Diabetic macular edema: pathogenesis and treatment

PACAP and VIP Inhibit HIF-1α-Mediated VEGF Expression in a Model of Diabetic Macular Edema

Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) exert a protective role against retinal injuries, including diabetic macular edema (DME). The macular damage is induced by hyperglycemia, which damages vessels supplying blood to the retina and induces hypoxia. The microenvironmental changes stimulate the expression of hypoxia-inducible factors (HIFs), which promote the choroidal endothelial cell transmigration across the retinal pigmented epithelium (RPE) into neurosensory retina, where they proliferate into new vessels under stimulation of the vascular endothelial growth factor (VEGF). In the present study, we have investigated whether PACAP and VIP prevent retinal damage by modulating the expression of HIFs, VEGF, and its receptors. In accord to our hypothesis, we have shown that both peptides are able to significantly reduce HIF-1α and increase HIF-3α expression in ARPE-19 cells exposed to hyperglycemic/hypoxic insult. This effect is also related to a reduction of VEGF and its receptors expression. Moreover, both peptides also reduce the activation of p38 mitogen-activated protein kinase (MAPK), a pro-apoptotic signaling pathway, which is activated by VEGFR-1 and 2 receptors. In conclusion, our study has further elucidated the protective role performed by PACAP and VIP, against the harmful combined effect of hyperglycemia/hypoxia characterizing the DME microenvironment. J. Cell. Physiol. 232: 1209-1215, 2017. © 2016 Wiley Periodicals, Inc.

Intravitreal Conbercept Injection with and without Grid Laser Photocoagulation in the Treatment of Diffuse Diabetic Macular Edema in Real-Life Clinical Practice

Purpose. To evaluate the efficacy of intravitreal conbercept (IVC) plus modified grid laser photocoagulation (MGP) versus IVC alone for treatment of diffuse diabetic macular edema (DDME). Methods. In this retrospective study, 51 DDME patients were treated with either IVC alone (IVC group) or IVC plus MGP (combined group) with 12 months of follow-up. The clinical records of those patients were reviewed. Results. 26 patients (31 eyes) received IVC alone and 25 patients (30 eyes) received combined therapy. At month 12, the mean best-corrected visual acuity (BCVA) letter score improvement was 9.1 ± 4.5 and 7.5 ± 4.2 in the IVC group and the combined group and the mean central retinal thickness (CRT) reduction was 145.1 ± 69.9 μm and 168.5 ± 53.6 μm, respectively. There was no statistically significant difference of improvement in BCVA (P = 0.164) and decrease in CRT (P = 0.149) between the two groups. The mean number of injections delivered was significantly higher (P < 0.001) in the IVC group (5.6 ± 0.8 per eye) than in the combined group (3.3 ± 1.2 per eye). Conclusions. IVC alone or combined with MGP appeared to be effective for treatment of DDME, achieving the similar clinical efficacy. Moreover, MGP helps to reduce the number of injections.

A Review on Recent Developments for Detection of Diabetic Retinopathy

Diabetic retinopathy is caused by the retinal micro vasculature which may be formed as a result of diabetes mellitus. Blindness may appear as a result of unchecked and severe cases of diabetic retinopathy. Manual inspection of fundus images to check morphological changes in microaneurysms, exudates, blood vessels, hemorrhages, and macula is a very time-consuming and tedious work. It can be made easily with the help of computer-aided system and intervariability for the observer. In this paper, several techniques for detecting microaneurysms, hemorrhages, and exudates are discussed for ultimate detection of nonproliferative diabetic retinopathy. Blood vessels detection techniques are also discussed for the diagnosis of proliferative diabetic retinopathy. Furthermore, the paper elaborates a discussion on the experiments accessed by authors for the detection of diabetic retinopathy. This work will be helpful for the researchers and technical persons who want to utilize the ongoing research in this area.

Histone Deacetylase Inhibition Restores Retinal Pigment Epithelium Function in Hyperglycemia

In diabetic individuals, macular edema is a major cause of vision loss. This condition is refractory to insulin therapy and has been attributed to metabolic memory. The retinal pigment epithelium (RPE) is central to maintaining fluid balance in the retina, and this function is compromised by the activation of advanced glycation end-product receptors (RAGE). Here we provide evidence that acute administration of the RAGE agonist, glycated-albumin (gAlb) or vascular endothelial growth factor (VEGF), increased histone deacetylase (HDAC) activity in RPE cells. The administration of the class I/II HDAC inhibitor, trichostatin-A (TSA), suppressed gAlb-induced reductions in RPE transepithelial resistance (in vitro) and fluid transport (in vivo). Systemic TSA also restored normal RPE fluid transport in rats with subchronic hyperglycemia. Both gAlb and VEGF increased HDAC activity and reduced acetyl-α-tubulin levels. Tubastatin-A, a relatively specific antagonist of HDAC6, inhibited gAlb-induced changes in RPE cell resistance. These data are consistent with the idea that RPE dysfunction following exposure to gAlb, VEGF, or hyperglycemia is associated with increased HDAC6 activity and decreased acetyl-α-tubulin. Therefore, we propose inhibiting HDAC6 in the RPE as a potential therapy for preserving normal fluid homeostasis in the hyperglycemic retina.

Diabetic Retinopathy in Patients with Diabetic Nephropathy: Development and Progression

The purpose of current study aims to investigate the development and progression of diabetic retinopathy (DR) in patients with diabetic nephropathy (DN) in a nationwide population-based cohort in Taiwan. Newly diagnosed DN patients and age- and sex-matched controls were identified from the Taiwanese Longitudinal Health Insurance Database from 2000 to 2010. We studied the effects of age, sex, hypertension, dyslipidemia, diabetic polyneuropathy (DPN), and medications on the development of nonproliferative DR (NPDR), proliferative DR (PDR), and diabetic macular edema (DME) in patients with DN. Cox proportional hazard regression analyses were used to estimate the adjusted hazard ratios (HRs) of the development of DR. Our results show that the adjusted HRs of NPDR and PDR were 5.01 (95% confidence interval (CI) = 4.68-5.37) and 9.7 (95% CI = 8.15-11.5), respectively, in patients with DN as compared with patients in the non-DN cohort. At 5-year follow-up, patients with DN showed an increased HR of NPDR progression to PDR (HR = 2.26, 95% CI = 1.68-3.03), and the major comorbidities were hypertension (HR = 1.23, 95% CI = 1.10-1.38 with NPDR; HR = 1.33, 95% CI = 1.02-1.72 with PDR) and DPN (HR = 2.03, 95% CI = 1.72-2.41 in NPDR; HR = 2.95, 95% CI = 2.16-4.03 in PDR). Dyslipidemia increased the HR of developing NPDR but not PDR or DME. Moreover, DN did not significantly affect DME development (HR = 1.47, 95% CI = 0.87-2.48) or progression (HR = 0.37, 95% CI = 0.11-1.20). We concluded that DN was an independent risk factor for DR development and progression; however, DN did not markedly affect DME development in this study, and the potential association between these disorders requires further investigation.

Subfoveal choroidal thickness in patients with diabetic retinopathy and diabetic macular oedema

PurposeTo investigate the relationship between subfoveal choroidal thickness, severity of diabetic retinopathy (DR), and the presence of diabetic macular oedema (DMO) using enhanced depth imaging spectral domain optical coherence tomography (EDI-OCT) in patients with type 2 diabetes.MethodsA retrospective study of 145 eyes from untreated, type 2 diabetic patients who attended clinic at the Oxford Eye Hospital between January 2012 and February 2013, and underwent fundus photography and EDI-OCT imaging. Eyes were divided into two groups based on the presence or absence of foveal involving DMO and classified according to retinopathy grade: R1 (mild non-proliferative diabetic retinopathy (NPDR), R2 (moderate-severe NPDR), and R3 (proliferative diabetic retinopathy (PDR). Subfoveal choroidal thickness was measured on the EDI-OCT images and statistically analysed using Student's t-test.ResultsIn mild NPDR (n=87), the mean subfoveal choroidal thickness was 217.7 microns. In moderate-severe NPDR (n=37), the mean subfoveal choroidal thickness was 221.7 microns. In PDR (n=21), the mean subfoveal choroidal thickness was 242.1 microns. There was a statistically significant increase in choroidal thickness in PDR when compared with the mild NPDR group, P=0.027. DMO was associated with a non-statistically significant increase in choroidal thickness (225.4 microns) compared with eyes without DMO (209.3 microns), P=0.13.ConclusionSubfoveal choroidal thickness increased with the severity of diabetic retinopathy but showed no statistically significant association with the presence of DMO. This suggests that the choroidal layer is responsive to retinal vascular changes.

Angiogenesis and Inflammation Crosstalk in Diabetic Retinopathy

Diabetic retinopathy (DR) is one of the most prevalent microvascular complications of diabetes and one of the most frequent causes of blindness in active age. Etiopathogenesis behind this important complication is related to several biochemical, hemodynamic and endocrine mechanisms with a preponderant initial role assumed by polyol pathways, increment of growth factors, accumulation of advanced glycation end products (AGE), activation of protein kinase C (PKC), activation of the renin-angiotensin-aldosterone system (RAAS), and leukostasis. Chronic and sustained hyperglycemia works as a trigger to the early alterations that culminate in vascular dysfunction. Hypoxia also plays an essential role in disease progression with promotion of neovascularization and vascular dystrophies with vitreous hemorrhages induction. Thus, the accumulation of fluids and protein exudates in ocular cavities leads to an opacity augmentation of the cornea that associated to neurodegeneration results in vision loss, being this a devastating characteristic of the disease final stage. During disease progression, inflammatory molecules are produced and angiogenesis occur. Furthermore, VEGF is overexpressed by the maintained hyperglycemic environment and up-regulated by tissue hypoxia. Also pro-inflammatory mediators regulated by cytokines, such as tumor necrosis factor (TNF-α) and interleukin-1 beta (IL-1β), and growth factors leads to the progression of these processes, culminating in vasopermeability (diabetes macular edema) and/or pathological angiogenesis (proliferative diabetic retinopathy). It was found a mutual contribution between inflammation and angiogenesis along the process. J. Cell. Biochem. 117: 2443-2453, 2016. © 2016 Wiley Periodicals, Inc.

Efficacy and safety of sustained-delivery fluocinolone acetonide intravitreal implant in patients with chronic diabetic macular edema insufficiently responsive to available therapies: a real-life study

Purpose

To evaluate the efficacy and safety of sustained-delivery fluocinolone acetonide (FAc) intravitreal implant for diabetic macular edema (DME).

Patients and methods

Prospective study in patients with DME insufficiently responsive to laser and anti-vascular endothelial growth factor (anti-VEGF). Patients with history of rise of intraocular pressure after intravitreal corticosteroids were excluded.

Results

The macular edema rapidly decreased both in group 1 (prior laser only; n=7 eyes) and group 2 (prior laser and ≥3 monthly anti-VEGF therapy; n=10 eyes) and central subfield thickness was reduced by −299 μm (P=0.008) and −251 μm (P=0.016) at 12 months, respectively. Mean area under the curve from baseline to last value for pseudophakic eyes was +4.2 letters in group 1 and +9.5 letters in group 2. Overall, the FAc implant was well tolerated.

Conclusion

This prospective study confirms the efficacy of the FAc implant in DME patients insufficiently responsive to laser and anti-VEGF. Moreover, with a careful patient selection, our safety results would support an earlier use of FAc in the DME treatment pathway.

Plasma E-selectin levels can play a role in the development of diabetic retinopathy

PURPOSE

Diabetic retinopathy is one of the leading causes of blindness. There are several risk factors, such as the duration of diabetes or glycemic control of the patient; however, several biochemical factors also alter the process. Our aim was to investigate the role of soluble E-selectin in the formation of diabetic retinopathy.

PATIENTS AND METHODS

Fifty-seven patients (37 female and 20 male, aged 61.71 ± 12.31 years) and 14 healthy control subjects (ten female and four male, aged 63.06 ± 10.46 years) were enrolled in the study. We measured the soluble E-selectin level in the plasma of patients by ELISA. All patients underwent careful ophthalmological examination, including ophthalmoscopy and color fundus photography, while diabetic retinopathy grading was performed in line with the 2012 classification of the American Academy of Ophthalmology (AAO).

RESULTS

The soluble E-selectin level was significantly higher in patients with diabetes compared to controls (32.95 ng/ml vs. 26.55 ng/ml, p = 0.03). Dividing patients into groups by the presence of retinopathy, the E-selectin level was also significantly higher in the retinopathy group (p < 0.05). When we examined diabetic patients by the severity of retinopathy (groups A, B, and C, by the guidelines of the AAO), however, we did not find any significant difference in soluble E-selectin levels, although it tended to be higher in group B.

CONCLUSIONS

An elevated E-selectin level can play a role in the development of diabetic retinopathy, but it does not seem to alter disease severity. However, glycemic control and the reduction of cardiovascular risk factors may also alter the level of E-selectin that might play a role in the prevention of diabetic retinopathy.

Indocyanine-green-guided targeted laser photocoagulation of capillary macroaneurysms in macular oedema: a pilot study

AIMS

In longstanding diabetic macular oedema (DME) or retinal vein occlusion (RVO), capillary macroaneurysms may develop. Indocyanine green angiography (ICGA) has been shown to optimise their detection. Here, we report the anatomical and functional outcome of the elective photocoagulation of capillary macroaneurysms.

METHODS

A retrospective, interventional, two-centre study. In eyes with chronic macular oedema and severe hard exsudates due to diabetic retinopathy or RVO, the presence of capillary macroaneurysms (defined by a diameter larger than 150 µm) was assessed by ICGA and optical coherence tomography (OCT). Capillary macroaneurysms were selectively photocoagulated, the presence of photothrombosis within the lumen being assessed by immediate OCT.

RESULTS

Four eyes from three patients with DME and five eyes from five patients with RVO were included. The median duration of visual loss was 4 years. Median initial visual acuity (VA) was 20/200. The median number of capillary macroaneurysms per eye was 2 (range, 1-8) and their median size was 410 µm (range, 154-603). Six months after photocoagulation, there was a significant reduction in macular thickness (mean±SD, 528 µm±200 vs 271 µm±152, p<0.05) and improvement of VA (mean log MAR, 0.82 vs 0.58, p<0.05).

CONCLUSIONS

During macular oedema with severe hard exsudates due to DME or RVO, systematic detection of capillary macroaneurysms by ICGA followed by their OCT-controlled photocoagulation may be of interest. These results may contribute to re-evaluate the role of photocoagulation in the management of longstanding macular oedema.

The Effects of 23-Gauge Pars Plana Vitrectomy on Orbital Circulation Using Doppler Ultrasonography in Diabetic Macular Edema with Epiretinal Membrane and Taut Posterior Hyaloid

PURPOSE

To evaluate using Doppler ultrasonography (DUS) how pars plana vitrectomy (PPV) affects orbital circulation in diffuse diabetic macular edema (DME) associated with either the epiretinal membrane (ERM) or taut posterior hyaloid (TPH).

METHODS

The sample included 46 eyes of 42 patients with DME associated with the ERM (n = 22, Group 1) or TPH (n = 24, Group 2). All participants received panretinal laser photocoagulation and antivascular endothelial growth factor injections preoperatively and underwent 23-gauge PPV combined with ERM or TPH removal and internal limiting membrane (ILM) peeling. Pre- and postoperative peak systolic velocity (PSV), end-diastolic velocity (EDV), and the resistivity index (RI) of the ophthalmic artery (OA), central retinal artery (CRA), posterior ciliary artery (PCA), and central retinal vein were measured with DUS.

RESULTS

Statistically significant decreases in the PSV and EDV of the OA, CRA, and PCA were detected in all groups. In Group 1, the PSV of the OA and CRA as well as the EDV and PSV of the PCA declined significantly. In Group 2, the EDV of the OA and both the PSV and EDV of the CRA and PCA decreased. Postoperatively, the CRA's PSV and EDV were lower in Group 2, while the preoperative and postoperative RI of the CRA and preoperative RI of the PCA were greater in Group 2 than in Group 1. Changes in the CRA's RI, PSV, and EDV were greater in Group 2 after surgery.

CONCLUSIONS

23-Gauge PPV combined with ERM or TPH removal and ILM peeling in DME reduces blood flow rates of both choroidal and retinal vessels. In eyes with TPH, the RIs of the CRA and PCA were significantly greater preoperatively and the changes in the CRA's RI, PSV, and EDV were greater postoperatively. The removal of the TPH may play a role in regulating blood flow.

Progression of Diabetic Capillary Occlusion: A Model

An explanatory computational model is developed of the contiguous areas of retinal capillary loss which play a large role in diabetic maculapathy and diabetic retinal neovascularization. Strictly random leukocyte mediated capillary occlusion cannot explain the occurrence of large contiguous areas of retinal ischemia. Therefore occlusion of an individual capillary must increase the probability of occlusion of surrounding capillaries. A retinal perifoveal vascular sector as well as a peripheral retinal capillary network and a deleted hexagonal capillary network are modelled using Compucell3D. The perifoveal modelling produces a pattern of spreading capillary loss with associated macular edema. In the peripheral network, spreading ischemia results from the progressive loss of the ladder capillaries which connect peripheral arterioles and venules. System blood flow was elevated in the macular model before a later reduction in flow in cases with progression of capillary occlusions. Simulations differing only in initial vascular network structures but with identical dynamics for oxygen, growth factors and vascular occlusions, replicate key clinical observations of ischemia and macular edema in the posterior pole and ischemia in the retinal periphery. The simulation results also seem consistent with quantitative data on macular blood flow and qualitative data on venous oxygenation. One computational model applied to distinct capillary networks in different retinal regions yielded results comparable to clinical observations in those regions.

MicroRNA-126 contributes to Niaspan treatment induced vascular restoration after diabetic retinopathy

Diabetic retinopathy (DR) is a serious microvascular complication of diabetes and a major cause of blindness in the developing world. Early diabetic retinopathy is characterized by a loss of pericytes and vascular endothelial cells, a breakdown of the blood–retinal barrier, vascular dysfunction and vascular-neuroinflammation. However, optimal treatment options and related mechanisms are still unclear. MicroRNA-126 (miR-126) plays a potential role in the pathogenesis in DR, which may regulate VEGF, Ang-1 and VCAM-1 expressions. This study investigated the therapeutic effects and mechanisms of Niaspan treatment of DR in diabetes (DM) rats. DM rats exhibits significantly decreased miR-126 and tight junction Claudin-5/Occludin/ZO-1 genes expression, and increased Blood retinal-barrier (BRB) breakdown, retinal apoptosis and VEGF/VEGFR, as well as VCAM-1/CD45 expressions in the retina compared to normal control group. Niaspan treatment significantly improved clinical and histopathological outcomes; decreased the expressions of VEGF/VEGFR, VCAM-1/CD45, apoptosis and BRB breakdown, significantly increased tight junction proteins and Ang-1/Tie-2 expressions, as well as increased retinal miR-126 expression compared to non-treatment diabetic rats. These data are the first to show that Niaspan treatment ameliorates DR through its repair vascular and inhibits inflammatory effects, and also suggest that the miR-126 pathway may contribute to Niaspan treatment induced benefit effects.

Three-month outcome of intravitreal ziv-aflibercept in eyes with diabetic macular oedema

PURPOSE

We report the 3-month efficacy of monthly intravitreal ziv-aflibercept in patients with diabetic macular oedema (DME).

METHODS

Prospectively, consecutive patients with DME underwent intravitreal injection of 0.05 ml of compounded ziv-aflibercept (1.25 mg) from March 2015 to November 2015. Monitoring of best-corrected visual acuity (BCVA), intraocular inflammation, cataract progression and retinal structure by spectral domain optical coherence tomography was carried out at baseline, 1 week, 1 month, 2 months and 3 months after 3 monthly injections.

RESULTS

A total of 17 eyes (11 right eyes and 6 left eyes) were treated. The participants were divided into 10 Caucasians and 6 Indians, 11 men and 5 women, and had a mean age of 61.5 years. Five eyes were treatment-naïve cases and 12 eyes were treatment non- naïve with last treatment received at least more than 4-month interval. Mean BCVA in log MAR (equivalent Snellen visual acuity) improved from baseline 0.70 (20/100) to 0.49 (20/60) at 1 month, 0.43 (20/50) at 2 months and 0.42 (20/50) at 3 months (p ≤ 0.003). Central macular thickness decreased from mean baseline 517.5 to 388.1 μm at 1 week, 355.4 μm at 1 month, 351.4 μm at 2 months and 322.2 μm at 3 months (p ≤ 0.001).

CONCLUSIONS

Off-label use of intravitreal ziv-aflibercept improves visual acuity, without detectable ocular toxicity or systemic side effects in DME. It offers a less expensive alternative to the approved intravitreal aflibercept (Eylea), especially in the low/middle-income countries and in countries where Eylea is not available.

Diabetic Macular Edema

Diabetic macular edema (DME), one the most prevalent causes of visual loss in industrialized countries, may be diagnosed at any stage of diabetic retinopathy. The diagnosis, treatment, and follow up of DME have become straightforward with recent developments in fundus imaging, such as optical coherence tomography. Laser photocoagulation, intravitreal injections, and pars plana vitrectomy surgery are the current treatment modalities; however, the positive effects of currently available intravitreally injected agents are temporary. At this point, further treatment choices are needed for a permanent effect.

Short-pulse duration retinal lasers: a review

The development of lasers for biological use was an important medical advance in the 20th century with numerous evidence-based therapeutic applications to retinal disease, including capillary leakage at the macula. Although the role of photocoagulative laser in the treatment of macular oedema has diminished, there is evidence for a modified role in clinical management, particularly for extrafoveal leakage. Additionally, it may reduce the frequency of required intravitreal injections and assist in visual stabilization when used as an adjunct. The tissue destructive effect of photocoagulative lasers has motivated the development of safer macular lasers and the search for novel therapeutic applications, including treatment of drusen and regeneration of dysfunctional retinal pigment epithelium.

Intravitreal Injection of Ozurdex(®) Implant in Patients with Persistent Diabetic Macular Edema, with Six-Month Follow-Up

AIM

To evaluate the efficacy of intravitreal dexamethasone injections in diabetic macular edema (DME).

METHODS

A 700 μg slow-release intravitreal dexamethasone implant (Ozurdex®) was placed in the vitreal cavity of 17 patients (19 eyes) affected with persistent DME. Best corrected visual acuity (BCVA) was assessed through Early Treatment Diabetic Retinopathy Study (ETDRS). Central macular thickness (CMT) was measured by spectral-domain optical coherence tomography. BCVA and CMT examinations were carried out at baseline (T0) and repeated after three days, one month (T1), three months (T3), four months (T4), and six months (T6) post injection.

RESULTS

Dexamethasone implant induced an improvement in ETDRS at T1, T3, T4, and T6 post injection. CMT was reduced at T1, T3, and T4, while at T6, CMT values were not statistically different from baseline. No complications were observed during the follow-up.

CONCLUSION

Our data suggest that dexamethasone implant is effective in reducing DME symptoms within a six-month frame.

EFFECT OF INTERNAL LIMITING MEMBRANE PEELING DURING VITRECTOMY FOR DIABETIC MACULAR EDEMA: Systematic Review and Meta-analysis

PURPOSE

To evaluate the effect of internal limiting membrane (ILM) peeling during vitrectomy for diabetic macular edema.

METHODS

MEDLINE, EMBASE, and CENTRAL were systematically reviewed. Eligible studies included randomized or nonrandomized studies that compared surgical outcomes of vitrectomy with or without ILM peeling for diabetic macular edema. The primary and secondary outcome measures were postoperative best-corrected visual acuity and central macular thickness. Meta-analysis on mean differences between vitrectomy with and without ILM peeling was performed using inverse variance method in random effects.

RESULTS

Five studies (7 articles) with 741 patients were eligible for analysis. Superiority (95% confidence interval) in postoperative best-corrected visual acuity in ILM peeling group compared with nonpeeling group was 0.04 (-0.05 to 0.13) logMAR (equivalent to 2.0 ETDRS letters, P = 0.37), and superiority in best-corrected visual acuity change in ILM peeling group was 0.04 (-0.02 to 0.09) logMAR (equivalent to 2.0 ETDRS letters, P = 0.16). There was no significant difference in postoperative central macular thickness and central macular thickness reduction between the two groups.

CONCLUSION

The visual acuity outcomes using pars plana vitrectomy with ILM peeling versus no ILM peeling were not significantly different. A larger randomized prospective study would be necessary to adequately address the effectiveness of ILM peeling on visual acuity outcomes.

Comorbidity and Health Care Resource Use Among Commercially Insured Non-Elderly Patients With Diabetic Macular Edema

BACKGROUND AND OBJECTIVE

Diabetic macular edema (DME) is a leading cause of blindness for non-elderly adults; however, health care-associated burden data from this population is lacking. The authors describe health care-associated burden in non-elderly patients with DME compared to those with diabetes and no DME.

PATIENTS AND METHODS

In this retrospective, large-cohort study examines enrollment and health care claims (2007 to 2011) from a national database of insured patients aged 18 to 63 years (mean: 51). Comorbidity and health care utilization differences between patients with DME (n = 24,326) and matched controls with diabetes but no DME (n = 122,710) were analyzed over 1 and 3 years.

RESULTS

DME patients had significantly more baseline comorbidities, and generally developed them at a higher rate over the study. Health care resource utilization rates were significantly higher in DME patients for every category analyzed. Patients with DME averaged more than 10 health care visits more than those with diabetes but no DME (25.5 vs 14.9; P < .001).

CONCLUSION

Working-age patients with DME exhibit a complicated comorbidity profile and high associated burden of health care consumption. Considering this burden is critical for managing this complex population.

Novel strategies for the treatment of diabetic macular edema

Macular edema such as diabetic macular edema (DME) and diabetic retinopathy are devastating back-of-the-eye retinal diseases leading to loss of vision. This area is receiving considerable medical attention. Posterior ocular diseases are challenging to treat due to complex ocular physiology and barrier properties. Major ocular barriers are static (corneal epithelium, corneal stroma, and blood-aqueous barrier) and dynamic barriers (blood-retinal barrier, conjunctival blood flow, lymph flow, and tear drainage). Moreover, metabolic barriers impede posterior ocular drug delivery and treatment. To overcome such barriers and treat back-of-the-eye diseases, several strategies have been recently developed which include vitreal drainage, laser photocoagulation and treatment with biologics and/or small molecule drugs. In this article, we have provided an overview of several emerging novel strategies including nanotechnology based drug delivery approach for posterior ocular drug delivery and treatment with an emphasis on DME.

Anti-inflammatory effects of the hydroxycarboxylic acid receptor 2

The hydroxycarboxylic acid receptors (HCA1-3) are a family of G-protein-coupled receptors that are critical for sensing endogenous intermediates of metabolism. All three receptors are predominantly expressed on adipocytes and mediate anti-lipolytic effects. In addition to adipocytes, HCA2 is highly expressed on immune cells, including macrophages, monocytes, neutrophils and dermal dendritic cells, among other cell types. The endogenous ligand for HCA2 is beta-hydroxybutyrate (β-OHB), a ketone body produced by the liver through β-oxidation when an individual is in a negative energy balance. Recent studies demonstrate that HCA2 mediates profound anti-inflammatory effects in a variety of tissues, indicating that HCA2 may be an important therapeutic target for treating inflammatory disease processes. This review summarizes the roles of HCA2 on inflammation in a number of tissues and clinical states.

The effectiveness of vitrectomy for diffuse diabetic macular edema may depend on its preoperative optical coherence tomography pattern

BACKGROUND

To investigate the effectiveness of vitrectomy for diffuse diabetic macular edema (DDME) and its dependence on optical coherence tomography (OCT) findings.

METHODS

The records of 65 patients and 81 eyes who received vitrectomy for DDME and followed up for at least 6 months were retrospectively reviewed. All eyes were classified according to their morphological characteristics on OCT including sponge-like diffuse retinal thickening (SDRT: n = 13), cystoid macular edema (CME: n = 42), serous retinal detachment (SRD: n = 13), and the combination of all morphological characteristics (FULL: n = 13). The best-corrected visual acuity (BCVA) and spectral domain OCT were investigated preoperatively and at 1, 3, and 6 months postoperatively.

RESULTS

At six months after surgery, BCVA in logMAR units was significantly improved in all groups except the SDRT group. The improvement was -0.04 ± 0.20 in the SDRT group (P = 0.504), -0.16 ± 0.24 in the CME group (P < 0.01), -0.32 ± 0.32 in the SRD group (P < 0.01), and -0.26 ± 0.19 in the FULL group (P < 0.01), and significantly better in eyes with subretinal fluid (SRF; the SRD and FULL groups) than in eyes without SRF (the SDRT and CME groups, P = 0.003).

CONCLUSIONS

Vitrectomy can be a useful treatment option for DDME, particularly for eyes with SRF.

Fluocinolone acetonide for the treatment of diabetic macular edema

In addition to VEGF inhibitors such as ranibizumab, aflibercept or bevacizumab, clinical and experimental investigations have revealed the great potential of steroids in the treatment of DME. At present two intravitreal steroid inserts are approved for the treatment of DME containing either dexamethasone or fluocinolone acetat (FA) as a pharmacological compound. The non degradable intravitreal FA insert releases 0.2 µg FA per day (Iluvien, Alimera Sciences). Clinical phase III studies have demonstrated the beneficial effect of the FA insert to last up to three years, especially in patients with a prolonged history of DME of at least three years at the initiation of therapy. While the treatment appears to be well tolerated over all, side effects such as cataract formation in nearly all treated phakic patients and raise of intraocular pressure need to be discussed with the patients as potential complications of the treatment.

New Diagnostic and Therapeutic Approaches for Preventing the Progression of Diabetic Retinopathy

Diabetic retinopathy (DR) is a severe sight-threatening complication of diabetes mellitus. Retinal laser photocoagulation, antivascular endothelial growth factors, steroid therapy, and pars plana vitrectomy are now used extensively to treat advanced stages of diabetic retinopathy. Currently, diagnostic devices like ultrawide field fundus fluorescein angiography and the improvement of optical coherence tomography have provided quicker and more precise diagnosis of early diabetic retinopathy. Thus, treatment protocols have been modified accordingly. Various types of lasers, including the subthreshold micropulse laser and RPE-targeting laser, and selective targeted photocoagulation may be future alternatives to conventional retinal photocoagulation, with fewer complications. The new developed intravitreal medications and implants have provided more therapeutic options, with promising results.

Morphology and Function over a One-Year Follow Up Period after Intravitreal Dexamethasone Implant (Ozurdex) in Patients with Diabetic Macular Edema

Background

To investigate changes in macular morphology and function after an intravitreal dexamethasone implant for diabetic macular edema (DME).

Methods

Twenty-seven eyes in 27 treatment-naive patients affected by DME were treated with intravitreal Ozurdex® injections (IVOI) and followed up 12 months to evaluate morphological and functional changes by means of best-corrected visual acuity (BCVA), microperimetry (MP1), multifocal electroretinography (mfERG), pattern electroretinography (PERG) and spectral domain optical coherence tomography (SD-OCT).

Results

Both BCVA and retinal sensitivity improved significantly at one month after the IVOI (p = 0.031 and p<0.0001, respectively). After five months, the improvement of BCVA remained statistically significant compared with baseline values (p = 0.022); retinal sensitivity improvement was statistically significant for up to four months after the IVOI (p = 0.059). Moreover, central macular thickness significantly decreased for up to four months. Interestingly, PERG and mfERG values did not change significantly for up to four months post-IVOI, but then began to worsen.

Conclusions

In eyes with DME, intravitreal dexamethasone implant determined morphological and functional improvement as soon as one month and for up to four months after the treatment.

Efficacy of single-dose dexamethasone implantation in patients with persistent diabetic macular edema

To investigate the efficacy of single-dose intravitreal dexamethasone implantation in the treatment of persistent diabetic macular edema (DME) unresponsive to 3 consecutive ranibizumab injections over a period of 6 months. Forty-one patients with a previous history of treatment for DME including at least three consecutive intravitreal ranibizumab injections were enrolled in this retrospective study. Main outcome measures were change in best-corrected visual acuity (BCVA), central macular thickness (CMT), and intraocular pressure from baseline to 6th month. At the baseline, the mean CMT was 572.4 ± 123.1 μm which improved to 264.2 ± 114.4, 317.7 ± 141.7, 410.6 ± 169.1, and 382.8 ± 181.5 μm at the 1st, 3rd, 5th, and 6th month, respectively (p < 0.05). The preoperative mean BCVA was 0.85 ± 0.54 logMAR units which improved to 0.76 ± 0.5 (p = 0.08), 0.69 ± 0.4 (p = 0.02), 0.74 ± 0.4 (p = 0.284), and 0.72 ± 0.3 (p = 0.489) logMAR units at the 1st, 3rd, 5th, and 6th months, respectively. Additional injections were required for 13 (31 %) eyes at 3rd month and 14 (34 %) eyes at 5th month due to recurrence of macular edema. Intravitreal dexamethasone implantation caused a significant improvement of BCVA and reduction of CMT in the patients with persistent DME that were unresponsive to 3 consecutive ranibizumab injections. However, retreatment before 6 months in the majority of the patients was needed despite the beneficial effects after the index procedure.

Effects of intravitreal injection of netrin-1 in retinal neovascularization of streptozotocin-induced diabetic rats

Background

In a previous study, we confirmed that netrin-1 acts as an antiangiogenic factor by inhibiting alkali burn-induced corneal neovascularization in rats. Here, we continue working on the role of netrin-1 in retinal neovascularization.

Methods

Using an in vitro angiogenesis assay, we detected the effects of netrin-1 on human umbilical vein endothelial cell tube formation, viability and proliferation, migration, and invasion at concentrations of 0.1 μg/mL or 5 μg/mL. We intravitreally injected 0.1 μg/mL or 5 μg/mL netrin-1 into streptozotocin-induced rats to assess retinal neovascularization using retinal electrophysiology and electroretinography, enzyme-linked immunosorbent assay, fundus fluoresce in angiography, measurement of inner blood retinal barrier, retinal hematoxylin-eosin staining, and retinal flat-mount fluorescence assays.

Results

Human umbilical vein endothelial cell tube formation, viability and proliferation, migration, and invasion were upregulated by netrin-1 at a concentration of 0.1 μg/mL (P<0.05), while 5 μg/mL netrin-1 had an opposite effect (P<0.05) in our in vitro angiogenesis assay. Retinal electrophysiology testing revealed that intravitreal injection of netrin-1 affected the amplitude of a- and b-waves (a-wave: 0.1 μg/mL netrin-1 =17.67±3.39 μm, 5 μg/mL netrin-1 =28.50±1.31 μm, phosphate-buffered saline [PBS]-treated =17.67±3.39 μm; b-wave: 0.1 μg/mL netrin-1 =44.67±4.80 μm, 5 μg/mL netrin-1 =97.17±9.63 μm, PBS-treated =44.67±4.80 μm) and the expression of VEGF-A (no-treatment rats, 9.29±0.80 pg/mL; PBS-treated rats, 19.64±3.77 pg/mL; 0.1 μg/mL netrin-1 treated rats, 21.37±3.64 pg/mL; 5 μg/mL netrin-1 treated rats, 9.85±0.54 pg/mL, at 6 weeks after induction). By comparing fluoresce in angiography, level of inner blood retinal barrier breakdown (% of control), retinal hematoxylin-eosin staining, and collagen-IV fluorescence assays in the retinas of PBS-treated rats, netrin-1 was found to suppress and reverse retinal neovascularization at a concentration of 5 μg/mL (P<0.05), while 0.1 μg/mL netrin-1 (P<0.05) led to an increase in the number of new retinal blood vessels, after 6 weeks’ injection.

Conclusion

Netrin-1 could play a significant role in retinal neovascularization by dual-direction regulating angiogenesis dependent on dosage.

Anatomical effects of dexamethasone intravitreal implant in diabetic macular oedema: a pooled analysis of 3-year phase III trials

BACKGROUND/AIM

To assess long-term effects of dexamethasone intravitreal implant (DEX implant) monotherapy on retinal morphology in diabetic macular oedema (DME).

METHODS

Two multicentre, masked, phase III studies with identical protocols randomised patients with DME, best-corrected visual acuity of 34-68 Early Treatment Diabetic Retinopathy Study letters and central subfield retinal thickness (CSRT) ≥300 µm to DEX implant 0.7, 0.35 mg or sham procedure. Patients were followed up for 3 years (39 months if treated at month 36), with retreatment allowed at ≥6-month intervals. Patients needing other macular oedema (ME) therapy exited the study. Changes from baseline in CSRT, macular volume and ME grade, area of retinal thickening, macular leakage, macular capillary loss and diabetic retinopathy severity were assessed.

RESULTS

After 3 years, more eyes treated with DEX implant 0.7 and 0.35 mg than sham showed improvement (although small) in ME grade (p<0.05 vs sham). DEX implant 0.7 mg delayed time to onset of two-step progression in diabetic retinopathy severity by ∼12 months. DEX implant 0.7 and 0.35 mg produced small, non-sustained reductions in macular leakage but had no significant effect on macular capillary loss.

CONCLUSIONS

DEX implant 0.7 or 0.35 mg, administered at ≥6-month intervals over 3 years, produced sustained retinal structural improvement in DME.

TRIAL REGISTRATION NUMBER

NCT00168337 and NCT00168389.

Spectral-domain optical coherence tomography findings of tractional retinal elevation in patients with diabetic retinopathy

PURPOSE

To evaluate the clinical and morphological characteristics as well as the surgical outcomes of tractional retinal elevation (TRE) in patients with proliferative diabetic retinopathy (PDR) by analyzing spectral-domain optical coherence tomography (SD-OCT).

METHODS

SD-OCT images of 26 eyes (24 patients) who visited our clinic because of TRE and PDR from August 2011 to August 2014 were reviewed. According to the presence or absence of tractional retinal detachment (TRD), patients were classified into group 1 (without TRD) or group 2 (with TRD), and the clinical characteristics and surgical outcomes of the two groups were compared. Furthermore, we categorized the SD-OCT morphological components into sponge, cystoid, saw tooth, bridging columnar, and TRD and compared the characteristics among patients who had different components.

RESULTS

Group 1 had 18 eyes and group 2 had eight eyes. No differences in age, best corrected visual acuity (BCVA), or spherical equivalent were observed between the two groups, but group 2 had longer axial length than that of group 1 (p = 0.02). A large variety of combined OCT findings was found in group 1 compared to that in group 2. TRD was the least combined form with the other morphological components. Although 92 % of eyes with the bridging columnar component had the cystoid component, TRD and tractional retinoschisis (TRS, bridging columnar morphology) were combined in only one eye.

CONCLUSION

Diabetic TRE may progress to TRD or TRS, which are mutually exclusive. They may progress to TRD in eyes with a long axial length, and cystoid macular edema seems to develop into TRS.

Ranibizumab 0.5 mg treat-and-extend regimen for diabetic macular oedema: the RETAIN study

Aims

To demonstrate non-inferiority of ranibizumab treat-and-extend (T&E) with/without laser to ranibizumab pro re nata (PRN) for best-corrected visual acuity (BCVA) in patients with diabetic macular oedema (DMO).

Methods

A 24-month single-masked study with patients randomised 1:1:1 to T&E+laser (n=121), T&E (n=128) or PRN (control; n=123). All patients received monthly injections until BCVA stabilisation. The investigator decided on re-treatment in the PRN and treatment-interval adaptations in the T&E groups based on loss of BCVA stability due to DMO activity. Likewise, laser treatment was at investigator's discretion. Collectively, these features reflect a real-life scenario. Endpoints included mean average change in BCVA from baseline to months 1–12 (primary), mean BCVA change from baseline to months 12 and 24, treatment exposure and safety profile.

Results

Both T&E regimens were non-inferior to PRN based on mean average BCVA change from baseline to months 1–12 (T&E+laser: +5.9 and T&E: +6.1 vs PRN: +6.2 letters; both p<0.0001). Mean BCVA change at month 24 was similar across groups (+8.3, +6.5 and +8.1 letters, respectively). The mean number of injections was 12.4 and 12.8 in the T&E+laser and T&E groups and 10.7 in the PRN group. The T&E regimens showed 46% reduction in the number of clinic visits. Over 70% of patients maintained their BCVA, with treatment intervals of ≥2 months over 24 months. Safety profile was consistent with that described in the product information.

Conclusions

T&E is a feasible treatment option for patients with DMO, with a potential to reduce treatment burden. Slightly more injections were required versus PRN, likely due to the specifics of the T&E regimen applied here.

Trial registration number

NCT01171976.

Application of different imaging modalities for diagnosis of Diabetic Macular Edema: A review

Diabetic Macular Edema (DME) is caused by accumulation of extracellular fluid from hyperpermeable capillaries within the macula. DME is one of the leading causes of blindness among Diabetes Mellitus (DM) patients. Early detection followed by laser photocoagulation can save the visual loss. This review discusses various imaging modalities viz. biomicroscopy, Fluorescein Angiography (FA), Optical Coherence Tomography (OCT) and colour fundus photographs used for diagnosis of DME. Various automated DME grading systems using retinal fundus images, associated retinal image processing techniques for fovea, exudate detection and segmentation are presented. We have also compared various imaging modalities and automated screening methods used for DME grading. The reviewed literature indicates that FA and OCT identify DME related changes accurately. FA is an invasive method, which uses fluorescein dye, and OCT is an expensive imaging method compared to fundus photographs. Moreover, using fundus images DME can be identified and automated. DME grading algorithms can be implemented for telescreening. Hence, fundus imaging based DME grading is more suitable and affordable method compared to biomicroscopy, FA, and OCT modalities.

Retinal Damage Induced by Internal Limiting Membrane Removal

The internal limiting membrane (ILM), the basement membrane of the Müller cells, serves as the interface between the vitreous body and the retinal nerve fiber layer. It has a fundamental role in the development, structure, and function of the retina, although it also is a pathologic component in the various vitreoretinal disorders, most notably in macular holes. It was not until understanding of the evolution of idiopathic macular holes and the advent of idiopathic macular hole surgery that the idea of adjuvant ILM peeling in the treatment of tractional maculopathies was explored. Today intentional ILM peeling is a commonly applied surgical technique among vitreoretinal surgeons as it has been found to increase the rate of successful macular hole closure and improve surgical outcomes in other vitreoretinal diseases. Though ILM peeling has refined surgery for tractional maculopathies, like all surgical procedures it is not immune to perioperative risk. The essential role of the ILM to the integrity of the retina and risk of trauma to retinal tissue spurs suspicion with regard to its routine removal. Several authors have investigated the retinal damage induced by ILM peeling and these complications have been manifested across many different diagnostic studies.

Safety and Efficacy of Intravitreal Preservative-Free Triamcinolone Acetonide (Triesence) for Macular Edema

PURPOSE

To evaluate the efficacy and safety of preservative-free triamcinolone acetonide (Triesence) for the treatment of macular edema.

METHODS

A retrospective study was conducted on patients who attended a tertiary retinal clinic from June 2009 to July 2012 with macular edema due to various causes. Patients who received at least 1 intravitreal Triesence injection and completed 6 months of follow-up were recruited. Data, including best-corrected Snellen visual acuity, central macular thickness (CMT), intraocular pressure (IOP), and adverse events (AEs), were collected at baseline, week 1, month 1, month 3, and month 6 after initiation of treatment. Snellen visual acuity was converted to visual acuity score (VAS) for statistical analysis using paired t-tests and linear regression.

RESULTS

One hundred two eyes from 102 patients were included in the study. Mean VAS was significantly improved at all follow-up time points compared to baseline (P≤0.002), with highest mean gain at month 1 (6.1±8.9 letters). Mean CMT decreased significantly at all follow-up points compared to baseline (P≤0.0005), with the greatest reduction at week 1 (146.6±109.4 μm). A total of 22 AEs were observed, and IOP elevation was the most common AE related to Triesence treatment (17/22, 77.3%). No sterile or infectious endophthalmitis was observed.

CONCLUSION

Intravitreal Triesence improves visual acuity and reduces macular thickness in eyes with macular edema from various causes. Treatment-associated IOP elevation was manageable with antiglaucoma medications. There were no serious vision-threatening complications associated with intravitreal Triesence therapy during the study period.

Dexamethasone intravitreal implant in the treatment of diabetic macular edema

Diabetic macular edema (DME) resembles a chronic, low-grade inflammatory reaction, and is characterized by blood–retinal barrier (BRB) breakdown and retinal capillary leakage. Corticosteroids are of therapeutic benefit because of their anti-inflammatory, antiangiogenic, and BRB-stabilizing properties. Delivery modes include periocular and intravitreal (via pars plana) injection. To offset the short intravitreal half-life of corticosteroid solutions (~3 hours) and the need for frequent intravitreal injections, sustained-release intravitreal corticosteroid implants have been developed. Dexamethasone intravitreal implant provides retinal drug delivery for ≤6 months and recently has been approved for use in the treatment of DME. Pooled findings (n=1,048) from two large-scale, randomized Phase III trials indicated that dexamethasone intravitreal implant (0.35 mg and 0.7 mg) administered at ≥6-month intervals produced sustained improvements in best-corrected visual acuity (BCVA) and macular edema. Significantly more patients showed a ≥15-letter gain in BCVA at 3 years with dexamethasone intravitreal implant 0.35 mg and 0.7 mg than with sham injection (18.4% and 22.2% vs 12.0%). Anatomical assessments showed rapid and sustained reductions in macular edema and slowing of retinopathy progression. Phase II study findings suggest that dexamethasone intravitreal implant is effective in focal, cystoid, and diffuse DME, in vitrectomized eyes, and in combination with laser therapy. Ocular complications of dexamethasone intravitreal implant in Phase III trials included cataract-related events (66.0% in phakic patients), intraocular pressure elevation ≥25 mmHg (29.7%), conjunctival hemorrhage (23.5%), vitreous hemorrhage (10.0%), macular fibrosis (8.3%), conjunctival hyperemia (7.2%), eye pain (6.1%), vitreous detachment (5.8%), and dry eye (5.8%); injection-related complications (eg, retinal tear/detachment, vitreous loss, endophthalmitis) were infrequent (<2%). Dexamethasone intravitreal implant offers a viable treatment option for DME, especially in cases that are persistent or treatment (anti-vascular endothelial growth factor/laser) refractory.

Posterior Subtenon's Capsule Triamcinolone Acetonide Injection for the Treatment of Diabetic Macular Edema

PURPOSE

To evaluate and compare the efficacy of posterior subtenon's triamcinolone injections versus grid laser photocoagulation (GLP) combined with posterior subtenon's triamcinolone injection in eyes with diabetic macular edema (DME).

METHODS

In this prospective clinical study, 42 eyes with DME that showed a decrease in visual acuity (VA) were included. The first group consisted of 22 eyes that received a posterior subtenon's injection of 40 mg of triamcinolone acetonide under topical anesthesia. The second group of 20 eyes received macular GLP applied 1 month after subtenon's triamcinolone acetonide (STTA) injection. All patients were evaluated at baseline and 1 day; 1, 2, 4, 6, and 8 weeks; and 3 and 6 months after injection. In some patients, injections were repeated after 3 months. The main outcome measures were VA, central macular thickness (CMT), intraocular pressure, cataract progression, and frequency of complications.

RESULTS

The mean baseline CMT for Group I was 456.85 ± 56.90 μm. The mean baseline CMT for Group II was 455.66 ± 57 μm. In the first group, mean CMTs for second week, 8th week, 12th week, and 6th month were 258.15, 276.50, 280.05, and 433.30 μm, respectively. In the second group, mean CMTs for second week, 8th week, 12th week, and 6th month were 261.42, 272.76, 284.71, and 291.76 μm, respectively. Before treatment, in the first group, the mean best-corrected visual acuity (BCVA) measured using a Snellen chart was 0.19, while the first week, third, and sixth month BCVA means were 0.59, 0.57, and 0.41, respectively. Before treatment, BCVA in the second group was 0.17, while the first week, third, and sixth month means were 0.61, 0.64, and 0.60, respectively. Treatment complications included cataracts in 4 eyes and glaucoma in 1 eye.

CONCLUSION

There is a temporary therapeutic effect of posterior subtenon's triamcinolone injection without laser photocoagulation. GLP improves VA and reduces the risk of recurrent macular edema after posterior STTA injection.

Long-term outcomes of phakic patients with diabetic macular oedema treated with intravitreal fluocinolone acetonide (FAc) implants

PURPOSE

Diabetic macular oedema (DMO) is a leading cause of blindness in working-age adults. Slow-release, nonbioerodible fluocinolone acetonide (FAc) implants have shown efficacy in the treatment of DMO; however, the National Institute for Health and Care Excellence recommends that FAc should be used in patients with chronic DMO considered insufficiently responsive to other available therapies only if the eye to be treated is pseudophakic. The goal of this analysis was to examine treatment outcomes in phakic patients who received 0.2 μg/day FAc implant.

METHODS

This analysis of the phase 3 FAME (Fluocinolone Acetonide in Diabetic Macular Edema) data examines the safety and efficacy of FAc implants in patients who underwent cataract extraction before (cataract before implant (CBI) group) or after (cataract after implant (CAI) group) receiving the implant. The data were further examined by DMO duration.

RESULTS

Best corrected visual acuity (BCVA) after 36 months was comparable in the CAI and CBI groups. Both the percentage of patients gaining ≥ 3 lines of vision and mean change in BCVA letter score were numerically greater in the CAI group. In addition, most patients who underwent cataract surgery experienced a net gain in BCVA from presurgery baseline as well as from original study baseline.

CONCLUSIONS

These data support the use of 0.2 μg/day FAc implants in phakic as well as in pseudophakic patients. These findings will serve as a pilot for design of future studies to evaluate the potential protective effect of FAc implants before cataract surgery in patients with DMO and cataract.

A review of therapies for diabetic macular oedema and rationale for combination therapy

Diabetic macular oedema (DMO) is responsible for significant visual impairment in diabetic patients. The primary cause of DMO is fluid leakage resulting from increased vascular permeability through contributory anatomical and biochemical changes. These include endothelial cell (EC) death or dysfunction, pericyte loss or dysfunction, thickened basement membrane, loss or dysfunction of glial cells, and loss/change of EC Glycocalyx. The molecular changes include increased reactive oxygen species, pro-inflammatory changes: advanced glycation end products, intracellular adhesion molecule-1, Complement 5-9 deposition and cytokines, which result in increased paracellular permeability, tight junction disruption, and increased transcellular permeability. Laser photocoagulation has been the mainstay of treatment until recently when pharmacological treatments were introduced. The current treatments for DMO target reducing vascular leak in the macula once it has occurred, they do not attempt to treat the underlying pathology. These pharmacological treatments are aimed at antagonising vascular endothelial growth factor (VEGF) or non-VEGF inflammatory pathways, and include intravitreal injections of anti-VEGFs (ranibizumab, aflibercept or bevacizumab) or steroids (fluocinolone, dexamethasone or triamcinolone) as single therapies. The available evidence suggests that each individual treatment modality in DMO does not result in a completely dry macula in most cases. The ideal treatment for DMO should improve vision and improve morphological changes in the macular (eg, reduce macular oedema) for a significant duration, reduced adverse events, reduced treatment burden and costs, and be well tolerated by patients. This review evaluates the individual treatments available as monotherapies, and discusses the rationale and potential for combination therapy in DMO. A comprehensive review of clinical trials related to DMO and their outcomes was completed. Where phase III randomised control trials were available, these were referenced, if not available, phase II trials have been included.

Current intravitreal pharmacologic therapies for diabetic macular edema

INTRODUCTION

Diabetic retinopathy is the leading cause of vision loss in working-age adults; it is a highly prevalent cause of vision loss overall and has a potent impact on the quality of life in those with diabetes mellitus and public health in general. Diabetic macular edema (DME) is the most common cause of vision loss from diabetic retinopathy. In patients with diabetes mellitus, chronic hyperglycemia leads to activation of the inflammatory cascade and retinal capillary damage that result in microaneurysm formation in the retina. In addition to the possibility of associated ischemia, microaneurysms are hyperpermeable; the resultant loss of the blood-retinal barrier leads to vision loss if consequent edema involves the center of the fovea. The standard of DME therapy for >25 years was focal laser photocoagulation applied to or near the microaneurysms. However, results from clinical trials of intravitreal vascular endothelial growth factor (VEGF) blockers and corticosteroids for the treatment of DME have led to a dramatic paradigm shift away from laser therapy to primary treatment with these pharmacologic agents.

METHODS

Medline literature search of approaches for treating DME.

RESULTS

Intravitreal pharmacologic treatments with anti-VEGF agents and corticosteroids have recently been shown to be superior to laser treatment of DME.

CONCLUSION

The existence of pharmacologic treatment of DME, shown to be superior to laser monotherapy, has created a seismic change in the approach of treatment of these patients. This review provides a summary of the therapies and the rationale regarding the current pharmacologic therapy of DME.