunction

Diabetes predominantly affects the microvascular circulation of the retina resulting in a range of structural changes unique to this tissue. These changes ultimately lead to altered permeability, hyperproliferation of endothelial cells and edema, and abnormal vascularization of the retina with resulting loss of vision. Enhanced production of inflammatory mediators and oxidative stress are primary insults with significant contribution to the pathogenesis of diabetic retinopathy (DR). We have determined the identity of the retinal vascular cells affected by hyperglycemia, and have delineated the cell autonomous impact of high glucose on function of these cells. We discuss some of the high glucose specific changes in retinal vascular cells and their contribution to retinal vascular dysfunction. This knowledge provides novel insight into the molecular and cellular defects contributing to the development and progression of diabetic retinopathy, and will aid in the development of innovative, as well as target specific therapeutic approaches for prevention and treatment of DR.

Diabetic macular oedema quantified with spectral-domain optical coherence tomography--evaluation of boundary line artefacts and the effect on retinal thickness

PURPOSE

To characterize frequency, morphological cause and time-dependent change of boundary line artefacts in optical coherence tomography (OCT) examinations of centre-involved diabetic macular oedema (ciDME) patients who underwent ranibizumab treatment with 1-year follow-up and to evaluate the impact of artefacts on retinal thickness.

METHODS

One hundred and fourteen patients were examined with radial scan protocol by Topcon 3D OCT at baseline, 3 and 12 months. All B scans from all visits were examined for boundary line artefacts (artefacts) and were stratified by morphological element causing artefacts including hard exudates (HE), epiretinal membranes (ERM), optical opacities and serous detachments. Boundary line artefacts were manually corrected and the corrected central subfield thickness (CST) and macular volume were compared with automated values. Data were compared with a repeatability coefficient of 25 μm.

RESULTS

Boundary line artefacts were found in 51.8% of the total 342 OCT examinations and in 25.5% of the total 2052 B scans. Morphological elements that caused artefacts in the total 2052 B scans were HE (10.6%), ERM (10.3%), optical opacities (4.4%), serous detachments (1.7%) and others (1.2%). The number of artefacts due to HE decreased significantly (p = 0.0005), and the number of artefacts due to ERM were unchanged (p = 0.087) during 12 months. In OCT examinations with artefacts caused by HE, manually corrected CST was statistically significant higher than automated value at baseline and 3 months. For ERM, manually corrected CST was statistically significant lower than automated value at baseline and 12 months.

CONCLUSION

Boundary line artefacts in OCT examinations of ciDME patients using Topcon 3D OCT occur in 51.8%. In situation of boundary line artefacts in centre 1-mm area every fourth OCT examination has a change in CST beyond 25 μm.

Fully automatic segmentation of fluorescein leakage in subjects with diabetic macular edema

PURPOSE

To create and validate software to automatically segment leakage area in real-world clinical fluorescein angiography (FA) images of subjects with diabetic macular edema (DME).

METHODS

Fluorescein angiography images obtained from 24 eyes of 24 subjects with DME were retrospectively analyzed. Both video and still-frame images were obtained using a Heidelberg Spectralis 6-mode HRA/OCT unit. We aligned early and late FA frames in the video by a two-step nonrigid registration method. To remove background artifacts, we subtracted early and late FA frames. Finally, after postprocessing steps, including detection and inpainting of the vessels, a robust active contour method was utilized to obtain leakage area in a 1500-μm-radius circular region centered at the fovea. Images were captured at different fields of view (FOVs) and were often contaminated with outliers, as is the case in real-world clinical imaging. Our algorithm was applied to these images with no manual input. Separately, all images were manually segmented by two retina specialists. The sensitivity, specificity, and accuracy of manual interobserver, manual intraobserver, and automatic methods were calculated.

RESULTS

The mean accuracy was 0.86 ± 0.08 for automatic versus manual, 0.83 ± 0.16 for manual interobserver, and 0.90 ± 0.08 for manual intraobserver segmentation methods.

CONCLUSIONS

Our fully automated algorithm can reproducibly and accurately quantify the area of leakage of clinical-grade FA video and is congruent with expert manual segmentation. The performance was reliable for different DME subtypes. This approach has the potential to reduce time and labor costs and may yield objective and reproducible quantitative measurements of DME imaging biomarkers.

Dexamethasone Intravitreal Implant for Diabetic Macular Edema: Indications for a PRN Regimen of Treatment

Purpose

To define the mean time of first recurrence of diabetic macular edema (DME) after a single injection of dexamethasone intravitreal implant (DEX-I), reducing the burden of monthly visits during a PRN regimen of treatment.

Methods

Twenty phakic eyes with DME (12 eyes naïve and 8 eyes with edema persistent after previous treatments) were followed monthly after DEX-I injection until evidence of first recurrence of edema, defined as a change in visual acuity (VA) ≥5 letters and/or in foveal thickness (FT) ≥50 µm. Reaching this point, the eyes were re-treated. Monitored parameters were changes in VA, FT, intraocular pressure (IOP), and lens opacity.

Results

Maximal efficacy was registered at month 1, when mean VA improved by 14 letters (19%), FT decreased by 325 µm (43.7%), and in 15 eyes (75%) edema was completely reabsorbed. The mean time of first recurrence was 5.1 months. No statistical difference was found between eyes with naïve or persistent DME. Five eyes needed topical medication for modest temporary IOP increase (21-24 mm Hg) between months 2 and 4. No increase in lens opacities was registered during follow-up.

Conclusions

According to the results of this study, the first signs of DME recurrence after DEX-I injection appear at a mean time of 5 months, suggesting that an appropriate and prudent time schedule for a PRN regimen could be limited to monthly tonometry and a first complete examination not before 4 months.

Macular hypotrophy after internal limiting membrane removal for diabetic macular edema

PURPOSE

To compare the anatomic and functional effects of three different approaches to nontractional diabetic macular edema.

METHODS

Retrospective comparative study. Sixty eyes of 60 patients diagnosed with cystoid diabetic macular edema and treated with 1.25 mg/mL intravitreal bevacizumab (Group A), laser photocoagulation (Group B), or vitrectomy with inner limiting membrane peeling (Group C) were included in the study. Changes in number of Early Treatment Diabetic Retinopathy Study letters, central macular thickness, largest diameter of the intraretinal cysts (IC), and choroidal thickness were investigated. Analyses were performed during follow-up visits at Months 1, 3, 6, 9, and 12.

RESULTS

Visual acuity only significantly improved in Group A at the last follow-up (P = 0.004). Central macular thickness significantly decreased in every group throughout the follow-up period. Differences in central macular thickness between Groups A and B (P < 0.01), A and C (P < 0.01), and B and C (P < 0.01) were significant. Intraretinal cysts also significantly decreased in each group throughout the follow-up period. Differences in IC size between Groups A and B (P = 0.8), A and C (P = 0.1), and B and C (P = 0.1) were not significant. Choroidal thickness did not undergo any significant change in any group throughout the follow-up period. A significant correlation was also found in Group A between best-corrected visual acuity at month 12 and baseline central macular thickness (R = 0.3; P = 0.006), and in Group B between postoperative best-corrected visual acuity at month 12 and baseline IC size (R = 0.8; P < 0.01, negatively correlated at 92.4%).

CONCLUSION

According to our retrospective data, diabetic macular edema with intraretinal cysts larger than 390 μm should not be treated with vitrectomy with ILM peeling, because this may induce subfoveal atrophy, defined as the "Floor Effect," and subsequent visual deterioration.

Optical coherence tomography confirmed resolution of macular edema in a diabetic patient after hemodialysis

PURPOSE

The authors report the first case, to their knowledge, of resolution of diffuse macular edema after hemodialysis, which has been confirmed by optical coherence tomography.

METHODS

A 53-year-old white woman with type 2 diabetes developed worsening macular edema and was examined in the ophthalmology clinic and scheduled for macular grid laser photocoagulation. The laser, however, was deferred for 4 weeks because she had also developed end-stage renal failure and required hemodialysis.

RESULTS

When she was reviewed in the ophthalmology clinic 4 weeks later for laser therapy, it was found that her macular edema had resolved, vision had improved, and laser was unnecessary. Review at 6 months showed that the macular edema remains resolved.

CONCLUSION

Ophthalmologists should be aware that hemodialysis may reduce macular edema in such patients.

Cost-effectiveness of ranibizumab versus aflibercept in the treatment of visual impairment due to diabetic macular edema: a UK healthcare perspective

BACKGROUND

Ranibizumab and aflibercept are alternative anti-vascular endothelial growth factor agents approved for the treatment of visual impairment (VI) due to diabetic macular edema (DME).

OBJECTIVE

To estimate, from a UK healthcare perspective, the cost-effectiveness of ranibizumab 0.5 mg pro re nata (PRN) and ranibizumab 0.5 mg treat and extend (T&E) compared with aflibercept 2 mg every 8 weeks after five initial monthly doses (2q8) in the treatment of VI due to DME.

METHODS

A Markov model previously reviewed by the National Institute for Health and Care Excellence was used to simulate the long-term outcomes and costs of treating DME. Health states were defined by increments of ten letters in best-corrected visual acuity (BCVA), with a 3-month cycle length. Patients could gain (or lose) a maximum of two health states between cycles. A 3-year treatment time frame and a lifetime horizon were used. Future costs and health outcomes were discounted at 3.5% per annum. Patient baseline characteristics and the efficacy of ranibizumab PRN were derived using data from the RESTORE study. The relative efficacies of ranibizumab PRN, ranibizumab T&E, and aflibercept were assessed with a network meta-analysis. Different utilities were assigned based on BCVA and whether the treated eye was the better- or the worse-seeing eye. Sensitivity analyses tested the robustness of the model.

RESULTS

Lifetime costs per patient of treating DME were £20,019 for ranibizumab PRN, £22,930 for ranibizumab T&E, and £25,859 for aflibercept 2q8. Ranibizumab was dominant over aflibercept, with an incremental gain of 0.05 quality-adjusted life-years (QALYs) and cost savings of £5,841 (PRN) and £2,930 (T&E) compared with aflibercept. Ranibizumab PRN and ranibizumab T&E had 79% and 67% probability, respectively, of being cost-effective relative to aflibercept at a willingness-to-pay threshold of £20,000/QALY. When assuming the higher end of PRN injection frequency (15.9 over 3 years), the cost savings associated with ranibizumab were £3,969.

CONCLUSION

From a UK healthcare perspective, ranibizumab provides greater health gains with lower overall costs than aflibercept in patients with VI due to DME.

Role of implants in the treatment of diabetic macular edema: focus on the dexamethasone intravitreal implant

Diabetic macular edema (DME) is the leading cause of sight-threatening complication in diabetic patients, and several treatment modalities have been developed and evaluated to treat this pathology. Intravitreal agents, such as anti-vascular endothelial growth factors (anti-VEGF) or corticosteroids, have become more popular in recent years and are widely used for treating DME. Sustained release drugs appear to be mentioned more often nowadays for extending the period of intravitreal activity, and corticosteroids play a key role in inhibiting the inflammatory process in DME. A potent corticosteroid, dexamethasone (Ozurdex(®)), in the form of an intravitreal implant, has been approved for various ocular etiologies among which DME is also one. This review evaluates the role of implants in the treatment of DME, mainly focusing on the dexamethasone intravitreal implant.

Diabetic Retinopathy: Vascular and Inflammatory Disease

Diabetic retinopathy (DR) is the leading cause of visual impairment in the working-age population of the Western world. The pathogenesis of DR is complex and several vascular, inflammatory, and neuronal mechanisms are involved. Inflammation mediates structural and molecular alterations associated with DR. However, the molecular mechanisms underlying the inflammatory pathways associated with DR are not completely characterized. Previous studies indicate that tissue hypoxia and dysregulation of immune responses associated with diabetes mellitus can induce increased expression of numerous vitreous mediators responsible for DR development. Thus, analysis of vitreous humor obtained from diabetic patients has made it possible to identify some of the mediators (cytokines, chemokines, and other factors) responsible for DR pathogenesis. Further studies are needed to better understand the relationship between inflammation and DR. Herein the main vitreous-related factors triggering the occurrence of retinal complication in diabetes are highlighted.

Updates in the management of diabetic macular edema

Diabetes mellitus is a chronic disease which has multiple effects on different end-organs, including the retina. In this paper, we discuss updates on diabetic macular edema (DME) and the management options. The underlying pathology of DME is the leakage of exudates from retinal microaneurysms, which trigger subsequent inflammatory reactions. Both clinical and imaging techniques are useful in diagnosing, classifying, and gauging the severity of DME. We performed a comprehensive literature search using the keywords "diabetes," "macula edema," "epidemiology," "pathogenesis," "optical coherence tomography," "intravitreal injections," "systemic treatment," "hypertension," "hyperlipidemia," "anemia," and "renal disease" and collated a total of 47 relevant articles published in English language. The main modalities of treatment currently in use comprise laser photocoagulation, intravitreal pharmacological and selected systemic pharmacological options. In addition, we mention some novel therapies that show promise in treating DME. We also review systemic factors associated with exacerbation or improvement in DME.

Fluorescein angiography versus optical coherence tomography-guided planning for macular laser photocoagulation in diabetic macular edema

PURPOSE

To compare laser photocoagulation plans for diabetic macular edema (DME) using fluorescein angiography (FA) versus optical coherence tomography (OCT) thickness map superimposed on the retina.

METHODS

Fourteen eyes with DME undergoing navigated laser photocoagulation with navigated photocoagulator had FA taken using the same instrument. Optical coherence tomography central retinal thickness map was imported to the photocoagulator and with same magnification aligned onto the retina. Three retina specialists placed laser spot marks separately on FA and OCT image in a masked fashion. The spots placed by each physician were compared between FA and OCT and among physicians. The area of dye leakage on FA and increased central retinal thickness on OCT of the same eye were also compared.

RESULTS

The average number of spots using FA and OCT template was 36.64 and 40.61, respectively (P = 0.0201). The average area of dye leakage was 7.45 mm, whereas the average area of increased central retinal thickness on OCT of the same eye was 10.92 mm (P = 0.013).

CONCLUSION

There is variability in the treatment planning for macular photocoagulation with a tendency to place more spots when guided by OCT than by FA. Integration of OCT map aligned to the retina may have an impact on treatment plan once such information is available.

RaScaL: A Pilot Study to Assess the Efficacy, Durability, and Safety of a Single Intervention with Ranibizumab plus Peripheral Laser for Diabetic Macular Edema Associated with Peripheral Nonperfusion on Ultrawide-Field Fluorescein Angiography

Background and Objectives: To determine the efficacy, durability, and safety of a single treatment with intravitreal ranibizumab plus peripheral scatter laser (RaScaL) in patients with diabetic macular edema associated with peripheral retinal nonperfusion on ultrawide-field fluorescein angiography (UWFA). Study Design: A 6-month, randomized, controlled, prospective phase I/II study of 30 treatment-naïve eyes of 22 patients (8 bilateral patients) with visual impairment secondary to diabetic macular edema associated with peripheral nonperfusion on UWFA. Patients were randomized to receive ranibizumab plus UWFA-guided peripheral scatter laser (n = 15) or triamcinolone acetonide plus macular laser (n = 15). Results: At 6 months, the RaScaL group patients had fewer recurrences warranting retreatment (33% vs. 80%, p < 0.003). Mean change in final visual acuity and central foveal thickness were not statistically significant between groups. Conclusion: This pilot study suggests the efficacy, safety and durability of the RaScaL treatment regimen in patients with diabetic macular edema associated with peripheral nonperfusion on UWFA. © 2014 S. Karger AG, Basel.

Diabetic macular edema: changing treatment paradigms

PURPOSE OF REVIEW

To review the current management and recent changes in treatment paradigm for diabetic macular edema (DME).

RECENT FINDINGS

During the review period (1 year), several prospective studies analyzed the beneficial effect of anti-vascular endothelial growth factor agents in the management of DME. An exploratory analysis concluded that intravitreal ranibizumab appears to be associated with a reduced risk of diabetic retinopathy worsening. A randomized, controlled, multicenter, double-masked, parallel-group, 12-month trial to evaluate a dexamethasone intravitreal implant (DEX implant) combined with laser photocoagulation compared with laser alone for treatment of DME concluded that there was no significant between-group difference at month 12. A multicenter, prospective, observational study found that in eyes with diabetic retinopathy without concurrent central-involved DME, presence of noncentral-involved DME immediately prior to cataract surgery or history of DME treatment may increase the risk of developing central-involved macular edema after cataract extraction. Another randomized trial to evaluate whether intravitreal ranibizumab injection at cataract surgery prevents postoperative DME concluded that intravitreal ranibizumab injection at cataract surgery may prevent the postoperative worsening of macular edema.

SUMMARY

The results of clinical trials have shown the superiority of some of these anti-vascular endothelial growth factor agents to laser therapy. However, with the availability of several of these newer agents, it may be difficult to individualize treatment options, especially if DME patients respond differently to various therapies.

Cardiac and vascular effects of fingolimod: mechanistic basis and clinical implications

Fingolimod, a sphingosine-1-phosphate receptor (S1PR) modulator, was the first oral disease-modifying therapy approved for relapsing forms of multiple sclerosis; it reduces autoreactive lymphocytes' egress from lymphoid tissues by down-regulating S1PRs. Sphingosine-1-phosphate signaling is implicated in a range of physiologic functions, and S1PRs are expressed differentially in various tissues, including the cardiovascular system. Modulation of S1PRs on cardiac cells provides an explanation for the transient effects of fingolimod on heart rate and atrioventricular conduction at initiation of fingolimod therapy, and for the mild but more persistent effects on blood pressure observed in some patients on long-term treatment. This review describes the nontherapeutic actions of fingolimod in the context of sphingosine-1-phosphate signaling in the cardiovascular system, as well as providing a summary of the associated clinical implications useful to physicians considering initiation of fingolimod therapy in patients. A transient reduction in heart rate (mean decrease of 8 beats per minute) and, less commonly, a temporary delay in atrioventricular conduction observed in some patients when initiating fingolimod therapy are both due to activation of S1PR subtype 1 on cardiac myocytes. These effects are a reflection of fingolimod first acting as a full S1PR agonist and thereafter functioning as an S1PR antagonist after down-regulation of S1PR subtype 1 at the cell surface. For most individuals, first-dose effects of fingolimod are asymptomatic, but all patients need to be monitored for at least 6 hours after the first dose, in accordance with the label recommendations.

Novel Approaches for Retinal Drug and Gene Delivery

The ARVO 2014 minisymposium on "Novel Approaches for Retinal Drug and Gene Delivery" was held on May 6, 2014 in Orlando, FL. The main intent of the symposium was to review recent advances in retinal drug and gene delivery with specific emphasis on novel approaches that address current limitations and have the potential to translate into clinical practice. The symposium was sponsored by Translational Vision Science and Technology.

Dexamethasone intravitreal implant in vitrectomized versus nonvitrectomized eyes for treatment of patients with persistent diabetic macular edema

PURPOSE

To compare the 6-month anatomic and best-corrected visual acuity (BCVA) response after sustained-release dexamethasone (DEX) intravitreal implant between nonvitrectomized and vitrectomized eyes with persistent diabetic macular edema (DME).

METHODS

Retrospective, comparative, and consecutive review of the medical records of 58 patients with decreased visual acuity, due to refractory DME, who underwent a single injection of Ozurdex between November 2010 and January 2012, at the Instituto de Microcirurgia Ocular, Barcelona, Spain. Then, we divided patients into 2 groups: 24 eyes who had undergone standard pars plana vitrectomy (vitrectomized group), and 34 eyes that were not operated on (nonvitrectomized group). Outcomes measured were BCVA and foveal thickness (FT) at baseline and at months 1, 3, and 6.

RESULTS

Twenty-four of 58 eyes had prior vitrectomy (41%). Statistically significant improvement in BCVA also was seen at 1 month after treatment with a DEX implant and at each subsequent follow-up visit, in either groups (P<0.05). All of the FT reduction outcomes were statistically significant in both groups, with respect to baseline data (P<0.05). There were no statistically significant differences in BCVA and FT between nonvitrectomized and vitrectomized eyes at any time point (P<0.05).

CONCLUSION

In this study, the clinical findings were similar between nonvitrectomized and vitrectomized eyes. Intravitreal treatment with a DEX implant safely reduced DME and improved visual acuity in both groups. No statistically significant differences were found between the 2 groups regarding FT and BCVA.

Laser-based strategies to treat diabetic macular edema: history and new promising therapies

Diabetic macular edema (DME) is the main cause of visual impairment in diabetic patients. The management of DME is complex and often various treatment approaches are needed. At the present time, despite the enthusiasm for evaluating several new treatments for DME, including the intravitreal pharmacologic therapies (e.g., corticosteroids and anti-VEGF drugs), laser photocoagulation still remains the current standard in DME. The purpose of this review is to update our knowledge on laser photocoagulation for DME and describe the developments in laser systems. And we will also discuss the new laser techniques and review the latest results including benefits of combined therapy. In this paper, we briefly summarize the major laser therapeutics for the treatment of diabetic macular edema and allude to some future promising laser therapies.

Differential systemic gene expression profile in patients with diabetic macular edema: responders versus nonresponders to standard treatment

Introduction:

Diabetic macular edema (DME) is a vision-threatening complication of diabetic retinopathy. The current practice of management is a trial and error method of using intravitreal antivascular endothelial growth factor (VEGF)” or steroids to treat the patient and watch the response. However, if the patient's genetic profile helps us choose appropriate medicine, it would help customize treatment option for each patient. This forms the basis of our study.

Materials and Methods:

A case-control, prospective, observational series, where DME patients were treated with bevacizumab and subclassified as treatment naοve, treatment responders, and treatment nonresponders. Blood samples of 20 subjects were studied, with five patients in each of the groups (nondiabetic- group 1, treatment naοve- group 2, treatment responder- group 3, and treatment nonresponder-group 4). Whole blood RNA extraction followed by labeling, amplification and hybridization was done, and microarray data analyzed. Genes were classified based on functional category and pathways.

Results:

The total number of genes upregulated among all three experimental groups was 5, whereas 105 genes were downregulated. There were no common genes upregulated between the responders and nonresponders. There was only one gene upregulated between the diabetic and diabetic responders posttreatment. There were 19 genes upregulated and 8 genes downregulated in the inflammatory pathway in group 2 versus group 1. There were no downregulated genes detected in vascular angiogenesis and transcription group. There were identical numbers of genes up- and downregulated in the inflammatory pathway. Seventeen genes were upreguated and 11 genes downregulated in receptor activity, which remained the predominant group in the group classification.

Discussion:

In summary, this study would provide an insight into the probable signaling mechanisms for disease pathogenesis as well as progression. This type of study eventually would aid in developing or improvising existing treatment modules with a rational approach towards personalized medicine, in future addressing the differential responses to treatment.

Effect of intravitreal bevacizumab on diabetic macular edema with hard exudates

Background

We evaluated the efficacy of intravitreal bevacizumab on diabetic macular edema with subfoveal and perifoveal hard exudates.

Materials and methods

Eleven eyes (11 patients) exhibiting diabetic macular edema with subfoveal and perifoveal hard exudates were included in this prospective, nonrandomized interventional pilot study. All patients were treated with monthly scheduled intravitreal bevacizumab injections for 6 months. Changes in the Early Treatment Diabetic Retinopathy Study best corrected visual acuity, amount of hard exudates on fundus photography, and macular edema detected by central subfield thickness on spectral domain optical coherence tomography after six serial injections, were assessed. The amount of hard exudates at each visit was evaluated as pixels in fundus photography, using an Adobe Photoshop program.

Results

Ten of 11 patients completed follow-up. The mean Early Treatment Diabetic Retinopathy Study best corrected visual acuity was 59.9±5.7 letters (Snellen equivalent, 20/63) at baseline evaluation. The best corrected visual acuity exhibited no significant difference at month 6 compared with at baseline (57.9±6.0 letters or 20/70 at month 6; P=0.085). At month 6, mean central subfield thickness decreased from 370.4±56.5 to 334.6±65.0 μm (P=0.009). The mean amount of hard exudates increased from 4467.1±2736.1 to 6592.4±2498.3 pixels at month 6 (P=0.022). No serious adverse events occurred.

Conclusion

Continuous intravitreal bevacizumab was found to have no benefit in visual acuity and amount of hard exudates, despite the improvement of macular edema at 6 months.

Safety monitoring of ophthalmic biologics: a systematic review of pre- and postmarketing safety data

PURPOSE

The present study evaluates the safety of the biologics approved for the treatment of ocular diseases.

METHODS

The European medicines agency Website was searched to identify biologics with approved ophthalmologic therapeutic indications. A systematic search was performed using MEDLINE, the Cochrane Central Register of Controlled Trials (CENTRAL) and the International Clinical Trials Registry Platform up to December 2013. Pre-marketing, phase III randomized controlled trials (RCT), postmarketing clinical trials, observational longitudinal studies, and case reports involving adverse events (AE) were included. Methodological quality was assessed by Downs & Black checklist. All European spontaneous reports of AE included in the Eudravigilance up to December 2013 were also considered. AE were classified as ocular (related and non-related with the injection procedure) and non-ocular (related or non-related with vascular endothelial growth factor inhibition). Incidences of all reported AEs were estimated.

RESULTS

Pegaptanib, ranibizumab, and aflibercept were identified as ophthalmic biologics. Fourteen premarketing RCT, 7 postmarketing clinical trials, 31 observational studies, along with 31 case reports and 7,720 spontaneous reports were identified and included in this study. Both in pre- and postmarketing settings, ocular AEs were more frequent than non-ocular AEs. Premarketing safety data inform the most common AEs. Postmarketing studies suggest an increased number of events such as retinal pigmented epithelium tears (0.6%-24%), thromboembolic events (0.8%-5%), and mortality (2.8%-4%).

CONCLUSIONS

This study highlights the need to properly evaluate the risk for rare, serious, and long-term AEs, such as thromboembolic events, since they can lead to imbalances in the benefit-risk ratio of biologics in ophthalmology.

The changing role of the endocrinologist in the care of patients with diabetic retinopathy

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and still represents a leading cause of visual impairment in working age in industrialized countries. It develops following non proliferative (mild, moderate, or severe) and proliferative stages, the earliest being often asymptomatic and with diabetic macular edema potentially developing at any of these. The prevalence and incidence of DR increase with diabetes duration and worsening of metabolic and blood pressure control. Current approaches to prevent and/or treat DR include optimized control of blood glucose and blood pressure and screening for early identification of high risk, though still asymptomatic retinal lesions. Results from the recent clinical trials suggest a role for blockers of the renin-angiotensin system (angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers) and for fenofibrate in reducing progression and/or inducing regression of mild to moderate non proliferative DR. Intra-vitreal administration of anti-vascular endothelial growth factor agents was shown to reduce visual loss in more advanced stages of DR, especially in macular edema.

Pharmacokinetic evaluation of pegaptanib octasodium for the treatment of diabetic edema

INTRODUCTION

Diabetic macular edema (DME) is a leading cause of visual impairment in patients with diabetic retinopathy. Pegaptanib octasodium (Macugen) was the first anti-VEGF agent approved for the treatment of neovascular age-related macular degeneration. It is a selective anti-VEGF agent, which only blocks VEGF. It has been shown to be safe and effective in treatment of DME in randomized controlled trials and it may be a safer first-line treatment in patients with diabetes with a predisposition to cardiovascular risk factors.

AREAS COVERED

This review covers the pharmacokinetics of pegaptanib octasodium. The authors also evaluate pegaptanib octasodium's clinical efficacy, safety and tolerability in DME.

EXPERT OPINION

DME is the most common cause of visual loss in patients with diabetes. Pegaptanib has been found to be more effective than laser therapy alone for center-involving DME, its efficacy might be slightly worse than other pan-VEGF blockers, but the number of patients that have significant improvement of vision after treatment are similar to those treated with pan-VEGF blockers. As a selective VEGF blocker, it may have a better ocular and systemic safety profile than pan-VEGF blocking agents. It is reasonable to consider pegaptanib as the first-line treatment for center-involving DME with pan-VEGF blockers reserved for non-responders.

Diabetic macular edema: new concepts in patho-physiology and treatment

Diabetic macular edema (DME), a serious eye complication caused primarily by hyperglycemia, is one of the major causes of blindness. DME, which is characterized by cystic retinal thickening or lipid deposition, is prone to relapse after successful treatment. DME is a complex pathological process caused by multiple factors, including breakdown of the inner and outer blood-retinal barriers, oxidative stress, and elevated levels of vascular endothelial growth factor which have been demonstrated in both preclinical and clinical studies. Starling's law theory explains many of the features of DME. Early detection and treatment of DME can prevent vision loss. Current effective interventions for DME include treatment of systemic risk factors, such as elevated blood glucose, blood pressure and dyslipidemia. Ophthalmic treatments include laser photocoagulation, surgery and intraocular pharmacotherapy. New drugs, which are given by intraocular injection, have emerged in recent years to become first line treatment for DME that affects the central macula with loss of vision. Laser photocoagulation is still the gold standard of treatment for DME which does not involve the central macular. This review outlines these new treatments with particular emphasis on the optimal timing of how they are given.

In vivo adaptive optics microvascular imaging in diabetic patients without clinically severe diabetic retinopathy

We used a confocal adaptive optics scanning laser ophthalmoscope (AOSLO) to image the retina of subjects with non-proliferative diabetic retinopathy (NPDR). To improve visualization of different retinal features, the size and alignment of the confocal aperture were varied. The inner retinal layers contained clearly visualized retinal vessels. In diabetic subjects there was extensive capillary remodeling despite the subjects having only mild or moderate NPDR. Details of the retinal microvasculature were readily imaged with a larger confocal aperture. Hard exudates were observed with the AOSLO in all imaging modes. Photoreceptor layer images showed regions of bright cones and dark areas, corresponding in location to overlying vascular abnormalities and retinal edema. Clinically undetected intraretinal vessel remodeling and varying blood flow patterns were found. Perifoveal capillary diameters were larger in the diabetic subjects (p<0.01), and small arteriolar walls were thickened, based on wall to lumen measurements (p<.05). The results suggest that existing clinical classifications based on lower magnification clinical assessment may not adequately measure key vascular differences among individuals with NPDR.

Management paradigms for diabetic macular edema

PURPOSE

To provide evidence-based recommendations for diabetic macular edema (DME) management based on updated information from publications on DME treatment modalities.

DESIGN

Perspective.

METHODS

A literature search for "diabetic macular edema" or "diabetic maculopathy" was performed using the PubMed, Cochrane Library, and ClinicalTrials.gov databases to identify studies from January 1, 1985 to July 31, 2013. Meta-analyses, systematic reviews, and randomized controlled trials with at least 1 year of follow-up published in the past 5 years were preferred sources.

RESULTS

Although laser photocoagulation has been the standard treatment for DME for nearly 3 decades, there is increasing evidence that superior outcomes can be achieved with anti-vascular endothelial growth factor (anti-VEGF) therapy. Data providing the most robust evidence from large phase II and phase III clinical trials for ranibizumab demonstrated visual improvement and favorable safety profile for up to 3 years. Average best-corrected visual acuity change from baseline ranged from 6.1-10.6 Early Treatment Diabetic Retinopathy Study (ETDRS) letters for ranibizumab, compared to 1.4-5.9 ETDRS letters with laser. The proportion of patients gaining ≥ 10 or ≥ 15 letters with ranibizumab was at least 2 times higher than that of patients treated with laser. Patients were also more likely to experience visual loss with laser than with ranibizumab treatment. Ranibizumab was generally well tolerated in all studies. Studies for bevacizumab, aflibercept, and pegaptanib in DME were limited but also in favor of anti-VEGF therapy over laser.

CONCLUSIONS

Anti-VEGF therapy is superior to laser photocoagulation for treatment of moderate to severe visual impairment caused by DME.

Five-month observation of persistent diabetic macular edema after intravitreal injection of Ozurdex implant

Aims. This retrospective analysis was aimed at evaluating the effectiveness of treatment of persistent diabetic macular edema with intravitreal injections of 0.7 mg dexamethasone implant Ozurdex. The study comprised three male patients (6 eyes). Results. The average thickness of the retina at baseline was 632 μm, the medial BCVA was 0.8 logMAR, and corrected intraocular pressure was 13.7 mmHg. The maximum decrease in mean retinal thickness was observed at four weeks following the treatment and was 365 μm (−267 μm) and visual acuity improved by an average of two lines and was 0.6 logMAR. The largest increase in mean retinal thickness to average of 528 μm (+164 μm) occurred at 16 weeks and the average BCVA was 0.614 lines BCVA logMAR. In one eye, there was a steroid cataract development after the third dose of dexamethasone implant of 0.7 mg. Conclusions. The intravitreal dexamethasone implant treatment of patients with persistent diabetic macular edema in whom laser photocoagulation proved to be ineffective and as a result they required a monthly injection of anti-VEGF factors (Ranibizumab, Bevacizumab) may be a good alternative to extending the interval of injections. However, reinjections involve a high risk of developing poststeroid cataracts, which is not without significance in middle-aged patients.

Homocysteine is linked to macular edema in type 2 diabetes

AIM

To explore the relationship between plasma total homocysteine concentration and diabetic macular edema in patients with type 2 diabetes.

METHODS

Patients with type 2 diabetes (n = 176) were enrolled in a cross-sectional hospital-based study. Diabetic macular edema status was documented by fundus photographs. Plasma total homocysteine concentration was measured using fluorescence polarization immunoassay. Normal control plasma homocysteine was established in 115 healthy subjects. Risk factors for diabetic macular edema were obtained from fasting blood samples and interviewer questionnaire.

RESULTS

Diabetic patients had increased plasma homocysteine compared with normal control. Plasma homocysteine levels were higher in subjects with diabetic macular edema than without ((11.4 ± 2.7) versus (8.5 ± 1.9) (μmol/l), p = 0.000). The association of homocysteine with diabetic macular edema was independent of major risk factors for diabetic macular edema (duration of diabetes, HbA1c, lipid) and determinants of higher homocysteine concentration (age, gender, serum folate and vitamin B12, renal status, and biguanide use) (OR: 1.63 (1.02-2.14), p = 0.018). Furthermore, per increase of 5.0 μmol/l plasma homocysteine was related to macular edema, after controlling for per unit increase of other factors (OR: 1.64 (1.04-2.16), p = 0.019).

CONCLUSIONS

Plasma total homocysteine concentration is independently associated with the occurrence of macular edema in type 2 diabetes. Future prospective studies are warranted to clarify the relationship.

Higher age at onset of type 1 diabetes increases risk of macular oedema

PURPOSE

To investigate whether age at onset of type 1 diabetes is a risk factor for clinically significant macular oedema (CSME).

METHODS

A sample of 1354 patients with a mean duration of diabetes 24.6 ± 11.6 years was drawn from the FinnDiane Study population and divided into age at onset groups 0-4 (n = 184), 5-14 (n = 662) and 15-40 years (n = 508). Type 1 diabetes was defined as age at onset ≤40 years, C-peptide negativity and insulin treatment initiated within 1 year of diagnosis. Retinopathy status was assessed from fundus photographs and stereoscopic fundus examinations and graded with the ETDRS scale.

RESULTS

After 30 years of diabetes, the estimated cumulative incidences of CSME were 17% (95% CI 11-26) in age at onset group 0-4 years, 27% (95% CI 23-32) in age at onset group 5-14 years and 34% (95% CI 27-41) in age at onset group 15-40 years (p = 0.002, Gray's test). In a competing risks regression model, adjusted for covariates selected with Bayesian information criteria, age at onset 5-14 years (HR 1.89 [95% CI 1.22-2.91], p = 0.004), and age at onset 15-40 years (HR 3.72 [95% CI 2.35-5.89], p < 0.0001), were significant overall risk factors for CSME (p < 0.0001). Higher ETDRS score (HR 1.04 ([95% CI 1.03-1.05], p < 0.0001), HbA1c (HR 1.12 [95% CI 1.02-1.23], p = 0.016), and total cholesterol (HR 1.19 [95% CI 1.04-1.37], p = 0.013) also increased the risk of CSME.

CONCLUSIONS

Higher age at onset of type 1 diabetes is a significant risk factor for macular oedema. This suggests that ageing may modify the risk of retinopathy in type 1 diabetes.

[Randomized clinical trials in diabetic macular edema]

Diabetic macular edema (DME) is the main cause of visual acuity impairment in diabetic patients. The current standard therapy for patients with DME (focal/grid laser photocoagulation) usually does not improve impaired vision, and many patients continue to lose vision despite laser therapy. Vascular endothelial growth factor (VEGF) plays a key role in the pathogenesis of DME and is a major candidate as a therapeutic target for the treatment of DME. The advent of intravitreal anti-VEGF drugs, such a ranibizumab, has opened up a new era for the management of DME. The aim of this review is to summarize the evidence supporting the use of ranibizumab in clinical practice. The studies analyzed in this review are prospective, controlled, randomized clinical trials (RCT) that have focused on documenting the therapeutic effect of ranibizumab and its safety, providing encouraging results.

Adeno-associated virus mediated delivery of a non-membrane targeted human soluble CD59 attenuates some aspects of diabetic retinopathy in mice

Diabetic retinopathy is the leading cause of visual dysfunction in working adults and is attributed to retinal vascular and neural cell damage. Recent studies have described elevated levels of membrane attack complex (MAC) and reduced levels of membrane associated complement regulators including CD55 and CD59 in the retina of diabetic retinopathy patients as well as in animal models of this disease. We have previously described the development of a soluble membrane-independent form of CD59 (sCD59) that when delivered via a gene therapy approach using an adeno-associated virus vector (AAV2/8-sCD59) to the eyes of mice, can block MAC deposition and choroidal neovascularization. Here, we examine AAV2/8-sCD59 mediated attenuation of MAC deposition and ensuing complement mediated damage to the retina of mice following streptozotocin (STZ) induced diabetes. We observed a 60% reduction in leakage of retinal blood vessels in diabetic eyes pre-injected with AAV2/8-sCD59 relative to negative control virus injected diabetic eyes. AAV2/8-sCD59 injected eyes also exhibited protection from non-perfusion of retinal blood vessels. In addition, a 200% reduction in retinal ganglion cell apoptosis and a 40% reduction in MAC deposition were documented in diabetic eyes pre-injected with AAV2/8-sCD59 relative to diabetic eyes pre-injected with the control virus. This is the first study characterizing a viral gene therapy intervention that targets MAC in a model of diabetic retinopathy. Use of AAV2/8-sCD59 warrants further exploration as a potential therapy for advanced stages of diabetic retinopathy.

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.

Fluocinolone acetonide intravitreal implant (Iluvien®): in diabetic macular oedema

Fluocinolone acetonide intravitreal implant (Iluvien®) is an injectable, non-erodible, corticosteroid implant that is approved in several European countries for the treatment of chronic diabetic macular oedema (DMO). In analyses of two multinational trials in patients with DMO previously treated with macular laser photocoagulation, fluocinolone acetonide intravitreal implant 0.2 μg/day was significantly more efficacious than sham injection in improving visual acuity. At 24 months post injection, 29 % of fluocinolone acetonide intravitreal implant 0.2 μg/day recipients had an improvement in the best-corrected visual acuity (BCVA) letter score of ≥15 compared with 16 % in the sham injection group (p = 0.002) [primary endpoint]. Treatment benefit was most evident in the subgroup of patients whose duration of DMO was ≥3 years. In this subgroup at 36 months, 34 % of fluocinolone acetonide intravitreal implant 0.2 μg/day recipients had an increase in the BCVA score of ≥15, compared with 13 % of sham injection recipients (p < 0.001). Fluocinolone acetonide intravitreal implant recipients also had generally greater benefits than sham injection recipients on secondary endpoints. In patients who were phakic in the study eye at baseline, cataracts occurred in 82 % of fluocinolone acetonide intravitreal implant 0.2 μg/day recipients and 51 % of sham injection recipients. Overall, 37 % and 12 % of patients in the fluocinolone acetonide intravitreal implant and sham injection groups developed raised intraocular pressure (IOP), which was generally controlled with IOP-lowering drugs.

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.