Vitrectomy for diabetic macular edema: the role of posterior vitreous detachment and epimacular membrane

Evaluation of the efficacy of anti-vascular endothelial growth factors in diabetic macular edema with retinal inner and outer layers disorganization

AIMS

This study aims to compare the effectiveness of treatment between anti-vascular endothelial growth factor (anti-VEGF) agents in diabetic macular edema (DME) patients with disorganization of retinal inner layers (DRIL). Epiretinal membrane, serous macular detachment, ellipsoid zone (EZ) disorder, external limiting membrane (ELM) disorder, and hyperreflective foci were also examined.

METHODS

Patients treated for DME and also had DRIL were included in the study. The study design was retrospective and cross-sectional. The complete ophthalmologic records and imaging were scanned at the beginning, 3rd-month, 6th-month, and 12th-month follow-up, and the treatments administered were recorded. Anti-VEGF agents administered to the patients were examined in three groups: bevacizumab, ranibizumab, and aflibercept.

RESULT

A total of 141 eyes of 100 patients were included in our study. One hundred and fifteen eyes (81.6%) had a BCVA of 0, 5, or less at the beginning. There was no statistically significant difference between the three groups regarding initial BCVA and CMT and the change in BCVA and CMT at the beginning and the 12th month (p > 0.05). There was a negative correlation between EZ and ELM disorders in patients and the change in BCVA at 12 months (r: 0.45 p < 0.001, r: 0.32 p < 0.001, respectively). The number of injections over five was positively correlated with the change in CMT but not with BCVA (r: - 2.35 p = 0.005 and r: 0.147 p = 0.082, respectively).

CONCLUSIONS

No statistically significant difference was found between anti-VEGF agents when treating DME patients with DRIL. In addition, we have shown that anatomically better results were obtained in those who had five or more injections, although not in terms of BCVA.

Hyperreflective Membrane at the Vitreoretinal Interface in Diabetic Macular Edema: A Finding in Ultra-High-Resolution Optical Coherence Tomography

Purpose

Detecting subtle vitreoretinal interface (VRI) findings, such as a posterior hyaloid membrane, is difficult with conventional retinal imaging. We compared ultra-high-resolution spectral domain optical coherence tomography (UHR-SD-OCT) with standard-resolution OCT (SD-OCT) for the imaging of VRI abnormalities in diabetic retinopathy (DR).

Methods

This prospective cross-sectional study included 113 consecutive patients (91 patients with diabetes and 22 healthy controls). The VRI was evaluated, and the results were compared between the conventional SD-OCT and UHR-SD-OCT images. VRI findings were also investigated before and after internal limiting membrane peeling during vitrectomy for proliferative DR.

Results

A total of 159 eyes (87.4%) of 91 patients with diabetes were analyzed. UHR-SD-OCT could detect a hyperreflective layer at the VRI, in which en face OCT showed a membrane-like structure, termed the hyperreflective membrane (HRMe). The preoperative HRMe could not be detected in all patients with proliferative DR who underwent internal limiting membrane peeling during vitrectomy. Although the HRMe did not correlate with the DR stage, eyes with diabetic macular edema (DME) (64.5%) showed a significant HRMe with UHR-SD-OCT more frequently than those without DME (35.8%) (P = 0.005).

Conclusions

UHR-SD-OCT can detect the HRMe at the VRI in DR eyes, particularly in eyes with DME. The HRMe may present a thickened posterior hyaloid membrane that contributes to DME development.

Translational Relevance

UHR-SD-OCT detects slight changes in the VRI in DR eyes. In the future, it may help to elucidate the mechanism of DME formation.

Management of Diabetic Macular Edema: Guidelines from the Emirates Society of Ophthalmology

In the United Arab Emirates, retinopathy has been shown to be present in 19% of the diabetic population, with diabetes identified in up to 40% of individuals aged over 55 years. Despite the prevalence of diabetic retinal diseases, there are no unified national guidelines on the management of diabetic macular edema (DME). These published guidelines are based on evidence taken from the literature and published trials of therapies, and consensus opinion of a representative expert panel with an interest in this condition, convened by the Emirates Society of Ophthalmology. The aim is to provide evidence-based, clinical guidance for the best management of different aspects of DME, with a special focus on vision-threatening diabetic retinopathy. Treatment should be initiated in patients with best-corrected visual acuity 20/30 or worse, and/or features of DME as seen on optical coherence tomography (OCT) with central retinal thickness (CRT) of at least 300 μm or in symptomatic patients with vision better than 20/25, and/or CRT less than 300 μm where there are OCT features consistent with center-involving macular edema. The treatment of DME is effective irrespective of glycated hemoglobin (HbA1c) level, and treatment must not be denied or delayed in order to optimize systemic parameters. All ophthalmic treatment options should be discussed with the patient for better compliance and expectations. Non-center-involving DME can be initially observed until progression toward the center is documented. Macular laser no longer has a primary role in center-involving DME, and anti-vascular endothelial growth factor (anti-VEGF) therapy should be considered as first-line treatment for all patients, unless contraindicated. If anti-VEGF is contraindicated, a steroid dexamethasone implant can be considered for first-line treatment. Recommendations for the treatment of DME in special circumstances and in relapsing and refractory DME are also discussed.

Aqueous Lumican Correlates with Central Retinal Thickness in Patients with Idiopathic Epiretinal Membrane: A Proteome Study

Idiopathic epiretinal membrane (iERM) is a pathological fibrocellular change in the vitreoretinal junction over the macular area; however, possible pathogenic mechanisms remain unclear. Changes in the differential protein composition of the aqueous humor (AH) may represent potential molecular changes associated with iERM. To gain new insights into the molecular mechanisms of iERM pathology, a sensitive label-free proteomics analysis was performed to compare AH protein expressions in patients with cataracts with or without iERM. This study employed nanoflow ultra-high-performance liquid chromatography-tandem mass spectrometry to investigate protein compositions of the AH obtained from individual human cataract eyes from 10 patients with iERM and 10 age-matched controls without iERM. Eight proteins were differentially expressed between the iERM and control samples, among which six proteins were upregulated and two were downregulated. A gene ontology (GO) analysis revealed that iERM was closely associated with several biological processes, such as immunity interactions, cell proliferation, and extracellular matrix remodeling. Additionally, multiple proteins, including lumican, cyclin-dependent kinase 13, and collagen alpha-3(VI) chain, were correlated with the central retinal thickness, indicating a multifactorial response in the pathogenic process of iERM. Changes in the AH level of lumican between iERM and control samples were also confirmed by an enzyme-linked immunosorbent assay. In conclusion, several pathological pathways involved in iERM were identified in the AH by a proteomic analysis, including immune reactions, cell proliferation, and remodeling of the extracellular matrix. Lumican is a potential aqueous biomarker for predicting iERM development and monitoring its progression. More clinical parameters also need to be identified to complete the analysis, and those could provide additional targets for treating and preventing iERM.

Factors associated with diabetic macular edema in patients with proliferative diabetic retinopathy

PURPOSE

To identify factors associated with diabetic macular edema (DME) and to characterize the types of DME present in eyes with proliferative diabetic retinopathy (PDR).

METHODS

Observational, retrospective case series of PDR patients reviewed for demographic information, general medical history, ophthalmologic history, optical coherence tomography (OCT), and fluorescein angiogram image characteristics. DME and vitreomacular interface (VMI) status were determined using OCT images. DME was defined as center-involving DME (CI-DME) and noncenter-involving DME (NCI-DME). VMI was defined as vitreomacular adhesion (VMA), vitreomacular traction (VMT), or macular posterior vitreous detachment (PVD).

RESULTS

A total of 293 eyes of 210 screened patients with PDR were included. Of the eyes, 194/293 (66.2%) had DME, and 99/293 (33.8%) had no DME; in univariable analysis, there were no significant differences in VMI status (p = 0.4) or epiretinal membrane (ERM, p = 0.1) between them. Of 194 eyes with DME, 90/194 (46.4%) had CI-DME, and 104/194 (53.6%) had NCI-DME. In univariable analysis, CI-DME eyes were significantly more likely than NCI-DME eyes to have a PVD (p = 0.029) and ERM (p < 0.001). In multivariable analysis, the presence of younger age (p = 0.028) and presence of ERM (p = 0.001) were significantly more likely to be observed in eyes with CI-DME.

CONCLUSION

In this exploratory study focused on diabetic patients with PDR, we determined that VMI status did not have a significant association with DME in general, but VMI status, younger age, and presence of ERM may be associated with CI-DME.

Relationship Between Final Visual Acuity and Optical Coherence Tomography Findings in Patients with Diabetic Macular Edema Undergoing Anti-VEGF Therapy

Objectives:

To identify the prevalence of findings in optical coherence tomography (OCT) sections before intravitreal anti-VEGF treatment in patients with diabetic macular edema (DME), and to evaluate the relationship between these findings and final visual acuity and number of injections.

Materials and Methods:

This retrospective study included 296 eyes of 191 patients (104 male, 87 female) who started intravitreal ranibizumab treatment after being diagnosed with DME in the retina unit between January 2013 and April 2017 were included the study. Spectral domain OCT findings at the time of presentation such as presence of serous macular detachment (SD), vitreomacular traction (VMT), and epiretinal membrane (ERM) were recorded. In addition, the regularity of the ellipsoid zone (EZ) and inner retinal layers was also studied.

Results:

The mean central retinal thickness measured in SD-OCT was 449±81 μm before treatment and 350±96 μm after treatment (p<0.001). SD was detected in 155 eyes (52.4%), ERM in 67 eyes (22.6%), and VMT in 9 eyes (3%). Thirty eyes (10.1%) had disorganization of the retinal inner layers (DRIL) and 54 eyes (18.2%) had EZ deterioration. The presence of ERM, EZ irregularity, and DRIL were associated with significantly lower final visual acuity (p<0.0001), while there was no relationship between pre-treatment SD and final visual acuity (p=0.11). Injection number was higher in eyes with SD and ERM compared to those without, but this difference was statistically significant only in the presence of SD (p=0.01 and p=0.59, respectively). There was no difference in injection number according to EZ irregularity or presence of DRIL.

Conclusion:

The coexistence of SD with DME was associated with increased need for treatment but not with final visual acuity. EZ irregularities, DRIL, and ERM are findings that negatively affect visual acuity.

Pars Plana Vitrectomy with Internal Limiting Membrane Peeling for Treatment-Naïve Diabetic Macular Edema: A Prospective, Uncontrolled Pilot Study

Purpose

To report the outcomes in subjects undergoing pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling for the management of treatment-naïve diabetic macular edema (DME).

Methods

Ten treatment-naïve subjects with non-proliferative diabetic retinopathy prospectively underwent PPV with ILM peeling for the treatment of DME at a single university-affiliated institution. The preoperative features, intraoperative details and postoperative outcomes were collected and analyzed.

Results

All 10 subjects underwent PPV with ILM peeling without significant intraoperative or postoperative complications at 6 months follow-up. Visual acuity improved from a baseline of 0.74 (95% CI: 0.48–1.0) logMAR (Snellen 20/110) to 0.46 (95% CI: 0.3–0.62) logMAR (Snellen 20/58) at 6 months follow-up (p=0.045). Optical coherence tomography central macular thickness reduced from a baseline of 456 (95% CI: 394.7–516.4) microns to 316.8 (95% CI: 275.9–357.7) microns at 6 months follow-up (p < 0.001).

Conclusion

This pilot study suggests that PPV with ILM peeling may be a viable treatment option for the management of treatment naïve DME in subjects with non-proliferative diabetic retinopathy. Development of a randomized controlled trial may be justified to validate the results of this study.

Clinicaltrials.gov Identifier #

NCT03660345.

Isolated Central Epiretinal Membrane: A Rare Complication of Fovea-Sparing Internal Limiting Membrane Peeling Technique

Purpose

To report a rare complication presenting as an isolated central epiretinal membrane (ERM) related to fovea-sparing internal limiting membrane (ILM) peeling technique.

Methods

Five patients who received fovea-sparing ILM peeling were enrolled. Postoperatively, an isolated central ERM developed. Optical coherence tomography (OCT) was used to evaluate the serial anatomic change.

Results

Among the five included patients, one patient had high myopia with foveoschisis, two patients had vitreomacular traction, and two patients had proliferative diabetic retinopathy with tractional retinal detachment and a fovea cyst. With an average of 5.80 months, OCT showed the gradual development of the isolated central ERM with severe fovea distortion. Four patients received secondary revision surgery, with improvement of the fovea contour and visual acuity.

Conclusion

The fovea-sparing ILM peeling technique may cause a rare but serious complication as the isolated central ERM, which would cause significant fovea distortion as well as visual deterioration. Timely detection and intervention is recommended to prevent further visual loss. This trial is registered with NCT04445142.

EPIRETINAL MEMBRANE REMOVAL WITH FOVEAL-SPARING INTERNAL LIMITING MEMBRANE PEELING: A Pilot Study

PURPOSE

To compare the retinal sensitivity after complete internal limiting membrane (ILM) peeling with that after foveal-sparing ILM peeling during vitrectomy for Type I epiretinal membrane.

METHODS

This was a prospective, randomized, comparative study. Thirty-eight eyes were randomized to undergo complete peeling of the ILM (CP group) or peeling with foveal sparing (FS group). The main outcome measures were foveal and perifoveal retinal sensitivity, visual acuity, and central retinal thickness.

RESULTS

Foveal retinal sensitivity showed a significant improvement in the FS group (2.82 ± 0.85 dB, P = 0.037) versus a slight drop in the CP group (-0.66 ± 0.48 dB, P = 1). Perifoveal retinal sensitivity slightly improved in both groups (0.47 ± 0.37 dB, P = 1 in the CP group and 0.79 ± 0.42 dB, P = 0.77 in the FS group), showing a similar trend without significant differences. Significant improvements were observed in both visual acuity and central retinal thickness in both groups. However, three cases in the FS group showed epiretinal membrane recurrence and required revision surgery with complete ILM removal.

CONCLUSION

Internal limiting membrane peeling may reduce retinal sensitivity and significantly increase the incidence of microscotomas. However, the higher epiretinal membrane recurrence rate after the foveal-sparing technique limits the effectiveness of this procedure. Further studies must be conducted to determine if it is safe to leave a portion of the ILM in front of the fovea.

Novel imaging biomarkers in diabetic retinopathy and diabetic macular edema

Diabetic retinopathy is one of the major microvascular complications of diabetes mellitus. The most common causes of vision loss in diabetic retinopathy are diabetic macular edema and proliferative diabetic retinopathy. Recent developments in ocular imaging have played a significant role in early diagnosis and management of these complications. Color fundus photography is an imaging modality, which is helpful for screening patients with diabetic eye disease and monitoring its progression as well as response to treatment. Fundus fluorescein angiography (FFA) is a dye-based invasive test to detect subtle neovascularization, look for areas of capillary non-perfusion, diagnose macular ischemia, and differentiate between focal and diffuse capillary bed leak in cases of macular edema. Recent advances in retinal imaging like the introduction of spectral-domain and swept source-based optical coherence tomography (OCT), fundus autofluorescence (FAF), OCT angiography, and ultrawide field imaging and FFA have helped clinicians in the detection of certain biomarkers that can identify disease at an early stage and predict response to treatment in diabetic macular edema. This article will summarize the role of different imaging biomarkers in characterizing diabetic retinopathy and their potential contribution in its management.

The effects of epiretinal membranes on the treatment outcomes of intravitreal aflibercept injection in diabetic macular edema: a real-life study

PURPOSE

To evaluate the effects of epiretinal membrane (ERM) formation on the anatomic and functional results of subjects with diabetic macular edema (DME) who are receiving intravitreal aflibercept injections (IAIs).

MATERIALS AND METHODS

This retrospective comparative study includes 29 eyes with DME (Group 1) and 43 eyes with DME and ERM (Group 2). After three consecutive monthly 2.0 mg IAIs, subjects received monthly follow-ups and retreatment was performed if needed. Corrected visual acuity (CVA), central macular thickness (CMT), and central macular volume (CMV) parameters were recorded tri-monthly, and the 36-month follow-up was designated the primary endpoint of the study.

RESULTS

There was no significant difference between groups when comparing the mean ages and male-to-female ratios (p > 0.05, for both). At the baseline, the mean CVA value was significantly worse (p = 0.002), and the mean CMT was significantly lower (p = 0.016) in Group 1, while there was no significant difference in terms of the mean CMV (p = 0.625). The mean number of IAIs was similar at the first (p < 0.102), second (p = 0.363), and third year (p = 0.850) follow-ups. The mean CVA was significantly worse, and CMT was significantly lower in Group 1 at most of the visits in the first half of the follow-up period (p < 0.05, for all), while there was no significant difference in the second half of the follow-up period. There was no significant difference between groups in terms of CMV at any visit (p > 0.05, for all).

CONCLUSION

Despite a similar number of IAIs needed, worse baseline clinical parameters are associated with poorer early- or mid-term outcomes. At the long-term follow-up, CVA and CMT became similar in DME independent of ERM.

Revisiting pars plana vitrectomy in the primary treatment of diabetic macular edema in the era of pharmacological treatment

Diabetic macular edema (DME) is the most common cause of moderate visual loss in diabetic patients. The current treatment of choice for center-involved DME is anti-vascular endothelial growth factor (VEGF) treatment. Most patients that undergo pharmacological inhibition with anti-VEGF agents need multiple monitoring visits that include optical coherence tomography imaging and multiple injections. Despite this intensive treatment, up to 60% of eyes will have persistent DME after six consecutive monthly injections of an anti-VEGF. Its sustainability over the long term has been questioned. Pars plana vitrectomy (PPV) by increasing the vitreous cavity oxygenation, relieving vitreomacular traction, and removing cytokines from the vitreous cavity may cause long-term resolution of DME without the aforementioned concerns in selected cases. Eyes with vitreomacular traction clearly benefit from PPV as the primary treatment. The role of PPV for eyes with DME without tractional elements is less clear and needs to be explored further.

Surgical Therapy for Macular Edema: What We Have Learned through the Decades

Macular edema is a leading cause of functional visual loss in retinal vascular or ocular inflammatory diseases. Because persistent macular edema can lead to irreversible retinal damage, multi-approached treatment should be considered to achieve complete resolution of macular edema. With an enhanced understanding of its pathophysiology, numerous therapeutic options have been developed for the management of macular edema over the decades. Although medical therapies account for the mainstay of treatment, surgical approaches with vitrectomy can play an important role in the management of macular edema, depending on its mechanism of fluid accumulation. The index review focuses on the efficacy of surgical therapy for macular edema secondary to various ocular diseases including diabetic retinopathy, uveitis, and retinal vein occlusion, and consequently provides the evidences that may expand the knowledge and support the employment of surgical options.

Automatic identification and characterization of the epiretinal membrane in OCT images

Optical coherence tomography (OCT) is a medical image modality that is used to capture, non-invasively, high-resolution cross-sectional images of the retinal tissue. These images constitute a suitable scenario for the diagnosis of relevant eye diseases like the vitreomacular traction or the diabetic retinopathy. The identification of the epiretinal membrane (ERM) is a relevant issue as its presence constitutes a symptom of diseases like the macular edema, deteriorating the vision quality of the patients. This work presents an automatic methodology for the identification of the ERM presence in OCT scans. Initially, a complete and heterogeneous set of features was defined to capture the properties of the ERM in the OCT scans. Selected features went through a feature selection process to further improve the method efficiency. Additionally, representative classifiers were trained and tested to measure the suitability of the proposed approach. The method was tested with a dataset of 285 OCT scans labeled by a specialist. In particular, 3,600 samples were equally extracted from the dataset, representing zones with and without ERM presence. Different experiments were conducted to reach the most suitable approach. Finally, selected classifiers were trained and compared using different metrics, providing in the best configuration an accuracy of 89.35%.

Vitrectomy for Diabetic Macular Edema: Optical Coherence Tomography Criteria and Pathology of the Vitreomacular Interface

PURPOSE

To correlate spectral-domain optical coherence tomography (SDOCT) criteria and clinical data with pathology of the vitreomacular interface (VMI) in eyes with diabetic macular edema (DME).

DESIGN

Retrospective cross-sectional study and laboratory investigation.

METHODS

We included specimens of 27 eyes of 26 patients with center-involved DME that underwent vitrectomy with peeling of the internal limiting membrane (ILM). Selection of specimens was consecutive and in retrospect using our register of the Vitreoretinal Pathology Unit. Clinical data and SDOCT examinations were correlated to immunocytochemistry and transmission electron microscopy. Classification of DME comprised sponge-like diffuse retinal thickening, cystoid macular edema, and serous retinal detachment. VMI was evaluated for presence of epiretinal membrane (ERM) and thickened vitreous cortex (tVC).

RESULTS

ERMs and tVC were found in all DME types. Diffuse DME showed tVC more often than cystoid DME. Hyalocytes, contractile myofibroblasts, glial cells, matrix metalloproteinases-2 and -9, and collagen type I, II, and III were positive tested irrespective of DME type. There were no significant cell fragments at the retinal side of the ILM. Visual acuity improved in the majority of cases and macular thickness decreased significantly during mean follow-up of 17 ± 10 months.

CONCLUSIONS

All eyes presented pathologic VMI changes irrespective of the OCT classification of DME type or presence of ERM. Composition of fibrocellular membranes at the VMI indicated remodeling of vitreous cortex and transdifferentiation of hyalocytes into myofibroblasts. Our findings might argue for an early surgical intervention in eyes with DME irrespective of the presence of traction formation imaged by SDOCT.

Diabetic macular edema: Evidence-based management

Diabetic macular edema (DME) is the most common cause of vision loss in patients with diabetic retinopathy with an increasing prevalence tied to the global epidemic in type 2 diabetes mellitus. Its pathophysiology starts with decreased retinal oxygen tension that manifests as retinal capillary hyperpermeability and increased intravascular pressure mediated by vascular endothelial growth factor (VEGF) upregulation and retinal vascular autoregulation, respectively. Spectral domain optical coherence tomography (SD-OCT) is the cornerstone of clinical assessment of DME. The foundation of treatment is metabolic control of hyperglycemia and blood pressure. Specific ophthalmic treatments include intravitreal anti-VEGF drug injections, intravitreal corticosteroid injections, focal laser photocoagulation, and vitrectomy, but a substantial fraction of eyes respond incompletely to all of these modalities resulting in visual loss and disordered retinal structure and vasculature visible on SD-OCT and OCT angiography. Efforts to close the gap between the results of interventions within randomized clinical trials and in real-world contexts, and to reduce the cost of care increasingly occupy innovation in the social organization of ophthalmic care of DME. Pharmacologic research is exploring other biochemical pathways involved in retinal vascular homeostasis that may provide new points of intervention effective in those cases unresponsive to current treatments.

Quantitative assessment of macular contraction and vitreoretinal interface alterations in diabetic macular edema treated with intravitreal anti-VEGF injections

BACKGROUND

Macular contraction after anti-vascular endothelial growth factor (anti-VEGF) injections for diabetic macular edema (DME) was evaluated by documenting the displacement of macular capillary vessels and epiretinal membrane (ERM) formation.

METHODS

A total of 130 eyes were included in this retrospective study. The study group consisted of 63 eyes which had intravitreal anti-VEGF injections for DME, and the control group included 67 eyes without central DME. The study and the control groups were well balanced in terms of diabetes duration and HbA1c. The distances between the bifurcation of the macular capillary retinal vessels were measured, and ERM status was evaluated based on spectral-OCT findings on the initial and final visit.

RESULTS

In the study group, the mean number of injections was 4.7 ± 2.6 (3-14). The mean follow-up time was 16.7 ± 7.8 months in the study group whereas it was 20.7 ± 10.9 months in the control group (p = 0.132). The change in distance measurements between the reference points on macular capillary vessels was significant in all lines except line c (p < 0.05 for lines a, b, d, e, and f) in the study group whereas it was significant in only line e in the control group (p = 0.007, paired samples test). However, when the change in macular thickness was accounted as a confounding factor, the change in distances between the references points from the initial visit to the final visit lost its significance (repeated measures ANCOVA, p > 0.05). During follow-up, the number of cases with ERM changed from 10 to 12 in the study group whereas it remained three in the control group.

CONCLUSION

There was a displacement of macular capillary vessels which was associated with the change in macular thickness in eyes having anti-VEGF injections for DME. The number of ERM cases did not change significantly during the follow-up.

Effects of kallidinogenase in patients undergoing vitrectomy for diabetic macular edema

PURPOSE

To evaluate the effectiveness of the combination of vitrectomy with kallidinogenase for diabetic macular edema (DME).

METHODS

This study was designed as a prospective, randomized, multicenter study comparing 19 eyes of 19 patients who received 150 units of kallidinogenase administered a day for 52 weeks from the day after vitrectomy (study group) with 20 eyes of 20 patients who received no kallidinogenase (control group). The main outcome measurements included logMAR visual acuity and central foveal thickness (CFT) before surgery and at 3, 6, 9, and 12 months after vitrectomy.

RESULTS

During follow-up, 11 patients dropped out (six in the study group and five in the control group), leaving 28 eyes in 28 patients for analysis (13 in the study group and 15 in the control group). Visual acuity improved significantly at 12 months in both groups compared with before surgery. The degree of improvement did not differ significantly between the groups. At 12 months, the mean CFT decreased significantly in both groups, with no significant difference in the rate of change between the two groups. In the study group, the visual acuity and CFT significantly improved from 3 to 12 months and from 6 to 12 months, whereas these parameters did not continue to improve in the control group after 6 months (for visual acuity) or 3 months (for CFT).

CONCLUSION

After vitrectomy for DME, visual acuity and CFT improved significantly in both groups, but only patients treated with kallidinogenase continued to have significant improvement throughout the study period.

Vitrectomy in the management of diabetic macular edema in treatment-naïve patients

OBJECTIVE

To determine the efficacy of vitrectomy in eyes with treatment-naïve diabetic macular edema (DME).

METHODS

Consecutive patients with treatment-naïve DME who underwent pars plana vitrectomy with internal limiting membrane peeling at a single institution were identified from the electronic medical records. Morphologic and visual acuity changes from baseline were analyzed at both the primary temporal endpoint (6 months) and the final examination with the investigators. The primary outcome measures included changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT).

RESULTS

Forty-four eyes of 44 patients were included in this retrospective study. The mean BCVA improved significantly from baseline until the 6-month primary endpoint (1.35 logMAR vs 0.83 logMAR, p < 0.001) and stabilized through the final examination (0.77 logMAR). The BCVA improved by at least 0.1, 0.3, and 0.6 logMAR in 26 (60%), 24 (55%), and 14 (32%) of eyes, respectively, whereas it worsened by 0.3 logMAR in only 1 (2%) eye. Final BCVA correlated inversely with duration of diabetes (p = 0.01), presence of an epiretinal membrane (p = 0.02), and initial visual acuity (p = 0.03). Mean CRT decreased significantly from baseline through 6 months (595 µm vs 266 µm; p < 0.001), and edema recurred in only 3 eyes (6%), one of which was subsequently treated with intravitreal bevacizumab.

CONCLUSIONS

Pars plana vitrectomy significantly improves macular edema and visual acuity in eyes with treatment-naïve DME. Prospective randomized trials are needed to better determine the efficacy of early vitrectomy.

Management of diabetic macular edema in Japan: a review and expert opinion

Diabetic retinopathy is a frequent cause of visual impairment in working-age adults (≥ 30 years) and in Japan is most commonly observed in those aged 50-69 years. Diabetic macular edema (DME) is one of the main causes of vision disturbance in diabetic retinopathy, which is a clinically significant microvascular complication of diabetes. Anti-vascular endothelial growth factor (VEGF) therapy is becoming the mainstay of treatment for DME. However, to achieve sustained long-term improvement in visual acuity, conventional laser photocoagulation, vitrectomy and steroid therapy are also expected to play a role in the treatment of DME. This review summarizes the epidemiology and pathology of diabetic retinopathy and DME, evaluates the findings regarding the diagnosis and treatment of DME, and underscores the importance of systemic management of the disease in the context of the current health care situation in Japan. Finally, the unmet needs of patients with DME and prospects for research are discussed. The weight of evidence suggests that it is important to establish a multipronged treatment strategy centered on anti-VEGF therapy.

ILM peeling in nontractional diabetic macular edema: review and metanalysis

PURPOSE

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

METHODS

PUBMED, MEDLINE and CENTRAL were reviewed using the following terms (or combination of terms): diabetic macular edema, nontractional diabetic macular edema, internal limiting membrane peeling, vitrectomy, Müller cells. Randomized and nonrandomized studies were included. The eligible studies compared anatomical and functional outcomes of vitrectomy with or without ILM peeling for tractional and nontractional diabetic macular edema. Postoperative best-corrected visual acuity and central macular thickness were considered, respectively, the primary and secondary outcomes. Meta-analysis on mean differences between vitrectomy with and without ILM peeling was performed using inverse variance method in random effects.

RESULTS

Four studies with 672 patients were eligible for analysis. No significant difference was found between postoperative best-corrected visual acuity or best-corrected visual acuity change of ILM peeling group compared with nonpeeling group. There was no significant difference in postoperative central macular thickness and central macular thickness reduction between the two groups.

CONCLUSIONS

The visual acuity outcomes in patients affected by nontractional diabetic macular edema using pars plana vitrectomy with ILM peeling versus no ILM peeling were not significantly different. A larger prospective and randomized study would be necessary.

The predictability of ocriplasmin treatment effects: is there consensus among retinal experts? Results from the EXPORT study

PURPOSE

To evaluate the agreement and predictability of ocriplasmin treatment effects among retinal experts (raters) by assessment of retinal imaging data of eyes treated for vitreomacular traction in nine different centers in Germany and Austria.

METHODS

Retrospective cohort study. Combined confocal near-infrared scanning laser ophthalmoscopy and spectral-domain optical coherence tomography images (Spectralis® device, Heidelberg Engineering GmbH, Germany) from 136 eyes of 135 subjects were reviewed by 14 raters using an internet-based grading database and a standardized questionnaire. In addition to the images taken within 2 days prior to treatment, age, gender, and lens status were disclosed to the raters. Treatment success was defined as a complete cleavage of the posterior vitreous cortex at day 28±5. Main outcome was the agreement and predictability among raters for assessment of treatment success.

RESULTS

Raters generally accepted starting ocriplasmin treatment (chance for treatment success ≥ 1%) in 22.4 to 69.1% (median 53.2%) of eyes (moderate intra- and interrater agreements with kappa-values of 0.6 and 0.48). The likelihood for a high potential treatment success (equal or higher than 25%) was judged by the raters in 43.4% to 86.0% (median 62.6%) of eyes (moderate intra- and fair interrater agreements with kappa-values of 0.56 and 0.22). Allocating eyes for high potential treatment success overall increased the odds by 3.07, with odds ratios of single raters up to 4.06 to 6.16.

CONCLUSIONS

These results underscore the importance of training health care providers in the evaluation of retinal imaging data and also to define characteristic morphological features better in the presence of vitreoretinal interface diseases. The better results of single raters in the predictability of treatment success by the allocation of eyes in the high-potential group indicates the high relevance of the meticulous analysis of retinal images.

Vitreoretinal interface abnormalities in patients treatedwith ranibizumab for diabetic macular oedema

Purpose

Intravitreal anti-vascular endothelial growth factor (VEGF) agents are effective in the treatment of central involving diabetic macular oedema (DMO). Vitreoretinal interface abnormalities (VRIA) are common in patients with DMO, and the effect of these on the response to anti-VEGF treatment is unclear. Furthermore the effect of anti-VEGF agents on the VRIA itself is uncertain.

Method

Prospective study of consecutive patients treated with ranibizumab (RZB) for DMO as part of routine clinical care in one eye unit over a 1-year period. Visual acuity (Va), central retinal thickness (CRT) and injection frequency data was recorded on an electronic database. Treatment was initiated with four monthly RZB injections and then a monthly PRN regime. All patients underwent high-density spectral-domain optical coherence tomography (SDOCT) at baseline and 12 months. The SDOCTs were graded by two observers masked to the outcome.

Results

One hundred and four eyes (77 patients) were included in the analysis. The mean age was 62 years, and 62% were male. The mean presenting vision was 62 letters and CRT 472 μm. Eighty eyes retained stable Va, and 17 had an improvement in Va. At baseline, 39 eyes had associated focal vitreomacular adhesion (VMA) and by 12 months this reduced to 30 (p = 0.04), with 12 releasing VMA and three developing it. Patients with VMA had significantly better final Va than those without VMA. Improvement in CRT was greatest in those where VMA released during the study. Forty-five eyes had some degree of foveal involving epiretinal membrane (ERM) at baseline, and 28 were considered to have clinically significant ERM. There was no clinically relevant change in ERM during the study. Patients with significant ERM at baseline had a lower final vision. Multivariate analysis showed that ERM and more severe retinopathy at baseline were predictive of less visual improvement (p < 0.01). Shorter intraretinal cyst length, ERM and the absence of VMA at baseline were predictive of a worsened anatomical response (p < 0.001).

Conclusion

VRIA are related to outcome in patients treated with RZB. ERM was associated with a worsened visual and anatomic response, and VMA with an improved anatomical response particularly when spontaneous VMA release occurred during treatment. The presence and severity of ERM was not affected by RZB treatment.

Electronic supplementary material

The online version of this article (doi:10.1007/s00417-016-3562-0) contains supplementary material, which is available to authorized users.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

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.

Current Trends about Inner Limiting Membrane Peeling in Surgery for Epiretinal Membranes

The inner limiting membrane (ILM) is the basement membrane of the Müller cells and can act as a scaffold for cellular proliferation in the pathophysiology of disorders affecting the vitreomacular interface. The atraumatic removal of the macular ILM has been proposed for treating various forms of tractional maculopathy in particular for macular pucker. In the last decade, the removal of ILM has become a routine practice in the surgery of the epiretinal membranes (ERMs), with good anatomical results. However many recent studies showed that ILM peeling is a procedure that can cause immediate traumatic effects and progressive modification on the underlying inner retinal layers. Moreover, it is unclear whether ILM peeling is helpful to improve vision after surgery for ERM. In this review, we describe the current understanding about ILM peeling and highlight the beneficial and adverse effects associated with this surgical procedure.

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.

The correlation between visual acuity outcomes and optical coherence tomography parameters following surgery for diabetic epiretinal membrane and taut posterior hyaloid

Purpose

To evaluate the relationship between visual outcomes and the determinants detected by spectral domain optical coherence tomography (OCT) in eyes with epiretinal membrane (ERM) and/or taut posterior hyaloid (TPH) that underwent pars plana vitrectomy (PPV).

Materials and methods

A total of 30 participants with diabetic ERM and TPH were included in the study. All study participants underwent PPV. Preoperative and postoperative best corrected visual acuity (BCVA), peripapillary retinal nerve fiber layer (RNFL), macular RNFL, ganglion cell layer, inner plexiform layer, and ganglion cell complex thicknesses were measured in each participant. Linear regression analyses were performed to determine the association between the OCT parameters and the visual acuity measured at the time of the OCT measurement.

Results

The postoperative BCVA logarithm of the minimum angle of resolution (logMAR) values were statistically higher than the preoperative values in the ERM group and TPH group (P=0.001 and P<0.001, respectively). The postoperative BCVA logMAR value was negatively correlated with average RNFL, inferior RNFL thicknesses, and image quality (P=0.002, P=0.004, and P=0.006, respectively). The preoperative and postoperative BCVA logMAR value difference was not correlated with age and all of the OCT parameters measured (P>0.05).

Conclusion

This study shows that achievement of better peripapillary RNFL thickness results in better visual outcome after PPV and ERM/TPH removal.

Prognosis of patients with diabetic macular edema before Japanese approval of anti-vascular endothelial growth factor

PURPOSE

To examine the prognosis of patients with diabetic macular edema (DME) before Japanese approval of antivascular endothelial growth factor (VEGF).

METHODS

This retrospective study included 135 eyes of 115 patients who received treatments (photocoagulation, pharmacological treatments, vitrectomy) for DME between January 2003 and August 2012. The best-corrected visual acuity (BCVA) before and 1, 3, 6, 12, and 24 months after treatment was examined. BCVA was classified based on the decimal value of BCVA before treatment as good (BCVA > 0.7, BCVA = 0.7), moderate (BCVA > 0.7 but <0.2), or poor (BCVA < 0.2, BCVA = 0.2), and each prognosis of BCVA was investigated.

RESULTS

Thirty-five (25.9%) patients were classified with good BCVA, while 69 (51.1%) had moderate and 31 (23.0%) poor BCVA. Following 24 months of treatment, the averaged good BCVA maintained its value (0.0513 ± 0.0954 to 0.0773 ± 0.258). Similarly, the averaged moderate BCVA maintained its value (0.449 ± 0.169 to 0.441 ± 0.431), whereas the averaged poor BCVA significantly improved (1.070 ± 0.291 to 0.879 ± 0.361: p < 0.001). Specifically, the averaged BCVA of patients who initially received vitrectomy increased 0.380 logMAR after 24 months (0.859 ± 0.414 to 0.479 ± 0.549).

CONCLUSION

DME patients with good BCVA at the time of initial treatment generally maintained the averaged BCVA at 24 months, while patients with moderate BCVA did not significantly improve without a standard regimen of anti-VEGF therapy. However, the results indicate that early vitrectomy is a potential treatment option for DME patients with poor BCVA.

Vitreous proteomic analysis of idiopathic epiretinal membranes

To understand the molecular mechanisms of idiopathic epiretinal membranes (iERMs), the vitreous proteomes of patients with iERMs were investigated. The vitreous proteome in patients with iERMs (n = 8) and donor samples (n = 8) was analysed using reversed phase high-performance liquid chromatography (RP-HPLC) coupled with electrospray ionization tandem mass spectrometry (ESI-MS/MS) and GeneGo Metacore™. This research followed the tenets of the Declaration of Helsinki for the use of human subjects. In this current study, 226 significant changes in protein abundance (abundance ratio >2, p < 0.01) were identified in the vitreous proteome of iERM patients compared to normal control vitreous, including 122 proteins that were present at lower levels and 104 proteins that were present at higher levels. In the iERM vitreous samples, complement components, inflammation-related proteins and matrix metalloproteinase were present at higher levels, while normal cytoskeleton proteins were present at lower levels. The top GeneGo pathway was "immune response", the top process network was "inflammation", and the top KEGG pathway was "coagulation cascades". The essential 2-node proteins of the network were estrogen receptor 1 (ESR1) and p300. Among those found at higher levels, ubiquitin-conjugating enzyme E2O (UBE2O) and complement C4A (C4A) were the most abundant proteins, and could be detected in each of the iERM vitreous samples. It can be concluded that iERMs are a complicated pathological process involving inflammation, immune response, and cytoskeleton remolding. UBE2O and C4A may be candidate biomarkers for iERMs.

Ocular complications of diabetes mellitus

Diabetes mellitus (DM) is a important health problem that induces ernestful complications and it causes significant morbidity owing to specific microvascular complications such as, retinopathy, nephropathy and neuropathy, and macrovascular complications such as, ischaemic heart disease, and peripheral vasculopathy. It can affect children, young people and adults and is becoming more common. Ocular complications associated with DM are progressive and rapidly becoming the world’s most significant cause of morbidity and are preventable with early detection and timely treatment. This review provides an overview of five main ocular complications associated with DM, diabetic retinopathy and papillopathy, cataract, glaucoma, and ocular surface diseases.

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.

Current status in diabetic macular edema treatments

Diabetes is a serious chronic condition, which increase the risk of cardiovascular diseases, kidney failure and nerve damage leading to amputation. Furthermore the ocular complications include diabetic macular edema, is the leading cause of blindness among adults in the industrialized countries. Today, blindness from diabetic macular edema is largely preventable with timely detection and appropriate interventional therapy. The treatment should include an optimized control of glycemia, arterial tension, lipids and renal status. The photocoagulation laser is currently restricted to focal macular edema in some countries, but due the high cost of intravitreal drugs, the use of laser treatment for focal and diffuse diabetic macular edema (DME), can be valid as gold standard in many countries. The intravitreal anti vascular endothelial growth factor drugs (ranibizumab and bevacizumab), are indicated in the treatment of all types of DME, but the correct protocol for administration should be defined for the different Retina Scientific Societies. The corticosteroids for diffuse DME, has a place in pseudophakic patients, but its complications restricted the use of these drugs for some patients. Finally the intravitreal interface plays an important role and its exploration is mandatory in all DME patients.

Pathophysiology of proliferative vitreoretinopathy in retinal detachment

Because proliferative vitreoretinopathy cannot be effectively treated, its prevention is indispensable for the success of surgery for retinal detachment. The elaboration of preventive and therapeutic strategies depends upon the identification of patients who are genetically predisposed to develop the disease, as well as upon an understanding of the biological process involved and the role of local factors, such as the status of the uveovascular barrier. Detachment of the retina or vitreous activates glia to release cytokines and ATP, which not only protect the neuroretina but also promote inflammation, retinal ischemia, cell proliferation, and tissue remodeling. The vitreal microenvironment favors cellular de-differentiation and proliferation of cells with nonspecific nutritional requirements. This may render a pharmacological inhibition of their growth difficult without causing damage to the pharmacologically vulnerable neuroretina. Moreover, reattachment of the retina relies upon the local induction of a controlled wound-healing response involving macrophages and proliferating glia. Hence, the functional outcome of proliferative vitreoretinopathy will be determined by the equilibrium established between protective and destructive repair mechanisms, which will be influenced by the location and the degree of damage to the photoreceptor cells that is induced by peri-retinal gliosis.

Preretinal partial pressure of oxygen gradients before and after experimental pars plana vitrectomy

PURPOSE

To evaluate preretinal partial pressure of oxygen (PO2) gradients before and after experimental pars plana vitrectomy.

METHODS

Arteriolar, venous, and intervascular preretinal PO2 gradients were recorded in 7 minipigs during slow withdrawal of oxygen-sensitive microelectrodes (10-μm tip diameter) from the vitreoretinal interface to 2 mm into the vitreous cavity. Recordings were repeated after pars plana vitrectomy and balanced salt solution (BSS) intraocular perfusion.

RESULTS

Arteriolar, venous, and intervascular preretinal PO2 at the vitreoretinal interface were 62.3 ± 13.8, 22.5 ± 3.3, and 17.0 ± 7.5 mmHg, respectively, before vitrectomy; 97.7 ± 19.9, 40.0 ± 21.9, and 56.3 ± 28.4 mmHg, respectively, immediately after vitrectomy; and 59.0 ± 27.4, 25.2 ± 3.0, and 21.5 ± 4.5 mmHg, respectively, 2½ hours after interruption of BSS perfusion. PO2 2 mm from the vitreoretinal interface was 28.4 ± 3.6 mmHg before vitrectomy; 151.8 ± 4.5 mmHg immediately after vitrectomy; and 34.8 ± 4.1 mmHg 2½ hours after interruption of BSS perfusion. PO2 gradients were still present after vitrectomy, with the same patterns as before vitrectomy.

CONCLUSION

Preretinal PO2 gradients are not eliminated after pars plana vitrectomy. During BSS perfusion, vitreous cavity PO2 is very high. Interruption of BSS perfusion evokes progressive equilibration of vitreous cavity PO2 with concomitant progressive return of preretinal PO2 gradients to their previtrectomy patterns. This indicates that preretinal diffusion of oxygen is not altered after vitrectomy. The beneficial effect of vitrectomy in ischemic retinal diseases or macular edema may be related to other mechanisms, such as increased oxygen convection currents or removal of growth factors and cytokines secreted in the vitreous.

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.

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.

Difluprednate ophthalmic emulsion 0.05% as adjunctive treatment to panretinal photocoagulation for proliferative diabetic retinopathy with clinically significant macular edema

PURPOSE

The purpose of this study was to evaluate the efficacy of topical difluprednate ophthalmic emulsion in controlling progressive diabetic macular edema after panretinal photocoagulation.

METHODS

This was a case report of two patients with proliferative diabetic retinopathy combined with diabetic macular edema who underwent panretinal photocoagulation combined with use of a topical difluprednate ophthalmic emulsion.

RESULTS

In the Case 1, retinal thickness was decreased 29% 1 month after the start of difluprednate treatment and best-corrected visual acuity was improved 20/40 to 20/25. In Case 2, retinal thickness was decreased 43% after 1 month, and best-corrected visual acuity was improved 20/100 to 20/60 after 3 months. During the follow-up period, elevation of intraocular pressure, ocular infection, and progression of cataract were not detected, though superficial punctuate keratitis was observed in one case.

CONCLUSION

Topical difluprednate ophthalmic emulsion was one of the possible choices to treat progressive diabetic macular edema after panretinal photocoagulation. It is mandatory to evaluate the effects and safety in further studies including many cases.