Comparative therapy evaluation of intravitreal bevacizumab and triamcinolone acetonide on persistent diffuse diabetic macular edema

Visual outcome after intravitreal bevacizumab depends on the optical coherence tomographic patterns of patients with diffuse diabetic macular edema

PURPOSE

The purpose of this study was to evaluate the effectiveness of intravitreal bevacizumab (IVB) on the reduction of diffuse diabetic macular edema in patients with different optical coherence tomography patterns.

DESIGN

Prospective interventional case series.

METHODS

One hundred and forty-three eyes with diffuse diabetic macular edema, without a history of any previous treatment, were classified according to their optical coherence tomography patterns: sponge-like diffuse retinal thickening (SDRT) (n = 50), cystoid macular edema (CME) (n = 38), serous retinal detachment (SRD) (n = 25), and the combination of all patterns (FULL: n = 30). All the participants received a single dose (1.25 mg in 0.05 mL) of IVB. The foveal thickness obtained with optical coherence tomography images and logarithm of the minimum angle of resolution visual acuity were assessed before receiving IVB and subsequently every 2 weeks for 12 weeks.

RESULTS

After IVB, the foveal thickness in all the groups was reduced but the reduction ratio in the SDRT (29.6 ± 15.6%) and CME (27.1 ± 20.5%) groups was significantly greater than in the SRD group (16.4 ± 17.7%) (P < 0.001). Similarly, improvement of visual acuity in the SDRT (-0.21 ± 0.16) and CME (-0.17 ± 0.24) groups was significantly greater than in the SRD (-0.12 ± 0.15) and FULL (-0.11 ± 0.13) (P = 0.047) groups. Interestingly, the efficacy of IVB for regression of diffuse diabetic macular edema was dependent on the duration of diabetes in the SDRT and CME groups but not in the SRD or FULL groups.

CONCLUSION

The effectiveness of IVB on diffuse diabetic macular edema was dependent on the optical coherence tomography pattern (SDRT ≥ CME >> SRD), indicating that vascular endothelial growth factor plays a critical role in the pathogenesis of SDRT and CME, and was greater in patients having diabetes for a shorter duration of time.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Foveal thickness between stratus and spectralis optical coherence tomography in retinal diseases

Purpose

To compare the foveal thickness (FT) parameters measured by Stratus optical coherence tomography (OCT) and Spectralis OCT in various retinal diseases and to construct conversion formulas between the two types of OCT devices.

Methods

We examined 366 consecutive patients (475 eyes) with retinal diseases and 13 normal controls (13 eyes). The patients were categorized into eight retinal disease groups. The mean amount and distribution of foveal thickness differences (FTD) measured by Stratus and Spectralis OCT were determined, and conversion formulas were constructed for Stratus OCT FT from Spectralis OCT FT for each retinal disease group.

Results

Among retinal diseases, the mean FTD was significantly larger in exudative age-related macular degeneration (AMD) patients (mean ± SD, 94.0 ± 55.0 µm) compared to normal subjects (66.2 ± 11.7 µm; p < 0.0001). The proportion of eyes with a mean FTD outside 1.96 standard deviations of normal subject FTD was greatest in the exudative AMD (50.0%) group and smallest in the macular hole (18.2%) group. The predicted FTs obtained through the conversion formulas showed lower variance than the actual FTD values, especially in the exudative AMD group. The prediction line for exudative AMD deviated most from that of normal subjects.

Conclusions

FTD shows diverse values and variances among various retinal diseases, especially in exudative AMD, which indicates that Stratus OCT FT cannot be predicted from Spectralis OCT FT by FTD value alone. We constructed statistically significant conversion formulas, which provided more reliable methods to predict Stratus OCT-measured FT from Spectralis OCT measurements for different retinal disease groups.

Treatment options for diffuse diabetic macular edema

PURPOSE

To describe the current management of diffuse diabetic macular edema (DDME).

METHODS

Review and discussion of the literature regarding DDME.

RESULTS

Diffuse diabetic macular edema is a condition that can be managed by means of several treatment options, including focal/grid laser photocoagulation, intravitreal or periocular corticosteroids, intravitreal anti-vascular endothelial growth factor (VEGF), and vitrectomy with or without internal limiting membrane peeling.

CONCLUSIONS

Even though there is no randomized clinical trial specifically designed to assess the best treatment approach for DDME, new therapeutic approaches based on intravitreal injections of corticosteroid and anti-VEGF molecules offer new hope for its management.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

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

BACKGROUND

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

PURPOSE

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

SETTINGS AND DESIGN

Prospective randomized study in a tertiary eye care center.

MATERIALS AND METHODS

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

STATISTICS

Analysis was performed using SPSS 14.0

RESULTS

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

CONCLUSIONS

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

Molecular basis of the inner blood-retinal barrier and its breakdown in diabetic macular edema and other pathological conditions

Breakdown of the inner endothelial blood-retinal barrier (BRB), as occurs in diabetic retinopathy, age-related macular degeneration, retinal vein occlusions, uveitis and other chronic retinal diseases, results in vasogenic edema and neural tissue damage, causing loss of vision. The central mechanism of altered BRB function is a change in the permeability characteristics of retinal endothelial cells caused by elevated levels of growth factors, cytokines, advanced glycation end products, inflammation, hyperglycemia and loss of pericytes. Subsequently, paracellular but also transcellular transport across the retinal vascular wall increases via opening of endothelial intercellular junctions and qualitative and quantitative changes in endothelial caveolar transcellular transport, respectively. Functional changes in pericytes and astrocytes, as well as structural changes in the composition of the endothelial glycocalyx and the basal lamina around BRB endothelium further facilitate BRB leakage. As Starling's rules apply, active transcellular transport of plasma proteins by the BRB endothelial cells causing increased interstitial osmotic pressure is probably the main factor in the formation of macular edema. The understanding of the complex cellular and molecular processes involved in BRB leakage has grown rapidly in recent years. Although appropriate animal models for human conditions like diabetic macular edema are lacking, these insights have provided tools for rational design of drugs aimed at restoring the BRB as well as for design of effective transport of drugs across the BRB, to treat the chronic retinal diseases such as diabetic macular edema that affect the quality-of-life of millions of patients.

Pathophysiology and treatment of diabetic retinopathy

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

Two-year results of a randomized trial of intravitreal bevacizumab alone or combined with triamcinolone versus laser in diabetic macular edema

PURPOSE

The purpose of this study was to report the 24-month findings of a randomized clinical trial comparing intravitreal bevacizumab (IVB) injection alone or in combination with intravitreal triamcinolone acetonide (IVT) versus macular laser photocoagulation (MPC) as a primary treatment for diabetic macular edema.

METHODS

The eyes were randomly assigned to 1 of the 3 study arms: the IVB group, patients who received 1.25 mg IVB; the IVB/IVT group, patients who received 1.25 mg of IVB and 2 mg of IVT; and the MPC group, patients who underwent focal or modified grid laser. Of 150 eyes (50 in each group) in the primary trial, 123, 119, and 113 eyes completed follow-ups at 12, 18, and 24 months, respectively. A total of 39 (78%), 36 (72%), and 38 (76%) eyes in the IVB, IVB/IVT, and MPC groups remained in the study within 24 months, respectively. Retreatment was performed at 3-month intervals whenever indicated. Data from a 24-month follow-up are presented. Changes in best-corrected visual acuity and central macular thickness up to 24 months were the main outcome measures in this study.

RESULTS

Retreatment was required in 37 (94.9%), 27 (75.0%), and 31 (81.6%) eyes, respectively, in the IVB, IVB/IVT, and MPC groups up to 24 months. The significant superiority of visual acuity improvement in the IVB group, which had been noted at Month 6, did not sustain thereafter up to 24 months, and the difference among the groups was not significant at all visits. However, the mean visual acuity improvement was greater in the IVB group than the other groups and in the IVB/IVT group compared with the MPC group. The reduction of central macular thickness was more in the IVB group in relation to the other two treatment groups; however, the difference among the groups was not statistically significant at any of the follow-up visits.

CONCLUSION

In terms of vision improvement, the significant superiority of the IVB over the combined IVB/IVT and MPC treatment that had been observed at Month 6 did not sustain up to 24 months. This means that although IVB treatment may be a better choice than two other options in short term, the magnitude of this beneficial effect diminishes over time.

Comparing intravitreal triamcinolone acetonide and bevacizumab injections for the treatment of diabetic macular oedema: a randomized double-blind study

PURPOSE

To compare the effect of a single intravitreal injection of triamcinolone acetonide and bevacizumab in reducing macular thickness, which was measured by optical coherence tomography (OCT) in patients with diabetic macular oedema (DMO).

METHODS

  The patients received a single intravitreal injection of 1.25 mg bevacizumab in one randomly selected eye and 4.0 mg triamcinolone acetonide in the contralateral eye. Central foveal thickness measurement (CFT) with OCT was taken at the initial visit and at the 4-week, 12-week and 24-week visits.

RESULTS

Eleven patients (22 eyes) were enrolled and statistically analysed. CFT reduced in the eyes treated with triamcinolone and those treated with bevacizumab in weeks 4 and 12 (p < 0.05). At the 24-week follow-up, no significant difference was noted, relative to the initial visit. Comparing the two groups treated with different drugs, a statistically significant difference in CFT in weeks 4 and 12 was noted, with a more significant reduction in triamcinolone-treated eyes (p < 0.05). Regarding visual acuity (VA), patients treated with triamcinolone had improvement in VA at 4-week (p = 0.02) and 12-week follow-up (p = 0.01), while the group treated with bevacizumab had VA improvement at 4 -week follow-up (p = 0.02). Among the eyes treated with triamcinolone, intraocular pressure (IOP) measurement of more than 21 mmHg was found in three eyes (27.3%).

CONCLUSIONS

Intravitreal triamcinolone proved to be more efficient in reducing DMO, providing longer lasting visual improvement, relative to bevacizumab. Eyes treated with triamcinolone had the highest percentage increase in IOP. Further studies are needed to corroborate these findings.

Phacoemulsification with intravitreal bevacizumab and triamcinolone acetonide injection in diabetic patients with clinically significant macular edema and cataract

PURPOSE

The purpose of this study was to evaluate the results of phacoemulsification with intravitreal bevacizumab and triamcinolone acetonide injection in patients with diabetic clinically significant macular edema and cataract.

METHODS

The records of 22 diabetic patients, with clinically significant macular edema and cataract who have undergone phacoemulsification with intravitreal injection of 1.25 mg bevacizumab and 2 mg triamcinolone acetonide, were retrospectively evaluated. All patients have undergone focal or modified grid argon laser photocoagulation 1 month after the surgery. All patients were evaluated by spectral OCT/OCT SLO before, 1 month, and 3 months after the surgery. The main parameters were the best-corrected visual acuity (BCVA) and central macular thickness (CMT). Paired samples t-test was used for statistical analysis.

RESULTS

The mean initial best-corrected visual acuity was 0.15 ± 0.09 (0.05-0.3), whereas it was 0.6 ± 0.28 (SD) (0.3-0.7), 0.6 ± 0.22 (SD) (0.4-0.7) at 1 month and 3 months after the surgery, respectively. The BCVA levels recorded at 1 month and 3 months after the surgery were significantly higher than the initial BCVA (P = 0.002). The mean initial CMT was 392.2 ± 109.5 μm, whereas it was 295 ± 57.2 μm and 265.5 ± 30.3 μm at 1 month and 3 months after the surgery, respectively. The CMT values recorded at 1 month and 3 months after the surgery were significantly lower than the initial CMT (P < 0.001, P < 0.001).

CONCLUSION

Phacoemulsification with intravitreal injection of bevacizumab and triamcinolone acetonide provides a decrease in CMT with a gain in BCVA in diabetic patients with clinically significant macular edema and cataract.

Comparison of intravitreal bevacizumab alone or combined with triamcinolone versus triamcinolone in diabetic macular edema: a randomized clinical trial

PURPOSE

To compare the effect of an intravitreal injection of bevacizumab alone (IVB) or combined with triamcinolone (IVB/IVT) versus triamcinolone (IVT) in patients with diabetic macular edema (DME).

METHODS

In this randomized three-arm clinical trial, eligible eyes were assigned randomly to one of the three study arms: the IVB group, 2 injections of 1.25 mg of bevacizumab with 6-week intervals; the IVB/IVT group, 1.25 mg of IVB with 2 mg of IVT, and the IVT group, 2 mg of IVT. The clinical course of best-corrected visual acuity and central macular thickness by optical coherence tomography was monitored for up to 12 months after the initial injection.

RESULTS

One hundred eleven eyes of 105 patients with DME completed 12 months of follow-up. The IVB/IVT group and the IVT group showed better visual acuity and reduced central macular thickness at 6 weeks and 3 months, compared with the IVB group (p = 0.041, p = 0.02 at 6 weeks; p = 0.045, p = 0.043 at 3 months, respectively). However, no significant difference in visual acuity and central macular thickness was observed between the three groups at 12 months (p = 0.088, p = 0.132, respectively). The frequency of retreatment was lower in the IVB/IVT and IVT groups during the 12-month period (p < 0.001). No significant differences in visual acuity or central macular thickness were observed between the IVB/IVT and IVT groups during the follow-up.

CONCLUSION

IVB/IVT and IVT showed more pronounced effects during the earlier postinjection period. However, levels of visual acuity or central macular thickness at 12 months were comparable in the three study groups. No beneficial effect of the combination injection was observed.

Changes in aqueous concentrations of various cytokines after intravitreal triamcinolone versus bevacizumab for diabetic macular edema

PURPOSE

To investigate the changes in aqueous inflammatory and angiogenic cytokine levels after intravitreal injection of triamcinolone or bevacizumab for reducing foveal thickness in diabetic macular edema (DME).

DESIGN

Prospective, interventional case series.

METHODS

Twenty-two eyes of 11 patients with bilateral DME and 6 eyes of 6 patients undergoing cataract surgery participated in this study. In each DME patient, 1 eye received an intravitreal injection of 4 mg triamcinolone acetonide and the other eye received 1.25 mg bevacizumab. Aqueous humor samples were obtained before and 4 weeks after the intravitreal injection in the DME group and before the surgery in the control group. Aqueous concentrations of interleukin (IL)-6, IL-8, interferon-induced protein (IP)-10, monocyte chemotactic protein (MCP)-1, platelet-derived growth factor (PDGF)-AA, and vascular endothelial growth factor (VEGF) were measured by multiplex bead assay.

RESULTS

Before the administration of the drugs, aqueous levels of IL-8, IP-10, MCP-1, and VEGF were significantly higher in the DME group than in the control group. After intravitreal injection, foveal thickness was more decreased in the triamcinolone acetonide (IVTA) group compared with the bevacizumab (IVBe) group. IL-6, IP-10, MCP-1, PDGF-AA, and VEGF were significantly decreased in the IVTA group, but only VEGF in the IVBe group. Aqueous levels of VEGF were more decreased in the IVBe group than in the IVTA group.

CONCLUSIONS

These findings suggest that the pathogenesis of DME is not only related to VEGF dependency, but also to other mechanisms suppressed by corticosteroids. We suppose that these cytokines would have an important role in both the pathogenesis of DME and the underlying mechanism of intravitreal injections.

Comparative study of vitrectomy versus intravitreous triamcinolone for diabetic macular edema on randomized paired-eyes

BACKGROUND

The present study was performed to compare the effects of pars plana vitrectomy (PPV) and single intravitreaous triamcinolone acetonide (IVTA) on diabetic macular edema (DME) in paired eyes.

METHODS

Prospective comparative study on randomized paired-eyes was carried out at two hospitals. Forty eyes of 20 patients with bilateral DME were included. One randomly-selected eye was treated with PPV (PPV group), and the other eye was treated with IVTA (4 mg, IVTA group). The central macular thickness (CMT) measured by optical coherence tomography (OCT) and best-corrected visual acuity (BCVA) were monitored for 12 months after treatment. Changes from baseline and differences between groups were analyzed using a mixed model.

RESULTS

At 1 and 3 months, CMT decreased significantly in the IVTA group compared to baseline (p < 0.0001 both), but CMT then increased gradually and no significant difference was found at 12 months (p = 0.90). In the PPV group, CMT decreased continuously and reached a significant level at 12 months (p < 0.0001). CMT of the IVTA group was significantly less than that of the PPV group at 1 month (p = 0.009); however, there was no significant difference at 3 months. Conversely, CMT was significantly less in the PPV group than in the IVTA group at 12 months (p = 0.0003). The changes of BCVA paralleled those of CMT, but no significant difference was detected between baseline BCVA and any time point.

CONCLUSIONS

Despite the short-term improvement, DME recurred 6 months after IVTA, while it remained resolved after PPV. Although this study did not reveal a significant change of BCVA with either treatment, PPV resolved DME more effectively than IVTA at 1 year.

Pharmacokinetics of triamcinolone acetonide for the treatment of macular edema

INTRODUCTION

The use of intravitreal triamcinolone acetonide (TA) for the treatment of various types of macular edema has been widespread, particularly for the last decade. Currently, there is a scant amount of evidence-based literature evaluating the pharmacokinetic profile of TA despite clinical data showing the efficacy of intravitreal TA for multiple forms of macular edema.

AREAS COVERED

This paper is an extensive review of human and experimental studies published on the pharmacokinetics of TA for the treatment of macular edema. The literature search was conducted via OVID, TRIP Database and EMBASE, up to April 2011.

EXPERT OPINION

The pharmacokinetic profile of TA is unpredictable and the agent has a time-limited therapeutic action due to its relatively short half-life. This has led to the need for repeated injections. Future research should investigate the pharmacokinetic profiles of TA when administered intravitreally, as well as through alternate routes in more robust studies.

Treatment of diabetic retinopathy with anti-VEGF drugs

The aim of this review is to summarize the latest developments in the treatment of diabetic retinopathy (DR) with anti-vascular endothelial growth factor (VEGF) drugs. We reviewed recent studies that evaluated the role of the anti-VEGF agents bevacizumab, ranibizumab and pegaptanib in the treatment of DR. There was only one large randomized controlled trial that evaluated the role of ranibizumab in diabetic macular oedema (DME). Other prospective and retrospective studies provided important insight into the role of anti-VEGF drugs in DR, but most of them were not conducted in large scales. The growing evidence indicates that anti-VEGF drugs are beneficial in DR, especially in DME. Further studies are needed to fully evaluate the role of these agents, especially in proliferative DR and in DR candidates for vitrectomy surgery.

Vitreous proteomics and diabetic retinopathy

Diabetic retinopathy is the major cause of acquired blindness in working-age adults. Studies of the vitreous proteome have provided insights into the etiology of diabetic retinopathy and suggested potential molecular targets for treatments. Further characterization of the protein changes associated with the progression of this disease may suggest additional therapeutic approaches as well as reveal novel factors that may be useful in predicting risk and functional outcomes of interventional therapies. This article provides an overview of the various techniques used for proteomic analysis of the vitreous and details results from various studies evaluating vitreous of diabetic patients using the proteomic approach.

Advances in the treatment of diabetic retinopathy

Diabetic retinopathy, the most common long-term complication of diabetes mellitus, remains one of the leading causes of blindness worldwide. Strict metabolic control, tight blood pressure control, laser photocoagulation, and vitrectomy remain the standard care for diabetic retinopathy. Focal/grid photocoagulation is a better treatment than intravitreal triamcinolone acetonide in eyes with diabetic macular edema and should be considered as the first-line therapeutic option. The current evidence suggests that intravitreal triamcinolone acetonide or anti-vascular endothelial growth factor agents result in a temporary improvement of visual acuity and a short-term reduction in central macular thickness in patients with refractory diabetic macular edema and are an effective adjunctive treatments to laser photocoagulation or vitrectomy. However, triamcinolone is associated with risks of elevated intraocular pressure and cataract. Vitrectomy with the removal of the posterior hyaloid without internal limiting membrane peeling seems to be effective in eyes with persistent diffuse diabetic macular edema, particularly in eyes with associated vitreomacular traction. Emerging therapies include islet cell transplantation, fenofibrate, ruboxistaurin, pharmacologic vitreolysis, rennin-angiotensin system blockers, and peroxisome proliferator-activated receptor gamma agonists.

Inflammatory and angiogenic factors in the aqueous humor and the relationship to diabetic retinopathy

PURPOSE

To determine the relationship between the aqueous concentrations of inflammatory and angiogenic factors and the severity of diabetic retinopathy and diabetic macular edema.

METHODS

Aqueous samples were obtained from 50 eyes of diabetic patients and 28 eyes of nondiabetic subjects. The aqueous levels of inflammatory factors, including IL-1β, TNF-α, MCP-1, IP-10, IL-8, IL-6, and VEGF were measured with multiplex bead array assays. The aqueous levels of cytokines were investigated according to the severity of diabetic retinopathy and diabetic macular edema measured by optical coherence tomography.

RESULTS

The aqueous levels of MCP-1, IP-10, IL-8, and VEGF were higher in eyes of diabetic patients than in eyes of nondiabetic subjects. The aqueous levels of MCP-1 and IP-10 were elevated in eyes with severe NPDR and PDR compared to eyes with less severe DR and eyes of nondiabetic subjects. There was a trend toward elevated IL-8 levels in eyes with severe NPDR compared to eyes of nondiabetic subjects. The aqueous levels of VEGF were markedly elevated in eyes with PDR that had not received PRP compared to eyes with severe NPDR. Eyes with PDR that had received PRP treatment showed higher MCP-1 and IP-10 levels than eyes with PDR that had not received PRP treatment. The aqueous levels of IL-6 were positively correlated with TMV and CSMT in eyes with DR.

CONCLUSIONS

Elevation of MCP-1, IP-10, and IL-8 levels in eyes with severe NPDR suggests that inflammatory change precedes the development of neovascularization in PDR. The positive correlation between the aqueous levels of IL-6 and macular thickness indicates that IL-6 may play a central role in the development of diabetic macular edema.

Increased levels of vascular endothelial growth factor in the aqueous humor of patients with diabetic retinopathy

Purpose:

This study aims to investigate the levels of aqueous vascular endothelial growth factor (VEGF) in diabetic patient groups in comparison to normal subjects, and to correlate elevated VEGF with the severity of diabetic retinopathy (DR).

Materials and Methods:

Aqueous samples were obtained from 78 eyes of 74 patients undergoing intraocular surgery and they were examined by the enzyme-linked immunosorbent assay. Color photographs, optical coherence tomography scans, and fluorescein angiography were used to evaluate patients preoperatively.

Results:

A strong statistical correlation was found to exist between the level of aqueous VEGF and the severity of DR (P < 0.001), whereas, the VEGF levels in a control group and a diabetic group without DR were not significantly different (P = 0.985). Aqueous VEGF levels were significantly elevated in patients with proliferative DR (PDR) as compared to the control group (P < 0.001), to diabetic patients without retinopathy (NDR) (P < 0.001), and to diabetic patients with nonproliferative DR (NPDR) (P < 0.001). The aqueous VEGF levels were significantly higher in patients with active PDR than in those with quiescent PDR (P = 0.001). On the other hand, a statistically insignificant (P = 0.065) correlation was found between elevated aqueous VEGF and the presence of macular edema in the NPDR group.

Conclusions:

VEGF was elevated in the aqueous humor of patients with DR compared to that in normal eyes. The aqueous VEGF level had a strong correlation with the severity of retinopathy along with a statistically insignificant difference in macular edema.

Associations between chronic glycosylated haemoglobin (HbA1c) level and macular volume in diabetes patients without macular oedema

PURPOSE

This study aimed to examine the correlation between glycosylated haemoglobin (HbA1c) level and macular volume in diabetes patients without diabetic macular oedema (DMO).

METHODS

We carried out an observational, cross-sectional study. Patients who had diabetes mellitus (DM) of ≥ 10 years duration without DMO were included. Only one eye of each patient was selected for analysis. Eyes with proliferative diabetic retinopathy were excluded. Central subfield thickness (CST), central subfield volume (CSV) and total macular volume (TMV) were measured by optical coherence tomography (OCT). Chronic HbA1c level was defined as the mean HbA1c value in the year prior to enrolment.

RESULTS

We included 97 eyes from 97 patients (47 women, 50 men; mean age 62.2 years). They included eight type 1 and 89 type 2 DM patients. The mean duration of DM was 15.5 years. Forty-two (43%) eyes had no diabetic retinopathy and 55 (57%) eyes had non-proliferative diabetic retinopathy. In statistical analysis, CST (mean 188.80 ± 27.64 μm; r = 0.220, p = 0.030), CSV (mean 0.149 ± 0.021 mm(3) ; r = 0.213, p = 0.036) and TMV (mean 6.497 ± 0.715 mm(3) ; r = 0.299, p = 0.003) positively correlated with chronic HbA1c level (7.95 ± 1.29%). The linear regression model showed that chronic HbA1c level (standardized coefficient 0.253; p = 0.013) and age (standardized coefficient - 0.206; p = 0.040) were factors significantly related to TMV.

CONCLUSIONS

Chronic HbA1c level positively correlates with macular thickness and volume in patients with DM of ≥ 10 years duration without DMO. Our results suggest that subclinical macular volume and thickness changes may occur before DMO becomes clinically evident. Early tight glycaemic control prior to the onset of DMO may play an important role in preventing the deterioration of macular function by altering macular haemodynamics.

The multifactorial nature of retinal vascular disease

Retinal vascular disease is the most common cause of macular edema (ME). While there are several etiologies of vascular compromise and subsequent macular leakage, diabetic retinopathy is the most prevalent and continues to challenge ophthalmologists and frustrate patients due to its refractory nature. In response to this epidemic, diabetic ME (DME) along with cystoid ME (CME) have been areas of active investigation both in the clinic and the laboratory. Several decades of basic science research have revealed a growing and complex array of cytokine growth factors and proinflammatory mediators which are capable of inciting the cellular changes that result in accumulation of fluid within the retina. Much of this new molecular foundation provides the current and fundamental scaffold for understanding the pathologic process of ME while simultaneously identifying potential therapeutic targets. Whereas CME has classically been treated with corticosteroids and nonsteroidal antiinflammatory drugs, recent clinical studies have demonstrated improved visual outcomes for DME treatment with light focal/grid laser, corticosteroids and anti-vascular endothelial growth factor antibodies. Yet, each of these treatments has differential effects on the multifactorial mechanisms of ME. This article reviews the anatomical, cellular and molecular derangements associated with ME and highlights specific pathways targeted by current treatments.

Development of novel drugs for ocular diseases: possibilities for individualized therapy

In clinical ophthalmology, new and old drug regimens are available for the treatment of major eye diseases, including potentially blinding conditions, such as glaucoma, and various macular diseases. In glaucoma, therapeutic treatment mainly deals with control of intraocular pressure at low levels but the clinical courses of patients can be very variable. Very often, specific drug combinations and dosages have to be formulated for individual glaucoma patients. In neovascular age-related macular degeneration, choroidal neovascularization can lead to progressive and irreversible visual impairment if not treated early. In recent years, clinical trials using photodynamic therapy with verteporfin and various anti-VEGF antibodies, such as ranibizumab and bevacizumab, have enhanced the treatment outcomes of neovascular age-related macular degeneration. In diabetic macular edema, intravitreal triamcinolone acetonide and anti-VEGF therapy are effective in some patients. Again, responses to treatment are not uniform in all macular patients. Traditional herbal medicine has long been known to play a role in the practice of personalized formulations in Asia. Potential preventive and therapeutic effects have been claimed in individual eye patients. Meanwhile, advanced technologies in molecular biology have led to identification of genes associated with many eye diseases and development of the concept of individual medicine, in which the genotype of a person can be used as a basis for disease prediction or prophylactic treatments. Moreover, pharmacogenomic studies have demonstrated the association of various genotypes or haplotypes with responses to drug therapies, providing hope for tailormade personalized treatments. The combination of genotypic information with clinical features for the prescription of treatment modes in eye diseases is under vigorous research.

Vitreous traction and epiretinal membranes in diabetic macular oedema using spectral-domain optical coherence tomography

PURPOSE

The purpose of this study was to present an association between diabetic macular oedema (DME) and vitreoretinal interface abnormalities using 3D spectral domain optical coherence tomography (SD-OCT).

METHODS

In a retrospective study, charts and SD-OCT of consecutive patients with diffuse or focal DME were reviewed. Only one randomly chosen eye per patient with DME was included, and eyes that had another retinopathy that could affect the study analysis or that underwent vitreoretinal surgery were excluded.

RESULTS

Out of 58 eyes (58 patients) with DME, 11 eyes (19.0%) had vitreofoveal traction (Group A), either unifocally (n=6) or multifocally; that is, associated with additional extrafoveal traction site(s). Group B comprised 20 eyes (34.5%) that had sole extrafoveal vitreous traction, at either retinal and/or papillary sites. In each, the retinal oedema underlying extrafoveal traction was in continuum in at least one site with that at the central macula, as verified by the macular maps, thus presented as diffuse macular oedema. In Group C, 13 eyes (22.4%) had an epiretinal membrane (ERM), 1.5 × 3 mm to ≥6 × 6 mm in size that overlaid diffuse oedematous macula. Group D included 14 eyes (24.1%) that had neither vitreous traction nor ERM; 12 (20.7%) of them had DME secondary to leaking microaneurysms with or without leaking capillary beds, and the remaining two had leakage from non-microaneurysms sources.

CONCLUSIONS

DME was detected by the SD-OCT to be associated with sole extrafoveal vitreous traction in one-third of the patients. Further studies are required to evaluate the clinical consequences of these observations.

Steroid injection in addition to macular laser grid photocoagulation in diabetic macular oedema: a systematic review

OBJECTIVES

This study aimed to evaluate the evidence for the effects of steroid injection in addition to macular laser grid (MLG) photocoagulation versus those of MLG photocoagulation alone on visual acuity (VA) in patients with diabetic macular oedema (DMO).

METHODS

An extensive literature search in Medline (PubMed), Experta Medica (EMBASE) and the Cochrane Library (CENTRAL) using synonyms for MLG photocoagulation, steroid injection and DMO found 181 articles. Of the articles that met selection criteria, three studies in which patients receiving MLG photocoagulation were randomized to additional pretreatment with steroids provided the best available evidence. In addition to VA, central foveal thickness (CFT) was measured at baseline and at 6 months in all three studies.

RESULTS

Two studies, with total populations of 73 and 42 eyes, respectively, reported no additional effect of steroid injection on VA. One study, with a total of 41 eyes, reported a beneficial effect of pretreatment with steroids on VA of -0.21 ETDRS logMAR units. All three studies reported larger reductions in CFT in eyes pretreated with steroids, the smallest of which was 64 microm.

CONCLUSIONS

Although there is a greater reduction in CFT in eyes pretreated with steroids, this does not consistently result in higher VA. The literature search does not provide sufficiently strong evidence to recommend steroid injection before MLG photocoagulation in DMO.

Use of antivascular endothelial growth factor for diabetic macular edema

BACKGROUND

Diabetic macular edema (DME) is one of the manifestations of diabetic retinopathy leading to loss of central vision and visual acuity. It manifests itself with swelling around the central part of the retina, the area responsible for sharp vision. Current treatment includes laser therapy and intravitreal steroids with preventative measures including diabetes control. No one treatment has guaranteed control of diabetic macular edema which leads to deteriorating visual acuity, function and quality of life in patients. Vascular endothelial growth factor (VEGF) has been shown to be a critical stimulus in the pathogenesis of macular edema secondary to diabetes.1 Antiangiogenic therapy encompassed treatment with anti-VEGF which inhibits VEGF-driven neovascularization hence macular edema leading to decreased visual acuity.

OBJECTIVE

For this review, we evaluated the effectiveness of intravitreal anti-VEGF in treating DME.

DATA SOURCES

We identified five trials (n = 525) using electronic databases (Cochrane Central Register of Controlled Trials [Central], Medline((R)), and Excerpta Medica Database [EMBASE((R))]) in October 2008, supplemented by hand searching of reference lists, review articles, and conference abstracts.

METHODS

We included all randomized clinical trials (RCTs) evaluating any form of intravitreal anti-VEGF for treating DME. The main outcome factor was change in best-corrected visual acuity and central macular thickness. One author assessed eligibility, methodological quality, and extracted data. Meta analysis was performed when appropriate.

RESULTS

We included three trials of adequate methodological quality in our meta-analysis. Patients treated with anti-VEGF showed improvement in visual acuity of -0.17 (95% confidence interval [CI]: -0.23, -0.10) and central macular thickness -84.69 (95% CI: -117.09, -52.30). Patients treated with combined anti-VEGF and intravitreal triamcinolone showed improvement of visual acuity of -0.19 (95% CI: -0.27, -0.11) and central macular thickness mean change being -111.20 (95% CI: -148.13, -74.28).

CONCLUSIONS

Anti-VEGF has been associated with an improvement in visual acuity and central macular thickness in the analysis, however trial analysis was of a short duration and further research is needed to determine long-term benefits.

Pharmacotherapeutic efficacy of preservative-free intravitreal triamcinolone acetonide

Preservative-free formulations of triamcinolone acetonide have recently been introduced to the market over concerns of local toxicity of the vehicle and preservatives, including benzyl alcohol in the original formulation, which was not designed for intraocular use. The pharmacokinetics and pharmacodynamics of intravitreal triamcinolone (IVTA) are discussed. The therapeutic effects of IVTA include improvement of visual acuity and reduction of macular edema. However, ongoing treatment is usually required to maintain its effects. The efficacy of IVTA for both FDA-approved and 'off-labeled' indications is reviewed. Elevation of intraocular pressure and cataract formation are the two major side effects of IVTA; these are manageable but require close long-term follow-up. More studies are required to determine the optimal dosage and treatment frequency in different posterior segment disease.

Intravitreal bevacizumab vs intravitreal triamcinolone combined with macular laser grid for diffuse diabetic macular oedema

OBJECTIVE

To evaluate the 12-month clinical outcome of patients with persistent non-ischaemic diffuse diabetic macular oedema (DME) treated with intravitreal bevacizumab (IVB) or with intravitreal injection of triamcinolone combined with macular laser grid (IVTA-MLG) from September 2005 to February 2008.

METHODS

Retrospective interventional comparative study. Best-corrected visual acuity (BCVA, ETDRS LogMAR scale) and foveal thickness (FT) at optical coherence tomography (OCT) were obtained at baseline and during 12 months after first treatment. Re-treatment was based on clinical or OCT-based evidence of persistent macular oedema or deterioration in visual acuity.

RESULTS

Forty-three eyes (32 patients) with DME were treated with IVB. Ninety-six eyes (52 patients) with DME were treated with combined laser grid treatment and intravitreal triamcinolone. At baseline, mean BCVA and FT were 0.92+/-0.34 LogMAR and 372+/-22 microm in the IVTA-MLG group, and 1.07+/-0.49 LogMAR and 423+/-33 microm in the IVB group, respectively. At 1- and 3-month visits, BCVA and FT had significantly improved in both groups. After 6 and 12 months, the IVB group experienced a statistically significant improvement in visual acuity (0.83+/-0.21 LogMAR, P<0.001 at 6 months; BCVA 0.86+/-0.24 LogMAR, P<0.001 at 12 months) and FT (248+/-18 microm, P<0.001 at 6 months; 262+/-28 microm, P=0.001 at 12 months) when compared with baseline, whereas the IVTA-MLG group did not show statistically significant improvement in vision and FT. An increase in intraocular pressure (IOP) was present in 10 of 96 (10.4%) eyes treated with IVTA-MLG, and in two cases it was resistant to topical treatment. No significant side effects were reported in the IVB group.

CONCLUSIONS

At 6 and 12 months after first treatment for chronic DME IVB provided significant improvement of BCVA and FT, whereas improvement after IVTA-MLG was not significant. Increased IOP occurred in 10.4% of patients who received IVTA, with two patients requiring trabeculectomy.

Intravitreal triamcinolone acetonide versus bevacizumab therapy for macular edema associated with branch retinal vein occlusion

PURPOSE

To compare visual outcomes after intravitreal triamcinolone acetonide (IVTA) injection and intravitreal bevacizumab (IVB) administration for treatment of macular edema associated with branch retinal vein occlusion (BRVO).

METHODS

A retrospective comparative case series of 134 consecutive patients that were treated with either IVTA or IVB for macular edema caused by BRVO. Visual acuity at baseline and 1, 3, 6, 9, and 12 months, and central macular thickness measured by OCT at baseline and 1, 3, 6, and 12 months. The time to recurrence of macular edema after treatment was also analyzed.

RESULTS

Visual acuity (Snellen equivalent) improved significantly from 0.87 logMAR (0.14) to 0.49 logMAR (0.33) in the IVTA group, and from 0.91 logMAR (0.13) to 0.45 logMAR (0.36) in the IVB group 12 months after injection (p < 0.001). Central macular thickness decreased significantly from 491.0 microm to 255.8 microm in the IVTA group, and from 477.4 microm to 218.9 microm in the IVB group 12 months after injection (p < 0.001). In between-group comparisons, neither visual acuity (p = 0.892) nor macular thickness (p = 0.612) improvements were statistically significantly different. In the IVTA-all group, recurrence of macular edema occurred in 7.6% of patients at a mean of 12.6 months postoperatively, and the average number of injections was 1.08. In the IVB-all group, 26.0% of patients suffered recurrences at a mean of 5.3 months after treatment, and received a mean of 1.89 injections. Recurrence was more frequent in the IVB group compared to the IVTA group (Kaplan-Meier survival analysis log-rank test, p < 0.0001).

CONCLUSIONS

IVTA and IVB injections were similarly effective for improving visual acuity in patients with macular edema secondary to BRVO. However, the IVTA group showed longer mean improvement duration and less disease recurrence, and required fewer injections than the IVB group.

A review of clinical trials of anti-VEGF agents for diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a leading cause of vision loss in the working-age population worldwide. Many observational and preclinical studies have implicated vascular endothelial growth factor (VEGF) in the pathogenesis of DR, and recent successes with anti-VEGF therapy for age-related macular degeneration (AMD) have prompted research into the application of anti-VEGF drugs to DR. Here we review the numerous early studies that suggest an important potential role for anti-VEGF agents in the management of diabetic retinopathy.

CONCLUSIONS

For diabetic macular edema, phase II trials of intravitreal pegaptanib and intravitreal ranibizumab have shown short-term benefit in visual acuity. Intravitreal bevacizumab also has been shown to have beneficial short-term effects on both visual acuity and retinal thickness. For proliferative diabetic retinopathy (PDR), early studies suggest that intravitreal bevacizumab temporarily decreases leakage from diabetic neovascular lesions, but this treatment may be associated with tractional retinal detachment (TRD). Furthermore, several studies indicate that bevacizumab is likely to prove a helpful adjunct to diabetic pars plana vitrectomy (PPV) for TRD. Finally, three small series suggest a potential beneficial effect of a single dose of bevacizumab to prevent worsening of DME after cataract surgery. Use of anti-VEGF medications for any of these indications is off-label. Despite promising early reports on the safety of these medications, we eagerly await the results of large, controlled trials to substantiate the safety and efficacy of anti-VEGF drugs for diabetic retinopathy.

Cataract surgery after pars plana vitrectomy

PURPOSE OF REVIEW

To review recent studies and advances and their possible implications in the care of patients undergoing cataract surgery after pars plana vitrectomy.

RECENT FINDINGS

Optical biometry has shown to be superior to ultrasound biometry in vitrectomized eyes but still not achieving as good results as it does in nonvitrectomized eyes. Blue light-filter intraocular lenses, with their possible advantage of macular protection, have shown no operative or functional disadvantages in vitrectomized eyes, and thus their routine use can be justified. However, presbyopia-correcting intraocular lenses, at least at their current stage of development, generally, are still not accepted for vitrectomized eyes. Combining cataract surgery with intravitreal injections of bevacizumab or triamcinolone acetonide in patients with macular edema and cataract is advisable to avoid exacerbation of the condition and improve visual outcome. Despite the recent advances, incidences of posterior capsular opacification and retinal detachment are still considerable.

SUMMARY

Understanding ocular anatomical alterations imposed by the previous pars plana vitrectomy surgery and the underlying vitreoretinal disease will allow the surgeon to address the special challenges. Despite that, recent advances in techniques and instrumentation have improved the surgical safety and outcomes, reported complications rates are still relatively high.

Systemic bevacizumab leads to resolution of diabetic macular edema

PURPOSE

The purpose of this study is to report a case of diabetic macular edema that resolved after systemic bevacizumab.

METHODS

This is an observational case report of a patient with diabetic macular edema.

RESULTS

After initiation of systemic bevacizumab for a central nervous system glioblastoma, the diabetic macular edema resolved.

CONCLUSION

Systemic bevacizumab may result in the resolution of macular edema secondary to diabetes.

Phacoemulsification with intravitreal bevacizumab injection in diabetic patients with macular edema and cataract

PURPOSE

The purpose of this study was to evaluate the results of phacoemulsification with intravitreal bevacizumab injection in patients with diabetic clinically significant macular edema and cataract.

METHODS

The records of 31 patients with diabetic clinically significant macular edema and cataract, which would interfere with macular laser photocoagulation, who have undergone phacoemulsification with intravitreal injection of 1.25 mg bevacizumab were retrospectively evaluated. All patients had undergone focal or modified grid laser photocoagulation 1 month after the surgery. All patients were evaluated by spectral optical coherence tomography/optical coherence tomography SLO before and 1 and 3 months after the surgery beyond complete ophthalmologic examination. The best-corrected visual acuity (BCVA) levels and central macular thickness (CMT) recorded at the first and third months after the surgery were compared with the initial values. Paired samples t test was used for statistical analysis.

RESULTS

The mean initial BCVA was 0.10 +/- 0.04 (range, 0.05-0.2). The mean BCVA at the first and third months after the surgery were 0.47 +/- 0.16 (standard deviation) (range, 0.2-0.5) and 0.51 +/- 0.12 (standard deviation) (range, 0.3-0.6), respectively. The BCVA level recorded at the first and third months after the surgery were significantly higher than the initial BCVA (P = 0.004). The mean initial CMT was 387.5 +/- 109.5 microm. The mean CMT at the first and third months after the surgery were 292.7 +/- 57.2 and 275.5 +/- 40.3. The CMT recorded at the first and third months after the surgery were significantly lower than the initial CMT (P < 0.001, P < 0.001).

CONCLUSION

Phacoemulsification with intravitreal injection of bevacizumab provides improvement in clinically significant macular edema with a gain in BCVA in patients with diabetes with clinically significant macular edema and cataract.