Diabetic vitrectomy: risks, prognosis, future trends

Vitreous rebleeding rate after vitrectomy or phacovitrectomy in patients with proliferative diabetic retinopathy: A retrospective study

BACKGROUND

The most common complication after vitrectomy is the rebleeding in vitreous cavity. It is important to detect the different factors that can increase the vitreous rebleeding rate in these patients.

OBJECTIVE

To carry out a retrospective review of the rate of vitreous rebleeding after vitrectomy or phacovitrectomy.

METHOD

Retrospective, descriptive and comparative study of patients with a diagnosis of proliferative diabetic retinopathy with phacovitrectomy or vitrectomy procedure. Personal background data, type of surgical intervention and grade of the surgeon who carried out the procedure were obtained.

RESULTS

1227 files of diabetic patients with vitrectomy or phacovitrectomy were reviewed. 65% presented systemic arterial hypertension. The average glomerular filtration rate was 63.50 (±32.36) ml/min/1.73 m2 and glycosylated hemoglobin (HBA1C) of 8% (4.6 to 15%). In the comparison of variables, a significant difference in the rate of vitreous rebleeding was obtained comparing phacovitrectomy with vitrectomy. (p = 0.003), in the relationship between vitrectomy with vitreous rebleeding, an odds ratio of 1.44 was obtained.

CONCLUSION

The results obtained show a lower rate of rebleeding in patients undergoing phacovitrectomy in patients with proliferative diabetic retinopathy.

Investigation of the recurrent vitreous hemorrhage risk factors after early 25G vitrectomy in diabetic vitreous hemorrhage

Vitreous hemorrhage (VH) is one of the main causes of vision loss in diabetic retinopathy (DRP). Early surgery increases the visibility of the retina, allowing early recognition of DRP complications and additional treatments. One of the most important reasons affecting success after surgery is recurrent vitreous hemorrhage (RVH). We aimed to investigate the risk factors for RVH after early 25G vitrectomy in diabetic VH. Eighty eyes of eighty patients who underwent early 25G PPV surgery with a diagnosis of VH due to proliferative diabetic retinopathy (PDR) were included in this retrospective study. Vision acuity changes and intraocular pressure (IOP) changes were compared. The effect of arterial hypertension (HT), coronary artery disease (CAD), preoperative antiglaucomatous usage, and anticoagulant usage on RVH was investigated. A value of P < .05 was accepted as statistically significant. Postoperative RVH was observed in 18 (22.5%) patients. There was no correlation between the age of the patients and the development of postoperative RVH (r = -0.197, P = .08). The rate of HT and the mean HbA1C levels were found to be higher in the patients who developed RVH than in those who did not (P = .04 and < 0.001, respectively). The presence of CAD, preoperative glaucoma disease, and the use of anticoagulants did not have any effect on RVH (P = .229, 0.843, 0.932, respectively). HT and increased HbA1c were found to be risk factors for RVH in VH patients who underwent 25G vitrectomy in the early period in our study.

VITRECTOMY FOR VITREOUS HEMORRHAGE ASSOCIATED WITH RETINAL VEIN OCCLUSION: Visual Outcomes, Prognostic Factors, and Sequelae

PURPOSE

To report the outcomes of pars plana vitrectomy for vitreous hemorrhage (VH) associated with retinal vein occlusion and to identify prognostic indicators.

METHODS

Interventional, retrospective consecutive case series between 2015 and 2021.

RESULTS

The study included 138 eyes of 138 patients (64 female and 74 male); 81 patients had branch retinal vein occlusion and 57 had central retinal vein occlusion. The mean age was 69.8 years. The mean duration between the diagnosis of VH and surgery was 79.6 ± 115.3 (range, 1-572) days. The mean follow-up was 27.2 months. The logarithm of the minimum angle of resolution visual acuity significantly improved from 1.95 ± 0.72 (Snellen equivalent, 20/1782) to 0.99 ± 0.87 (20/195) at 6 months and to 1.06 ± 0.96 (20/230) at the final visit (both P < 0.001). The visual acuity at 6 months improved by three or more lines in 103 eyes (75%). Postoperative complications during follow-up included recurrent VH in 16 eyes (12%) (of which 8 eyes underwent reoperations), rhegmatogenous retinal detachment in six eyes (4%), and new neovascular glaucoma in three eyes (2%). Worse final visual acuity was significantly associated with older age ( P = 0.007), concurrent neovascular glaucoma ( P < 0.001), central retinal vein occlusion ( P < 0.001), worse preoperative visual acuity ( P < 0.001), postoperative new neovascular glaucoma ( P = 0.021), and postoperative retinal detachment ( P < 0.001). The duration of VH was not associated with visual outcomes ( P = 0.684). Preoperative antivascular endothelial growth factor injections and tamponade did not prevent postoperative recurrent VH.

CONCLUSION

Pars plana vitrectomy is effective for VH associated with retinal vein occlusion, regardless of the duration of hemorrhage. However, pre-existing risk factors and postoperative sequelae may limit visual recovery.

Post-vitrectomy delayed retinal breaks in proliferative diabetic retinopathy

PURPOSE

To report a series of cases of post-operative new secondary retinal breaks following vitrectomy for proliferative diabetic retinopathy (PDR).

METHODS

This retrospective case series included data of patients diagnosed with post-operative retinal breaks following uneventful vitrectomy surgery for PDR from January 2018 to December 2021.

RESULTS

New post-vitrectomy retinal breaks in PDR were seen in 7% of eyes (n = 10/148 eyes; 10 patients). Age of study patients ranged from 45 to 69 years and there were 8 males. Vitreous surgery was performed for vitreous hemorrhage in six eyes, macular tractional retinal detachment in three eyes and epiretinal membrane in one eye. Tractional fibrovascular proliferation near the retinal break prior to its development was noted either pre- or intra-operatively in 8 eyes. Mean time interval between the vitreous surgery and secondary retinal break development was 6.4 months. Residual fibrous tissue post-surgery adjacent to the break was noted in 4 cases. Sclerosed retinal vessel was noted in 4 eyes and associated inner retinal thinning or schisis in 5 eyes. No retinal detachment was noted in any case. Prophylactic barrage was done in 4 eyes. Last follow-up interval ranged from 4 to 53 months and visual acuity ranged from 6/6 to 6/60. No subretinal fluid, traction or break enlargement was noted at the last visit.

CONCLUSION

Delayed post-operative retinal breaks following vitrectomy are uncommon in PDR eyes. Careful preoperative evaluation of the retinal proliferations, intraoperative dissection of the membranes and regular post-operative reviews are vital in anticipating the development of delayed post-vitrectomy retinal breaks. Observation could be the management strategy for these breaks.

Surgical management of diabetic tractional retinal detachments

Tractional retinal detachment is an end-stage form of diabetic retinopathy that occurs when contractile forces in the vitreous and neovascular tissue lead to the detachment of the neurosensory retina. We review the literature related to the management of this disease. Preoperative planning includes appropriate patient selection, diagnostic and prognostic imaging, and medical optimization with reduction of systemic risk factors. Use of antivascular endothelial growth factor for preoperative treatment has had significant benefits for tractional retinal detachment repair in improving surgical efficiency and outcomes. Advances in microsurgical instrumentation are discussed, with attention to small-gauge vitrectomy with improved flow dynamics, viewing strategies, and lighting allowing bimanual surgery. Special emphasis is placed on bimanual surgical technique, choice of tamponade, and the avoidance of iatrogenic damage. Complications and special considerations are further explored. Based on our compilation of relevant literature, we propose a surgical algorithm for the management of these complex patients.

Current management of diabetic tractional retinal detachments

Twenty-five percent of diabetes-related vision loss stems from complications of proliferative diabetic retinopathy (PDR). Panretinal photocoagulation has been the preferred treatment of high-risk PDR for decades and more recently intravitreal injections of drugs that inhibit the actions of vascular endothelial growth factor have become popular. But despite these treatments PDR may progress uncontrollably to advanced pathologies such as traction retinal detachments (TRDs), combined traction/rhegmatogenous retinal detachments (TRD/RRDs), vitreous hemorrhages, rubeosis iridis, and traction maculopathies, which produce mild-to-severe loss of vision. TDR have long been the most common indication for PDR-related vitreoretinal surgery. Vitrectomy surgery is indicated for recent (<6 months duration) TRD involving the macula, progressive TRD that threatens the macula, and recent data suggest that chronic macula-involving TRDs (>6 months duration) may also benefit. Combined TRD/RRD represents a particularly challenging surgical condition but advances in surgical instrumentation, dissection techniques, and post-operative tamponade have produced excellent success rates. The recent development of small-gauge vitrectomy systems has persuaded most surgeons to switch platforms since these appear to produce shorter surgical times and quicker post-operative recoveries. Pre-operative injections of bevacizumab are frequently administered for persistent neovascularization to facilitate surgical dissection of pre-retinal fibrosis and reduce the incidence of post-operative hemorrhages. Recent trends toward earlier surgical intervention and expanded indications are likely to continue as surgical instrumentation and techniques are further developed.

Vitreous rebleed following sutureless vitrectomy: Incidence and risk factors

Purpose

This study aims to evaluate the incidence and risk factors for vitreous rebleed (VRB) following 25-gauge sutureless vitrectomy for vitreous hemorrhage (VH) in diabetic retinopathy.

Methods

A retrospective review of 190 diabetic patients having undergone vitrectomy for VH at a tertiary eye care center was analyzed. Demographic data of patients along with risk factors such as blood sugar levels (BSL), blood pressure (BP), anticoagulant use, and pan-retinal photocoagulation status (PRP) were tabulated. Depending on the commencement of VRB, patients were divided into immediate rebleed-within 2 weeks and delayed rebleed-beyond 2-4 weeks.

Results

Forty-one patients had VRB, out of which 18 patients had immediate VRB and 23 patients had delayed VRB. The average duration between vitrectomy and VRB was 3.28 months. Twenty-eight patients were male and 13 were females. Average age at presentation was 53.8 years. Thirty-four patients (82.9%) were found to have high BSL and 28 patients (68.3%) had high BP and they developed rebleed (P < 0.01) after an initial hemorrhage-free period (average = 5.15 months). Fifteen patients (36.6%) underwent first time PRP intraoperatively, and they had immediate rebleed (P < 0.01) without any hemorrhage-free period (average = 0.9 months). Eight patients (19.5%) were on perioperative anticoagulants; however, their statistical significance did not persist in the multivariable model. There were neither age nor gender predilection toward rebleed (P > 0.05).

Conclusion

The incidence rate of VRB was found to be 21.6%. Age and gender did not contribute to rebleed. Intraoperative PRP was a risk factor for immediate rebleed. Poor glycemic and BP control was a risk factor for delayed rebleed.

Angiogenesis and Inflammation Crosstalk in Diabetic Retinopathy

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

Segmentation and removal of fibrovascular membranes with high-speed 23 G transconjunctival sutureless vitrectomy, in severe proliferative diabetic retinopathy

Aim

To evaluate the effectiveness and safety of high-speed (5,000 cuts per minute) 23 G transconjunctival sutureless vitrectomy (TSV) in severe diabetic fibrovascular proliferation (DFVP).

Patients and methods

In this retrospective consecutive case series, patients who underwent 23 G TSV for severe DFVP between October 2011 and March 2014 at our institution were evaluated. 23 G TSV was performed with a high-speed (5,000 cuts per minute) cutter without a chandelier light.

Results

The mean follow-up period was 8 months (range: 4–23 months). Of the 27 eyes of 27 patients, 14 eyes (52%) underwent concomitant phacoemulsification with posterior chamber intraocular lens implantation, nine eyes (33%) were pseudophakic, and four eyes were phakic (15%). DFVP was removed with ease in all, and visual acuity was improved in 18 (67%) eyes. Iatrogenic retinal tear was observed in four eyes (15%) and treated successfully during surgery. Suture placement to a single sclerotomy was performed in eight eyes (30%). Postoperative intraocular hemorrhage was observed in five eyes (18%). Cataract formation was observed in two of the four phakic eyes. Three (11%) patients had postoperative intraocular pressure rise. Postoperative hypotony (≤6 mmHg) and endophthalmitis were not observed in any eye.

Conclusion

The segmentation and removal of fibrovascular membranes with high-speed 23 G TSV seems to be a safe and easy method in severe diabetic eye disease.

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.

Current nanotechnology approaches for the treatment and management of diabetic retinopathy

Diabetic retinopathy (DR) is a consequence of diabetes mellitus at the ocular level, leading to vision loss, and contributing to the decrease of patient's life quality. The biochemical and anatomic abnormalities that occur in DR are discussed in this review to better understand and manage the development of new therapeutic strategies. The use of new drug delivery systems based on nanoparticles (e.g. liposomes, dendrimers, cationic nanoemulsions, lipid and polymeric nanoparticles) is discussed along with the current traditional treatments, pointing out the advantages of the proposed nanomedicines to target this ocular disease. Despite the multifactorial nature of DR, which is not entirely understood, some strategies based on nanoparticles are being exploited for a more efficient drug delivery to the posterior segment of the eye. On the other hand, the use of some nanoparticles also seems to contribute to the development of DR symptoms (e.g. retinal neovascularization), which are also discussed in light of an efficient management of this ocular chronic disease.

α-Melanocyte-stimulating hormone protects retinal vascular endothelial cells from oxidative stress and apoptosis in a rat model of diabetes

AIMS

Oxidative stress and apoptosis are among the earliest lesions of diabetic retinopathy. This study sought to examine the anti-oxidative and anti-apoptotic effects of α-melanocyte-stimulating hormone (α-MSH) in early diabetic retinas and to explore the underlying mechanisms in retinal vascular endothelial cells.

METHODS

Sprague-Dawley rats were injected intravenously with streptozocin to induce diabetes. The diabetic rats were injected intravitreally with α-MSH or saline. At week 5 after diabetes, the retinas were analyzed for reactive oxygen species (ROS) and gene expression. One week later, the retinas were processed for terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and transmission electron microscopy. Retinal vascular endothelial cells were stimulated by high glucose (HG) with or without α-MSH. The expression of Forkhead box O genes (Foxos) was examined through real-time PCR. The Foxo4 gene was overexpressed in endothelial cells by transient transfection prior to α-MSH or HG treatment, and oxidative stress and apoptosis were analyzed through CM-H2DCFDA and annexin-V assays, respectively.

RESULTS

In diabetic retinas, the levels of H2O2 and ROS and the total anti-oxidant capacity were normalized, the apoptotic cell number was reduced, and the ultrastructural injuries were ameliorated by α-MSH. Treatment with α-MSH also corrected the aberrant changes in eNOS, iNOS, ICAM-1, and TNF-α expression levels in diabetic retinas. Furthermore, α-MSH inhibited Foxo4 up-regulation in diabetic retinas and in endothelial cells exposed to HG, whereas Foxo4 overexpression abrogated the anti-oxidative and anti-apoptotic effects of α-MSH in HG-stimulated retinal vascular endothelial cells.

CONCLUSIONS

α-MSH normalized oxidative stress, reduced apoptosis and ultrastructural injuries, and corrected gene expression levels in early diabetic retinas. The protective effects of α-MSH in retinal vascular endothelial cells may be mediated through the inhibition of Foxo4 up-regulation induced by HG. This study suggests an α-MSH-mediated potential intervention approach to early diabetic retinopathy and a novel regulatory mechanism involving Foxo4.

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.

Fibrovascular ingrowth after 25-gauge transconjunctival vitrectomy in proliferative diabetic retinopathy

The authors describe two patients with proliferative diabetic retinopathy bilaterally who were treated with transconjunctival 25-gauge pars plana vitrectomy (PPV) for dense vitreous hemorrhage (VH). After 4 and 10 months, respectively, both developed recurrent VH. They were initially managed with in-office gas-fluid exchange and anti-VEGF intravitreal injection. Soon after gas bubble resorption, the VH recurred. Color external photos revealed engorged episcleral vessels superotemporally, and ultrasound biomicroscopy confirmed the presence of fibrovascular ingrowth (FVI) at the sclerotomy site in both patients. They were successfully treated with a slightly modified 25-gauge PPV technique. Although FVI is well-recognized following conventional 20-gauge vitrectomy, this report is the first to detail FVI arising after small-gauge transconjunctival vitrectomy.

Pharmacologic and clinical profile of dexamethasone intravitreal implant

The challenge in the treatment of chronic retinal diseases is to deliver effective therapy to the target tissues in the back of the eye while limiting drug exposure in nontarget tissues. Intravitreal placement provides the most targeted drug delivery, but repeated penetration of the globe to deliver intravitreal therapy can pose safety risks. A more effective strategy for the treatment of chronic retinal diseases would be to combine intravitreal placement with sustained drug delivery. The dexamethasone intravitreal (DEX) implant is a biodegradable sustained-release intravitreal drug delivery system that is approved for the treatment of macular edema following branch or central retinal vein occlusion and for noninfectious uveitis affecting the posterior segment of the eye. A single DEX implant has been shown to provide clinical benefits for up to 6 months in eyes with retinal vein occlusion or intermediate or posterior uveitis.

Activation of retinal microglial cells is not associated with Müller cell reactivity in vitrectomized rabbit eyes

PURPOSE

Vitrectomy is a frequently performed surgical intervention in ophthalmology to remove vitreous traction and opacities or to treat complicated retinal detachments and diabetic changes. However, there is lack of information about cellular responses in retinal tissue after a surgical intervention such as vitrectomy. Microglia cells, the immune competent cells of neuronal tissue, are involved in nearly all neuropathological changes and are additionally activated by neurosurgical interventions. For most neurodegenerative changes, it is described that microglia activation is generally accompanied by a reactive gliosis of macroglial cells. However, it is not known whether microglial cell activation is necessarily associated with macroglial cell gliosis or whether these processes are regulated separately. Furthermore, there is an ongoing debate about possible detrimental consequences of microglial cell activation for neurons in central neural and retinal tissue.

METHODS

Using immunohistochemistry and whole-cell patch clamp experiments in a rabbit model of partial pars plana vitrectomy, we investigated micro- and macroglial cell reactivity after this intervention.

RESULTS

Partial vitrectomy induced a massive microglia response characterized by morphological changes, intraretinal migration and proliferation of retinal microglial cells, respectively. Microglial cell reactivity was observed 2 days after the operation and was down-regulated after 7 days. Microglia reactivity was associated with neither a general Müller cell gliosis nor an obvious neuronal cell loss. Electrophysiological examinations revealed no significant changes of whole-cell currents and membrane potentials of Müller cells from healthy and vitrectomized eyes up to 3 weeks after operation. Only a small number of individual Müller glial cells expressed GFAP or reduced their inward currents as a sign of Müller cell gliosis.

CONCLUSION

Vitrectomy induced a massive response of microglial cells. However, microglia activation and deactivation are effectively regulated and are not necessarily associated with macroglial (Müller) cell reactivity and with obvious detrimental effects to neurons.

Current and future approaches in the prevention and treatment of diabetic retinopathy

Diabetic retinopathy (DR) is a major cause of blindness worldwide and is the number one cause of blindness in working-age individuals in developed countries. We review the current literature and discuss the pathogenesis, modifying risk factors, genetics, and treatment of DR. Special focus is placed on the rationale and effectiveness of therapeutic modalities, both current and future.

Outcomes and complications of 25-gauge transconjunctival sutureless vitrectomy for proliferative diabetic retinopathy

PURPOSE

To investigate the feasibility and efficacy of 25-gauge vitrectomy in the treatment of proliferative diabetic retinopathy (PDR).

METHODS

All patients underwent primary 25-gauge vitrectomy for simple vitreous hemorrhage (VH), fibrovascular proliferation (FVP), or tractional retinal detachment (TD), and were followed for more than 1 month. Final visual outcomes and intraoperative and postoperative complications were evaluated.

RESULTS

167 eyes (138 patients) were used in this study, 65 eyes (39%) with VH, 66 eyes (40%) with FVP, and 36 eyes (21%) with TD. Measured using the mean logarithm of the minimum angle of resolution (logMAR), visual acuity (VA) significantly improved (p < 0.0001). Intraoperative iatrogenic retinal breaks developed in 19 eyes (11%). Concerning postoperative complications, VH in 36 eyes (22%), retinal detachment in 2 eyes (1%), and neovascular glaucoma 12 eyes (7%) were observed. No endophthalmitis developed.

CONCLUSIONS

Twenty-five-gauge vitrectomy can successfully treat PDR. Clinical outcomes and complications are comparable to those of 20-gauge vitrectomy.

[Use of silicone oil in vitreal hemorrhage complicating proliferated diabetic retinopathy]

INTRODUCTION

Vitreous hemorrhage is a frequent complication of proliferated diabetic retinopathy. Vitrectomy has vastly improved its prognosis. The purpose of this study was to evaluate the use of silicone oil in vitreal surgery in this indication.

METHODS

We present a retrospective study of 15 eyes that underwent vitrectomy and silicone oil injection for vitreal hemorrhage complicating proliferative diabetic retinopathy. For each patient, we noted the clinical and echographic features, the surgical procedure, and the postoperative outcome after a mean period of 20 months.

RESULTS

The indications for silicone injection were recurrent vitreal hemorrhage (seven eyes), aggressive fibrovascular proliferations (five eyes), and iatrogenic retinal breaks (three eyes). Anatomic success was noted in ten cases. Four patients had a hemorrhage reoccurrence after silicone oil removal and one patient developed neovascular glaucoma. Silicone cataract (seven eyes) and emulsification of silicone (one eye) were noted.

DISCUSSION

The use of silicone oil in vitreal surgery for complicated proliferated diabetic retinopathy contributes a hemostatic and plugging effect, but it still has a number of disadvantages such as the need to remove it and its own side effects. It can be beneficial in cases of rubeosis or recurrent hemorrhage. However, it is essentially indicated in recurrent hemorrhage in monophthalmos patients.

Posterior hyaloid changes following intravitreal triamcinolone and macular laser for diffuse diabetic macular edema

PURPOSE

To compare the effects of intravitreal triamcinolone and macular grid laser photocoagulation on the vitreomacular relationship in diffuse diabetic macular edema.

METHODS

Review of optical coherence tomography images gathered in a prospective, interventional randomized clinical trial.

SETTING

Institutional Practice.

PROCEDURES

Seventy-seven optical coherence tomography images of 88 consecutive patients entered into a randomized clinical trial of the treatment of persistent diffuse diabetic macular edema were reviewed by two independent observers. All patients in the trial had diabetic macular edema following at least two macular grid laser treatments and were randomized to intravitreal injections of 4 mg triamcinolone or to further macular grid laser. Optical coherence tomography images were recorded at baseline, 4, 8, and 12 months and the patterns of vitreomacular relationship were classified into six categories.

MAIN OUTCOME MEASURES

The patterns of vitreomacular relationship in the two groups were compared and correlated with the response to treatment. Outcome measures were defined as changes in best-corrected visual acuity Early Treatment Diabetic Retinopathy Study letters and central macular thickness on optical coherence tomography.

RESULTS

Six eyes had peri-foveal vitreous detachment with or without traction in each group at baseline. At 12 months, the prevalence of peri-foveal vitreous detachment was significantly higher after intravitreal triamcinolone (n = 11) than macular grid laser (n = 8). These patients had poorer visual outcome (P = 0.01) and increased central macular thickness (P = 0.002). The development of complete posterior vitreous detachment was associated with significantly decreased central macular thickness (P = 0.001) but not better visual outcome (P = 0.72).

CONCLUSION

These results suggest that posterior hyaloid changes may play a more influential role in the response to intravitreal triamcinolone than laser treatment for diffuse diabetic macular edema.

Cystoid macular edema

We review the epidemiology, pathophysiology, and etiology of cystoid macular edema (CME). Inflammatory, diabetic, post-cataract, and macular edema due to age-related macular degeneration is described. The role of chronic inflammation and hypoxia and direct macular traction is evaluated in each case according to different views from the literature. The different diagnostic methods for evaluating the edema are described. Special attention is given to fluoroangiography and the most modern methods of macula examination, such as ocular coherence tomography and multifocal electroretinography. Finally, we discuss the treatment of cystoid macular edema in relation to its etiology. In this chapter we briefly refer to the therapeutic value of laser treatment especially in diabetic maculopathy or vitrectomy in some selected cases. Our paper is focused mainly on recent therapeutic treatment with intravitreal injection of triamcinolone acetonide and anti-VEGF factors like bevacizumab (Avastin), ranibizumab (Lucentis), pegaptamid (Macugen), and others. The goal of this paper is to review the current status of this treatment for macular edema due to diabetic maculopathy, central retinal vein occlusion and post-cataract surgery. For this reason the results of recent multicenter clinical trials are quoted, as also our experience on the use of intravitreal injections of anti-VEGF factors and we discuss its value in clinical practice.

25-Gauge transconjunctival sutureless vitrectomy

PURPOSE OF REVIEW

The history and development of 25-gauge transconjunctival sutureless vitrectomy are reviewed in this paper. The expanded spectrum of appropriate cases and recent innovations in vitrectomy surgery are discussed, as are longer-term outcomes and possible complications.

RECENT FINDINGS

25-Gauge pars plana vitrectomy has evolved significantly since its introduction in 2002, with newer instruments and novel techniques expanding the scope and improving outcomes in vitreoretinal surgery. Proper case selection is imperative, as the smaller scale of the instruments and decreased fluidics work most efficiently when extensive manipulation of intraocular tissue or significant membrane dissection is not required. Unique complications of 25-gauge surgery such as hypotony and a possible increased rate of endophthalmitis may be related to unsutured sclerotomies, and revisions in surgical approach may help to decrease these potentially devastating complications.

SUMMARY

Clinical experience over the last several years has proven that this sutureless system is both safe and efficacious. Decreased surgical times, reduced postoperative inflammation, and more rapid patient recovery have all contributed to an increased acceptance of 25-gauge vitrectomy by retinal physicians.