Optical coherence tomography findings in persistent diabetic macular edema: the vitreomacular interface

Pharmacological adjuvants for diabetic vitrectomy surgery

Diabetic vitrectomy is a highly intricate surgical procedure performed during the advanced stages of diabetic retinopathy (DR). It is used to treat conditions such as tractional or combined retinal detachment, vitreous hemorrhage, and subhyaloid hemorrhage, which are all severe manifestations of proliferative DR. The results of the surgery are uncertain and variable. Vitreoretinal surgery has made significant progress since the early stages of vitrectomy. In the past ten years, advancements in intravitreal pharmacotherapy have emerged, offering new possibilities to improve the surgical results for our patients. Within the realm of medical terminology, an "adjunct" refers to a pharmaceutical or substance employed to aid or expedite the primary therapeutic intervention for a particular ailment. Their introduction has broadened the range of therapeutic choices that are accessible prior to, during, and following surgical procedures. This review article will specifically analyze the pharmacological adjuncts used in diabetic vitrectomy surgery, with a focus on their role in facilitating or aiding specific steps of the procedure. The implementation of this system of categorization offers benefits to the surgeon by allowing them to foresee potential difficulties that may occur during the surgical procedure and to choose the appropriate pharmacological agent to effectively tackle these challenges, thus enhancing surgical success rates.

Impact of Aflibercept vs Dexamethasone Treatment on Epiretinal Membrane Formation in Eyes with Diabetic Macular Edema

INTRODUCTION

This study aimed to investigate the impact of aflibercept and dexamethasone (DEX) on the formation of epiretinal membrane (ERM) and their treatment outcomes in eyes with diabetic macular edema (DME).

METHODS

In this retrospective cohort study, medical records of 124 eyes from 429 patients diagnosed with DME were reviewed between June 2017 and June 2019. Patients were categorized into two groups: the aflibercept group (67 eyes) and the DEX group (57 eyes). The primary endpoint was the secondary ERM incidence following intravitreal treatments and its correlation across different medications. Secondary endpoints included longitudinal changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT).

RESULTS

Over a 24-month follow-up, eyes treated with DEX had approximately a fourfold higher incidence of ERM development compared to aflibercept [hazard ratio (HR) = 3.97, p = 0.02]. These eyes also showed worse BCVA (p = 0.059) and increased CMT (p = 0.004), despite requiring fewer total injections (p = 0.000) in the survival analysis model. The cumulative probability of ERM formation was 13.7%. Additionally, DME eyes exhibited poor functional and anatomical outcomes after developing ERM, while age, A1c level, DR severity, initial BCVA and CMT, lens status, and previous laser treatment were not associated with an elevated incidence of ERM formation.

CONCLUSION

Intravitreal DEX implantation in DME eyes resulted in a higher incidence of secondary ERM formation compared to aflibercept over a 2-year period. The therapeutic efficacy for DME was diminished following ERM development, leading to worse anatomical outcomes. New therapeutic approaches should be explored to prevent ERM formation while maintaining both anatomical and functional outcomes in DME treatment.

[Anatomical and functional outcomes of the "3+PRN" therapeutic protocol in the treatment of diabetic macular edema]

PURPOSE

To evaluate the anatomical and functional results of the "3+PRN" protocol in the treatment of diabetic macular edema (DME), determine the predictive factors for good final visual acuity, and compare it to other protocols.

MATERIALS AND METHODS

We conducted a retrospective, descriptive, comparative, cross-sectional study of patients with DME, which we dubbed HTSM. All patients were treated with three monthly initial intravitreal injections (IVT) of 1.25mg bevacizumab and followed according to the pro re nata (PRN) protocol for a period of 3years. The protocol was based on a monthly monitoring schedule for the first 3months, then increasingly spaced out over time. "On-demand" treatment was indicated with resumption of bevacizumab IVT in the event of worsening of DME.

RESULTS

A total of 52 patients were included. The mean age was 65years. Type 2 was the most frequently observed type of diabetes. The mean duration of the PRN protocol was 6months, and the mean number of injections was 6. The mean visual acuity (VA), initially 1/10, improved to 3/10 by the conclusion of the 3+PRN protocol, with an improvement of more than 5 letters in 77.6% of cases. The mean initial central macular thickness (CMT) was 451.5μm. The final mean EMC decreased to 298.5μm, which corresponds to a reduction of 153μm compared to the initial value. The mean subfoveal choroidal thickness, initially 304.2μm, decreased to a mean of 284.5μm at completion. Comparative analysis of the results before and after the PRN protocol confirmed the existence of a statistically significant correlation between VA and CMT (P<0.05). No correlation was observed between age and visual acuity or between initial and final VA. The analysis of the various tomographic parameters and VA revealed a significantly better visual improvement in the group in whom the external limiting membrane (MLE) and ellipsoid zone (ZE) were intact (P=0.04), as well as in the group in whom serous retinal detachment (SRD) was absent (P<0.001). Posterior vitreous detachment (PVD) was the most frequently observed vitreomacular anomaly. The final VA was similar in the groups with and without PVD (P=0.04).

CONCLUSION

The 3+PRN protocol is effective both functionally and tomographically in the treatment of DME. Various tomographic parameters might influence therapeutic efficacy. However, further in-depth studies are needed to better investigate these parameters.

Exploration of potential novel drug targets for diabetic retinopathy by plasma proteome screening

The aim of this study is to identify novel potential drug targets for diabetic retinopathy (DR). A bidirectional two-sample Mendelian randomization (MR) analysis was performed using protein quantitative trait loci (pQTL) of 734 plasma proteins as the exposures and clinically diagnosed DR as the outcome. Genetic instruments for 734 plasma proteins were obtained from recently published genome-wide association studies (GWAS), and external plasma proteome data was retrieved from the Icelandic Decoding Genetics Study and UK Biobank Pharma Proteomics Project. Summary-level data of GWAS for DR were obtained from the Finngen Consortium, comprising 14,584 cases and 202,082 population controls. Steiger filtering, Bayesian co-localization, and phenotype scanning were used to further verify the causal relationships calculated by MR. Three significant (p < 6.81 × 10-5) plasma protein-DR pairs were identified during the primary MR analysis, including CFH (OR = 0.8; 95% CI 0.75-0.86; p = 1.29 × 10-9), B3GNT8 (OR = 1.09; 95% CI 1.05-1.12; p = 5.9 × 10-6) and CFHR4 (OR = 1.11; 95% CI 1.06-1.16; p = 1.95 × 10-6). None of the three proteins showed reverse causation. According to Bayesian colocalization analysis, CFH (coloc.abf-PPH4 = 0.534) and B3GNT8 (coloc.abf-PPH4 = 0.638) in plasma shared the same variant with DR. All three identified proteins were validated in external replication cohorts. Our research shows a cause-and-effect connection between genetically determined levels of CFH, B3GNT8 and CFHR4 plasma proteins and DR. The discovery implies that these proteins hold potential as drug target in the process of developing drugs to treat DR.

Vitreomacular interface abnormalities in the Ghanaian African

BACKGROUND/OBJECTIVE

Describe vitreomacular interface abnormalities (VMIA) using spectral-domain optical coherence tomography (SD-OCT), and correlations with age-related macular degeneration (AMD) grade in Ghanaian Africans.

SUBJECTS/METHODS

Prospective, cross-sectional study of adults aged ≥50 years recruited in Ghana AMD Study. Participant demographics, medical histories, ophthalmic examination, digital colour fundus photography (CFP) were obtained. High-resolution five-line raster OCT, Macular Cube 512 × 128 scans, and additional line scans in areas of clinical abnormality, were acquired. SD-OCT VMI features classified by International Vitreomacular Traction Study Group system and relationships to AMD grade were evaluated.

OUTCOMES

VMIA prevalence, posterior vitreous detachment (PVD), vitreomacular adhesions (VMA), vitreomacular traction (VMT), epiretinal membranes (ERM), correlations with AMD grade.

RESULTS

The full Ghana AMD cohort included 718 participants; 624 participants (1248 eyes) aged ≥50 years (range = 50-101, mean = 68.8), 68.9% female were included in this analysis. CFP with OCT scans were available for 776 eyes (397 participants); 707 (91.1%) had gradable CFP and OCT scans for both AMD and VMI grading forming the dataset for this report. PVD was absent in 504 (71.3%); partial and complete PVD occurred in 16.7% and 12.0% respectively. PVD did not increase with age (p = 0.720). VMIA without traction and macular holes were observed in 12.2% of eyes; 87.8% had no abnormalities. VMIA was not significantly correlated with AMD grade (p = 0.819).

CONCLUSIONS

This provides the first assessment of VMIA in Ghanaian Africans. VMIA are common in Africans; PVD may be less common than in Caucasians. There was no significant association of AMD grade with VMIA.

A real-world study for timely assessing the diabetic macular edema refractory to intravitreal anti-VEGF treatment

Background

Early Identifying and characterizing patients with diabetic macular edema (DME) is essential for individualized treatment and outcome optimization. This study aimed to timely investigate optical coherence tomography (OCT) biomarkers of DME refractory to intravitreal anti-vascular endothelial growth factor (VEGF) therapy.

Methods

We retrospective reviewed 72 eyes from 44 treatment-naïve patients who were treated with intravitreal anti-VEGF for DME. OCT scans prior to anti-VEGF were evaluated for serous retinal detachment (SRD), size of outer nuclear layer cystoid changes, diffuse retinal thickening, integrity of the inner segment-outer segment (IS-OS) junction, quantity and location of hyperreflective foci, vitreomacular interface abnormalities, and epiretinal membrane (ERM). The Baseline best-corrected visual acuity (BCVA) and central macular thickness was recorded at baseline and 4 months after treatment with anti-VEGF. The main outcome measure was the correlation between spectral-domain OCT measurements and BCVA response at baseline and after anti-VEGF treatment (mean change from baseline; ≥ 10 Early Treatment Diabetic Retinopathy Study letters in BCVA).

Results

Partially continuous IS-OS layers (partially vs. completely continuous: β, -0.138; Wald chi-square, 16.392; P<0.001) was predictor of better response to anti-VEGF treatment. In contrast, ERM (present vs. absent ERM: β, 0.215; Wald chi-square, 5.921; P=0.015) and vitreomacular traction (vitreomacular traction vs. posterior vitreous detachment: β=0.259; Wald chi-square=5.938; P=0.015) were the predictors of poor response. The improvement of BCVA trended toward the OCT predictive value of central macular thickness reduction; however, this was not significant.

Conclusion

Partially continuous IS-OS layers is predictive of better response to anti-VEGF therapy in DME. Meanwhile, ERM is a significant predictor of poor response.

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.

Vitrectomy for diabetic macular edema and the relevance of external limiting membrane

PURPOSE

To evaluate the relevance of external limiting membrane (ELM) on the visual and morphological results in eyes with diabetic macular edema (DME) that underwent pars plana vitrectomy (PPV) with epiretinal membrane (ERM) and internal limiting membrane (ILM) peeling.

METHODS

Medical records of patients with DME who underwent PPV at our unit between January 2017 and December 2019 were reviewed. We assessed preoperative and postoperative best-corrected visual acuity (BCVA), central macular thickness (CMT) using spectral domain OCT (optical coherence tomography). Exclusion criteria were previous PPV; incomplete data; concomitant diseases including retinal vein occlusion, age-related macular degeneration, uveitis; and a follow-up of less than 12 months. The surgeries were performed using 23- or 27-gauge vitrectomy. The ELM was graded depending on its configuration (grade 0 = intact, grade 1 to 3: disruption of varying extent).

RESULTS

Ninety-nine eyes were enrolled. The postoperative follow up averaged 23.7 months. The preoperative and final BCVA averaged 0.71 ± 0.28 and 0.52 ± 0.3 logMAR, respectively (p = 0.002). The CMT averaged 515.2 ± 209.1 μm preoperatively and 327 ± 66.1 μm postoperatively (p = 0.001). Eyes with intact ELM (n = 8) had a significantly better BCVA compared to those with ELM disruption (0.28 ± 0.14 vs. 0.7 ± 0.25 logMAR, p = 0.01). The final CMT was similar among the groups (intact ELM: 317 ± 54.6 μm; ELM disruption: 334 ± 75.2, p = 0.31).

CONCLUSIONS

PPV with ERM and ILM peeling is an effective treatment of DME. Eyes with intact ELM preoperatively had a significantly better final visual outcome. To maximize the benefit for patients with DME we recommend early PPV as long as ELM is intact.

NATURAL COURSE OF VITREOMACULAR TRACTION IN EYES WITH DIABETIC RETINOPATHY AND FACTORS ASSOCIATED WITH SPONTANEOUS RELEASE

PURPOSE

The aim of this study was to determine the natural course of vitreomacular traction (VMT) in patients with diabetic retinopathy and to evaluate the factors associated with VMT relief.

METHODS

Seventy-four eyes of 65 patients with VMT accompanying diabetic retinopathy were evaluated retrospectively. The presence of intravitreal injection and the presence of panretinal photocoagulation were obtained from the medical records of the patients. Spontaneous release of VMT, the horizontal length of vitreomacular traction, the presence of hyperreflective retinal spots, the presence of the epiretinal membrane, and the grade of VMT were evaluated from the spectral-domain optical coherence tomography images. Factors associated with the spontaneous release of VMT were evaluated by logistic regression analysis.

RESULTS

Spontaneous release was observed in 28 eyes (37.8%). The horizontal length of VMT was lower in the release of the VMT group compared with the persistent VMT group (P = 0.03). The persistent VMT group had a higher rate of hyperreflective retinal spots and epiretinal membrane compared with the release of the VMT group (respectively; P = 0.003 and P = 0.031). No statistically significant difference was observed between the release of VMT and persistent VMT groups in terms of intravitreal injection and panretinal photocoagulation treatment (respectively; P = 0.938 and P = 0.36). The absence of hyperreflective retinal spots was the most important prognostic factor for the spontaneous release of VMT (P = 0.029).

CONCLUSION

Spontaneous release of VMT observed higher rates of patients without hyperreflective retinal spots, epiretinal membrane, and patients with lower horizontal length of VMT.

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.

Incidence and treatment outcomes of secondary epiretinal membrane following intravitreal injection for diabetic macular edema

The purpose of this study was to investigate the incidence of secondary epiretinal membrane (ERM) after intravitreal injection and the effect of ERM on visual acuity and central macular thickness (CMT) in patients with diabetic macular edema (DME). We included 147 eyes of 95 patients over 18 years old who were diagnosed with DME from 2012 to 2016, treated with intravitreal injection, and followed-up more than 24 months. Mean CMT in the ERM group was significantly thicker than in the non-ERM group after 9, 12, 18, and 24 months. Secondary ERM developed in 9.5% of patients during follow-up. Compared to other agents, the incidence of secondary ERM was significantly higher after intravitreal injection of dexamethasone implant. Among patients in the ERM group, the mean decrease of CMT between pre-injection and 2 weeks post-injection was significantly less after secondary ERM formation than before ERM formation. Secondary ERM formation was significantly associated with the number of intravitreal injections and the use of dexamethasone implant. Therefore, secondary ERM develops more frequently as the number of intravitreal injections increases and after intravitreal dexamethasone implant injection. The therapeutic effects of intravitreal injections for DME patients decrease after secondary ERM formation.

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%.

EVALUATION OF ACCURACY AND UNIFORMITY OF THE NOMENCLATURE OF VITREORETINAL INTERFACE DISORDERS

PURPOSE

To evaluate the accuracy and uniformity of the definitions used to diagnose vitreoretinal (VR) interface disorders and to assess it after review of its definitions.

METHODS

A case-series study, consisting of a questionnaire of 46 optical coherence tomography images of six VR interface disorders: vitreomacular adhesion, vitreomacular traction, epiretinal membrane, full-thickness macular hole, lamellar macular hole, and pseudohole. Images were presented to 41 practicing ophthalmologists (13 residents, 11 VR specialists, and 17 non-VR specialists), and a diagnosis was recorded for each image. The questionnaire was repeated after review of the International Vitreomacular Traction Study (IVTS) group classification. Rates of accuracy and uniformity for each condition were analyzed.

RESULTS

Overall correct identification rates according to the IVTS classification were achieved in 67.4% of cases and were highest for epiretinal membrane and full-thickness macular hole, followed by vitreomacular adhesion, vitreomacular traction, and lamellar macular hole, and were significantly lower for pseudohole (P < 0.001). Accuracy was higher among VR specialists and was associated with previous familiarity with the IVTS classification (P = 0.043) but not with length of experience in ophthalmology (P = 0.74). After review of the IVTS classification, overall correct identification rates improved to 71.7% (P = 0.004), with the significant improvement in pseudohole identification (P = 0.002).

CONCLUSION

The IVTS classification is effective in standardizing the diagnosis of VR interface disorders. It is expected to become increasingly assimilated among ophthalmologists over time, leading to higher rates of accuracy and uniformity in diagnosing VR interface disorders.

Comparison of the effect of ranibizumab and dexamethasone implant in diabetic macular edema with concurrent epiretinal membrane

OBJECTIVE

To compare the efficacy and safety of intravitreal ranibizumab (RZB) injections and intravitreal dexamethasone (DEX) implant in diabetic macular edema (DME) with concurrent epiretinal membrane (ERM).

METHODS

This was a retrospective, observational, comparative study. Medical records of DME patients with concurrent ERM were retrospectively reviewed. Seventeen eyes of 16 patients treated with 3 consecutive monthly RZB injections (RZB group) and 22 eyes of 18 patients treated with a DEX implant (DEX group) were included. The groups were compared at baseline, 1st, 2nd, 3rd and 4th months in terms of best-corrected visual acuity (BCVA), central macular thickness (CMT), and intraocular pressure (IOP).

RESULTS

Eighteen of the 39 eyes (46.1%) were phakic at baseline, 9 (52.9%) of which were treated with RZB, whereas 9 (40.9%) were treated with DEX implant (P=0.528). Although CMT improved significantly in both the RZB and DEX groups (P<0.001); the trend was different (P=0.003). The mean change in CMT at 1month in the DEX group was greater (DEX: 188.2±142.7μm; RZB: 95.7±110.7μm; P=0.034); it was in favor of RZB group at the 3rd and 4th months (DEX: -52.7±86.9μm; RZB: 1.4±31.4μm; P=0.012. DEX: -63±67.3μm; RZB: -5.8±43.9μm; P=0.004, respectively). BCVA improved significantly in both groups (P<0.001). There was no statistical difference between the groups with regard to gain in BCVA or IOP change throughout the study period (P=0.572, P=0.064, respectively).

CONCLUSION

Both RZB and DEX are effective in improving anatomical and visual outcomes in DME with concurrent ERM. The DEX group was associated with a prompt anatomic response, but with a gradual decrease from 3rd month.

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.

Vitreomacular interface abnormalities in patients with diabetic macular oedema and their implications on the response to anti-VEGF therapy

Purpose

To determine whether the presence of vitreomacular interface abnormalities (VMIA) in patients with diabetic macular oedema (DMO) modifies the response to ranibizumab.

Methods

Medical records and spectral-domain optical coherence tomography (SD-OCT) scans of consecutive patients with centre-involving DMO initiating therapy with ranibizumab between December 2013 and March 2014 at the Belfast Health and Social Care Trust were reviewed. Patients were identified through an electronic database. Demographics; systemic baseline characteristics; history of previous ocular surgery/laser; best-corrected visual acuity (BCVA), central retinal thickness (CRT) and stage of retinopathy at presentation; and BCVA, CRT and presence/absence of fluid at the last follow-up were recorded. OCT scans were reviewed by a masked investigator who graded them for the presence/absence of VMIA at baseline and during follow-up and for the change in the posterior hyaloid face during follow-up. The association between (1) VMIA at baseline and (2) the change in the posterior hyaloid face during the follow-up and functional/anatomical outcomes was evaluated.

Results

One hundred forty-six eyes of 100 patients (mean age 63.5 years) followed for a mean of 9 months (range 2–14 months; only 9/146 dropped to follow-up before month 6) were included. Statistically significant differences were observed at baseline in BCVA (p = 0.007), previous macular laser and panretinal photocoagulation (PRP) (p = 0.006) and previous cataract surgery (p = 0.01) between eyes with and without VMIA, with better levels of vision, higher frequency of macular laser and lower frequency of PRP in eyes where no VMIA was present. Multivariable regression analysis did not disclose any statistically significant associations between VMIA at baseline or change in the posterior hyaloid face during the follow-up and functional and anatomical outcomes following treatment.

Conclusion

VMIA are associated with worse presenting vision in patients with DMO; VMIA or change in the posterior hyaloid face during the follow-up did not modify the response to ranibizumab in this study.

Vitreoretinal interface abnormalities in diabetic macular edema and effectiveness of anti-VEGF therapy: an optical coherence tomography study

Purpose

To study vitreoretinal interface (VRI) abnormalities in diabetic macular edema (DME) and the influence of these on the effectiveness of intravitreal anti-vascular endothelial growth factor (VEGF) therapy.

Methods

VRI status and central retinal thickness (CRT) were evaluated using line and 3D-reference scans obtained using spectral domain-optical coherence tomography RTVue-100 before and 1 month after intravitreal anti-VEGF injection (IVI). VRI status was categorized into five subgroups: normal VRI, retinal surface wrinkling associated with the eccentric epiretinal membrane (ERM), ERM involving the macular center, vitreomacular adhesion (VMA), and vitreomacular traction (VMT).

Results

A total of 105 eyes of 89 patients were included in the study. One month after IVI, the mean change of CRT in normal VRI eyes and eyes with VRI abnormalities was −128.0±144.7 µm and −53.0±96.4 µm (p<0.05), respectively. The mean change of CRT 1 month after IVI in each subgroup with VRI abnormalities, apart from the subgroup with retinal wrinkling associated with eccentric ERM, was statistically significantly lower compared to the eyes with normal VRI (p<0.05).

Conclusion

VRI abnormalities significantly reduce the effectiveness of intravitreal anti-VEGF therapy in eyes with DME. Eyes with noticeable changes of VRI, including ERM involving the macular center, VMA, and VMT have a poorer response to anti-VEGF therapy compared to eyes with normal VRI or eccentric ERM.

The incidence and risk factors for the development of vitreomacular interface abnormality in diabetic macular edema treated with intravitreal injection of anti-VEGF

PurposeTo report the incidence and associated factors for the development of vitreomacular interface abnormality (VMIA) in patients with diabetic macular edema (DME) who received intravitreal injection (IVI) of anti-VEGF (Bevacizumab and Ranibizumab) treatment.MethodsA retrospective observational study. Patients with DME followed at least 6 months were reviewed. Baseline best-corrected visual acuity (BCVA), central retinal thickness (CRT) and final BCVA, CRT in eyes with and without VMIA were compared. Multiple logistic regression was also used to investigate the risk factors of VMIA formation in patients with DME treated by anti-VEGF.ResultsA total of 201 eyes in 142 patients met the inclusion criteria of the study. VMIA developed in 44 eyes (21.89%) of patients during a mean follow-up period of 40.84 months. The estimated mean incidence of VMIA formation was 6.43% per year. Poor baseline BCVA was found to be a risk factor for VMIA development (P=0.001, odds ratio=5.299, 95% confidence interval: 1.972 to 14.238). There was no difference between eyes with and without VMIA formation in improving BCVA (P=0.557) and lowering the macular edema (eyes without VMIA formation: -107.72±171.91 μm; eyes with VMIA formation: -155.02±212.27 μm, P=0.133).ConclusionsThis study revealed the incidence of VMIA formation in IVI anti-VEGF treated DME eyes was 6.43%. Poor baseline BCVA was found to be a risk factor for VMIA formation. Both eyes with and without VMIA development had favorable response to anti-VEGF treatment.

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.

Application of different imaging modalities for diagnosis of Diabetic Macular Edema: A review

Diabetic Macular Edema (DME) is caused by accumulation of extracellular fluid from hyperpermeable capillaries within the macula. DME is one of the leading causes of blindness among Diabetes Mellitus (DM) patients. Early detection followed by laser photocoagulation can save the visual loss. This review discusses various imaging modalities viz. biomicroscopy, Fluorescein Angiography (FA), Optical Coherence Tomography (OCT) and colour fundus photographs used for diagnosis of DME. Various automated DME grading systems using retinal fundus images, associated retinal image processing techniques for fovea, exudate detection and segmentation are presented. We have also compared various imaging modalities and automated screening methods used for DME grading. The reviewed literature indicates that FA and OCT identify DME related changes accurately. FA is an invasive method, which uses fluorescein dye, and OCT is an expensive imaging method compared to fundus photographs. Moreover, using fundus images DME can be identified and automated. DME grading algorithms can be implemented for telescreening. Hence, fundus imaging based DME grading is more suitable and affordable method compared to biomicroscopy, FA, and OCT modalities.

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.

Phenotypes and biomarkers of diabetic retinopathy

Diabetic retinopathy (DR) remains a major cause of blindness as the prevalence of diabetes is expected to approximately double globally between 2000 and 2030. DR progresses over time at different rates in different individuals with only a limited number developing significant vision loss due to the two major vision-threatening complications, clinically significant macular edema and proliferative retinopathy. Good metabolic control is important to prevent and delay progression, but whereas some patients escape vision loss even with poor control, others develop vision loss despite good metabolic control. Our research group has been able to identify three different DR phenotypes characterized by different dominant retinal alterations and different risks of progression to vision-threatening complications. Microaneurysm turnover has been validated as a prognostic biomarker of development of clinically significant macular edema, whereas subclinical macular edema identified by OCT and mfERG appear to be also good candidates as organ-specific biomarkers of DR. Hemoglobin A1c remains the only confirmed systemic prognostic biomarker of DR progression. The availability of biomarkers of DR progression and the identification of different phenotypes of DR with different risks for development of vision-threatening complications offers new perspectives for understanding DR and for its personalized management.

Macular edema in the era of spectral-domain optical coherence tomography

The development of spectral-domain optical coherence tomography (OCT) allows for the highest commercially available resolution of in vivo retinal anatomic details to date. The ability to see the macula with ever increasing detail is dramatically improving our understanding of the pathogenesis of retinal disease. However, the only prospective study that partially evaluated spectral-domain OCT versus time-domain OCT failed to show any clinical benefit of increased OCT resolution. Clinical outcomes, eg, best-corrected visual acuity, central macular thickness and number of injections, with “newer” OCT technologies remain an unproven advantage.

The International Vitreomacular Traction Study Group classification of vitreomacular adhesion, traction, and macular hole

OBJECTIVE

The International Vitreomacular Traction Study (IVTS) Group was convened to develop an optical coherence tomography (OCT)-based anatomic classification system for diseases of the vitreomacular interface (VMI).

DESIGN

The IVTS applied their clinical experience, after reviewing the relevant literature, to support the development of a strictly anatomic OCT-based classification system.

PARTICIPANTS

A panel of vitreoretinal disease experts was the foundation of the International Classification System.

METHODS

Before the meeting, panel participants were asked to review 11 articles and to complete 3 questionnaires. The articles were preselected based on searches for comprehensive reviews covering diseases of the VMI. Responses to questionnaires and the group's opinions on definitions specified in the literature were used to guide the discussion.

MAIN OUTCOME MEASURES

Optical coherence tomography-based anatomic definitions and classification of vitreomacular adhesion, vitreomacular traction (VMT), and macular hole.

RESULTS

Vitreomacular adhesion is defined as perifoveal vitreous separation with remaining vitreomacular attachment and unperturbed foveal morphologic features. It is an OCT finding that is almost always the result of normal vitreous aging, which may lead to pathologic conditions. Vitreomacular traction is characterized by anomalous posterior vitreous detachment accompanied by anatomic distortion of the fovea, which may include pseudocysts, macular schisis, cystoid macular edema, and subretinal fluid. Vitreomacular traction can be subclassified by the diameter of vitreous attachment to the macular surface as measured by OCT, with attachment of 1500 μm or less defined as focal and attachment of more than 1500 μm as broad. When associated with other macular disease, VMT is classified as concurrent. Full-thickness macular hole (FTMH) is defined as a foveal lesion with interruption of all retinal layers from the internal limiting membrane to the retinal pigment epithelium. Full-thickness macular hole is primary if caused by vitreous traction or secondary if directly the result of pathologic characteristics other than VMT. Full-thickness macular hole is subclassified by size of the hole as determined by OCT and the presence or absence of VMT.

CONCLUSIONS

This classification system will support systematic diagnosis and management by creating a clinically applicable system that is predictive of therapeutic outcomes and is useful for the execution and analysis of clinical studies.

Spectral domain optical coherence tomography study of macular microhole morphology and its correlation with vitreomacular interface abnormalities

To describe the demographic, clinical and optical coherence tomography (OCT) characteristics of macular microholes and to determine if the size or character of the microholes has any correlation with vitreomacular interface abnormalities. Case records of 46 eyes of 39 consecutive patients with diagnosed macular microholes were reviewed as a non-interventional retrospective case study. Demographic and clinical features were noted from the detailed case records. Spectral domain OCT images were analysed for microhole and retinal characteristics. SPSS 16.0 was used for statistical analysis. Main outcome measure was the presence of vitreomacular interface abnormalities in large and small macular microholes. Of 39 patients, 21 were male and 18 were female. Most of these patients (56.4 %) presented with visual complaints. Clinically, the commonest feature was a 'red spot' at the fovea on indirect ophthalmoscopy (25 of 44 eyes; 54.3 %). Mean logMAR vision was 0.117 (±SD 0.21). 34 (76.08 %) eyes exhibited a photoreceptor loss, 38 eyes (82.6 %) had lamellar tissue defects involving layers posterior to the outer nuclear layer. The difference between means of the groups with and without vitreomacular interface abnormalities was analysed using the unpaired t test. The presence of vitreomacular interface abnormalities was significantly associated with the size of the microhole, with larger microholes being more likely to have vitreomacular interface abnormalities than smaller ones (p < 0.05). We concluded that there was a positive correlation between the size of the microhole and the presence of vitreomacular interface abnormalities. Visual acuity had no correlation with the size of the microhole; functional vision was generally well preserved in the affected eyes.

Predictive value of spectral-domain optical coherence tomography features in assessment of visual prognosis in eyes with neovascular age-related macular degeneration treated with ranibizumab

PURPOSE

To determine whether pretreatment (baseline) optical coherence tomography (OCT) features can be used as predictors of visual acuity outcome at 12 months in eyes with neovascular age-related macular degeneration treated with intravitreal ranibizumab and to assess whether baseline OCT features can predict a change in visual acuity from baseline to 12 months.

DESIGN

Retrospective, observational study.

METHODS

We retrospectively evaluated the serial cross-sectional images of the macula obtained using the Spectralis OCT (HRA+OCT; Heidelberg Engineering) in 100 eyes of 94 patients attending a single center and undergoing treatment with intravitreal ranibizumab for neovascular age-related macular degeneration. The baseline OCT characteristics and visual acuity were correlated to the final visual acuity (Early Treatment Diabetic Retinopathy Study letters) and change in visual acuity after 12 months of monitoring and treatment. Univariate and multivariate analyses were carried out to correlate these morphologic features with the final visual acuity and the change in visual acuity.

RESULTS

Intact ellipsoid zone (P = .0001) and external limiting membrane in the subfoveal area (P < .0001) at baseline were the only 2 independent good prognostic indicators of final visual acuity at 12 months. However, none of the morphologic features at baseline could predict the change in visual acuity by 12 months.

CONCLUSIONS

The results suggest that integrity of the outer retinal layers at baseline is crucial for determining final visual acuity at 12 months in eyes undergoing treatment with ranibizumab for neovascular age-related macular degeneration.

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.

Evidence for diffuse central retinal edema in vivo in diabetic male Sprague Dawley rats

Background

Investigations into the mechanism of diffuse retinal edema in diabetic subjects have been limited by a lack of animal models and techniques that co-localized retinal thickness and hydration in vivo. In this study we test the hypothesis that a previously reported supernormal central retinal thickness on MRI measured in experimental diabetic retinopathy in vivo represents a persistent and diffuse edema.

Methodology/Principal Findings

In diabetic and age-matched control rats, and in rats experiencing dilutional hyponatremia (as a positive edema control), whole central retinal thickness, intraretinal water content and apparent diffusion coefficients (ADC, ‘water mobility’) were measured in vivo using quantitative MRI methods. Glycated hemoglobin and retinal thickness ex vivo (histology) were also measured in control and diabetic groups. In the dilutional hyponatremia model, central retinal thickness and water content were supernormal by quantitative MRI, and intraretinal water mobility profiles changed in a manner consistent with intracellular edema. Groups of diabetic (2, 3, 4, 6, and 9 mo of diabetes), and age-matched controls were then investigated with MRI and all diabetic rats showed supernormal whole central retinal thickness. In a separate study in 4 mo diabetic rats (and controls), MRI retinal thickness and water content metrics were significantly greater than normal, and ADC was subnormal in the outer retina; the increase in retinal thickness was not detected histologically on sections of fixed and dehydrated retinas from these rats.

Conclusions/Significance

Diabetic male Sprague Dawley rats demonstrate a persistent and diffuse retinal edema in vivo, providing, for the first time, an important model for investigating its pathogenesis and treatment. These studies also validate MRI as a powerful approach for investigating mechanisms of diabetic retinal edema in future experimental and clinical investigations.

Qualitative and quantitative OCT response of diffuse diabetic macular oedema to macular laser photocoagulation

PURPOSE

To assess the quantitative and morphological changes of the macula in response to macular grid laser for diabetic macular oedema (DMO) using optical coherence tomography (OCT).

PATIENTS AND METHODS

Cirrus OCT macular cube scans of 30 eyes of 25 patients were retrospectively analysed before and 4 months after macular grid laser for diffuse DMO. The oedema was quantified and response evaluated in the nine early-treatment diabetic retinopathy study (ETDRS) zones of the macula. Post-laser OCT changes were compared with the baseline features, including morphology patterns, changes in both logarithmic transformed (logOCT) and standardised average macular thickness (AMT), total macular volume, number of parafoveal quadrants involved, and the presence of intact 3rd hyper-reflective band (HRB).

RESULTS

The rate of change of retinal thickness in response to laser was maximum in the central (8.17%) and perifoveal inferior quadrants (0.04%). Diffuse retinal thickening on OCT responded best to treatment. The AMT of 300-350 μm had the worst response (+0.94%). Eyes with less than four quadrants of oedema showed good response. Disrupted HRB was associated with poor visual gain (-0.33 ETDRS letters).

CONCLUSION

The topographic location of oedema on the retinal map and the morphological patterns of the oedema on OCT are useful predictors of treatment response in diffuse DMO.

Ocular coherence tomography and diabetic eye disease

Optical Coherence Tomography (OCT) is a high-resolution, cross-sectional imaging technique that allows detailed assessment of retinal thickness and morphologic evaluation of the neurosensory retinal layers. OCT imaging has rapidly been integrated into diagnosis and management of diabetic macular edema (DME) in routine clinical practice and clinical trials. OCT findings correlate well with other evaluation techniques for DME. Although there is a moderate correlation between OCT measured retinal thickness and visual acuity, OCT cannot replace visual acuity because there is a high degree of variability. Recent improvements in OCT technology have led to widespread interest in the use of spectral domain OCT, which is faster and has higher resolution than time domain OCT. Future research in OCT imaging will likely result in improvements in image quality. The ability to combine OCT with other various diagnostic modalities will further improve the evaluation of DME in both clinical practice and trials.

Predicting visual outcomes for macular disease using optical coherence tomography

In recent years, the management of macular disease has undergone radical changes, in part because of new therapeutic approaches, but also due to the introduction of a new imaging modality - optical coherence tomography (OCT). The application of OCT imaging has clarified many aspects of chorioretinal disease pathophysiology and elucidated many hitherto unrecognized disease characteristics. From an early stage in its development, OCT has also been revolutionary in attempting to extract clinically useful measurements from image data in an automated fashion. As a result, OCT-derived measurements of retinal thickness have been rapidly embraced in clinical and research settings. However, as knowledge of OCT image analysis has developed, it has become increasingly clear that even accurate measurements of retinal thickness may fail to predict visual outcomes for many diseases. As a result, the focus of much current clinical imaging research is on the identification of other OCT-derived anatomic biomarkers predictive of visual outcomes - such biomarkers could serve as surrogate endpoints in clinical trials and provide prognostic information in clinical practice. In this review, we begin by highlighting the importance of accurate visual function assessment and describing the fundamentals of OCT image evaluation, before describing the current state-of-the-art with regard to predicting visual outcomes, for a variety of macular diseases, using OCT.

Association of fluorescein angiographic features with visual acuity and with optical coherence tomographic and stereoscopic color fundus photographic features of diabetic macular edema in a randomized clinical trial

BACKGROUND

Fluorescein angiography (FA) has been performed as part of the management of diabetic macular edema for many years. Its current role relative to the role of optical coherence tomography (OCT) is not well defined.

PURPOSE

To evaluate the associations of FA features with visual acuity (VA) and with OCT and fundus photographic characteristics in eyes with diabetic macular edema.

METHODS

In a clinical trial, conducted by the Diabetic Retinopathy Clinical Research Network to compare two methods of laser photocoagulation to treat diabetic macular edema, FA (film and digital), color photographs, OCT, and VA measurements were obtained at baseline and at 1 year. Grading of morphologic features was performed at a reading center. Reproducibility of FAs was assessed, and the correlations of FA features with VA, OCT, and color photograph features were computed.

RESULTS

From 79 clinical sites, data of 323 study eyes and 203 fellow nonstudy eyes were analyzed. Fluorescein leakage area at baseline was associated with reduced VA, increased OCT measures of retinal thickness and volume, and color photographic measurements of retinal thickening (r = 0.33-0.58). No important associations were found with changes from baseline to 12 months in these parameters or with any of the other variables analyzed.

CONCLUSION

Fluorescein leakage is associated with VA and some OCT and color photographic variables. We did not identify any unique FA variables that had a stronger association with VA than OCT measures of retinal thickness. These data may be useful to investigators planning future diabetic macular edema clinical trials.

Optical coherence tomography imaging for diabetic retinopathy and macular edema

Optical coherence tomography (OCT) is a noninvasive imaging modality that uses low-coherent interferometry to visualize an optical cross-section of biological tissues. Over the past two decades, the ability to perform OCT imaging of the neural retina has afforded clinicians and researchers a highly reproducible method of diagnosing and following diabetic macular edema (DME) that compares favorably to other methods of DME assessment such as clinical examination and fundus photography. Although central subfield mean thickness has been the OCT parameter most commonly used to evaluate DME in clinical research trials, OCT also allows evaluation of morphologic changes that occur in DME, including compact retinal thickening, intraretinal cystic changes, subretinal fluid, and vitreomacular traction. OCT parameters have been shown to be only moderately correlated with visual acuity. However, improvements in technology leading to higher resolution, faster acquisition speed, image registration, and three-dimensional imaging that are available with newer spectral domain OCT models may allow future identification of valid OCT-derived surrogate markers for visual function in patients with diabetes.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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