Vitrectomy outcomes in eyes with diabetic macular edema and vitreomacular traction

[Intraoperative use of coherence tomography in vitreoretinal surgery]

BACKGROUND

Optical coherence tomography is a useful tool in several diseases. Its intraoperative use with the intention of improving anatomical results has recently been described.

PURPOSE

To determine the usefulness and safety of optical coherence tomography during pars plana vitrectomy for several vitreo-retinal diseases.

MATERIAL AND METHODS

A prospective case series is reported, in which the decision that influenced the use of the optical coherence tomography imaging during pars plana vitrectomy is evaluated. A RESCAN 700 microscope that includes a spectral domain tomography was used to obtain the images. At the end of each procedure the surgeons completed a questionnaire to determine if the tomographic image had an influence when making decisions during the surgery, or change the decision during the procedure.

RESULTS

Thirteen patients with pars plana vitrectomy were included, with cataract surgery also performed in 6 patients. The surgeon considered that the intraoperative image influenced the decision during the procedure in 8 cases.

CONCLUSION

Intraoperative optical coherence tomography is helpful for a safe patient diagnosis. It does not affect the surgery time, and in some cases it is useful for optimising the procedure in vitreous-retinal surgery.

Vitrectomy for center-involved diabetic macular edema

PURPOSE

To determine the effect of vitrectomy for center-involved diabetic macular edema (CI-DME).

METHODS

This was a retrospective study of 53 eyes of 45 patients who had vitrectomy for CI-DME and were followed up for at least 12 months. Charts were reviewed for visual acuity (VA), central subfield mean thickness measured by optical coherence tomography, presurgical and postsurgical interventions for CI-DME, and number of office visits in the first 12 months after surgery. Preoperative spectral domain optical coherence tomography was performed on 38 patients, and they were graded for ellipsoid zone (EZ) intactness by three independent graders with assessment of agreement between graders using intraclass correlation coefficients and Bland-Altman analysis.

RESULTS

The median VA improved from 20/100 (interquartile range [IQR], 20/63-20/200) at baseline to 20/63 (IQR, 20/32-20/125) at 12 months. The median central subfield mean thickness improved from 505 μm (IQR, 389-597 μm) at baseline to 279 μm (IQR, 246-339 μm) at 12 months. Intergrader agreement for EZ intactness was moderate (intraclass correlation coefficients 0.4294-0.6356). There was no relationship between preoperative intactness of the EZ and the 12-month change in VA.

CONCLUSION

Vitrectomy consistently thins the macula in CI-DME and, on average, leads to clinically significant improvement in VA comparable in size to that reported with serial intravitreal anti-vascular endothelial growth factor injections. A large, comparative, prospective, randomized clinical trial of these two treatments is needed to determine which is more effective and cost-effective.

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.

Advances in the management of diabetic macular oedema based on evidence from the Diabetic Retinopathy Clinical Research Network

The Diabetic Retinopathy Clinical Research Network (DRCR.net) performs studies on new treatments for diabetic retinopathy. This review aims to summarise recent findings from DRCR.net studies on the treatment of diabetic macular oedema. We performed a PubMed search of articles from the DRCR.net, which included all studies pertaining to the treatment of diabetic maculopathy. The main outcome measures were retinal thickening as assessed by central subfield thickness on optical coherence tomography and improvement of visual acuity on the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. Findings from each study were divided into modalities of treatment, namely photocoagulation, bevacizumab, triamcinolone, ranibizumab and vitrectomy. While modified ETDRS focal/grid laser remains the standard of care, intravitreal corticosteroids or anti-vascular endothelial growth factor agents have also proven to be effective, although they come with associated side effects. The choice of treatment modality for diabetic macular oedema is a clinical judgement call, and depends on the patient's clinical history and assessment.

Minimally Invasive Microincision Vitrectomy Surgery with an Intraoperative Dexamethasone Implant for Refractory Diabetic Macular Edema

PURPOSE

To evaluate the 1-year results of 25-gauge microincision vitrectomy surgery (MIVS25) combined with intraoperative dexamethasone (DEX) implant for persistent diabetic macular edema (DME).

METHODS

This study enrolled patients who had a history of DME for ≥12 months and underwent MIVS25 and DEX implant injection. Best corrected visual acuity (BCVA) and central retinal thickness (CRT) were assessed postoperatively.

RESULTS

Eighteen eyes were included in the analysis. Preoperatively, logMAR BCVA was 0.90 and CRT was 594 µm on average. CRT decreased until the 3-month follow-up visit and tended to increase at 6 months, but stabilized at 12 months with additional treatments in five eyes at 5 months postoperatively. Statistically significant improvement in BCVA was noted 1 month after treatment and at each subsequent follow-up visit (p < 0.001).

CONCLUSION

MIVS25 combined with DEX implant injection might be utilized as an effective and safe alternative treatment for intractable DME.

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.

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.

EFFECT OF INTERNAL LIMITING MEMBRANE PEELING ON LONG-TERM VISUAL OUTCOMES FOR DIABETIC MACULAR EDEMA

PURPOSE

To evaluate the effect of internal limiting membrane (ILM) peeling on the long-term visual outcomes in eyes with diffuse, nontractional diabetic macular edema.

METHODS

One hundred and sixteen eyes of 58 patients with the same degree of diabetic macular edema in both eyes underwent pars plana vitrectomy with the creation of a posterior vitreous detachment in both eyes. Internal limiting membrane peeling was performed in one randomly selected eye (ILM-off group), and ILM peeling was not performed (ILM-on group) in the fellow eye. The postoperative follow-up period ranged from 12 months to 161 months (average, 80.4 months).

RESULTS

In the ILM-off group, the mean best-corrected visual acuity in logMAR units (Snellen equivalent) increased from 0.55 ± 0.31 (20/71) before surgery to 0.35 ± 0.35 (20/45) at 1 year (P < 0.0001) and 0.46 ± 0.43 (20/59) at the final visit (P = 0.058). In the ILM-on group, the mean best-corrected visual acuity increased from 0.55 ± 0.41 (20/71) before surgery to 0.43 ± 0.38 (20/54) at 1 year (P = 0.010) and 0.44 ± 0.45 (20/56) at the final visit (P = 0.043). The differences in the best-corrected visual acuity between the two groups were not significant at any time point.

CONCLUSION

Pars plana vitrectomy with or without ILM peeling improves the long-term visual acuity of nontractional diabetic macular edema. Internal limiting membrane peeling does not affect the postoperative best-corrected visual acuity significantly.

Diabetic Retinopathy and Diabetic Macular Edema

Diabetic retinopathy and diabetic macular edema result from chronic damage to the neurovascular structures of the retina. The pathophysiology of retinal damage remains uncertain but includes metabolic and neuroinflammatory insults. These mechanisms are addressed by intensive metabolic control of the systemic disease and by the use of ocular anti-inflammatory agents, including vascular endothelial growth factor inhibitors and corticosteroids. Improved understanding of the ocular and systemic mechanisms that underlie diabetic retinopathy will lead to improved means to diagnose and treat retinopathy and better maintain vision.

The Vitreomacular Interface in Diabetic Retinopathy

Diabetic retinopathy (DR) is a leading health concern and a major cause of blindness. DR can be complicated by scar tissue formation, macular edema, and tractional retinal detachment. Optical coherence tomography has found that patients with DR often have diffuse retinal thickening, cystoid macular edema, posterior hyaloid traction, and tractional retinal detachment. Newer imaging techniques can even detect fine tangential folds and serous macular detachment. The interplay of the vitreous and the retina in the progression of DR involves multiple chemokine and other regulatory factors including VEGF. Understanding the cells infiltrating pathologic membranes at the vitreomacular interface has opened up the possibility of new targets for pharmacotherapy. Vitrectomies for DR remain a vital tool to help relieve tension on the macula by removing membranes, improving edema absorption, and eliminating the scaffold for new membrane formation. Newer treatments such as triamcinolone acetonide and VEGF inhibitors have become essential as a rapid way to control DR at the vitreomacular interface, improve macular edema, and reduce retinal neovascularization. These treatments alone, and in conjunction with PRP, help to prevent worsening of the VMI in patients with DR.

New Therapeutic Approaches in Diabetic Retinopathy

Diabetic retinopathy is a common microvascular complication of diabetes mellitus. It affects a substantial proportion of US adults over age 40. The condition is a leading cause of visual loss. Much attention has been given to expanding the role of current treatments along with investigating various novel therapies and drug delivery methods. In the treatment of diabetic macular edema (DME), intravitreal pharmacotherapies, especially anti-vascular endothelial growth factor (anti-VEGF) agents, have gained popularity. Currently, anti-VEGF agents are often used as first-line agents in center-involved DME, with recent data suggesting that among these agents, aflibercept leads to better visual outcomes in patients with worse baseline visual acuities. While photocoagulation remains the standard treatment for proliferative diabetic retinopathy (PDR), recent FDA approvals of ranibizumab and aflibercept in the management of diabetic retinopathy associated with DME may suggest a potential for pharmacologic treatments of PDR as well. Novel therapies, including small interfering RNAs, chemokines, kallikrein-kinin inhibitors, and various anti-angiogenic agents, are currently being evaluated for the management of diabetic retinopathy and DME. In addition to these strategies, novel drug delivery methods such as sustained-release implants and refillable reservoir implants are either under active evaluation or have recently gained FDA approval. This review provides an update on the novel developments in the treatment of diabetic retinopathy.

Imaging in diabetic retinopathy

While the primary method for evaluating diabetic retinopathy involves direct and indirect ophthalmoscopy, various imaging modalities are of significant utility in the screening, evaluation, diagnosis, and treatment of different presentations and manifestations of this disease. This manuscript is a review of the important imaging modalities that are used in diabetic retinopathy, including color fundus photography, fluorescein angiography, B-scan ultrasonography, and optical coherence tomography. The article will provide an overview of these different imaging techniques and how they can be most effectively used in current practice.

Macular ischemia and outcome of vitrectomy for diabetic macular edema

PURPOSE

To investigate the effect of vitrectomy on the treatment of diabetic macular edema (DME) refractory to nonsurgical therapies and to determine the preoperative prognostic factors related to surgical outcomes.

METHODS

Seventy-seven eyes from 74 patients who had undergone vitrectomy and macular photocoagulation 2 weeks after vitrectomy for nontractional DME refractory to anti-vascular endothelial growth factor or steroid injection and/or macular grid/focal photocoagulation were included. The eyes were divided into the responsive group (group 1) and the unresponsive group (group 2) according to the postoperative changes in central subfield thickness (CST). The changes in best-corrected visual acuity (BCVA) and CST were compared. Potential preoperative predictors including the size of the foveal avascular zone (FAZ) were assessed.

RESULTS

In group 1 (N = 51), the mean logarithm of the minimum angle of resolution BCVAs at baseline was 0.60 ± 0.30; 6 months after vitrectomy, 0.47 ± 0.28 (vs. baseline, p < 0.001); 12 months after vitrectomy, 0.38 ± 0.28 (vs. baseline, p < 0.001). However, in group 2 (N = 26), no significant change in BCVA was noted. Among the preoperative factors, only the size of the FAZ showed a significant difference between the two groups (0.45 ± 0.17 mm(2) in group 1 vs. 0.59 ± 0.26 mm(2) in group 2; p = 0.020). The enlarged FAZ was also significantly correlated with worse BCVA at the postoperative 6-month follow-up (r = 0.256, p = 0.025).

CONCLUSIONS

Vitrectomy is an effective treatment modality for DME refractory to nonsurgical therapies, especially in cases without enlarged FAZ. Preoperative evaluation of the perfusion status of the macula seems helpful to selecting candidates for vitrectomy.

Planned foveal detachment technique for the resolution of diffuse diabetic macular edema

PURPOSE

To evaluate the therapeutic efficacy of a novel surgical procedure for diffuse diabetic macular edema (DME), performed in conjunction with conventional vitrectomy.

METHODS

This prospective, interventional case series involved 20 eyes of 18 consecutive DME patients with best-corrected visual acuities (BCVAs) between 0.301 and 1.221 logarithm of the minimal angle of resolution (logMAR) units and central retinal thicknesses (CRTs) greater than 275 μm. After vitrectomy, a small retinal detachment was made in the macula by injecting 50-100 μl balanced salt solution into the subretinal space using a 38-gauge needle. Before finishing the surgery, fluid-air exchange was performed. Patients were asked to remain in prone position for 1 day postoperatively. The main outcome measures were CRT and BCVA.

RESULTS

The mean CRT of 554.6 ± 152.7 μm before surgery significantly decreased to 295.6 ± 92.5 μm (p < 0.0001) 1 week after surgery and to 185.8 ± 67.4 μm (p < 0.0001) at 6 months after surgery. The CRT was less than 250 μm in 18 eyes (90 %) at 6 months after surgery. The mean BCVA before surgery (0.706 ± 0.348) significantly improved at 6 months after surgery (0.431 ± 0.392, p < 0.0001). Postoperative BCVAs improved by more than 0.3 logMAR units in 13 eyes (65 %), remained unchanged in six eyes (30 %) and worsened in one eye (5 %). Macular edema recurred in three eyes (15 %) 2 months after surgery.

CONCLUSIONS

This novel planned foveal detachment technique facilitated a rapid resolution of DME and contributed to improved visual acuity.

Diabetic Macular Edema: Pathophysiology and Novel Therapeutic Targets

Diabetic macular edema (DME) is the major cause of vision loss in diabetic persons. Alteration of the blood-retinal barrier is the hallmark of this disease, characterized by pericyte loss and endothelial cell-cell junction breakdown. Recent animal and clinical studies strongly indicate that DME is an inflammatory disease. Multiple cytokines and chemokines are involved in the pathogenesis of DME, with multiple cellular involvement affecting the neurovascular unit. With the introduction of anti-vascular endothelial growth factor (VEGF) agents, the treatment of DME has been revolutionized, and the indication for laser therapy has been limited. However, the response to anti-VEGF drugs in DME is not as robust as in proliferative diabetic retinopathy, and many patients with DME do not show complete resolution of fluid despite multiple intravitreal injections. Potential novel therapies targeting molecules other than VEGF and using new drug-delivery systems currently are being developed and evaluated in clinical trials.

Treatment of vitreomacular traction syndrome with autologous plasmin enzyme

PURPOSE

To determine whether intravitreal injection of autologous plasmin enzyme (APE) is effective in vitreomacular traction syndrome (VMTS) by improving visual acuity and restoring macular morphology.

METHODS

A prospective study of 11 consecutive patients diagnosed with VMTS in the Ophthalmology Department from January to May, 2011.

INCLUSION CRITERIA

best corrected visual acuity (BCVA) less than 0.5, and vitreomacular attachment in foveal area resulting in macular thickness>250 microns diagnosed by optical coherence tomography (Cirrus OCT, Carl Zeiss Meditec, Inc, Oberkochen, Germany).

EXCLUSION CRITERIA

active proliferative diabetic retinopathy, axial myopia>26mm, vitrectomy, glaucoma, previous intravitreal injections and previous rhegmatogenous detachment. One to 3 monthly intravitreal injections of 0.2ml of APE were applied, interrupting if posterior vitreous detachment was attained. Wilcoxon's test was used for statistical analysis.

RESULTS

A total of 12 eyes of 11 patients were treated. A complete posterior vitreous detachment was achieved in 4 (33%) eyes at the end of the study, 2 of them with one injection, and 2 with 3 monthly injections. Improvement of BCVA was statistically significant (P=.017) and the decrease in central macular thickness also was statistically significant (P=.016). There was only one complication: intraocular hypertension after injection that subsided with a new paracentesis.

CONCLUSIONS

Intravitreal APE injections avoided vitrectomy in VMTS in one in every 3 patients.

New treatments for diabetic retinopathy

Diabetic retinopathy is the major cause of vision loss in middle-aged adults. Alteration of the blood-retinal barrier (BRB) is the hallmark of diabetic retinopathy and, subsequently, hypoxia may result in retinal neovascularization. Tight control of systemic factors such as blood glucose, blood pressure and blood lipids is essential in the management of this disease. Vascular endothelial growth factor (VEGF) is one of the most important factors responsible for alteration of the BRB. The introduction of anti-VEGF agents has revolutionized the therapeutic strategies used in people with diabetic retinopathy, and the use of laser therapy has been modified. In the present article, we examine the clinical features and pathophysiology of diabetic retinopathy and review the current status of new treatment recommendations for this disease, and also explore some possible future therapies.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Vitreopapillary traction in eyes with idiopathic epiretinal membrane: a spectral-domain optical coherence tomography study

PURPOSE

To investigate the prevalence of vitreopapillary traction (VPT) and its effect on peripapillary structure and visual function in eyes with idiopathic epiretinal membrane (ERM).

DESIGN

Observational, comparative study.

PARTICIPANTS

Patients with idiopathic ERM (n = 116 eyes) and controls with similar age (n = 62 eyes).

METHODS

Spectral domain optical coherence tomography (SD-OCT) axial optic disc scans were evaluated to identify VPT in eyes with idiopathic ERM. Based on VPT presence/absence, eyes were categorized as ERM with VPT (ERM+VPT, n = 52 eyes) or ERM without VPT (ERM-VPT, n = 64 eyes). Optic nerve head (ONH) parameters, average and sectoral retinal nerve fiber layer (RNFL) thickness, and central macular thickness (CMT) were compared between groups. Best-corrected visual acuity (BCVA) and visual field (VF) (automated Humphrey central 30-2 perimetry) mean deviation (MD) and pattern standard deviation (PSD) were compared between groups.

MAIN OUTCOME MEASURES

The ONH parameters, peripapillary RNFL thickness, BCVA, VF MD, and PSD.

RESULTS

Fifty-two of 116 eyes (44.8%) with idiopathic ERM had VPT. The ERM+VPT group had larger rim area, smaller average and vertical cup-to-disc ratios, and smaller cup volume than ERM-VPT and normal groups (all P < 0.001). Eyes with VPT had greater CMT than eyes without VPT (421.87±97.31 μm vs. 377.08±75.1 μm; P = 0.006). Average and temporal RNFL thickness was higher in ERM+VPT (98.64±9.33 μm and 93.90±23.42 μm) than in normal eyes (94.02±8.45 μm and 66.42±12.71 μm). No significant difference in BCVA was found between ERM-VPT and ERM+VPT eyes, but MD was lower in ERM+VPT than in ERM-VPT (-3.91±3.68 dB vs. -2.18±2.42 dB; P = 0.005). Additionally, PSD was greater in ERM+VPT. Multivariate logistic regression analysis revealed that age (odds ratio [OR], 1.190; P = 0.014) and increased CMT (OR, 1.013; P = 0.005) were associated with vision loss, whereas VPT presence was associated with VF defects (OR, 6.290; P = 0.024).

CONCLUSIONS

Vitreopapillary traction was observed in >40% of eyes with idiopathic ERM, as confirmed by SD-OCT imaging. Vitreopapillary traction with idiopathic ERM was associated with altered optic disc architecture, increased average and temporal RNFL thickness, and VF defects.

Ocriplasmin for symptomatic vitreomacular adhesion: an evidence-based review of its potential

Vitreomacular traction is a multicategory entity that may cause substantial visual loss due to the formation of a macular hole or traction-induced tissue distortion. The advent of optical coherent tomography (OCT) has demonstrated the anatomic features of persistent vitreomacular attachment (VMA) more definitively, including in many asymptomatic or minimally symptomatic patients. The indications for intervention are unclear, since it is not possible to predict which eyes might be likely to develop progressive visual loss. This has been especially important since for many years, the only treatment option involved surgical intervention (vitrectomy) to release the persistent VMA. Recently, a pharmacolytic agent, ocriplasmin, has become available after many years of development and investigation, and may offer a feasible alternative to surgery, or even a risk/benefit ratio sufficiently favorable to offer intervention at an earlier stage of VMA. Several studies, including a large, prospective clinical trial, have established the foundation of its rationale and efficacy, providing the basis of its approval. The role for ocriplasmin in clinical practice is in the process of being determined. This paper summarizes current knowledge and status of investigations regarding ocriplasmin-induced pharmacologic vitreolysis, and offers some evidence-based considerations for its use.

Management paradigms for diabetic macular edema

PURPOSE

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

DESIGN

Perspective.

METHODS

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

RESULTS

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

CONCLUSIONS

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

Surgical management of diabetic retinopathy

Surgery for late complications of proliferative diabetic retinopathy remains the cornerstone of management even in patients who have received optimal laser photocoagulation and medical therapy. With improvisation in the surgical techniques and development of micro-incision surgical techniques for vitrectomy, the indications for surgical intervention are expanding to include diabetic macular edema with a greater number of patients undergoing early intervention. This review describes the current indications, surgical techniques, adjunctive anti-vascular endothelial growth factor therapy, surgical outcomes, and postoperative complications of pars plana vitrectomy for proliferative diabetic retinopathy and macular edema.

Evolving strategies in the management of diabetic retinopathy

Diabetic retinopathy (DR), the most common long-term complication of diabetes mellitus, remains one of the leading causes of blindness worldwide. Tight glycemic and blood pressure control has been shown to significantly decrease the risk of development as well as the progression of retinopathy and represents the cornerstone of medical management of DR. The two most threatening complications of DR are diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR). Focal/grid photocoagulation and panretinal photocoagulation are standard treatments for both DME and PDR, respectively. Focal/grid photocoagulation is a better treatment than intravitreal triamcinolone acetonide in eyes with DME. Currently, most experts consider combination focal/grid laser therapy and pharmacotherapy with intravitreal antivascular endothelial growth factor agents in patients with center-involving DME. Combination therapy reduces the frequency of injections needed to control edema. Vitrectomy with removal of the posterior hyaloid seems to be effective in eyes with persistent diffuse DME, particularly in eyes with associated vitreomacular traction. Emerging therapies include fenofibrate, ruboxistaurin, renin-angiotensin system blockers, peroxisome proliferator-activated receptor gamma agonists, pharmacologic vitreolysis, and islet cell transplantation.

Association between cystoid spaces on indocyanine green hyperfluorescence and optical coherence tomography after vitrectomy for diabetic macular oedema

PURPOSE

To study retrospectively the characteristics of residual indocyanine green (ICG) fluorescence after ICG-assisted vitrectomy and the association with spectral-domain optical coherence tomography (SD-OCT) findings in diabetic macular oedema (DMO).

METHODS

Thirteen consecutive eyes of 12 patients for whom fundus near-infrared fluorescence and 20° retinal sectional images were obtained using HRA2 and Spectralis OCT, respectively, 5 days after vitrectomy combined with ICG-assisted inner limiting membrane peeling for DMO. The relationship between the characteristics of the ICG hyperfluorescence and the cystoid spaces in the outer plexiform layer (OPL) on SD-OCT images was evaluated.

RESULTS

A total of 390 well-demarcated areas of ICG hyperfluorescence were delineated on 20° radial OCT scans dissecting the fovea 5 days after vitrectomy. The areas of ICG hyperfluorescence in the parafovea or perifovea were significantly smaller than those at the fovea. Most areas of hyperfluorescence were irregularly shaped in the parafovea and perifovea, whereas 18 of 38 areas of hyperfluorescence were round or oval at the fovea (P<0.001). SD-OCT delineated the cystoid spaces in the OPL in 73 areas of hyperfluorescence that were round or oval and accompanied by dark spots more frequently than that without cystoid spaces on OCT images (P<0.001 and P=0.002). Of the 123 cystoid spaces in the OPL on OCT images, 44 did not have ICG hyperfluorescence, had lower OCT reflectivity, and contained fewer hyperreflective foci than those with ICG hyperfluorescence (P<0.001 and P=0.020).

CONCLUSION

The results provided novel interpretations of the ICG hyperfluorescence and its association with OCT characteristics of the cystoid spaces in DMO.

Proteomic interactions in the mouse vitreous-retina complex

PURPOSE

Human vitreoretinal diseases are due to presumed abnormal mechanical interactions between the vitreous and retina, and translational models are limited. This study determined whether nonstructural proteins and potential retinal biomarkers were expressed by the normal mouse vitreous and retina.

METHODS

Vitreous and retina samples from mice were collected by evisceration and analyzed by liquid chromatography-tandem mass spectrometry. Identified proteins were further analyzed for differential expression and functional interactions using bioinformatic software.

RESULTS

We identified 1,680 unique proteins in the retina and 675 unique proteins in the vitreous. Unbiased clustering identified protein pathways that distinguish retina from vitreous including oxidative phosphorylation and neurofilament cytoskeletal remodeling, whereas the vitreous expressed oxidative stress and innate immunology pathways. Some intracellular protein pathways were found in both retina and vitreous, such as glycolysis and gluconeogenesis and neuronal signaling, suggesting proteins might be shuttled between the retina and vitreous. We also identified human disease biomarkers represented in the mouse vitreous and retina, including carbonic anhydrase-2 and 3, crystallins, macrophage inhibitory factor, glutathione peroxidase, peroxiredoxins, S100 precursors, and von Willebrand factor.

CONCLUSIONS

Our analysis suggests the vitreous expresses nonstructural proteins that functionally interact with the retina to manage oxidative stress, immune reactions, and intracellular proteins may be exchanged between the retina and vitreous. This novel proteomic dataset can be used for investigating human vitreoretinopathies in mouse models. Validation of vitreoretinal biomarkers for human ocular diseases will provide a critical tool for diagnostics and an avenue for therapeutics.

The evolving treatment options for diabetic macular edema

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

Structural changes in individual retinal layers in diabetic macular edema

Optical coherence tomography (OCT) has enabled objective measurement of the total retinal thickness in diabetic macular edema (DME). The central retinal thickness is correlated modestly with visual impairment and changes paradoxically after treatments compared to the visual acuity. This suggests the clinical relevance of the central retinal thickness in DME and the presence of other factors that affect visual disturbance. Recent advances in spectral-domain (SD) OCT have provided better delineation of the structural changes and fine lesions in the individual retinal layers. Cystoid spaces in the inner nuclear layer and outer plexiform layer are related to quantitative and qualitative parameters in fluorescein angiography. OCT often shows vitreoretinal interface abnormalities in eyes with sponge-like retinal swelling. Serous retinal detachment is sometimes accompanied by hyperreflective foci in the subretinal fluid, which exacerbates the pathogenesis at the interface of the photoreceptors and retinal pigment epithelium. Photoreceptor damage at the fovea is thought to be represented by disruption of the external limiting membrane or the junction between the inner and outer segment lines and is correlated with visual impairment. Hyperreflective foci in the outer retinal layers on SD-OCT images, another marker of visual disturbance, are associated with foveal photoreceptor damage.

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.

Posterior vitreous detachment following intravitreal drug injection

Background

To evaluate the incidence of posterior vitreous detachment (PVD) induced by intravitreal injection of different intravitreal drugs.

Methods

This prospective observational study included 61 patients (61 eyes) with different underlying retinal diseases: exudative age-related macular degeneration (n = 47), cystoid macular edema (CME) after retinal vein occlusion (n = 8), and CME of other origin (n = 6). Bevazicumab (1.25 mg) was injected into 25 eyes, ranibizumab (0.5 mg) into 27 eyes, triamcinolone (4 mg) into six eyes, and a combination of bevacizumab and triamcinolone into three eyes. Patients with initial PVD were excluded. Patients were followed for at least 4–6 weeks after their last injection by Fourier-domain OCT, fundus biomicroscopy and ultrasound B-examination.

Results

Overall, 15 of 61 eyes developed a PVD after intravitreal injection (n = 6 after ranibizumab, n = 7 after bevacizumab and n = 2 after triamcinolon) within a mean follow-up period of 11.1 weeks. PVD occurred in three eyes after the first injection, in three eyes after the second, and in seven eyes after the third injection. Incidence of PVD correlated with increasing age.

Conclusion

Intravitreal injection of commonly-used drugs seems to induce posterior vitreous detachment, which may thus influence the outcome of the underlying disease.

Intravitreal injection of expansile perfluoropropane (c(3)f(8)) for the treatment of vitreomacular traction

PURPOSE

To study the efficacy of a single intravitreal injection of expansile gas in releasing vitreomacular traction.

DESIGN

Retrospective, interventional case series.

METHODS

Fifteen eyes of 14 consecutive patients with symptomatic and persistent vitreomacular traction (>3 months' duration) on spectral-domain optical coherence tomography (SD OCT) received a single intravitreal injection of 0.3 mL 100% perfluoropropane (C(3)F(8)) as an alternative to pars plana vitrectomy (PPV). Primary outcome was the number of eyes with complete vitreomacular traction release on OCT 1 month following treatment. Secondary outcomes included changes in visual acuity (VA), foveal contour, central foveal thickness, and maximal foveal thickness 1 month following treatment, and final VA.

RESULTS

Mean age (± SD) was 72.1 ± 12.6 years. Mean follow-up was 398.7 ± 174.4 days. Vitreomacular traction was idiopathic in 7 eyes and associated with diabetes in 6. One month following treatment, vitreomacular traction was released in 6 eyes (40%). Three further eyes (20%) had resolution of vitreomacular traction within 6 months, 4 (27%) underwent PPV, and 2 (13%) subsequently declined surgery. Foveal contour was restored in 7 eyes (47%). VA and central foveal thickness were similar 1 month following treatment, but maximal foveal thickness decreased by 65.8 μm (P = .041). Mean final VA decreased 0.03 logMAR units from baseline (P = .536). Eyes with vitreomacular traction release within 1 month had less extensive vitreomacular traction (P = .037), low vitreous face reflectivity, and maximal foveal thickness <500 μm (P = .004) pretreatment. There were no associated adverse events.

CONCLUSIONS

Intravitreal C(3)F(8) injection could offer a minimally invasive alternative to PPV in patients with symptomatic and persistent vitreomacular traction. It appears particularly effective in eyes with less extensive vitreomacular traction and low vitreous face reflectivity on SD OCT. Further studies are warranted.

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.