Diabetic macular edema: pathogenesis and treatment

Nanotechnology-Ocular Devices for Glaucoma Treatment: A Literature Review

Nanotechnology enabled the development of materials and devices with great utility in different fields of medicine. By using engineered-based nano-devices and structures, human biological systems may be controlled and repaired at a molecular scale, ultimately leading to a biological benefit. In particular, in the field of glaucoma treatment, nanotechnology may, for example, enhance drug residence time on the ocular surface and ocular bioavailability, as well as improve surgical success by both optimizing postoperative scarring and providing a wider safety window. Further studies are still needed to entirely explain the pharmacodynamics of nanotechnology-based therapeutic approaches and prove their biological consequences in human eyes. This review aims to summarize the literature concerning the advances in nanotechnology, specifically regarding ocular devices applied to the treatment of glaucoma.

Experiences and perceptions of patients undergoing treatment and quality of life impact of diabetic macular edema: a systematic review

Diabetic macular edema (DME) is a common cause of visual impairment. Current treatments for DME include laser photocoagulation, corticosteroids and Vascular Endothelial Growth Factor (VEGF) antagonists, which are administered via intravitreal injection. The purpose of this systematic review is to explore the experiences and perceptions of patients undergoing laser, corticosteroid implants and intravitreal injection treatment for DME and the impact on Quality of Life (QoL). A systematic search of the Embase, Medline, PsycINFO and Cinahl electronic databases was conducted to identify all studies with an unlimited date range, published in the English language, full text and incorporating human participants. Hand searching identified two articles. Following the application of the Critical Appraisal Skills Programme (CASP) Quantitative and Qualitative Research Checklist 21 articles were selected for inclusion, as they were deemed pertinent for the purpose of this review. Limited studies have examined DME patients' experiences and perceptions of treatment and QoL. The outcomes of these studies lack agreement on the effectiveness of treatment, treatment preferences and impact of QoL in patients with DME. Future research which enhances current knowledge will therefore serve to improve treatment outcomes and QoL in these patients.

The efficacy and safety of aflibercept and conbercept in diabetic macular edema

Diabetic macular edema (DME) has shown an increasing prevalence during the past years and is the leading cause of diabetic retinopathy blindness. Traditional treatment modalities include laser and corticosteroid therapy, which, however, either act through unclear mechanisms or cause cataracts and elevated intraocular pressure. In recent years, as the pathogenic role of VEGF in DME has been well-recognized, the intravitreal injection of anti-VEGF drugs has become the first-line treatment of DME due to their great efficacy in improving visual acuity and mitigating macular edema. Advantages have been shown for aflibercept and conbercept, the two recombinant decoy receptors that can bind VEGF with high specificity and affinity, in DME treatment in clinical trials conducted both worldwide and in People’s Republic of China. This review introduces the structural characteristics and molecular mechanisms of action of these two anti-VEGF drugs, and summarizes the clinical trials evaluating their efficacy and safety, with the hope to provide clues for designing optimal and personalized therapeutic regimens for DME patients.

Intravitreal diclofenac versus intravitreal bevacizumab in persistent diabetic macular edema: Anatomical and functional outcome

PURPOSE

To compare the efficacy of diclofenac versus bevacizumab following single intravitreal injection in eyes with persistent diabetic macular edema.

METHODS

Fifty eyes with persistent DME were randomly allocated to intravitreal injection of 500 µg/0.1 ml of diclofenac (N = 20) or 1.25 mg/0.05 mL of bevacizumab (N = 20) or to non-treatment (10 eyes). Preoperative and postoperative visual acuity, central, paracentral macular thickness and intraocular pressure (IOP) were recorded and compared between the three groups up to 4 weeks.

RESULTS

Diclofenac and bevacizumab groups showed statistically significant reduction in central and paracentral macular thickness (diclofenac: p = 0.006, 0.02 and bevacizumab: p = 0.02, 0.01), without statistically significant difference between the two groups. The two groups showed no statistically significant difference in mean visual acuity or mean line improvement. Mean visual acuity improvement didn't reach statistical significance in either group. Diclofenac group showed statistically significant reduced IOP (P = 0.02). Control eyes did not show any change in mean visual acuity, macular thickness or IOP.

CONCLUSION

In persistent DME, diclofenac has a structural effect comparable to bevacizumab on central macular thickness. However, significant functional gain may not be accomplished by single injection. Unlike naïve DME, persistent cases may be confounded by systemic and local factors necessitating repeated injection of diclofenac.

Remodeling of Retinal Architecture in Diabetic Retinopathy: Disruption of Ocular Physiology and Visual Functions by Inflammatory Gene Products and Pyroptosis

Diabetic patients suffer from a host of physiological abnormalities beyond just those of glucose metabolism. These abnormalities often lead to systemic inflammation via modulation of several inflammation-related genes, their respective gene products, homocysteine metabolism, and pyroptosis. The very nature of this homeostatic disruption re-sets the overall physiology of diabetics via upregulation of immune responses, enhanced retinal neovascularization, upregulation of epigenetic events, and disturbances in cells' redox regulatory system. This altered pathophysiological milieu can lead to the development of diabetic retinopathy (DR), a debilitating vision-threatening eye condition with microvascular complications. DR is the most prevalent cause of irreversible blindness in the working-age adults throughout the world as it can lead to severe structural and functional remodeling of the retina, decreasing vision and thus diminishing the quality of life. In this manuscript, we attempt to summarize recent developments and new insights to explore the very nature of this intertwined crosstalk between components of the immune system and their metabolic orchestrations to elucidate the pathophysiology of DR. Understanding the multifaceted nature of the cellular and molecular factors that are involved in DR could reveal new targets for effective diagnostics, therapeutics, prognostics, preventive tools, and finally strategies to combat the development and progression of DR in susceptible subjects.

Subtle changes in diabetic retinas localised in 3D using OCT

PURPOSE

To detect and localise subtle changes in retinas of diabetic patients who clinically have no diabetic retinopathy (DR) or non-proliferative DR (NPDR) as compared to age- and sex- matched controls. Spectral Domain Optical Coherence Tomography (SD-OCT) and software to examine all retinal layers, including deeper layers, were used to quantify foveal avascular zone size and inner and outer retinal layer thicknesses, as well as to detect axial location of prominent lesions.

METHODS

Diabetic subjects, 19 total with 16 having no DR and three having non-proliferative retinopathy, were matched with 19 controls with respect to age and sex. Macular-centred SD-OCT grids of 20 × 15° were taken with the Spectralis. En face or transverse images were generated from the SD-OCT data by automatically segmenting all retinal layers. The transverse images were investigated for foveal avascular zone (FAZ) size, retinal vessel calibre, and structural changes. The size of the FAZ was compared for diabetics vs controls using vendor software and manual marking in Photoshop. Inner retinal layer (IRL_FAZ ) and outer nuclear layer (ONL_FAZ ) thicknesses at the margins of the FAZ were measured using vendor software.

RESULTS

The FAZ area was larger for diabetics (mean ± S.D. = 0.388 ± 0.074 mm² ) than controls (0.243 ± 0.113 mm² ), t₁₈ = 5.27, p < 0.0001, using vendor software. The mean IRL_FAZ was thicker for the diabetics (86.8 ± 14.5 μm) than controls (65.2 ± 16.3 μm), t₁₈ = 4.59, p = 0.00023, despite lack of exudation by clinical exam. There was no significant association between FAZ area and mean IRL_FAZ for the diabetics, r = 0.099, p = 0.69. Vessels not clinically detected were visible in the NFL transverse image of most diabetics, especially for a mild NPDR patient. A prominent lesion found in the en face infra-red image of a mild NPDR subject was localised in the photoreceptor layer by SD-OCT, as well as additional outer retinal changes in other subjects.

CONCLUSIONS

Our results demonstrate changes in inner and outer diabetic retinas not readily detectable by clinical exam. IRL_FAZ had not thinned at the margins of the large FAZs, indicating neural mass did not yet decrease despite potential ischemia.

Evaluation of systemic risk factors in different optical coherence tomographic patterns of diabetic macular edema

AIM

To elucidate the relationship between systemic risk factors and different patterns of diabetic macular edema (DME) determined with optical coherence tomography (OCT).

METHODS

In this cross-sectional study, DME was classified by OCT as diffuse retinal thickness (DRT), cystoid macular edema (CME) and serous retinal detachment (SRD) and the relationship between the systemic risk factors and DME patterns was evaluated.

RESULTS

Of the 57 patients with DME, 21 (36.8%) had DRT, 24 (42.1%) had CME and 12 (21.0%) had SRD. Micro- or macro-albuminuria was significantly higher in the DRT pattern (61.9%) compared with the SRD (50.0%) and CME patterns (25.0%; P=0.040). Hemoglobin A1c (HbA1c) level was significantly higher and patients were younger in the DRT pattern group (P=0.034, P=0.032). Best corrected visual acuity was the worst and central macular thickness was the thickest in the CME pattern group.

CONCLUSION

Micro- or macro-albuminuria may be more frequent and HbA1c level may be higher in patients with DRT. These patients are also seen to be younger than patients with non-DRT.

Biomarkers and predictors for functional and anatomic outcomes for small gauge pars plana vitrectomy and peeling of the internal limiting membrane in naïve diabetic macular edema: The VITAL Study

Purpose

We aimed to investigate biomarkers and predictive factors for visual and anatomical outcome in patients with naïve diabetic macular edema (DME) who underwent small gauge pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling as a first line treatment.

Design

Multicenter, retrospective, interventional study.

Participants

120 eyes from 120 patients with naïve DME treated with PPV and ILM peeling with a follow up of 24 months.

Methods

Change in baseline best corrected visual acuity (BCVA) and central subfoveal thickness (CST) 1, 6, 12 and 24 months after surgery. Predictive value of baseline BCVA, CST, optical coherence tomography (OCT) features (presence of subretinal fluid (SRF) and photoreceptor damage), and time between DME diagnosis and surgery. Additional treatment for DME needed. Intra- and post-operative complications (cataract rate formation, increased intraocular pressure).

Main outcome measures

The correlation between baseline characteristics and BCVA response (mean change from baseline; categorized improvement ≥5 or ≥10; Early Treatment Diabetic Retinopathy Study (ETDRS) letters) 12 and 24 months after surgery.

Results

Mean BCVA was 0.66 ± 0.14 logMAR, 0.52 ± 0.21 logMAR, and 0.53 ± 0.21 logMAR (p<0.001) at baseline, 12 and 24 months, respectively. Shorter time from DME diagnosis until PPV (OR: 0.98, 95% CI: 0.97–0.99, p<0.001) was a predictor for good functional treatment response (area under the curve 0.828). For every day PPV is postponed, the patient’s chances to gain ≥5 letters at 24 months decrease by 1.8%.

Presence of SRF was identified as an anatomical predictor of a better visual outcome, (OR: 6.29, 95% CI: 1.16–34.08, p = 0.033). Safety profile was acceptable.

Conclusions

Our results reveal a significant functional and anatomical improvement of DME 24 months after primary PPV, without the need for additional treatment. Early surgical intervention and presence of SRF predict good visual outcome. These biomarkers should be considered when treatment is chosen.

Acuity and colour vision changes post intravitreal dexamethasone implant injection in patients with diabetic macular oedema

Purpose

To evaluate changes in colour vision following intravitreal injection of Dexamethasone implant (Ozurdex) in patients with diabetic macular oedema (DMO). Both red-green (RG) and yellow-blue (YB) chromatic sensitivity were assessed using the Colour Assessment & Diagnosis (CAD) test which isolates the use of colour signals and provides age-corrected, statistical limits for normal trichromats. To determine whether colour changes and visual acuity (VA) post-treatment relate to central sub-field retinal thickness (CST).

Methods

Fourteen patients with DMO who were undergoing treatment with Ozurdex were recruited for this study. RG and YB colour thresholds were measured using the CAD test, best corrected visual acuity was assessed using the ETDRS chart and CST was measured using spectral domain optical coherence tomography (SD-OCT). All tests were performed monocularly at baseline and 24 weeks post injection.

Results

All patients (n = 14 eyes), had significant loss of RG and YB chromatic sensitivity at baseline (p<0.05). The mean age was 56 ± 9.5 years. The age specific, monocular, upper normal limits for a 56 year old subject are 2.66 for RG and 2.85 for YB. In this study, the measured, pre injection thresholds (mean±SD) were 22.6 ± 11.3 for RG and 16.2 ± 3.76 for YB. There was significant improvement in RG threshold post injection (i.e., 19.2 ± 10.8 (p<0.05)). No significant changes were found in the YB thresholds with corresponding mean and range values of: 15.8 ± 4.6 (p = 0.23). CST pre-treatment was 542 ±135 μm. After treatment and by week 24 the CST values decreased to 435 ±127 μm.

Conclusions

RG colour thresholds provide a sensitive measure of functional change in diabetic subjects with macular oedema. The YB system is damaged severely in the DMO patients studied and shows little or no recovery post treatment. The improvement in VA and particularly in RG colour vision correlate well with the measured decrease in CST. The results suggest that the improvement in the RG chromatic sensitivity can provide a useful biomarker for monitoring the efficacy of treatment in DMO.

Impact of estimated glomerular filtration rate on diabetic macular edema

PURPOSE

Diabetic macular edema (DME) is a major cause of visual impairment in patients with diabetes and is influenced by various systemic factors. This study evaluates the effect of renal status on DME using estimated glomerular filtration rate (eGFR) as a study marker.

METHODS

This was a prospective observational cross-sectional study. One hundred and ninety-five patients of diabetic retinopathy (DR) were included. Group 1 had patients of DR without DME (n = 100), and group 2 had patients of DR with DME (n = 95). All patients were evaluated for DR/DME-related risk factors. eGFR was calculated in all patients. Spectral domain optical coherence tomography (SDOCT) was done to identify the various patterns and severity of DME.

RESULTS

Group 2 patients had significantly higher comorbidities than those in group 1 (p < 0.001). Hba1c, total cholesterol, triglycerides, LDL/HDL ratio, systolic and diastolic blood pressures were significantly higher in group II (p < 0.001 in each). There was no significant difference between the groups in terms of blood urea, serum creatinine or eGFR. eGFR did not show a significant association with a specific SDOCT pattern or severity of DME.

CONCLUSION

Comorbidities are more common and more severe in patients with DME. However, eGFR as a marker was not useful in predicting either the severity or pattern of DME. eGFR, in its present form, may not be useful in the evaluation and management of patients with DME.

Vitreous IL-8 and VEGF levels in diabetic macular edema with or without subretinal fluid

PURPOSE

To determine the cytokine levels in vitreous samples of diabetic macular edema (DME) patients in comparison with nondiabetic patients, and to evaluate the effect of subretinal fluid on the cytokine levels of vitreous samples.

METHODS

In this prospective case-control study, 11 eyes of 11 patients with DME and subretinal fluid, 11 eyes of 11 patients with DME without subretinal fluid, and 14 eyes of 14 patients who had undergone vitreoretinal surgery for the epiretinal membrane or a macular hole (control group) were evaluated. The blood glycated hemoglobin (HbA1c) level, vitreous vascular endothelial growth factor (VEGF), and interleukin-8 (IL-8) levels were determined.

RESULTS

The vitreous VEGF level of patients in DME groups was significantly higher than the control group (p < 0.001) without significant difference between DME patients with and without subretinal fluid (p = 0.796). The vitreous IL-8 level of DME patients with subretinal fluid was significantly higher than both control (p = 0.002) and DME without subretinal fluid groups (p = 0.019). The blood HbA1c level was significantly higher in DME group with subretinal fluid than those without subretinal fluid (8.7 ± 1.32 and 7.1 ± 1.13%, respectively, p = 0.010). The only significant correlation was between vitreous VEGF level and blood HbA1c level in DME patients without subretinal fluid (r = 0.813, p = 0.002).

CONCLUSIONS

IL-8 level in vitreous samples was higher in DME patients with subretinal fluid than those without subretinal fluid, suggesting that inflammation is an important factor in the progression of DME leading to the subretinal fluid formation in diabetic patients.

EFFICACY AND SAFETY OUTCOMES OF INTRAVITREAL AFLIBERCEPT FOCUSING ON PATIENTS WITH DIABETIC MACULAR EDEMA FROM JAPAN

PURPOSE

To evaluate the efficacy and safety of intravitreal aflibercept injection (IAI) in Japanese patients with diabetic macular edema (DME).

METHODS

VIVID-DME was a Phase 3 study comprising patients with DME randomized 1:1:1 to IAI 2 mg every 4 weeks (2q4), IAI 2 mg every 4 weeks until Week 16 then 8-week dosing (2q8), and laser. A total of 403 patients (76 Japanese) were included in this study. VIVID-Japan (72; all Japanese patients) was a nonrandomized, open-label study comprising Japanese patients with DME receiving IAI 2q4 until Week 16, then 2q8. Primary efficacy endpoint (Week 52) of VIVID-DME was mean change from baseline in best-corrected visual acuity; VIVID-Japan evaluated safety and tolerability.

RESULTS

Mean change in best-corrected visual acuity (letters) for 2q4, 2q8, and laser groups was +10.6, +10.9, and +1.2 and +9.8, +9.5, and +1.1 in the non-Japanese and Japanese populations of VIVID-DME, respectively. In VIVID-Japan, it was +9.3 for IAI 2q8. Intravitreal aflibercept injection also provided consistently greater benefits for anatomical outcomes versus laser. Adverse events were consistent with the known safety profile of IAI.

CONCLUSION

In Japanese patients with DME, IAI treatment was superior to laser for visual and anatomical outcomes and resulted in efficacy and safety outcomes similar to those in a non-Japanese patient population.

The role of patient's systemic characteristics and plateletcrit in developing toxic anterior segment syndrome after uneventful phaco surgery: A case-control study

PURPOSE

To compare the systemic and ocular characteristics and laboratory findings of patients developing toxic anterior segment syndrome (TASS) after uneventful phaco surgery with unaffected subjects undergoing the same surgery in the same session.

DESIGN

A retrospective case-control study.

METHODS

The study group consisted of 26 eyes of 26 patients who underwent uneventful phaco surgery and who went on to develop TASS, while the control group included 39 subjects who had routine phaco surgery in the same session by the same surgeon. The sterilization stages of reusable instruments, disposable instruments, and compositions were recorded. The preoperative systemic diseases, complete blood count parameters, glycosylated hemoglobin (HbA1c), biochemical parameters, thyroid hormone profiles, and the surgical features were compared between the two groups.

RESULTS

Type 2 diabetes mellitus (DM), systemic hypertension (HT), hyperlipidemia, chronic ischaemic heart disease, and chronic renal failure were significantly more common in the TASS group (p < 0.05). Proliferative diabetic retinopathy was also more frequent in the TASS group (p = 0.003). Mean HbA1c% values, white blood cell count, neutrophil/lymphocyte ratio, platelet counts, platelet distribution width, and plateletcrit parameters were significantly higher in the TASS group (p < 0.05). Multivariate logistic regression analysis revealed that a high plateletcrit level (p = 0.001, odds ratio [95% CI]; 22.27 [3.36-147.76]) and systemic HT (p = 0.044, odds ratio [95% CI]; 7.13 [1.05-48.12]) are independently associated with the development of TASS.

CONCLUSION

Although TASS may arise as a result of insufficient sterilization of instruments or intraocular solutions, patient factors may also contribute to its development. Systemic vascular disorders such as uncontrolled type 2 DM, systemic hypertension, and hyperlipidemia may increase the risk of TASS after uneventful phaco surgery. Abnormal parameters associated with systemic inflammation, such as higher plateletcrit level, may facilitate the development of TASS. These findings may be a predicting factor of TASS development for uneventful cataract surgeries.

Intravitreal dexamethasone implants for diabetic macular edema

AIM

To evaluate the safety and efficacy of a dexamethasone (DEX) intravitreal implant for diabetic macular edema (DME).

METHODS

Totally 113 eyes of 84 patients were divided in three subgroups: naive patients (n=11), pseudophakic patients (n=72) and phakic patients (n=30). Inclusive criterion comprised adult diabetic patients with central fovea thickening and impaired visual acuity resulting from DME for whom previous standard treatments showed no improvement in both central macular thickness (CMT) and best corrected visual acuity (BCVA) after at least 3mo of treatment. Outcome data were obtained from patient visits at baseline and at months 1, 3, 5, 9 and 12 after the first DEX implant injection. At each of these visits, patients underwent measurement of BCVA, a complete eye examination and measurement of CMT and macular volume (MV) carried out with optical coherence tomography (OCT) images.

RESULTS

Seventy-three eyes (64.5%) received a single implant, 30 (26.5%) received two implants and 10 (9%) received three implants. At baseline, average in BCVA, CMT and MV were 43.5±20.8, 462.8±145 and 12.6±2.5 respectively. These values improved significantly at 1mo (BCVA: 47.2±19.5, CMT: 339.6±120, MV: 11.11±1.4) and 3mo (BCVA: 53.2±18.1, CMT: 353.8±141, MV: 11.3±1.3) (P≤0.05). At 5mo (BCVA: 50.9±19.8, CMT: 425±150, MV: 12.27±2.3), 9mo (BCVA: 48.4±17.6, CMT: 445.5±170, MV: 12.5±2.3) and 12mo (BCVA: 47.7±18.8, CMT: 413.2±149, MV: 12.03±2.5), improvements in the three parameters were no longer statistically significant and decreased progressively but did not reach baseline values. There were no clinical differences between subgroups. Ocular complications were minimal.

CONCLUSION

Patients with DEX implants show maximum efficacy at 3mo which then declined progressively, but is still better than baseline values at the end of follow-up.

The Role of Microglia in Diabetic Retinopathy: Inflammation, Microvasculature Defects and Neurodegeneration

Diabetic retinopathy is a common complication of diabetes mellitus, which appears in one third of all diabetic patients and is a prominent cause of vision loss. First discovered as a microvascular disease, intensive research in the field identified inflammation and neurodegeneration to be part of diabetic retinopathy. Microglia, the resident monocytes of the retina, are activated due to a complex interplay between the different cell types of the retina and diverse pathological pathways. The trigger for developing diabetic retinopathy is diabetes-induced hyperglycemia, accompanied by leukostasis and vascular leakages. Transcriptional changes in activated microglia, mediated via the nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and extracellular signal–regulated kinase (ERK) signaling pathways, results in release of various pro-inflammatory mediators, including cytokines, chemokines, caspases and glutamate. Activated microglia additionally increased proliferation and migration. Among other consequences, these changes in microglia severely affected retinal neurons, causing increased apoptosis and subsequent thinning of the nerve fiber layer, resulting in visual loss. New potential therapeutics need to interfere with these diabetic complications even before changes in the retina are diagnosed, to prevent neuronal apoptosis and blindness in patients.

Levels of Inflammatory Cytokines IL-1β, IL-6, IL-8, IL-17A, and TNF-α in Aqueous Humour of Patients with Diabetic Retinopathy

Diabetic retinopathy is the leading cause of blindness in working age individuals in developed countries. However, the role of inflammation in the pathogenesis of DR is not completely understood. This is an observational clinical research enrolling 80 type II diabetic patients who had undergone cataract surgeries either with DR or without DR. All cases were further categorized by the proliferative stages of retinal neovascularization and by the lengths of diabetic history. The levels of inflammatory cytokines including IL-1β, IL-6, IL-8, IL-17, and TNF-α in aqueous humour were tested. Results in this study indicated that these cytokine levels were increased in DR patients and might have a synergistic effect on the pathogenesis of this disease. They were also elevated along with the progression of neovascularization, reflecting the severity of DR. The results also suggested that for diabetic patients, the higher these levels are, the sooner retinal complications might appear. In conclusion, the levels of inflammatory cytokines IL-1β, IL-6, IL-8, IL-17A, and TNF-α in aqueous humour may be associated with the pathogenesis, severity, and prognosis of DR.

Dexamethasone Intravitreal Implant in Diabetic Macular Edema: Real-Life Data from a Prospective Study and Predictive Factors for Visual Outcome

INTRODUCTION

The purpose of the study was to evaluate the long-term anatomical and functional outcomes in patients with diabetic macular edema (DME) treated with intravitreal dexamethasone implant and to determine the predictive factors for the final visual outcome.

METHODS

The study included 54 patients with DME refractory to previous antivascular endothelial growth factor (anti-VEGF) who were treated with intravitreal dexamethasone implant. Predictive factors for visual outcome were assessed. In addition, the change in best-corrected visual acuity (BCVA) and the percentage of patients with edema resolution were evaluated.

RESULTS

At the end of the 12-month follow-up, patients with DME gained + 5.2 letters (about 1 Snellen line), while 57.4% of patients presented total resolution of macular edema. Negative predictive factors for the final visual outcome were found to be increasing age, increasing macular thickness, phakic status, the presence of intraretinal fluid, hyperreflective foci, hard exudates, as well as external limiting membrane and ellipsoid zone disruption. The mean number of injections was 2.1.

CONCLUSIONS

The various predictive factors that determine the visual outcome and possibly define patient prognosis after dexamethasone intravitreal implant in DME cases have been studied. The long follow-up showed that dexamethasone intravitreal implant seems to be a safe and effective treatment for this disease, requiring a limited number of injections.

Correlation of various serum biomarkers with the severity of diabetic retinopathy

Hyperglycemia induced inflammation and angiogenic factors are implicated as a contributor to the onset and progression of diabetic retinopathy (DR) in type 2 diabetes mellitus patients (T2DM). Tumor necrosis factor (TNF-alpha) and C-reactive protein (CRP) are inflammatory cytokines which induce retinal VEGF and are involved in the progression of proliferative diabetic retinopathy (PDR). Therefore the aim of the present study is to investigate the relationship between diabetic retinopathy and systemic inflammation in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

Patients with T2DM, with or without diabetic retinopathy were included in the study. Serum inflammatory cytokines, vascular growth factor were studied in different stages of DR.

RESULTS

Patients with T2DM with and without diabetic retinopathy were compared. Patients with diabetic retinopathy had increased serum levels of inflammatory cytokines CRP, TNF-alpha, as well as VEGF compared to serum levels of diabetic patients without retinopathy.

CONCLUSION

T2DM patients with retinopathy have higher levels of circulating inflammatory cytokines and VEGF compared to patients without retinopathy. These proinflammatory cytokines and angiogenic factors are involved in the progression of DR and proliferative diabetic retinopathy. The results showed the importance of inflammation and vascular endothelial growth factor in the progression of NPDR and PDR.

Macular oedema as manifestation of diabetic retinopathy

Diabetes mellitus is the third most dangerous disease of our time preceded by cardiovascular diseases and oncologic pathology. According to the International Diabetes Federation (January 1, 2016), worldwide approximately 415 million people aged 2079 years suffer from diabetes. The most significant manifestations of diabetes mellitus are lesions of the retina and blood vessels, which manifest as diabetic retinopathy and macular oedema, which lead to the inevitable loss of vision and disability in patients of working age. The existence of multile diagnostic methods and a broad classification provide an evidence of the complex nature of the pathological process of the macular zone in diabetes mellitus. However, to date, a single, generalised and accepted classification does not exist. Difficulties in the treatment of diabetic maculopathy are attributed to various forms of retinal lesions and ambiguities in the approach used to choose the disease management. It determines the importance of the development of diagnostic methods for the further correction of the standard treatment approach. New directions of surgical treatment allow relying on the best results of diabetic maculopathy treatment.

Aflibercept in the Treatment of Diabetic Macular Edema: A Review and Consensus Paper

Purpose

To reach a consensus, among experts, on the role of aflibercept in diabetic macular edema (DME) through literature review.

Methods

Two round tables, involving 12 Italian experts, were organized: in the first one, 6 pharmacologic and clinical questions were selected and analyzed by a systematic literature review, using a population, intervention, control, and outcomes framework; in the second one, the nominal group technique was used to discuss relevant evidence related to each question. The consensus was assessed using the 5-point Delphi score.

Results

Agreement on statements was reached on 6/6 questions. The final statements were as follows: 1) High levels of both vascular endothelial growth factor (VEGF) and placental growth factor play an important role in the pathogenesis of DME. 2) The aflibercept pharmacologic profile is notably different from that of other anti-VEGF. 3) Aflibercept significantly improves functional and anatomical outcomes, and rapidly improves best-corrected visual acuity up to its peak; these results remain stable over time. 4) Diabetic macular edema aflibercept treatment requires a 5-monthly injection loading phase. Alternatively, a personalized pro re nata (PRN) regimen based on monthly monitoring and strict retreatment criteria can be used. 5) As an alternative to the bimonthly fixed regimen, in the maintenance phase the treatment schedule may be a PRN regimen with strict retreatment criteria or a treat and extend regimen. 6) No concerns on aflibercept ocular and systemic safety emerged from the literature.

Conclusions

Consensus was reached among experts on how to best treat patients with DME with aflibercept.

VEGF-A gene polymorphisms and responses to intravitreal ranibizumab treatment in patients with diabetic macular edema

PURPOSE

To investigate the association between VEGF gene polymorphisms and the responses to treatment with intravitreal ranibizumab (IVR) in patients with diabetic macular edema (DME).

METHODS

This prospective study, conducted at the Kutahya Dumlupinar University Faculty of Medicine, included 95 patients with DME that were treated with IVR and 32 patients without DME despite proliferative diabetic retinopathy (PDR). The participants were divided into three groups: DME with non-proliferative diabetic retinopathy, DME with PDR, and PDR without DME; patients with DME who were treated with IVR were further divided into two groups based on their response to the treatment. Each patient was genotyped for five single nucleotide variations (SNVs) in VEGF-A: rs2010963, rs2146323, rs10434, rs833069, and rs6921438.

RESULT

There was a statistically significant difference in allelic distribution of VEGF-A rs833069 polymorphism in relation to the severity of diabetic retinopathy (DRP) (p = 0.031). The allelic distribution of VEGF-A rs2146323 polymorphism tended to be associated with the severity of DRP (p = 0.069). There were no statistically significant differences in the allelic distribution of the studied five SNVs in DME patients regarding the patients' responses to IVR therapy.

CONCLUSIONS

There is no association between the studied VEGF-A SNVs and the responses to IVR therapy in DME. However, the VEGF-A rs833069 gene polymorphism has a clear association with the severity of diabetic retinopathy.

Quantitative evaluation of hard exudates in diabetic macular edema after short-term intravitreal triamcinolone, dexamethasone implant or bevacizumab injections

Background

To quantitatively compare short-term hard exudates (HEs) alteration in patients with diabetic macular edema (DME) after intravitreal triamcinolone, dexamethasone implant or bevacizumab injections.

Methods

This retrospective study enrolled DME eyes with HEs that underwent a single-dose intravitreal injection of triamcinolone (25 eyes), dexamethasone implant (20 eyes), or three monthly injections of bevacizumab (25 eyes) and completed at least three months of follow-up. All patients were examined before and after 1, 2 and 3 months of injections. Using color fundus photographs, the amount of HEs was quantified by two masked graders. The difference in HEs area between baseline and each follow-up visit was compared among the three groups.

Results

After three months, HEs area was reduced to 52.9 ± 4.21% (P < 0.001) in the triamcinolone group, 63.6 ± 6.08% (P = 0.002) in the dexamethasone implant group, and 85.2 ± 5.07% (P = 0.198) in the bevacizumab group. A significant reduction in HEs appeared at one month in the triamcinolone group (53.5 ± 4.91%, P < 0.001) and at two months in the dexamethasone implant group (70.1 ± 5.21%, P = 0.039).

Conclusions

Our study suggests intravitreal steroids (triamcinolone, dexamethasone implants) significantly reduce HEs in DME patients on short-term follow-up, whereas intravitreal bevacizumab does not. Therefore, intravitreal steroids may be useful in DME with HEs in the fovea.

Recurrent Diabetic Macular Edema: What to Do

Diabetic macular edema (DME) is a leading cause of blindness in the working population. Herein, we report the case of a patient with recurrent DME for about 6 years, uncontrolled by several medical and surgical treatments, that was successfully treated with a single sustained-release fluocinolone acetonide intravitreal implant in her right eye. The affected eye had presented a visual acuity of 2/10 and a central macular thickness of 488 µm prior to the injection. After treatment with the fluocinolone acetonide intravitreal implant, the patient's right eye presented an improvement in best corrected visual acuity to 6/10 and a reduction of central macular thickness to 198 µm. These functional and anatomical results were continuous and sustained during a follow-up period of more than 12 months, and with an acceptable and manageable safety profile. These results show that fluocinolone acetonide intravitreal implantation is an effective treatment option in DME and should be considered in the DME treatment pathway.

Ranibizumab in Diabetic Macular Oedema - A Benefit-risk Analysis of Ranibizumab 0.5 mg PRN Versus Laser Treatment

INTRODUCTION

The structured Benefit-risk Action Team (BRAT) approach aims to assist healthcare decision makers in treatment assessments. We applied BRAT to compare the benefit-risk profile of ranibizumab 0.5 mg versus laser photocoagulation for the treatment of diabetic macular oedema (DMO).

METHODS

One-year data for the ranibizumab 0.5 mg pro re nata (PRN) and laser arms of the phase III trials RESPOND (NCT01135914; n=220), RESTORE (NCT00687804; n=345), and REVEAL (NCT00989989; n=396) were included in the analysis. The benefit measures included ≥10 letters gain/avoidance of loss in best-corrected visual acuity (BCVA), achieving central retinal thickness (CRT) <275 μm, and 25-item Visual Function Questionnaire (VFQ-25) outcomes. The risks measures included endophthalmitis, intraocular pressure increase, hypertension, proteinuria, arterial/venous thromboembolic events and deaths.

RESULTS

Ranibizumab treatment provided significant benefits compared with laser for ≥10 letter BCVA gain at month 12 (387/1,000 versus 152/1,000 patients), CRT <275 μm at 12 months (474/1,000 versus 348/1,000 patients), and improvement of ≥6.06 on the VFQ-25 near activities subscale (325/1,000 versus 245/1,000 patients). Results for the risk measures were similar for both treatments.

CONCLUSIONS

Superior clinically relevant outcomes were observed with ranibizumab 0.5 mg PRN compared with laser without compromising on safety. This analysis further supports the positive benefit-risk profile of ranibizumab 0.5 mg PRN.

Ultra-wide-field imaging in diabetic retinopathy

Since 1991, 7-field images captured with 30-50 degree cameras in the Early Treatment Diabetic Retinopathy Study were the gold standard for fundus imaging to study diabetic retinopathy. Ultra-wide-field images cover significantly more area (up to 82%) of the fundus and with ocular steering can in many cases image 100% of the fundus ("panretinal"). Recent advances in image analysis of ultra-wide-field imaging allow for precise measurements of the peripheral retinal lesions. There is a growing consensus in the literature that ultra-wide-field imaging improves detection of peripheral lesions in diabetic retinopathy and leads to more accurate classification of the disease. There is discordance among studies, however, on the correlation between peripheral diabetic lesions and diabetic macular edema and optimal management strategies to treat diabetic retinopathy.

Alterations to the Foveal Cone Mosaic of Diabetic Patients

Purpose

We measured localized changes occurring in the foveal cone photoreceptors and related defects in the cone mosaic to alterations in the nearby retinal vasculature.

Methods

The central 4° of the retina of 54 diabetic (53.7 ± 12.5 years) and 85 control (35.8 ± 15.2 years) participants were imaged with the Indiana adaptive optics scanning laser ophthalmoscope. Foveal cones and overlying retinal capillaries were imaged and infrared scanning laser ophthalmoscopy (IR SLO) images and optical coherence tomography (OCT) B-scans were obtained. Follow-up imaging sessions were performed with intervals from 4 to 50 months for 22 of the 54 diabetic participants.

Results

The foveal cone mosaics of 49 of 54 diabetic participants were of sufficient quality to assess the absence or presence of small localized defects in the cone mosaic. In 13 of these 49 diabetic participants we found localized defects, visualized as sharp-edged areas of cones with diminished reflectivity. These small, localized areas ranged in size from 10 × 10 μm to 75 × 30 μm. Of these 13 participants with cone defects, 11 were imaged over periods from 4 to 50 months and the defects remained relatively stable. These dark regions were not shadows of overlying retinal vessels, but all participants with these localized defects had alterations in the juxtafoveal capillary network.

Conclusions

The foveal cone mosaic can show localized areas of dark cones that persist over time, that apparently correspond to either missing or nonreflecting cones, and may be related to local retinal ischemia.

HYPERREFLECTIVE FOCI AS AN INDEPENDENT VISUAL OUTCOME PREDICTOR IN MACULAR EDEMA DUE TO RETINAL VASCULAR DISEASES TREATED WITH INTRAVITREAL DEXAMETHASONE OR RANIBIZUMAB

PURPOSE

To evaluate the potential role of hyperreflective foci (HF) in predicting visual outcome in patients undergoing treatment for macular edema due to retinal vascular diseases.

METHODS

Data and images of 92 patients with macular edema due to diabetes mellitus or branch retinal vein occlusion, treated with either intravitreal dexamethasone implant or ranibizumab, were analyzed. All patients underwent best-corrected visual acuity measurement, slit-lamp examination, spectral domain optical coherence tomography at baseline and at all time points of the follow-up (Month 1, 2, 3, 6, and 9). Generalized least squares random effects linear or logistic regression analysis was used to investigate potential factors associated with the final best-corrected visual acuity and number of HF, respectively.

RESULTS

Increasing age (P < 0.001), central retinal thickness (P < 0.001), number of HF (P = 0.028), presence of subretinal fluid (P < 0.001), intraretinal fluid (P < 0.001), intraretinal cysts (P < 0.001), and disruption of ellipsoid zone/external limiting membrane (P < 0.001) were significantly associated with poorer visual outcome. Factors associated with HF were increasing central retinal thickness (P = 0.003), presence of subretinal fluid (P = 0.049), intraretinal fluid (P = 0.002), cysts (P = 0.015), and disruption of ellipsoid zone (P = 0.047). No significant differences in change in best-corrected visual acuity, central retinal thickness, and HF were observed between the two treatment groups.

CONCLUSION

Hyperreflective foci are associated with poorer visual outcome in patients with macular edema due to retinal vascular diseases. Similar reductions in HF are achieved by intravitreal steroid and anti-vascular endothelial growth factor agent.

Visualization of changes in the foveal avascular zone in both observed and treated diabetic macular edema using optical coherence tomography angiography

BACKGROUND

Central vision loss in diabetic retinopathy is commonly related to diabetic macular edema (DME). The objective of this study was to describe changes between consecutive visits on optical coherence tomography angiography (OCTA) of the foveal avascular zone (FAZ) in eyes with DME.

METHODS

20 eyes from 14 patients with DME were imaged on 2 successive clinic visits separated by at least 1 month. The mean interval between visits was 3.2 months. The only intervention used was intravitreal anti-VEGF in 11 eyes; the others were observed over time without treatment. Two different readers measured FAZ area using a pseudo-automated tool in comparison to a manual tracing tool. Qualitative changes in the appearance of the vasculature surrounding the FAZ were also recorded. The retinal capillary plexus was segmented into deep and superficial plexuses, and FAZ measurements were done on the superficial, deep, and summated plexuses.

RESULTS

Pseudo-automated and manual measurements of FAZ area decreased significantly (p < 0.05) between visits in the deep, superficial, and summated plexuses. Qualitative analysis of vasculature surrounding the FAZ showed that most of the vascular changes (65%) over time were visible in the deep plexus, compared to 30 and 20% in the superficial and summated plexuses, respectively.

CONCLUSIONS

The most significant differences in FAZ size over time were in the summated plexus (p < 0.001), while changes in FAZ appearance were most prominent in the deep plexus. Absolute decrease in FAZ size over visits was largest in the deep plexus. Our results demonstrate that OCTA can effectively be used to measure FAZ area in patients with DME, visualize qualitative changes in retinal vasculature, and visualize the segmentation levels at which these changes can be best appreciated. However, larger studies are needed to evaluate the reproducibility of manual and pseudo-automated measuring techniques.

Interleukin-6 participation in pathology of ocular diseases

Interleukin-6 (IL-6) is a multifunctional cytokine that affects a variety of cells in the body such as osteoclasts, hepatocytes, endothelial cells, epithelial cells, white and red blood cells and etc. Elevated levels of IL-6 have been detected in many ocular diseases. Studies show that IL-6 has a major role in the pathology of glaucoma, CRVO, macular edema, ocular neovascularization, posterior capsule opacity formation, keratitis, dry eye disease, allergic eye disease, ocular autoimmune disease, corneal chemical burn, ocular inflammation and so on. IL-6 does its effects through the classic or trans-signal pathways in cells. Blocking of IL-6 signal pathways via Tocilizumab or other chemicals and therapeutics will help to overcome complications related to ocular diseases.

Ranibizumab in the Treatment of Diabetic Macular Edema: A Review of the Current Status, Unmet Needs, and Emerging Challenges

Diabetic retinopathy (more specifically diabetic macular edema, DME) is the most common cause of loss of vision in the working population in developed countries. Anti-vascular endothelial growth factor (anti-VEGF) agents considerably changed the treatment algorithms and improved prognosis of center-involving DME. Ranibizumab was the first approved anti-VEGF agent that revolutionized DME treatment. The vast increase in the number of patients undergoing intravitreal treatment and the role of anti-VEGF pharmacotherapy as the mainstay of DME treatment have triggered several challenges. Among them, of considerable interest is the quest for an optimal dosing scheme and the search for combination therapies. Although a significant body of research is directed towards other molecules that could potentially be new therapeutic targets, VEGF inhibition is expected to play an important long-term role in the treatment of DME considering the pathogenesis of the disease. Finally, recent studies revealed that ranibizumab may constitute a significant treatment modality in the management of other diabetic vision-threatening complications including proliferative diabetic retinopathy.

Corticosteroid Treatment in Diabetic Macular Edema

Diabetic macular edema is the most common cause of visual impairment in patients with diabetes mellitus. The pathogenesis of macular edema is complex and multifactorial. For many years, laser photocoagulation has been considered the standard therapy for the treatment of diabetic macular edema; however, few patients achieve significant improvements in visual acuity. Today the intravitreal administration of anti-inflammatory or anti-angiogenic agents together with the use of laser photocoagulation represents the standard of care for the treatment of this complication. The intravitreal route of administration minimizes the systemic side effects of corticosteroids. Steroid-related ocular side effects are elevated intraocular pressure and cataract, while injection-related complications include endophthalmitis, vitreous hemorrhage, and retinal detachment. In order to reduce the risks and complications, intravitreal implants have been developed recently to provide sustained release of corticosteroids and reduce repeated injections for the management of diabetic macular edema. In this review, the efficacy, safety, and therapeutic potential of intravitreal corticosteroids in diabetic macular edema are discussed with a review of recent literature.

Oxidative stress and diabetic retinopathy: development and treatment

Diabetic retinopathy (DR) is the most common microvascular complication in diabetic patients and one of the main causes of acquired blindness in the world. From the 90s until date, the incidence of this complication has increased. Reactive oxygen species (ROS) is a free radical with impaired electron that usually participates in the redox mechanisms of some body molecules such as enzymes, proteins, and so on. In normal biological conditions, ROS is maintained in equilibrium, however its overproduction can lead to biological process called oxidative stress and this is considered the main pathogenesis of DR. The retina is susceptible to ROS because of high-energy demands and exposure to light. When the balance is broken, ROS produces retinal cell injury by interacting with the cellular components. This article describes the possible role of oxidative stress in the development of DR and proposes some treatment options based on its stages. The review of the topic shows that blindness caused by DR can be avoided by early detection and timely treatment.

Considerations for management of patients with diabetic macular edema: Optimizing treatment outcomes and minimizing safety concerns through interdisciplinary collaboration

Diabetes is a growing worldwide epidemic and a leading cause of blindness in working-age people around the world. Diabetic retinopathy (DR) and diabetic macular edema (DME) are common causes of visual impairment in people with diabetes and often indicate the presence of diabetes-associated preclinical micro- and macrovascular complications. As such, patients with DR and DME often display complex, highly comorbid profiles. Several treatments are currently available for the treatment of DME, including anti-vascular endothelial growth factor (VEGF) agents, which are administered via intravitreal injection. While the safety profiles of approved ocular anti-VEGF therapies have been reassuring, the high-risk nature of the DME patient population means that treatment must be carefully considered and a holistic approach to disease management should be taken. This requires multidisciplinary, collaborative care involving all relevant specialties to ensure that patients not only receive prompt treatment for DME but also appropriate consideration is taken of any systemic comorbidities to evaluate and minimize potentially serious safety issues.

Efficacy and Safety of Intravitreal Dexamethasone Implants for Treatment of Refractory Diabetic Macular Edema

Purpose

To evaluate the safety and efficacy of intravitreal dexamethasone (IVD) implants in eyes with diabetic macular edema that did not respond to previous treatment.

Methods

We included 46 eyes of 46 patients in this retrospective study. Each month, we recorded patient visual acuity with logarithm of the minimum angle of resolution using the Early Treatment Diabetic Retinopathy Study chart, central macular thickness measurements with optical coherence tomography, intraocular pressure (IOP), and posttreatment complication occurrence.

Results

The mean follow-up time was 8.95 ± 1.33 months (range, 6 to 12). Best-corrected visual acuity improved significantly in the first 4 months after IVD, but no statistically significant change was observed over the following 2 months. Although a statistically significant decrease in central macular thickness was observed in the first 3 months, the change was not statistically significant in the following 3 months. There was a statistically significant increase in IOP in the first 2 months, but no statistically significant change was observed in the following months. IOP was controlled with medication in all patients with elevated IOP. Of the 26 phakic patients, two had cataracts requiring surgery.

Conclusions

Cases of refractory diabetic macular edema that did not respond to previous treatment, such as anti-vascular endothelial growth factor injections and laser photocoagulation, exhibited improvements in visual acuity and decreases in retinal thickness after IVD implantation. Both functional and anatomical effects were observed in the first 3 months after injection. Repeat injections and frequent examination might be required for continued improvement. Side effects, such as cataracts and elevation of IOP, may require medical or surgical treatment.

Adrenomedullin Suppresses Vascular Endothelial Growth Factor-Induced Vascular Hyperpermeability and Inflammation in Retinopathy

Diabetic macular edema (DME) is caused by blood-retinal barrier breakdown associated with retinal vascular hyperpermeability and inflammation, and it is the major cause of visual dysfunction in diabetic retinopathy. Adrenomedullin (ADM) is an endogenous peptide first identified as a strong vasodilator. ADM is expressed in the eyes and is up-regulated in various eye diseases, although the pathophysiological significance is largely unknown. We investigated the effect of ADM on DME. In Kimba mice, which overexpress human vascular endothelial growth factor in their retinas, the capillary dropout, vascular leakage, and vascular fragility characteristic of diabetic retinopathy were observed. Intravitreal or systemic administration of ADM to Kimba mice ameliorated both the capillary dropout and vascular leakage. Evaluation of the transendothelial electrical resistance and fluorescein isothiocyanate-dextran permeability of an endothelial cell monolayer using TR-iBRB retinal capillary endothelial cells revealed that vascular endothelial growth factor enhanced vascular permeability but that co-administration of ADM suppressed the effect, in part by enhancing tight junction formation between endothelial cells. In addition, a comprehensive PCR array analysis showed that ADM administration suppressed various molecules related to inflammation and NF-κB signaling within retinas. From these results, we suggest that by exerting inhibitory effects on retinal inflammation, vascular permeability, and blood-retinal barrier breakdown, ADM could serve as a novel therapeutic agent for the treatment of DME.

Combination of Anti-VEGF and Laser Photocoagulation for Diabetic Macular Edema: A Review

Diabetic macular edema (DME) is the most common cause of vision loss in diabetic patients. Thirty years ago, the Early Treatment Diabetic Retinopathy Study (ETDRS) demonstrated that focal/grid laser photocoagulation reduces moderate vision loss from DME by 50% or more; thus, macular photocoagulation became the gold standard treatment for DME. However, with the development of anti-VEGF drugs (bevacizumab, ranibizumab, and aflibercept), better outcomes were obtained in terms of visual acuity gain and decrease in macular thickness in some studies when antiangiogenic drugs were administered in monotherapy. Macular laser therapy may still play an important role as an adjuvant treatment because it is able to improve macular thickness outcomes and reduce the number of injections needed. Here, we review some of the clinical trials that have assessed the efficacy of macular laser treatment, either as part of the treatment protocol or as rescue therapy.

INTRAOCULAR PRESSURE IN PATIENTS WITH DIABETIC MACULAR EDEMA TREATED WITH DEXAMETHASONE INTRAVITREAL IMPLANT IN THE 3-YEAR MEAD STUDY

PURPOSE

To evaluate the occurrence, management, and clinical significance of increases in intraocular pressure (IOP) in patients with diabetic macular edema treated with dexamethasone intravitreal implant (DEX implant).

METHODS

Randomized, multicenter, 3-year, Phase III study. Patients (N = 1,048) with diabetic macular edema were randomized to DEX implant 0.7-mg, DEX implant 0.35-mg, or sham procedure with retreatment allowed at ≥6-month intervals (seven injections maximum).

RESULTS

In the DEX implant 0.7-mg, DEX implant 0.35-mg, and sham groups, respectively, ≥10-mmHg IOP increases from baseline occurred in 27.7%, 24.8%, and 3.7% of patients, and their frequency did not increase with repeat injections. IOP-lowering medication was used by 41.5%, 37.6%, and 9.1% of patients. Only one patient (0.3%) in each DEX implant group had filtering surgery to manage a steroid-induced IOP increase. Among DEX implant 0.7-mg-treated patients with and without a ≥10-mmHg IOP increase, 21.9% (21 of 96) and 22.4% (57 of 255), respectively, achieved ≥15-letter best-corrected visual acuity gain at the end of the study, and mean average change in central retinal thickness from baseline was -127 μm and -106 μm, respectively.

CONCLUSION

DEX implant demonstrated clear benefit of treatment despite increases in IOP. Sequential implants had no cumulative effect on IOP.

Evidence-based review of diabetic macular edema management: Consensus statement on Indian treatment guidelines

The purpose of the study was to review the current evidence and design a diabetic macular edema (DME) management guideline specific for India. The published DME guidelines from different organizations and publications were weighed against the practice trends in India. This included the recently approved drugs. DME management consisted of control of diabetes and other associated systemic conditions, such as hypertension and hyperlipidemia, and specific therapy to reduce macular edema. Quantification of macular edema is precisely made with the optical coherence tomography and treatment options include retinal laser, intravitreal anti-vascular endothelial growth factors (VEGF), and implantable dexamethasone. Specific use of these modalities depends on the presenting vision and extent of macular involvement. Invariable eyes with center-involving macular edema benefit from intravitreal anti-VEGF or dexamethasone implant therapy, and eyes with macular edema not involving the macula center benefit from retinal laser. The results are illustrated with adequate case studies and frequently asked questions. This guideline prepared on the current published evidence is meant as a guideline for the treating physicians.

The anti-ALS drug riluzole attenuates pericyte loss in the diabetic retinopathy of streptozotocin-treated mice

Loss of pericytes, considered an early hallmark of diabetic retinopathy, is thought to involve abnormal activation of protein kinase C (PKC). We previously showed that the anti-amyotrophic lateral sclerosis (ALS) drug riluzole functions as a PKC inhibitor. Here, we examined the effects of riluzole on pathological changes in diabetic retinopathy. Pathological endpoints examined in vivo included the number of pericytes and integrity of retinal vessels in streptozotocin (STZ)-induced diabetic mice. In addition, PKC activation and the induction of monocyte chemotactic protein (MCP1) were assessed in diabetic mice and in human retinal pericytes exposed to advanced glycation end product (AGE) or modified low-density lipoprotein (mLDL). The diameter of retinal vessels and the number of pericytes were severely reduced, and the levels of MCP1 and PKC were increased in STZ-induced diabetic mice. Administration of riluzole reversed all of these changes. Furthermore, the increased expression of MCP1 in AGE- or mLDL-treated cultured retinal pericytes was inhibited by treatment with riluzole or the PKC inhibitor GF109203X. In silico modeling showed that riluzole fits well within the catalytic pocket of PKC. Taken together, our results demonstrate that riluzole attenuates both MCP1 induction and pericyte loss in diabetic retinopathy, likely through its direct inhibitory effect on PKC.

Comparison of Cysts in Red and Green Images for Diabetic Macular Edema

PURPOSE

To investigate whether cysts in diabetic macular edema are better visualized in the red channel of color fundus camera images, as compared with the green channel, because color fundus camera screening methods that emphasize short-wavelength light may miss cysts in patients with dark fundi or changes to outer blood retinal barrier.

METHODS

Fundus images for diabetic retinopathy photoscreening were acquired for a study with Aeon Imaging, EyePACS, University of California Berkeley, and Indiana University. There were 2047 underserved, adult diabetic patients, of whom over 90% self-identified as a racial/ethnic identify other than non-Hispanic white. Color fundus images at nominally 45 degrees were acquired with a Canon Cr-DGi non-mydriatic camera (Tokyo, Japan) then graded by an EyePACS certified grader. From the 148 patients graded to have clinically significant macular edema by the presence of hard exudates in the central 1500 μm of the fovea, we evaluated macular cysts in 13 patients with cystoid macular edema. Age ranged from 33 to 68 years. Color fundus images were split into red, green, and blue channels with custom Matlab software (Mathworks, Natick, MA). The diameter of a cyst or confluent cysts was quantified in the red-channel and green-channel images separately.

RESULTS

Cyst identification gave complete agreement between red-channel images and the standard full-color images. This was not the case for green-channel images, which did not expose cysts visible with standard full-color images in five cases, who had dark fundi. Cysts appeared more numerous and covered a larger area in the red channel (733 ± 604 μm) than in the green channel (349 ± 433 μm, P < .006).

CONCLUSIONS

Cysts may be underdetected with the present fundus camera methods, particularly when short-wavelength light is emphasized or in patients with dark fundi. Longer wavelength techniques may improve the detection of cysts and provide more information concerning the early stages of diabetic macular edema or the outer blood retinal barrier.

An eighteen-month follow-up study on the effects of Intravitreal Dexamethasone Implant in diabetic macular edema refractory to anti-VEGF therapy

AIM

To evaluate the long-term efficacy and safety of dexamethasone implants in subjects affected by diabetic macular edema (DME) resistant to anti-vascular endothelial growth factor (VEGF) therapy.

METHODS

Thirty-two DME patients were enrolled. A 700 microgram slow release Intravitreal Dexamethasone Implant (Ozurdex^®) was placed in the vitreous cavity. All patients were followed for 18mo. Best-corrected visual acuity (BCVA) measured with Early Treatment Diabetic Retinopathy Study (ETDRS) and central macular thickness (CMT) exams were carried out at baseline (T0) and after 1 (T1), 3 (T3), 4 (T4), 6 (T6), 9 (T9), 12 (T12), 15 (T15), and 18mo (T18) post injection.

RESULTS

Repeated measures ANOVA showed an effect of treatment on ETDRS (P<0.0001). Post hoc analyses revealed that ETDRS values were significantly increased at T1, T3, T4, T9, and T15 (P<0.001) as compared to baseline value (T0). At T6, T12, and T18, ETDRS values were still statistically higher than baseline (P<0.001 vs T0). However, at these time points, we observed a trend to return to baseline conditions. ANOVA also showed an effect of treatment (P<0.0001). CMT decreased significantly at T1, T3, T4, T9, and T15 (P<0.001). At T6 (P<0.01), T12 and T18 (P<0.001) CMT was also significantly lower than T0 although a trend to return to the baseline conditions was also observed.

CONCLUSION

Our findings demonstrate that Intravitreal Dexamethasone Implant is a good option to improve BCVA and CMT in DME patients resistant to anti-VEGF therapy. Our data also show that the use of drugs administered directly into the vitreous allows achieving appropriate and long-lasting concentration at the site of disease without systemic side effects.