Vitrectomy outcomes in eyes with diabetic macular edema and vitreomacular traction

Diabetic macular edema: therapeutic options

Treatment for diabetic macular edema (DME) is continuously evolving with the advent of pharmacologic therapies. Focal laser photocoagulation remains the historical standard of care; however, a new wave of studies is rapidly emerging that shows the benefit of intravitreal antivascular endothelial growth factor medications and corticosteroids. The goal of this review is to compare the various treatment options for DME, and include data from the most recent clinical trials of therapies for this complex condition.

Diabetic macular edema: new trends in management

The treatment of diabetic macular edema may be evolving from a laser ablative approach into a pharmacotherapeutic approach. The exponential growth that has occurred over the past decade in the retinal pharmacotherapy field has led to the development of several pharmacotherapies for retinal vascular diseases such as diabetic macular edema. Many of these agents, in the form of intravitreal injections or sustained delivery devices, have already undergone clinical trial testing for safety and efficacy and many others are currently being similarly evaluated. Some of these agents have proven to be more efficacious than traditional laser therapy, and it is possible that traditional laser therapy for diabetic macular edema may be abandoned altogether in the near future, especially with the introduction of the micropulse laser. However, more research and experience is still needed in order to determine the best treatment agent or combination of therapeutic modalities, as well as the best treatment regimen for a given patient. In this article, we briefly review the major new developments in the field of diabetic macular edema treatment. In addition, we touch on some of the promising forthcoming therapies.

Resolution of vitreomacular traction following intravitreal triamcinolone acetonide injection in an eye with branch retinal vein occlusion

A 60-year-old woman with a past medical history of branch retinal vein occlusion presented with decreased vision and metamorphopsia in her left eye. A fundus examination revealed a tortuous retinal vein with a few retinal hemorrhages in the inferotemporal quadrant. Optical coherence tomography revealed a partially separated posterior vitreous membrane pulling up the fovea. The patient refused surgical treatment so intravitreal triamcinolone acetonide (4 mg/0.1 mL) was administered. The patient reported resolution of symptoms in her left eye following this treatment, but her visual acuity did not show any improvement. Optical coherence tomography scanning revealed a complete detachment of the posterior hyaloid with release of the vitreomacular traction. In patients with vitreomacular traction and branch retinal vein occlusion, the combination of the possible vitreous liquefaction and mechanical increase of vitreous volume caused by an intravitreal injection with a degree of reduction in retinal thickness may play a role in the resolution of vitreomacular traction.

Virtual retinectomy: indocyanine green-assisted internal limiting membrane peeling as a surgical adjunct in repair of recurrent rhegmatogenous retinal detachment due to PVR

Background

The purpose of this study was to describe and evaluate a surgical approach, known as internal limiting membrane (ILM) peeling, as an adjunct to repair of recurrent retinal detachment due to proliferative vitreoretinopathy (PVR).

Methods

This was a retrospective case series. All eyes underwent repair of recurrent PVR-related rhegmatogenous retinal detachment incorporating macular indocyanine green-assisted ILM peeling. Patients with primary detachments, diabetes, staphyloma, or macular holes were excluded. The main outcome measure was the anatomic success of single surgery. The characteristics of the group were studied, including the number and types of previous detachment repair attempts, as well as the subsequent surgeries.

Results

Fourteen eyes from 14 patients were included. Anatomic success with single surgery was achieved in 11 of 14 (79%) of the operated eyes using this technique, and eventual success was achieved in all eyes (100%). Among the failed repairs prior to ILM peeling, 8/14 eyes had scleral buckles, 7/14 had silicone oil tamponade, and two had inferior retinectomies. There was no subsequent development of epiretinal membranes after ILM peeling.

Conclusion

ILM peeling in conjunction with vitrectomy and peeling of peripheral membranes is an effective technique with a high anatomic success rate in the challenging scenario of PVR-related recurrent detachments. We describe the technique as an alternative to the traditional retinectomy.

Optical coherence tomography in the diagnosis and management of diabetic macular edema: time-domain versus spectral-domain

Optical coherence tomography (OCT) is an important imaging modality in the setting of diabetic macular edema (DME). Its use allows more precise evaluation of retinal pathology in DME, including retinal thickness and edema, vitreomacular interface abnormalities, subretinal fluid, and foveal microstructural changes. Additional advantages include its ability to quantitatively monitor response to treatment of DME by laser, intravitreal pharmacotherapies, and vitreoretinal surgery. OCT measurements are now used in all major clinical studies of DME treatment as critical endpoints. This article presents a review of both time-domain and spectral-domain OCT in the diagnosis and management of DME. The authors discuss the various parameters evaluated by the OCT systems and provide an evidence-based evaluation of their accuracy, significance, reliability, and limitations. As the capability of OCT continues to advance, it appears that its use will play an increasingly important role in the understanding, evaluation, and treatment of DME.

Emerging pharmacotherapies for diabetic macular edema

Diabetic macular edema (DME) remains an important cause of visual loss in patients with diabetes mellitus. Although photocoagulation and intensive control of systemic metabolic factors have been reported to achieve improved outcomes in large randomized clinical trials (RCTs), some patients with DME continue to lose vision despite treatment. Pharmacotherapies for DME include locally and systemically administered agents. We review several agents that have been studied for the treatment of DME.

Relationship between fluorescein pooling and optical coherence tomographic reflectivity of cystoid spaces in diabetic macular edema

OBJECTIVE

To study the characteristics of the reflectivity of the cystoid spaces and serous retinal detachment (SRD) on spectral-domain optical coherence tomography (SD-OCT) and the correlation with fluorescein findings in diabetic macular edema (DME).

DESIGN

Retrospective, observational, cross-sectional study.

PARTICIPANTS

Consecutive 134 eyes of 114 patients with clinically significant macular edema for whom SD-OCT and fluorescein angiography (FA) were performed on the same day.

METHODS

Fluorescein angiography using Heidelberg Retina Angiograph 2 (Heidelberg Engineering, Heidelberg, Germany) and OCT images using Spectralis OCT (Heidelberg Engineering) were obtained. The reflectivity of the cystoid spaces and SRD on the OCT images was evaluated qualitatively and quantitatively and compared with the fluorescein pooling intensity on FA images.

MAIN OUTCOME MEASURES

The relationship between the fluorescein pooling and the reflectivity characteristics of the cystoid spaces on SD-OCT images.

RESULTS

A total of 141 cystoid spaces in 101 eyes were delineated on OCT images, and 138 spaces (97.9%) had fluorescein pooling. Fifty-five cystoid spaces (39.9%) with marked fluorescein pooling intensity had lower reflectivity on OCT images than those with modest pooling (12.1±10.4 vs. 22.0±15.4, P < 0.001). The heterogeneity of the reflectivity of the cystoid spaces on the OCT images was associated significantly (P < 0.001) with modest fluorescein pooling. The hyperreflective foci in the cystoid spaces were correlated significantly with modest fluorescein pooling and higher or heterogeneous reflectivity on OCT images (P < 0.001, P < 0.001, and P=0.005, respectively). In addition, the cystoid spaces with microaneurysms had higher or heterogeneous reflectivity on OCT images more frequently than those without microaneurysms (P < 0.001 and P=0.019, respectively). The reflectivity levels in the SRD were significantly (P=0.005) lower than in the cystoid spaces, and only 1 eye (3.3%) had heterogeneous reflectivity on OCT images.

CONCLUSIONS

The results provided a novel interpretation of fluorescein pooling and OCT characteristics of cystoid spaces and SRD in DME and suggested several mechanisms by which the blood-retinal barrier is disrupted and concomitant edematous changes develop.

Aging changes of vitreomacular interface

PURPOSE

The posterior precortical vitreous pocket (the pocket) is a premacular liquefied lacuna, the physiologic presence of which was reported in autopsy eyes. We describe the morphologic features of the pocket in normal individuals.

METHODS

We performed spectral-domain optical coherence tomography in 102 eyes of 51 normal subjects of various ages in a sitting position.

RESULTS

The pocket was identified as an optically lucent space anterior to the posterior fundus in 85 of 102 eyes (83.3%) in the age-group. The vitreous cortex was extremely thin at the central fovea, and it gradually thickened along with age in the perifoveal area. A shallow perifoveal posterior vitreous detachment developed in 16 of 32 eyes (50%) of subjects aged >51 years. The lamellar structure of the vitreous cortex was seen in 7 of the 32 eyes (22%) of subjects aged >51 years.

CONCLUSION

Spectral-domain optical coherence tomography confirmed the presence of the pocket in all ages. Thickened vitreous cortex and perifoveal posterior vitreous detachment were physiologic findings in older individuals. The lamellar structure of the vitreous cortex may be related to the vitreoschisis.

Dexamethasone intravitreal implant for treatment of diabetic macular edema in vitrectomized patients

PURPOSE

To evaluate the safety and efficacy of Ozurdex (dexamethasone intravitreal implant) 0.7 mg in the treatment of diabetic macular edema in vitrectomized eyes.

METHODS

This was a prospective, multicenter, open-label, 26-week study. Fifty-five patients with treatment-resistant diabetic macular edema and a history of previous pars plana vitrectomy in the study eye received a single intravitreal injection of 0.7-mg dexamethasone intravitreal implant. The primary efficacy outcome measure was the change in central retinal thickness from baseline to Week 26 measured by optical coherence tomography.

RESULTS

The mean age of patients was 62 years. The mean duration of diabetic macular edema was 43 months. The mean (95% confidence interval) change from baseline central retinal thickness (403 μm) was -156 μm (-190, -122 μm) at Week 8 (P < 0.001) and -39 μm (-65, -13 μm) at Week 26 (P = 0.004). The mean (95% CI) increase in best-corrected visual acuity from baseline (54.5 letters) was 6.0 letters (3.9, 8.1 letters) at Week 8 (P < 0.001) and 3.0 letters (0.1, 6.0 letters) at Week 26 (P = 0.046). At Week 8, 30.4% of patients had gained ≥10 letters in best-corrected visual acuity. Conjunctival hemorrhage, conjunctival hyperemia, eye pain, and increased intraocular pressure were the most common adverse events.

CONCLUSION

Treatment with dexamethasone intravitreal implant led to statistically and clinically significant improvements in both vision and vascular leakage from diabetic macular edema in difficult-to-treat vitrectomized eyes and had an acceptable safety profile.

Correlation of macular thickness and posterior hyaloid change following bevacizumab and triamcinolone in diffuse diabetic macular edema in middle-aged patients

To compare changes in posterior vitreous detachment (PVD) following intravitreal injection of bevacizumab and triamcinolone in diffuse diabetic macular edema in middle-aged type 2 diabetes patients and to correlate this change with change in central macular thickness (CMT).

DESIGN

cross sectional study. Fifteen consecutive patients treated by intravitreal bevacizumab (group A) and ten patients treated by intravitreal triamcinolone (group B). Institutional study carried out by retrospective analysis of patient registers including serial optical coherence tomography (OCT) images at baseline, and after 1 and 4 months. A central macular thickness (CMT) and vitreomacular relationship was noted on OCT. PVD was graded on a linear scale (0-4). Change in grade of PVD was correlated with change in CMT at each follow-up. At month 4, the decrease in mean CMT from baseline was 51.2 μ (P = 0.000) and 45 μ (P = 0.022) in group A and group B, respectively, with no significant difference between the two groups (P = 0.874). A change in grades of PVD from baseline to month 4 was significant in both group A (P = 0.001) and group B (P = 0.004) with no significant difference between the two groups (P = 0.906). A significant correlation between change in PVD and reduction of CMT was observed in group A (P = 0.011) but not in group B (P = 0.315). Both bevacizumab and triamcinolone caused a significant reduction in macular thickness and a significant change in grade of PVD. Change in PVD played an influential role in the reduction of macular thickness following bevacizumab.

Imaging of diabetic retinopathy and diabetic macular edema

Imaging of the retinal complications of diabetes mellitus is rapidly changing from the emergence of new technology such as optical coherence tomography. In particular, the characterization of diabetic macular edema is much easier for the clinician and there are new, more sensitive clinical research end points. However, our understanding of structure-functional relationships remains suboptimal and the classification of macular edema by optical coherence tomography continues to evolve. The classification of diabetic retinopathy severity continues to rely upon fundus photography, although the transition from film to digital photography presents both challenges and advantages.

Economic considerations of macular edema therapies

PURPOSE

To relate costs and treatment benefits for diabetic macular edema (DME), branch retinal vein occlusion (BRVO), and central retinal vein occlusion (CRVO).

DESIGN

A model of resource use, outcomes, and cost-effectiveness and utility.

PARTICIPANTS

None.

METHODS

Results from published clinical trials (index studies) of laser, intravitreal corticosteroids, intravitreal anti-vascular endothelial growth factor (VEGF) agents, and vitrectomy trials were used to ascertain visual benefit and clinical protocols. Calculations followed from the costs of 1 year of treatment for each treatment modality and the visual benefits as ascertained.

MAIN OUTCOME MEASURES

Visual acuity (VA) saved, cost of therapy, cost per line saved, cost per line-year saved, and costs per quality-adjusted life years (QALYs).

RESULTS

The lines saved for DME (0.26-2.02), BRVO (0.74-4.92), and CRVO (1.2-3.75) yielded calculations of costs/line of saved VA for DME ($1329-$11,609), BRVO ($494-$13,039), and CRVO ($704-$7611); costs/line-year for DME ($60-$561), BRVO ($25-$754), and CRVO ($45-$473); and costs/QALY ($824 to $25,566).

CONCLUSIONS

Relative costs and benefits should be considered in perspective when applying and developing treatment strategies.

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.

Factors associated with visual acuity outcomes after vitrectomy for diabetic macular edema: diabetic retinopathy clinical research network

PURPOSE

To evaluate factors ¶associated with favorable outcomes after vitrectomy for diabetic macular edema.

METHODS

Data were collected prospectively on 241 eyes undergoing vitrectomy for diabetic macular edema. Multivariate models were used to evaluate associations of 20 preoperative and intraoperative factors with 6-month outcomes of visual acuity and retinal thickness.

RESULTS

Median central subfield thickness decreased from 412 μm to 278 μm at 6 months, but median visual acuity remained unchanged (20/80, Snellen equivalent). Greater visual acuity improvement occurred in eyes with worse baseline acuity (P < 0.001) and in eyes in which an epiretinal membrane was removed (P = 0.006). Greater reduction in central subfield thickness occurred with worse baseline visual acuity (P < 0.001), greater preoperative retinal thickness (P = 0.001), removal of internal limiting membrane (P = 0.003), and optical coherence tomography evidence of vitreoretinal abnormalities (P = 0.006). No associations with clinician's preoperative assessments of the posterior vitreous were identified.

CONCLUSION

These results suggest that the removal of epiretinal membranes may favorably affect visual outcome after vitrectomy. Preoperative presence of vitreoretinal abnormalities appeared to be associated with somewhat greater reductions in retinal thickness but not with visual acuity outcome. These results may be useful for future studies evaluating vitrectomy for diabetic macular edema.

Diabetic retinopathy

Diabetic retinopathy is a common and specific microvascular complication of diabetes, and remains the leading cause of preventable blindness in working-aged people. It is identified in a third of people with diabetes and associated with increased risk of life-threatening systemic vascular complications, including stroke, coronary heart disease, and heart failure. Optimum control of blood glucose, blood pressure, and possibly blood lipids remains the foundation for reduction of risk of retinopathy development and progression. Timely laser therapy is effective for preservation of sight in proliferative retinopathy and macular oedema, but its ability to reverse visual loss is poor. Vitrectomy surgery might occasionally be needed for advanced retinopathy. New therapies, such as intraocular injection of steroids and antivascular endothelial growth-factor agents, are less destructive to the retina than are older therapies, and could be useful in patients who respond poorly to conventional therapy. The outlook for future treatment modalities, such as inhibition of other angiogenic factors, regenerative therapy, and topical therapy, is promising.