Diabetic macular edema: pathogenesis and treatment

Intravitreal dexamethasone implant in naïve and previously treated patients with diabetic macular edema: a retrospective study

AIM

To assess the effect of the intravitreal dexamethasone implant (DEX) Ozurdex on the best corrected visual acuity (BCVA) and central retinal thickness (CRT) in patients with diabetic macular edema (DME).

METHODS

Totally 43 eyes (24 naïve and 19 previously treated) were included in the study. Retrospective and single-center study involved patients with a clinical diagnosed of DME, who received treatment with DEX implant and had a follow-up of at least 12mo. Primary endpoints included changes in BCVA and CRT.

RESULTS

At month 12, mean improvement in BCVA from baseline was 20.4±20.8 letters and 6.8±6.9 letters in naïve and previously treated patients, respectively (P=0.0132). The naïve patients achieved the BCVA improvement significantly faster (2.4±1.5mo) than the previously treated ones (3.5±2.4mo, P=0.0298; Mann-Whitney test). The proportion of eyes gaining ≥15 letters was 54.2% and 21.1% in the non-previously treated and previously treated groups, respectively (P=0.0293). CRT was significantly reduced from 484.0±119.8 and 487.5±159.9 µm to 272.0±39.2 and 233.5±65.7 µm in the naïve and previously treated patients, respectively; P<0.0001 each, respectively. The presence of subretinal fluid was significantly associated with the proportion of patients achieving a BCVA improvement ≥5 letters [HR (95%CI), 1.23 (1.04 to 1.45), P=0.0145]; ≥10 letters [HR (95%CI), 1.75 (1.10 to 2.77), P=0.0182]; and ≥15 letters [HR (95% CI), 2.04 (1.03 to 4.02), P=0.0407]. Naïve patients received less DEX implants throughout the study than the previously treated ones (1.8±0.6 vs 2.3±0.6, P=0.0172, respectively). Totally 9 patients (20.9%) have developed ocular hypertension, which was successfully controlled with topical hypotensive drugs. Of the 23 phakic eyes at baseline, 5 eyes (21.7%) either had new onset lens opacity or progression of an existing opacity during the study follow-up. Four of them (2 in the naïve group and 2 in the previously treated one) required cataract surgery at months 4, 6, 6, and 6, respectively.

CONCLUSION

The results obtained in this study may support the early use of DEX Ozurdex as first line therapy in naïve patients.

Defining Cystoid Macular Degeneration in Diabetic Macular Edema: An OCT-Based Single-center Study

Objectives:

To describe cystoid macular degeneration (CMD), which has no clear definition in diabetic macular edema (DME), and examine its features in optical coherence tomography (OCT) and fundus fluorescein angiography (FFA).

Materials and Methods:

This study was conducted using OCT images of patients who were followed in Gazi University between November 2011 and March 2015. A total of 259 eyes (187 patients) found to have cystic changes on OCT were included. Macular ischemia, peripheral ischemia, and type of edema were identified on FFA. Vitreomacular interface abnormalities, foveal contour integrity, internal reflectivity of the cysts, and outer retinal layer defects were analyzed from OCT images. The horizontal and vertical diameters of the largest cyst within 1000 μm of the foveal center were measured for the definition of CMD. Cut-offs for these values were determined by receiver operating characteristic curve analysis. Cystoid macular edema (CME) and CMD groups were created and their characteristics were analyzed.

Results:

The horizontal and vertical diameters of the largest cyst were moderately positively correlated with visual acuity (rs=0.349, r=0.419, respectively). Eyes with horizontal diameter of the largest cyst ≥450 μm were classified as CMD; in this group, sensitivity in the prediction of visual acuity ≤20/60 was 58%. Eyes with horizontal diameter of the largest cyst <450 μm were classified as CME; in this group, specificity in the prediction of visual acuity >20/60 was 73%. For the threshold of 300 μm determined for vertical diameter of the largest cyst, sensitivity was 62% and specificity was 69%. The CME and CMD groups were formed according to these cut-off values. Compared to the CME group, the CMD group had greater central subfield thickness and higher prevalence of outer retinal damage, severe disruption of foveal contour, macular ischemia, and diffuse/mixed type edema.

Conclusion:

In eyes with DME, CMD can be defined as the largest cyst within 1000 μm of the foveal center having a horizontal diameter of ≥450 μm and vertical diameter ≥300 μm, especially if associated with macular ischemia, outer retinal damage, loss of foveal contour, and diffuse/mixed type edema.

Postmarketing safety surveillance of dexamethasone intravitreal implant in the treatment of visual impairment due to diabetic macular edema in India

Background

Diabetic macular edema (DME) is the most common cause of vision loss in diabetic patients. As India has the second largest population of diabetic patients worldwide, availability of various treatment options for DME is essential. This postmarketing surveillance study was conducted to fulfill a commitment to the Regulatory Authority of India to examine the safety of dexamethasone intravitreal (DEX) implant over 1 year in Indian patients with DME receiving ≥1 DEX implant for DME-related visual impairment in clinical practice.

Methods

This observational, prospective, non-interventional study enrolled patients aged ≥18 years scheduled to receive DEX implant for DME-related visual impairment. Baseline demographics, medical history, date of last DEX implant injection, detailed information about adverse events (AEs), AEs of special interest (AESIs), serious AEs (SAEs), and adverse drug reactions (ADRs) reported during postinjection visits and investigator telephone calls were collected. Primary outcome measures were treatment-emergent AE (TEAE), AESI, SAE, and ADR occurrences.

Results

Of the enrolled patients (19 sites throughout India; n = 250), 84 had received DEX implant previously; mean (standard deviation; SD) duration between prior and study entry dose was 199.4 (156.0) days, and 91 (36.4%) had ≥1 prior ophthalmic condition. Over a mean of 182.6 (88.6) follow-up days (min–max: 0–364 days), 22 TEAEs were reported by 7 (2.8%) patients, 6 of whom had previously received DEX. AESIs of increased IOP (n = 3, 6 events) and glaucoma (n = 1, 1 event) were considered non-serious, of mild/moderate severity, and related to DEX treatment. Eyelid ptosis was reported in 1 patient (1 event). Nonocular AEs included cardiac AEs (n = 3, 4 events), pyrexia (n = 1, 2 events), and dyspnea (n = 1, 2 events). Three (1.2%) patients had 12 serious AEs; most were cardiac disorders; all were unrelated to DEX treatment. Two (0.8%) deaths were considered unrelated to treatment.

Conclusions

Based on voluntary reporting of adverse events in this surveillance study, DEX implant for treatment of DME-related visual impairment in the Indian population demonstrated a favorable safety profile with few treatment-related TEAEs (none were considered serious) during the 1-year follow-up. These data supplement previous findings and confirm the safety of DEX implant in this population during usual clinical practice.

Trial registration

World Health Organization Clinical Trials Registry: CTRI/2017/04/008396. Registered 24 April 2017.

A Real-World Study of Dexamethasone Implant in Treatment-Naïve Patients with Diabetic Macular Edema: Efficacy and Correlation Between Inflammatory Biomarkers and Treatment Outcome

Purpose

There has been an increasing clinical interest in specific retinal parameters as non-invasive biomarkers of retinal inflammation in diabetic macular edema (DME) that have been shown to have prognostic value, such as hyperreflective retinal fields (HRFs) and subfoveal neuroretinal detachment (SND).

Methods

We conducted a prospective, non-comparative study of treatment-naïve patients with DME to evaluate the efficacy of a Pro Re Nata (PRN) regimen of intravitreal dexamethasone implant 0.7 mg (DexI, Ozurdex™). After administration, patients underwent subsequent injections according to PRN criteria in case of edema relapse, but not earlier than 4 months after the previous treatment. Patients were evaluated at baseline, within 15 days of injection, and every month thereafter. During all visits, best-corrected visual acuity (BCVA) was recorded; central retinal thickness (CRT), type of edema, presence of SND, and presence and number of HRFs were evaluated using swept-source optical coherence tomography (SS-OCT) 3D. Treatment outcome was defined as changes in BCVA, CRT, SND and HRFs at 12 (T12) and 24 (T24) months compared with baseline (T0).

Results

The study enrolled 24 eyes of 18 patients. The mean duration of follow-up was 18±6.6 months; for all eyes, T12 data were available, while follow-up reached T24 for 12 eyes. BCVA improved significantly and CRT decreased significantly during treatment; the edema was no longer detectable in 13/24 eyes at T12 and 8/12 eyes at T24. No patient presented SND at T12 and T24, and the mean number of HRFs decreased significantly during treatment. Results with CRT and HRFs correlated with BCVA at 12 and 24 months. No significant adverse events were observed.

Conclusion

In patients with DME, the intravitreal dexamethasone implant was effective and safe in improving both functional and tomographic parameters. This result is consistent with improvement in biomarkers of inflammation.

Sub-clinical thickening of the fovea in diabetes and its relationship to glycaemic control: a study using swept-source optical coherence tomography

Background

Accumulation of multiple pockets of fluid at the fovea, as a complication of poor blood glucose control in diabetes, causes impairment of central vision. A new ability to demonstrate a pre-clinical phase of this maculopathy could be valuable, enabling diabetic individuals to be alerted to the need to improve their glycaemic control. This study aimed to use swept-source optical coherence tomography (SS-OCT) to measure foveal thickness and macular volume in diabetic individuals without cystoid macular oedema, and in non-diabetic individuals, and relate these measures to participants’ glycaemic control.

Methods

Centre point thickness (CPT) and total macular volume (TMV) were measured using SS-OCT (DRI OCT Triton™, Topcon, Tokyo, Japan). Participants’ glycosylated haemoglobin (HbA_1c) level was also assessed (A_1cNow®+ System, PTS Diagnostics, Indianapolis, IN, USA). The diabetic (n = 27) and non-diabetic (n = 27) groups were matched for age (p = 0.100) and sex (p = 0.414), and HbA_1c level differed between diabetic and non-diabetic groups (p < 0.0005). The diabetic group comprised type 1 (n = 7) and type 2 (n = 20) diabetic individuals who were matched for duration of diabetes (p = 0.617) and whose glycaemic control was similar (p = 0.814).

Results

Diabetic individuals had significantly higher CPT (t(37) = 3.859, p < 0.0005) than non-diabetic individuals. In the diabetic group, multiple linear regression analysis revealed a conspicuous relationship between CPT and HbA_1c level (β = 0.501, t(21) = 3.139, p = 0.005): there was a 19-μm increase in CPT for each 1% increase in HbA_1c level. This relationship was not present in the non-diabetic group (β = − 0.068, t(23) = − 0.373, p = 0.712).

Conclusions

SS-OCT is the only way to measure macular thickness in vivo. Diabetic individuals en bloc had higher CPT compared with non-diabetic individuals. Moreover, in the diabetic group, HbA_1c level significantly predicted CPT. Our results suggest that, in diabetes, sub-clinical thickening may occur at the fovea before cystoid macular oedema becomes clinically evident. This could provide diabetic individuals with an early warning of disease progression and motivate them to improve control of their diabetes, with a view to avoiding the need of intra-vitreal injections with their attendant risks.

Adherence of patients with diabetic macular oedema to intravitreal injections: A systematic review

The purpose of this study was to review adherence rates to intravitreal injections in the treatment of diabetic macula oedema and to identify factors associated with adherence. A systematic search of Embase, Medline, PsycINFO and CINAHL was conducted up to May 2020. Two authors independently screened, selected and appraised the studies. Seven articles on anti-VEGF treatment were found to meet the inclusion criteria. No studies were found on intravitreal corticosteroids or dexamethasone implants. Attendance rates varied between studies from 35% to 85%. The rate of missed or delayed attendance ranged from 14% to 51%, whereas 25% of patients were lost to follow-up at 12 months. Non-adherence was found to be multifactorial and included patient related reasons, demographic characteristics and clinical factors. Enablers to adherence included patient understanding of the disease and treatment. Further research in this area is warranted in order to better understand adherence in these patients and to improve patient outcomes.

Surgical outcomes of vitrectomy for intractable diabetic macular edema

PURPOSE

To investigate clinical outcomes of vitrectomy for intractable diabetic macular edema (DME) in which anti-vascular endothelial growth factor (anti-VEGF) agents or periocular steroid were not effective.

METHODS

This retrospective study examined 27 eyes of 25 cases. The main measurements included changes in visual acuity (VA) and retinal morphology. Vitrectomies were performed using the Constellation System 25G.

RESULTS

Prior to undergoing vitrectomy, patients were treated with anti-VEGF agents or periocular injection of triamcinolone acetonide. The average number of anti-VEGF agent injections was 3.1 ± 2.8. Triamcinolone was used in 15 eyes. There was no significant change in the mean logMAR best-corrected visual acuity (BCVA) between baseline and posttreatment, with values of 0.49 ± 0.29 and 0.55 ± 0.33, respectively (P = 0.31). Compared with preoperative BCVA, postoperative BCVA improved by more than two lines in 4 eyes (14%), remained the same in 17 eyes (63%), and decreased in 6 eyes (23%). Morphologically, retinal thickness improved by more than 50 μm in 16 eyes (59%), remained unchanged in 7 eyes (26%), and increased in 5 eyes (18%). Retinal edema resolved in all of the cases in which macular epiretinal membrane (ERM) or vitreomacular traction (VMT) was detected by optical coherence tomography during pretreatment.

CONCLUSIONS

Vitrectomy can potentially stabilize the retinal morphology in intractable DME and is likely more effective in DME cases accompanied by ERM or VMT.

Bradykinin 1 Receptor Antagonist BI1026706 Does Not Reduce Central Retinal Thickness in Center-Involved Diabetic Macular Edema

Purpose

The bradykinin 1 receptor may be important in inflammatory retinal vascular leakage in diabetic macular edema. BI 1026706 is an antagonist of bradykinin 1 receptor that has demonstrated efficacy in preclinical studies. Boehringer Ingelheim trial 1320.22 (NCT02732951) was a randomized, double-blind, placebo-controlled study. The pharmacodynamics, safety, and tolerability of oral BI 1026706 for 12 weeks were evaluated in patients with type 1 or type 2 diabetes mellitus and mild visual impairment owing to center-involved diabetic macular edema.

Methods

Patients (n = 105) were randomized to receive either oral BI 1026706 100 mg twice daily (morning and evening) or placebo for 12 weeks. The primary end point of the study was week 12 change from baseline in central subfield foveal thickness (CSFT) by spectral domain optical coherence tomography. Additional end points included absolute CSFT values, safety, and pharmacokinetics.

Results

After 12 weeks of treatment, there was no meaningful change from baseline in the adjusted mean CSFT in either treatment group (BI 1026706, 10.3 µm; placebo, –6.2 µm; adjusted mean treatment difference, 16.5 µm [95% confidence interval, –16.2 to 49.1]). There were also no differences in best-corrected visual acuity outcomes between treatment groups. Most reported adverse events were of mild or moderate intensity, and were balanced between treatment groups.

Conclusions

BI 1026706 was not superior to placebo in CSFT week-12 change from baseline. Therefore, BI 1026706 does not reduce CSFT, a morphologic sign of diabetic macular edema.

Translational Relevance

Kinin-kallikrein inhibition effects may not be apparent over 12 weeks for bradykinin 1 receptor inhibition alone.

Long-term lutein administration attenuates retinal inflammation and functional deficits in early diabetic retinopathy using the Ins2Akita/+ mice

INTRODUCTION

Lutein is a carotenoid whose protective effects in the retina have been reported in various studies. The effect of lutein has not been reported in the retina of the Ins2^Akita/+ mouse, a well-characterized genetic model for diabetic retinopathy (DR) in which the etiology of diabetes is better defined than the chemically induced diabetes. The objective of the present study is to investigate the effect of long-term administration of lutein in early stages of DR using the Ins2^Akita/+ mouse.

RESEARCH DESIGN AND METHODS

Heterozygous male Ins2^Akita/+ and age-matched wild-type mice were used. Lutein was administered to the mice in drinking water starting 6 weeks old daily until analysis at 4.5, 6.5 or 9 months of age. Plain water served as non-treatment control. Microglia were immunostained with ionized calcium-binding adapter molecule 1 (Iba-1) and cluster of differentiation 68 (CD68) in retinal flat-mounts. Vascular endothelial growth factor (VEGF) level in the retina was assessed by enzyme-linked immunosorbent assay (ELISA). Vascular permeability was analyzed in retinal flat-mounts after fluorescein isothiocyanate (FITC)-dextran perfusion. Retinal occludin expression was assessed via Western blots. Retinal function was examined by electroretinography (ERG).

RESULTS

Increased microglial reactivity was detected in the Ins2^Akita/+ mouse retina and was suppressed by lutein. Lutein administration also reduced the upregulation of VEGF in the Ins2^Akita/+ mouse retina. Increased vascular leakage and decreased occludin expression were observed in the Ins2^Akita/+ mouse retina, and these alterations were attenuated by lutein treatment. ERG recordings showed reduced a-wave and b-wave amplitudes in the Ins2^Akita/+ mice. With lutein treatment, the ERG deficits were significantly alleviated.

CONCLUSIONS

We showed beneficial effects of long-term lutein administration in the Ins2^Akita/+ mouse retina, including suppression of retinal inflammation, protection of retinal vasculature and preservation of retinal function. These results point to lutein's potential as a long-term therapeutic intervention for prevention of inflammation and retinal degeneration in patients with early DR.

Baseline SD-OCT characteristics of diabetic macular oedema patterns can predict morphological features and timing of recurrence in patients treated with dexamethasone intravitreal implants

AIMS

To evaluate the timing and spectral-domain optical coherence tomography (SD-OCT) features of diabetic macular oedema (DME) recurrence according to baseline OCT patterns in patients treated with dexamethasone implant (DEX-I).

METHODS

This is a retrospective observational study (72 eyes/65 patients). Best-corrected visual acuity, timing of DME recurrence, and SD-OCT pattern [intraretinal cysts (IRC), IRC plus subretinal fluid (mixed), external limiting membrane (ELM), ellipsoid (IS/OS) layer integrity] were assessed at baseline and monthly until first DME recurrence.

RESULTS

Forty-two (58.3%) and 30 (41.6%) DME eyes had an IRC and mixed DME pattern at baseline, respectively. Twenty-four out of thirty mixed eyes (80%) relapsed without subretinal fluid. At baseline, mixed eyes showed similar changes in ELM and IS/OS (60 and 76.6% of eyes, respectively) versus IRC eyes (42.8 and 80.9% of eyes). After DME recurrence, more mixed eyes at baseline showed ELM and IS/OS changes (63.3 and 86.6%) than IRC eyes (50 and 76.2%). 33.3% of mixed eyes had DME recurrence at ≥ 6 months from first DEX-I implant versus 19% of IRC eyes.

CONCLUSIONS

Mixed DME eyes were treated with DEX-I relapse later and more frequently without subretinal fluid than IRC eyes. SD-OCT characteristics of different DME patterns at baseline can predict morphological features and timing of DME recurrence.

Results of dexamethasone intravitreal implant (Ozurdex) in diabetic macular edema patients: Early versus late switch

PURPOSE

To assess the functional and anatomical outcomes of intravitreal dexamethasone implant Ozurdex® in eyes with diabetic macular edema that did not adequately respond to vascular endothelial growth factor inhibitors.

METHODS

Multicenter, retrospective, and real-life case series study conducted on consecutive diabetic macular edema patients who underwent treatment with one or more dexamethasone implant injections and were followed up for a minimum of 12 months. Subjects were divided into three groups: I-naïve patients, II-previously treated eyes that received three intravitreal antivascular endothelial growth factor inhibitors injections before the study (early switch), and III-previously treated eyes that received >3 intravitreal antivascular endothelial growth factor inhibitors injections before the study (late switch). Primary endpoints were best-corrected visual acuity and central retinal thickness at month 12.

RESULTS

A total of 129 eyes (21 naïve and 108 previously treated, Group II: 32 and Group III: 76) were included. At month 12, best-corrected visual acuity significantly improved from 0.27 ± 0.23 and 0.31 ± 0.22 at baseline to 0.36 ± 0.25 and 0.37 ± 0.23 at month 12 in naïve and previously treated eyes, respectively, and p = 0.0063 and 0.0060, respectively. Central retinal thickness, in naïve and previously treated eyes, was significantly reduced from 483.0 ± 143.4 and 431.3 ± 115.5 µm, at baseline, to 278.8 ± 72.1 and 269.3 ± 66.2 µm, at month 12, respectively, and p < 0.0001 each, respectively. Best-corrected visual acuity improvement was significantly greater in both absolute and percentage values, p = 0.0393 and 0.0118, respectively, in Group II than in Group III.

CONCLUSION

In eyes with insufficient response to antivascular endothelial growth factor inhibitors, switching to dexamethasone at the time to 3-monthly antivascular endothelial growth factor inhibitors injections provided better functional outcomes than those that received >3 antivascular endothelial growth factor inhibitors injections.

Optical Coherence Tomography Angiography in Diabetes and Diabetic Retinopathy

Diabetic retinopathy (DR) is a common complication of diabetes mellitus that disrupts the retinal microvasculature and is a leading cause of vision loss globally. Recently, optical coherence tomography angiography (OCTA) has been developed to image the retinal microvasculature, by generating 3-dimensional images based on the motion contrast of circulating blood cells. OCTA offers numerous benefits over traditional fluorescein angiography in visualizing the retinal vasculature in that it is non-invasive and safer; while its depth-resolved ability makes it possible to visualize the finer capillaries of the retinal capillary plexuses and choriocapillaris. High-quality OCTA images have also enabled the visualization of features associated with DR, including microaneurysms and neovascularization and the quantification of alterations in retinal capillary and choriocapillaris, thereby suggesting a promising role for OCTA as an objective technology for accurate DR classification. Of interest is the potential of OCTA to examine the effect of DR on individual retinal layers, and to detect DR even before it is clinically detectable on fundus examination. We will focus the review on the clinical applicability of OCTA derived quantitative metrics that appear to be clinically relevant to the diagnosis, classification, and management of patients with diabetes or DR. Future studies with longitudinal design of multiethnic multicenter populations, as well as the inclusion of pertinent systemic information that may affect vascular changes, will improve our understanding on the benefit of OCTA biomarkers in the detection and progression of DR.

Real-Life Management of Diabetic Macular Edema with Dexamethasone Intravitreal Implant: A Retrospective Analysis of Long-Term Clinical Outcomes

PURPOSE

Inflammation plays a key role in the pathogenesis of diabetic macular edema (DME), and intravitreal corticosteroids are among the recommended therapies. The goal of this retrospective analysis was to describe outcomes with dexamethasone intravitreal implant (DEX implant) in real life.

METHODS

Medical digital records of DME patients treated with DEX implant and followed up for 3 years were analyzed. Treatment with DEX implant was started either as first-line therapy in pseudophakic patients and in patients with cardiovascular comorbidities or as second-line therapy in patients refractory to the inhibitor of the vascular endothelial growth factor (anti-VEGF) therapy. Analyzed outcomes included central macular thickness (CMT) and best-corrected visual acuity (BCVA). Mean number of implant injections per patient and mean duration of the interval between injections were also estimated.

RESULTS

Seventy-five patients (mean age 65.7 (±12.3) years; 53 phakic and 22 pseudophakic) with DME were included. Overall, 84 eyes were treated. Mean CMT improved from 380.1 (±100.3) µm at baseline to 306.8 (±77.0) µm at 36 months (p=0.0003). Mean BCVA improved for up to 6 months (p=0.08) and then started to decrease reaching values lower than baseline after 24 months. In pseudophakic patients, BCVA improvements were more pronounced and sustained up to 36 months (p=0.6). Over 36 months, each patient received on average 2.4 (±1.6) intravitreal injections of DEX implant. The time interval between consecutive injections was included between 180 and 240 days. No unexpected safety issues were reported.

CONCLUSIONS

With fewer than 3 injections per patient over a 3-year period, DEX implant was able to improve anatomic outcomes in DME patients. Only pseudophakic eyes showed also a long lasting functional benefit at 36 months.

Discontinuous to continuous therapy for persistent diabetic macular edema leads to reduction in treatment frequency

OBJECTIVE

To evaluate, in the setting of persistent diabetic macular edema, the impact that continuous fluocinolone acetonide delivery has on treatment burden, visual acuity, central retinal thickness, and intraocular pressure.

MATERIALS AND METHODS

A single-center, retrospective, cohort study of patients with persistent diabetic macular edema, previously treated with anti-vascular endothelial growth factor injections, dexamethasone implants, or focal laser, who were subsequently treated with fluocinolone acetonide was conducted. All retinal visits were analyzed prior to fluocinolone acetonide, until the most recent follow-up visit. Primary outcomes were pre- and post-fluocinolone acetonide changes in the best-corrected visual acuity and number of treatments required for diabetic macular edema. Secondary outcomes included changes in the central retinal thickness and intraocular pressure.

RESULTS

A total of 19 eyes with persistent diabetic macular edema were included and followed for a mean (SD) of 399.3 (222.9) days. Post-fluocinolone acetonide, the mean best-corrected visual acuity improved by 0.4 ETDRS letters for all eyes (p = 0.895) and the central retinal thickness decreased by 34.2 µm (p = 0.077). After fluocinolone acetonide, the number of treatments decreased from an average of one treatment every 2.7 months to one every 6 months (p = 0.009). Furthermore, post-fluocinolone acetonide, 10/19 eyes (52.6%) did not require additional treatment due to a dry macula, and those who did experienced a non-statistically significant reduction of treatments, from one every 2.6 months pre-fluocinolone acetonide, to one every 2.8 months post-fluocinolone acetonide (p = 0.622).

CONCLUSIONS

In the setting of persistent diabetic macular edema, fluocinolone acetonide significantly reduces the therapeutic burden, while maintaining best-corrected visual acuity and improving the central retinal thickness. In patient-centered discussions, judiciously employing fluocinolone acetonide should be performed to mitigate this therapeutic burden for patients.

Real Life Experience of Dexamethasone Implant in Refractory Diabetic Macular Oedema

Purpose

The purpose of this retrospective study was to examine the efficacy of dexamethasone implant in refractory diabetic macular oedema (DMO) in real life settings.

Methods

In all, 24 eyes of 22 patients that required treatment with single or multiple intravitreal dexamethasone implants for refractory DMO were included in the study. Patients having macular oedema for another retinal disease were excluded from the study. The patient data were collected and analyzed retrospectively. As a demographic data age, gender, the type of diabetes and the duration of DMO were collected. Changes in central foveal thickness and the number of hyper reflective spots (HRS) were analyzed with Heidelberg SD-OCT. Furthermore, the best-corrected visual acuity (BCVA) and changes in the intraocular pressure (IOP) were measured.

Results

In all, 50.0% of the eyes with baseline BCVA 0.45 (±2.4) lines in ETDRS LogMAR scale received only one implant during the follow-up of 332 (±79) days. At the end of the follow-up, BCVA was 0.26 (±2.0) lines. The other 50.0% of the eyes with baseline BCVA 0.64 (±3.0) lines received the second implant in 156 (±38) days. Central retinal thickness (CRT) at baseline was 333 (±44) μm in the eyes with only one implant and 497 (±125) μm in the eyes with 2 or more implants. IOP lowering medication was needed for 8.3% of the eyes. The decrease in the number of HRS was significant (8±17, p=0.048) in response to dexamethasone implantation.

Conclusion

The dexamethasone implant is a useful treatment in refractory DMO and HRS seen in the OCT might indicate inflammation in the retina.

Quantitative Analysis of Retinal Microvascular Perfusion and Novel Biomarkers of the Treatment Response in Diabetic Macular Edema

PURPOSE

We aimed to assess the changes of retinal microvascular parameters using optical coherence tomography angiography (OCTA) between diabetes macular edema (DME) and controls. We assessed the changes between the baseline microvascular parameters and final treatment response in patients with DME, initially treated with intravitreal dexamethasone (DEX) implant followed by antivascular endothelial growth factor (VEGF) injections on an as-needed basis.

METHODS

This retrospective study included 90 DME patients and 24 healthy control subjects. All subjects had their best-corrected visual acuity (BCVA) and central macular thickness (CMT) measured at baseline and after 12 months. Vessel density (VD) in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) and the deep/superficial flow ratio at baseline were analyzed. A subgroup analysis was used to compare the treatment response. A poor-response group was defined by five or more retreatments at 12 months.

RESULTS

BCVA and CMT showed a significant improvement at 12 months (all p < 0.001). The VD in the whole and parafoveal areas of the DCP was significantly reduced in DME patients compared to that in controls (all p < 0.05). The DCP/SCP flow ratio was also significantly reduced in the DME group (1.08 ± 0.03 vs. 1.05 ± 0.02, p = 0.001). In the subgroup analysis, the VD in the foveal and whole DCP areas was significantly lower in the poor-response group than that in the good-response group (p = 0.043 and p = 0.048, respectively). The DCP/SCP flow ratio was also significantly lower in the poor-response group (p = 0.011).

CONCLUSION

DME correlated with significant retinal microvascular impairment in the DCP. A decreased DCP/SCP flow ratio was observed in patients with DME that exhibited a poor treatment response. Retinal microvascular parameters could predict the treatment response in DME and help optimize clinical outcomes.

Differentiation of Underlying Pathologies of Macular Edema Using Spectral Domain Optical Coherence Tomography (SD-OCT)

Purpose: To describe the morphological characteristics of macular edema (ME) of different origins using spectral domain optical coherence tomography (SD-OCT). Methods: This article summarizes and highlights key morphologic findings, based on published articles, describing the characteristic presentations of ME of different origins using SD-OCT. The following pathologies were included: uveitic macular edema, pseudophakic cystoid macular edema (PCME), diabetic macular edema (DME), macular edema secondary to central or branch retinal vein occlusion (CRVO/BRVO), microcystic macular edema (MME), ME associated with epiretinal membrane (ERM), and retinitis pigmentosa (RP). Conclusions: Macular edema of different origins show characteristic patterns that are often indicative of the underlying cause and pathology. Thus, trained algorithms may in the future be able to automatically differentiate underlying causes and support clinical diagnosis. Knowledge of different appearances support the clinical diagnosis and can lead to improved and more targeted treatment of ME.

Association of Body Fluid Expansion With Optical Coherence Tomography Measurements in Diabetic Retinopathy and Diabetic Macular Edema

Purpose

To evaluate associations of body fluid status with optical coherence tomography measurements in patients with diabetic retinopathy (DR).

Methods

This prospective, cross-sectional study enrolled a total of 104 eyes from 104 patients with diabetes mellitus for fundus evaluations of DR and optical coherence tomography examinations. DR severity was graded via fundus photography. Systemic body fluid status was recorded via a body composition monitor with output values of total body water, extracellular water (ECW), intracellular water, and overhydration (OH). Relative overhydration (ROH) was defined as OH/ECW. Volume overload was defined as ROH ≥7%. Correlations of central subfield thickness (CST) with body fluid status were analyzed by partial correlation with adjustment for age, sex, and body mass index (BMI). Logistic regression analysis was used to evaluate factors associated with diabetic macular edema (DME).

Results

Higher levels of ECW, OH, and ROH were correlated with thick CST in patients with DR (P = 0.006, 0.021, and 0.008, respectively), but not in those without any DR (all P > 0.05), after adjusting for age, sex, and BMI. Patients with DME (n = 31) had higher OH than DR patients without DME (n = 28) or those without any DR (n = 45) (P = 0.002 and P < 0.001, respectively). Multiple regression model showed that volume overload was the independent factor for the presence of DME (odds ratio, 9.532; 95% confidence interval, 2.898-31.348; P < 0.001).

Conclusions

While both ECW and OH reflect CST in patients with DR, overhydration had particularly strong associations with DME. This study provides a novel insight into our current understanding regarding the pathogenesis for DME.

Submacular Injection of Ranibizumab as a New Surgical Treatment for Refractory Diabetic Macular Edema

Purpose

In this study, we describe a new surgical technique for the treatment of refractory DME. The technique consists of vitrectomy with ILM peeling with a subretinal injection of ranibizumab.

Methods

This is a prospective interventional noncomparative study including patients with refractory DME. Included patients were subjected to the new surgical technique of pars plana vitrectomy with subretinal injection of ranibizumab.

Results

The study included 19 eyes with refractory macular edema, in which this novel technique was attempted. There were 10 males and 9 females. The age of the patients ranged from 17 to 67 years with a mean of 55.58 ± 13.242 years. The duration of diabetes before enrollment in the study ranged from 7 to 25 years with a mean of 16.3 years. Preoperatively, the mean CMT of the eyes ranged from 352 to 883 microns with mean ± SD of 498.58 ± 152.16 microns. Postoperatively, this improved significantly to 373.5 ± 100.3, 355.9 ± 89.8, and 365.74 ± 120.12 microns at 1, 3, and 6 months, respectively (p ≤ 0.001 for all).

Conclusion

This novel surgical procedure of vitrectomy with ILM peeling with a subretinal injection of ranibizumab is effective in cases of refractory DME. The study has been registered in Contact ClinicalTrials.gov PRS Identifier: NCT03975088.

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.

A Collaborative Retrospective Study on the Efficacy and Safety of Intravitreal Dexamethasone Implant (Ozurdex) in Patients with Diabetic Macular Edema: The European DME Registry Study

PURPOSE

To evaluate the efficacy, effect profile, and safety of dexamethasone implant on diabetic macular edema (DME) in a real-life setting, further comparing results by DME duration, previous treatment status, and diabetic control.

DESIGN

A multicenter, retrospective cohort of 340 DME eyes of 287 patients from 25 clinical sites from 8 countries.

METHODS

Data were analyzed in 2 perspectives: per injection, in which all measurements were grouped and baseline was defined as the day of injection, and thus the pharmacodynamics of single injections could be assessed; and injection series, defined as 2 or more injections with 3 to 6 months between injections analyzing the outcome 3 to 6 months after the last injection.

MAIN OUTCOME MEASURES

Primary outcome was improvement of 15 or more letters in best-corrected visual acuity (BCVA) from baseline. Secondary outcomes included improvement of 10 letters or more in BCVA, change in central macular thickness (CMT), and time to maximum improvement and safety.

RESULTS

Overall, 762 injections were administered to 340 eyes of 287 patients. Injection series analysis included 171 series in 171 eyes of 150 patients, for a total of 444 injections, with a mean follow-up of 1.7±0.8 years. Of the 762 injections analyzed per injection, 22.7% achieved a 15-letter or more improvement, and 37.8% achieved a 10-letter or more improvement. Mean time to peak improvement was 81.9±39.7 days. Mean maximum change in CMT was -174±171 μm. Overall, 7.6% lost 15 or more letters. More eyes with early DME gained 10 or more letters and fewer eyes lost 10 or more letters compared with eyes with late DME (47.4% vs. 33.9% [P = 0.001] and 8.2% vs. 13.5% [P = 0.029], respectively). Patients with controlled diabetes showed greater CMT reduction (P = 0.0002). A higher percentage of treatment-naive patients gained 10 or 15 letter or more in BCVA (P = 0.001 and P = 0.006, respectively). Intraocular pressure elevation of more than 25 mmHg was found following 7.9% of injections; no endophthalmitis was reported.

CONCLUSIONS

Dexamethasone implant is an effective and safe treatment for DME. Peak improvement was achieved 3 months after injection and dissipated thereafter. Clinicians and providers may consider shortening treatment intervals.

Association of Abnormal Renal Profiles and Proliferative Diabetic Retinopathy and Diabetic Macular Edema in an Asian Population With Type 2 Diabetes

Importance

The comorbidity of chronic kidney disease and diabetic retinopathy (DR) is well known. However, to our knowledge, no cohort study has demonstrated the effect of chronic kidney disease on the development or progression of DR.

Objective

To investigate the association of chronic kidney disease with the development of DR and diabetic macular edema (DME) in type 2 diabetes.

Design, Setting, and Participants

This 8-year prospective cohort study that was conducted in 2 medical centers in Taiwan included 2135 patients with type 2 diabetes.

Exposures

The baseline and mean follow-up renal profiles including serum creatinine level, estimated glomerular filtration rate (eGFR), and urinary albumin/creatinine ratio (ACR).

Main Outcomes and Measures

Diabetic retinopathy and DME were detected with nonmydriatic fundus photography. Cox regression analyses was used to evaluate the hazard ratios (HRs) for the renal profiles of new-onset DR, proliferative DR, and DME.

Results

The mean (SD) age of the study participants was 63.4 (11.9) years and 1025 (48%) were women. A higher serum creatinine level (HR of 2.358 for an increase of 1 mg/dL [to convert to micromoles per liter, multiply by 76.25]; 95% CI, 1.901-2.924; P < .001), an estimated glomerular filtration rate of less than 60 mL/min/1.73m2 (40-60: HR, 2.235; 95% CI, 1.351-4.035; P = .002; 30-45: HR, 2.625; 95% CI, 1.436-4.798; P = .002; <30: HR, 5.488; 95% CI, 2.739-10.993; P < .001), and a urinary albumin to creatinine ratio (ACR) of more than 30 mg/g (31-300: HR, 3.202; 95% CI, 2.029-5.053; P < .001; >300: HR, 6.652; 95% CI, 3.922-11.285; P < .001) at baseline were all associated with the development of proliferative DR. A baseline urinary ACR of more than 30 mg/g (31-300: HR, 1.563; 95% CI, 1.078-2.267; P = .02; >300: HR, 2.707; 95% CI, 1.640-4.470; -2.707; P < 0.001) was associated with the development of DME. After adjusting the baseline values, the mean follow-up renal profiles, including a higher serum creatinine level (HR, 2.369 per mg/dL; 95% CI, 1.704-3.293; P < .001), an estimated glomerular filtration rate of less than 30 mL/min/1.73m2 (HR, 4.215; 95% CI, 1.265-14.039; P = .02), and a urinary ACR of more than 30 mg/g (31-300: HR, 2.344; 95% CI, 1.200-4.503; P = .01; >300: HR, 4.193; 95% CI, 1.638-10.735; P = .003) were still correlated with new-onset PDR during the follow-up periods.

Conclusions and Relevance

Abnormal renal profiles at baseline, including a high serum creatinine level, low estimated glomerular filtration rate, and high urinary ACR, were associated with the development of PDR in patients with type 2 diabetes. A high baseline urinary ACR was associated with DME. Abnormal mean follow-up renal profiles were still correlated with new-onset PDR after adjusting for baseline values. Aggressive treatment for chronic kidney disease may have a role in preventing the deterioration of DR.

Quantitative Ultra-Widefield Angiographic Features and Associations with Diabetic Macular Edema

PURPOSE

To examine the relationship between diabetic macular edema (DME) and quantitative ultra-widefield fluorescein angiography (UWFA) metrics of ischemia, leakage, and microaneurysms.

DESIGN

Retrospective image analysis study.

PARTICIPANTS

Eyes with diabetic retinopathy that had undergone spectral-domain OCT, UWFA, and ultra-widefield fundus photography.

METHODS

OCT images were analyzed to determine the presence or absence of DME, central subfield thickness (CST), and subretinal fluid. Using a semiautomated analysis platform, UWFA images were segmented for ischemia, leakage, and microaneurysms with manual correction as needed. Clinical variables, including age, gender, race, hemoglobin A1C levels, blood pressure, cholesterol levels, use of blood thinners, smoking status, and lens status also were evaluated.

MAIN OUTCOME MEASURES

Factors associated with the presence and severity of DME.

RESULTS

A total of 304 eyes (156 right eyes, 148 left eyes) from 178 diabetic patients were analyzed in the study. Panretinal leakage index, microaneurysm count, and ischemic index were not significantly different between eyes with and without DME in univariate assessment. Zonal assessments of macular microaneurysms and macular leakage index values revealed that eyes with DME showed a significantly higher microaneurysm count (P = 0.001) and leakage index (P < 0.0001) in the posterior pole compared with eyes without DME. Severity of macular thickening (i.e., CST) was associated significantly with macular leakage index and posterior pole microaneurysm count (P = 0.0002 and P = 0.03, respectively). In addition to posterior pole leakage index and microaneurysm count, DME was associated with older age (P < 0.01), higher systolic blood pressure (P < 0.001), and white race (P = 0.03). Multivariate assessment confirmed the independent association of presence of DME with macular leakage index and macular microaneurysm count (P < 0.01).

CONCLUSIONS

Quantitative measures of leakage index and microaneurysm count in the posterior pole on UWFA images were associated with the presence and severity of DME. Panretinal analyses were not linked to DME as strongly. Additional research is needed to determine the role of quantitative UWFA in predicting DME development and characterizing patient prognosis.

Pretreatment neutrophil-to-lymphocyte ratio predicts prognosis in patients with diabetic macular edema treated with ranibizumab

Background

To investigate the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) in patients with diabetic macular edema (DME) treated monthly with ranibizumab.

Methods

We retrospectively analyzed the medical records of all patients who received intravitreal ranibizumab (IVR) treatment for DME at the First Affiliated Hospital of Nanchang University between December 2015 and December 2017. Clinicopathological parameters, including NLR, were evaluated to identify predictors of better outcomes of IVR monotherapy.

Results

Ninety-one treatment-naïve eyes treated with IVR for DME were retrospectively analyzed in this study. Baseline best-corrected visual acuity (BCVA), neutrophils, NLR, monocyte-to-lymphocyte ratio, and platelet-to-lymphocyte ratio were negatively correlated with the changes in BCVA at 24 weeks compared with the baseline, while baseline central retinal thickness and lymphocytes were positively correlated with the changes in BCVA at 24 weeks compared with the baseline. Multiple linear regression analysis revealed that NLR was independently associated with the mean change of BCVA between baseline and week 24. In addition, patients with NLR < 2.27 showed a better improvement in letter score than those with NLR > 2.27.

Conclusion

Pretreatment NLR is independently associated with the BCVA in DME patients treated with IVR, and higher pretreatment NLR may contribute to inferior BCVA outcomes.

Expression of vascular infarction-related molecules after anti-vascular endothelium growth factor treatment for diabetic macular edema

To determine whether an intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) in eyes with diabetic macular edema (DME) affects the vascular infarction-related molecules (VIRMs). Nineteen eyes with DME were treated with 0.5 mg of intravitreal ranibizumab (IVR), and 22 eyes with DME were treated with 2 mg of intravitreal aflibercept (IVA). Blood was collected before, 1 week and 1 month after the injections. Aqueous humor was collected before and 1 month after the injections. The concentration of the VIRMs (cardiac myoglobin, cardiac troponin, intercellular adhesion molecule, monocyte chemotactic protein-1, matrix metalloproteinase-8, placental growth factor [PlGF], tenascin-C, tissue inhibitor of metalloproteinase-1, thrombospondin-2, vascular cell adhesion molecule-1, and VEGF) were determined by the multiplex assay. After the single injection of both types of anti-VEGF agents, the concentration of aqueous VEGF decreased significantly (P < 0.01). The plasma VEGF was reduced significantly at 1 week after the IVA (93.7 ± 17.6 to 39.5 ± 11.6 pg/ml; P < 0.01) but no significant change was seen after IVR (120.2 ± 11.3 to 137.4 ± 17.7 pg/ml). No significant changes were detected for the other VIRMs in the plasma and aqueous. A single intravitreal injection of anti-VEGF for DME does not significantly affect the concentration of several VIRMs.

Deep Learning Predicts OCT Measures of Diabetic Macular Thickening From Color Fundus Photographs

Purpose

To develop deep learning (DL) models for the automatic detection of optical coherence tomography (OCT) measures of diabetic macular thickening (MT) from color fundus photographs (CFPs).

Methods

Retrospective analysis on 17,997 CFPs and their associated OCT measurements from the phase 3 RIDE/RISE diabetic macular edema (DME) studies. DL with transfer-learning cascade was applied on CFPs to predict time-domain OCT (TD-OCT)-equivalent measures of MT, including central subfield thickness (CST) and central foveal thickness (CFT). MT was defined by using two OCT cutoff points: 250 μm and 400 μm. A DL regression model was developed to directly quantify the actual CFT and CST from CFPs.

Results

The best DL model was able to predict CST ≥ 250 μm and CFT ≥ 250 μm with an area under the curve (AUC) of 0.97 (95% confidence interval [CI], 0.89-1.00) and 0.91 (95% CI, 0.76-0.99), respectively. To predict CST ≥ 400 μm and CFT ≥ 400 μm, the best DL model had an AUC of 0.94 (95% CI, 0.82-1.00) and 0.96 (95% CI, 0.88-1.00), respectively. The best deep convolutional neural network regression model to quantify CST and CFT had an R2 of 0.74 (95% CI, 0.49-0.91) and 0.54 (95% CI, 0.20-0.87), respectively. The performance of the DL models declined when the CFPs were of poor quality or contained laser scars.

Conclusions

DL is capable of predicting key quantitative TD-OCT measurements related to MT from CFPs. The DL models presented here could enhance the efficiency of DME diagnosis in tele-ophthalmology programs, promoting better visual outcomes. Future research is needed to validate DL algorithms for MT in the real-world.

A review of the putative causal mechanisms associated with lower macular pigment in diabetes mellitus

Macular pigment (MP) confers potent antioxidant and anti-inflammatory effects at the macula, and may therefore protect retinal tissue from the oxidative stress and inflammation associated with ocular disease and ageing. There is a body of evidence implicating oxidative damage and inflammation as underlying pathological processes in diabetic retinopathy. MP has therefore become a focus of research in diabetes, with recent evidence suggesting that individuals with diabetes, particularly type 2 diabetes, have lower MP relative to healthy controls. The present review explores the currently available evidence to illuminate the metabolic perturbations that may possibly be involved in MP's depletion. Metabolic co-morbidities commonly associated with type 2 diabetes, such as overweight/obesity, dyslipidaemia, hyperglycaemia and insulin resistance, may have related and independent relationships with MP. Increased adiposity and dyslipidaemia may adversely affect MP by compromising the availability, transport and assimilation of these dietary carotenoids in the retina. Furthermore, carotenoid intake may be compromised by the dietary deficiencies characteristic of type 2 diabetes, thereby further compromising redox homeostasis. Candidate causal mechanisms to explain the lower MP levels reported in diabetes include increased oxidative stress, inflammation, hyperglycaemia, insulin resistance, overweight/obesity and dyslipidaemia; factors that may negatively affect redox status, and the availability, transport and stabilisation of carotenoids in the retina. Further study in diabetic populations is warranted to fully elucidate these relationships.

Correlations between visual acuity and macular microvasculature quantified with optical coherence tomography angiography in diabetic macular oedema

PURPOSE

To explore the impact of macular ischaemia on vision in diabetic macular oedema (DMO) by analysing the correlations between visual acuity and macular microvascular parameters using optical coherence tomography angiography (OCTA).

METHODS

OCTA was performed in 81 eyes of 48 patients with DMO, and 3 × 3-mm² en face OCTA images of the superficial capillary plexus and deep capillary plexus in the central macula were retrospectively collected. Microvascular parameters including the number of microaneurysms, area of foveal avascular zone (FAZ), acircularity index of FAZ, vessel density, skeleton density, vessel density index and fractal dimension were measured. Central retinal thickness (CRT) and the presence of ellipsoid zone disruption at the fovea were also recorded. Linear mixed models were used to evaluate the correlations between best-corrected visual acuity (BCVA) and the microvascular parameters.

RESULTS

After adjustment for CRT and ellipsoid zone disruption at the fovea, lower skeleton density and lower fractal dimension in the deep capillary plexus were correlated with poorer BCVA (P = 0.030 and 0.024, respectively). None of the microvascular parameters of the superficial capillary plexus were correlated with BCVA after adjustment for CRT and ellipsoid zone disruption (all, P > 0.05).

CONCLUSIONS

For eyes with DMO, low skeleton density and low branching complexity in the deep capillary plexus of central macula were correlated with poor vision. OCTA could offer quantified parameters of macular microvasculature to measure the impact of macular ischaemia on visual acuity in DMO.

Outer retinal hyperreflective deposits (ORYD): a new OCT feature in naïve diabetic macular oedema after PPV with ILM peeling

AIMS

We aimed to investigate a novel optical coherence tomography (OCT) finding of outer retinal hyperreflective deposits (ORYDs) in patients with naïve diabetic macular oedema (DMO) seen after small gauge pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling. Furthermore, we evaluated the predictive value of ORYD for visual outcome over 24 months follow-up.

METHODS

Retrospective cohort study including 111 eyes from 111 patients with naïve DMO treated by PPV and ILM peeling with a follow-up of 24 months. OCT scans were analysed for the presence of ORYD 1 week and 1, 6, 12, 18 and 24 months after surgery. Change in baseline best-corrected visual acuity (BCVA) and central subfoveal thickness (CST) after surgery were measured over the follow-up period. Presence of ORYD was correlated with baseline characteristics and BCVA after 24 months.

RESULTS

Hundred and eleven eyes from 111 patients were included (mean age 67.5±14.8 years). ORYD was identified in the outer plexiform layer as hyperreflective deposits in 92 patients (82.8%) 7 days after surgery but it was not present before surgery. There was a significant reduction in the presence of ORYD. After 24 months ORYD disappeared in all cases (p<0.001).

CONCLUSIONS

We describe a novel OCT feature of ORYD present in the early postoperative phase in the majority of patients after PPV with ILM peeling for naïve DMO, disappearing over the postoperative course. These deposits might be a result of sudden desinflammation and could shed new light on the process of DMO resolution after operative intervention.

Disorganization of retinal inner layers correlates with ellipsoid zone disruption and retinal nerve fiber layer thinning in diabetic retinopathy

PURPOSE

To study the correlation between disorganization of inner retinal layer (DRIL) and macular thickness parameters, ellipsoid zone (EZ) disruption and retinal nerve fiber layer (RNFL) thickness on spectral domain optical coherence tomography (SD-OCT) in diabetic retinopathy (DR), for the first time.

METHODS

A tertiary care center-based cross-sectional study was undertaken. One hundred and four consecutive study subjects of type 2 diabetes mellitus were included: diabetes mellitus with no retinopathy (No DR) (n = 26); non-proliferative DR (NPDR) (n = 26); proliferative DR (PDR) (n = 26) and healthy controls (n = 26). Best Corrected Visual Acuity (BCVA) was measured on the logarithm of the minimum angle of resolution (logMAR) scale. Clinician-friendly, SD-OCT based, grading systems were created for DRIL and EZ disruption, within the macular cube. DRIL was graded as: grade 0, DRIL absent; and grade 1, DRIL present. EZ disruption was graded as; Grade 0: Intact EZ; Grade 1: Focal disruption and Grade 2: Global disruption. Every study subject underwent RNFL thickness analysis.

RESULTS

DRIL was significantly associated with increase in severity of DR.Pearson correlation analysis showed significant positive correlation between DRIL and CST CAT and grades of EZ disruption . However, a significant negative correlation was found between DRIL and RNFL thickness .

CONCLUSION

Presence of DRIL correlates with severity of DR, EZ disruption and RNFL thinning.

BMP9 (Bone Morphogenetic Protein-9)/Alk1 (Activin-Like Kinase Receptor Type I) Signaling Prevents Hyperglycemia-Induced Vascular Permeability

Objective- Diabetic macular edema is a major cause of visual impairment. It is caused by blood-retinal barrier breakdown that leads to vascular hyperpermeability. Current therapeutic approaches consist of retinal photocoagulation or targeting VEGF (vascular endothelial growth factor) to limit vascular leakage. However, long-term intravitreal use of anti-VEGFs is associated with potential safety issues, and the identification of alternative regulators of vascular permeability may provide safer therapeutic options. The vascular specific BMP (bone morphogenetic protein) receptor ALK1 (activin-like kinase receptor type I) and its circulating ligand BMP9 have been shown to be potent vascular quiescence factors, but their role in the context of microvascular permeability associated with hyperglycemia has not been evaluated. Approach and Results- We investigated Alk1 signaling in hyperglycemic endothelial cells and assessed whether BMP9/Alk1 signaling could modulate vascular permeability. We show that high glucose concentrations impair Alk1 signaling, both in cultured endothelial cells and in a streptozotocin model of mouse diabetes mellitus. We observed that Alk1 signaling participates in the maintenance of vascular barrier function, as Alk1 haploinsufficiency worsens the vascular leakage observed in diabetic mice. Conversely, sustained delivery of BMP9 by adenoviral vectors significantly decreased the loss of retinal barrier function in diabetic mice. Mechanistically, we demonstrate that Alk1 signaling prevents VEGF-induced phosphorylation of VE-cadherin and induces the expression of occludin, thus strengthening vascular barrier functions. Conclusions- From these data, we suggest that by preventing retinal vascular permeability, BMP9 could serve as a novel therapeutic agent for diabetic macular edema.

Three-dimensional structural and angiographic evaluation of foveal ischemia in diabetic retinopathy: method and validation

Optical coherence tomography angiography (OCTA) allows us to noninvasively investigate foveal ischemia, a key feature of diabetic retinopathy (DR). However, the sizes of the foveal avascular zone (FAZ) have a significant variation in normal population, preventing the objective assessment of pathological enlargement of FAZ due to capillary dropout. Based on the relationship between FAZ and ganglion cell complex (GCC) thickness in normal eyes, we defined a theoretical baseline FAZ (tbFAZ) on structural OCT and measured 2D and 3D vessel density in its vicinity on the simultaneously acquired OCTA in normal and diabetic eyes. We found that the structure-based tbFAZ was a reliable reference to identify foveal ischemia and that the 3D vessel density demonstrated ischemia more effectively than the 2D method. The proposed 3D para-FAZ vessel density correlates well with DR severity and potentially is a useful diagnostic biomarker, especially in the early stages of DR.

Aflibercept with adjuvant micropulsed yellow laser versus aflibercept monotherapy in diabetic macular edema

PURPOSE

To assess the impact of micropulsed laser (MPL) on modifying the number of aflibercept injections when used as an adjuvant therapy in diabetic macular edema (DME).

METHODS

A prospective randomized interventional clinical study included patients with DME attending Al Hadi Clinic, Kuwait, during the period from May 2017 to December 2018. Patients were allocated in two groups; group A received aflibercept injections alone and group B received combined aflibercept injections followed by MPL within a week. The primary outcome was the number of Aflibercept injections in each group guided by the change in central macular thickness (CMT). All the patients were followed for 18 months. Secondary outcome measures included best corrected visual acuity (BCVA), contrast sensitivity (CS), and any recorded complications.

RESULTS

Fifty-four eyes of 51 patients were included (27 in each group). There was no statistically significant difference between the two groups in baseline characteristics except for the age that was statistically higher in group B (p = 0.001). The number of injections were significantly lower in group B (4.1 ± 1.1) than group A (7.3 ± 1.1) (p < 0.005). At 18th month, there was significant reduction in CMT in both groups (p < 0.005) with no statistical difference between the two groups (p = 0.989). Final BCVA in both groups showed statistically significant improvement (p < 0.005) without statistically significant difference between the two groups (p = 0.082). In both groups, the CS showed significant improvement from baseline (p < 0.005). No ocular or systemic adverse effects were observed in either group.

CONCLUSION

Supplemental MPL in eyes with DME may decrease the burden of the aflibercept injection frequency while resulting in comparable anatomical and visual outcomes.

Early versus late switch: How long should we extend the anti-vascular endothelial growth factor therapy in unresponsive diabetic macular edema patients?

PURPOSE

To compare the results of early versus late switch to the dexamethasone intravitreal implant Ozurdex^® in patients with diabetic macular edema who had a poor response to vascular endothelial growth factor inhibitors.

METHODS

Retrospective and single-center study conducted, in a real setting, on consecutive diabetic macular edema patients who were switch to an intravitreal dexamethasone implant after a poor response to anti-vascular endothelial growth factor treatment. Study sample was divided into two groups: (1) early-switch group, included those eyes who received three anti-vascular endothelial growth factor injections before switch and (2) late-switch group, included those eyes that received six or more anti-vascular endothelial growth factor injections before switch. The primary end-point was the difference in mean change in best-corrected visual acuity and in central subfoveal thickness.

RESULTS

A total of 69 (31 early-switch group and 38 late-switch group) eyes were included. In the early-switch group, median (25-75 quartile range) best-corrected visual acuity significantly increase from 0.2 (0.2-0.5) at baseline to 0.4 (0.3 -0.7) at month 24 (p = 0.0043). Whereas, in the late-switch group, best-corrected visual acuity did not increase (p = 0.8602). Central subfoveal thickness was significantly reduced in both early- and late-switch groups, p = 0.0002 and 0.0038, respectively. The proportion of eyes obtaining a central subfoveal thickness reduction ⩾ 10% was significantly greater in the early-switch group than in the late-switch group (71.0% vs 47.4%, respectively, p = 0.0498). Three (9.7%) and 10 (26.3%) eyes have developed ocular hypertension during the study in the early- and late-switch groups, respectively, p = 0.0816.

CONCLUSION

Early switch to Ozurdex in patients who did not adequately respond to anti-vascular endothelial growth factor therapy provided better functional and anatomical outcomes.

Human vitreous in proliferative diabetic retinopathy: Characterization and translational implications

Diabetic retinopathy (DR) is one of the leading causes of visual impairment in the working-age population. DR is a progressive eye disease caused by long-term accumulation of hyperglycaemia-mediated pathological alterations in the retina of diabetic patients. DR begins with asymptomatic retinal abnormalities and may progress to advanced-stage proliferative diabetic retinopathy (PDR), characterized by neovascularization or preretinal/vitreous haemorrhages. The vitreous, a transparent gel that fills the posterior cavity of the eye, plays a vital role in maintaining ocular function. Structural and molecular alterations of the vitreous, observed during DR progression, are consequences of metabolic and functional modifications of the retinal tissue. Thus, vitreal alterations reflect the pathological events occurring at the vitreoretinal interface. These events are caused by hypoxic, oxidative, inflammatory, neurodegenerative, and leukostatic conditions that occur during diabetes. Conversely, PDR vitreous can exert pathological effects on the diabetic retina, resulting in activation of a vicious cycle that contributes to disease progression. In this review, we recapitulate the major pathological features of DR/PDR, and focus on the structural and molecular changes that characterize the vitreal structure and composition during DR and progression to PDR. In PDR, vitreous represents a reservoir of pathological signalling molecules. Therefore, in this review we discuss how studying the biological activity of the vitreous in different in vitro, ex vivo, and in vivo experimental models can provide insights into the pathogenesis of PDR. In addition, the vitreous from PDR patients can represent a novel tool to obtain preclinical experimental evidences for the development and characterization of new therapeutic drug candidates for PDR therapy.

Dexamethasone Implant in Patients with Diabetic Macular Edema Resistant to Anti-VEGF Therapy

Objectives:

To investigate the efficacy of single dose intravitreal dexamethasone implant in patients with diabetic macular edema (DME) resistant to anti-VEGF therapy.

Materials and Methods:

Twenty eyes of 14 patients (8 male, 6 female; mean age, 65±5.7 years) with DME resistant to intravitreal ranibizumab injections were studied. A single intravitreal dexamethasone implant was injected into each eye and patients were followed up for 6 months. Response to therapy was assessed monthly by measuring intraocular pressure (IOP), best-corrected visual acuity (BCVA), and central foveal thickness (CFT).

Results:

Baseline (before injection) IOP was 14.9±2.7 mmHg and did not change significantly in the six months following injection. Baseline BCVA was 1.04±0.35 LogMAR and improved to 0.86±0.31 at month 1 without statistical significance (p=0.056). CFT was significantly lower in all monthly measurements compared to its baseline value of 682.2±229.2 μm. During the follow-up period, endophthalmitis, significant cataract, or rhegmatogenous retinal detachment were not detected.

Conclusion:

Intravitreal dexamethasone implant injection is associated with significant CFT reduction for up to six months without causing any complications. Although BCVA did not improve in parallel with the CFT reduction, intravitreal dexamethasone implant should be considered as an effective and safe treatment option in the management of DME patients resistant to anti-VEGF injections.

Dose-response analysis of ranibizumab as-needed regimens for visual improvement in patients with diabetic macular edema using a modelling approach

BACKGROUND

Ranibizumab and aflibercept are anti-vascular endothelial growth factor therapies for diabetic macular edema (DME) but have only been directly compared in one study: the Protocol T study, a 24-month randomized controlled trial which compared the safety and efficacy of three anti-VEGF agents (ranibizumab 0.3 mg, aflibercept 2.0 mg and bevacizumab 1.25 mg). The ranibizumab dose used in Protocol T is not licensed for use outside of the US, where a higher ranibizumab dose of 0.5 mg is approved. Therefore, the relevance of the head-to-head Protocol T study findings to healthcare providers in Europe is limited. The purpose of this research was to predict the visual outcomes that may have been achieved in Protocol T with ranibizumab 0.5 mg.

METHODS

A simplified dose-response model was constructed to describe the relationship between average monthly dose and one-year best corrected visual acuity (BCVA) change from baseline. A linear mixed effects model was evaluated and Bayesian Monte-Carlo Markov chains method was used to estimate the model parameters.

RESULTS

If ranibizumab 0.5 mg PRN had been studied in Protocol T, it would have resulted in a BCVA gain of 14-15 early treatment diabetic retinopathy study (ETDRS) letters; 3-4 letters more than the actual BCVA gain reported with ranibizumab 0.3 mg PRN. In Protocol T patients with poor baseline BCVA (<69 letters), a similar additional letter gain would have been achieved.

CONCLUSION

The relevance of the Protocol T study findings are limited due to the use of ranibizumab 0.3 mg PRN which, based on the modelling approach reported herein, resulted in sub-optimal visual gains.

Outcome and Predictors for 2-Year Visual Acuity in Eyes with Diabetic Macular Edema Treated with Ranibizumab

Purpose: To determine the role of baseline characteristics in predicting visual outcome in patients with diabetic macular edema (DME) treated with ranibizumab. Methods: A review was carried out of the charts of 97 eyes that received pro re nata (PRN) intravitreal ranibizumab (IR) 0.5 mg treatment for DME. The change in the mean best-corrected visual acuity (BCVA) was analyzed. The baseline demographics and ocular and optic coherence tomography findings were analyzed to determine the association with the 2-year visual acuity (VA). Results: BCVA increased from 0.54 ± 0.2 (0.05-1.0) to 0.41 ± 0.3 (0.0-1.0) log of the minimum angle of resolution (P < 0.001). Age (P = 0.012), gender (P = 0.018), baseline BCVA (P < 0.001), presence of leaking microaneurysms (MA) (P = 0.018), development of vitreomacular traction (VMT) (P = 0.001), development of posterior vitreous detachment (PVD) (P = 0.040), and disruption of ellipsoid zone (EZ) (P = 0.007) were found as predictors of 2-year VA. There was no association between visual outcome and the other characteristics. Conclusions: PRN treatment of IR provides significant benefits in VA gain and anatomic improvement in eyes with DME. Older age, female sex, lower baseline VA, VMT development, and EZ disruption are predictors for the poor final VA. Development of PVD and leaking MA are predictors for the good final VA.

Unfolded Protein Response Pathways Correlatively Modulate Endoplasmic Reticulum Stress Responses in Rat Retinal Müller Cells

Background

Endoplasmic reticulum stress (ERS) in the retinal Müller cells is a key factor contributing to the retinal inflammation and vascular leakage in diabetic retinopathy (DR). This study was to investigate the underlying mechanisms through which the 3 main unfolded protein response (UPR) pathways regulate ERS and to examine the expression levels of vascular endothelial growth factor (VEGF) in Müller cells in vitro.

Methods

Rat Müller cell lines were stimulated with high glucose to mimic a diabetic environment in vitro. PKR-like endoplasmic reticulum kinase (PERK), inositol-requiring enzyme 1 (IRE1) and activating transcription factor 6 (ATF6) were downregulated or upregulated with shRNA or overexpression plasmids. The transfected Müller cells were cultivated in high glucose medium for 48 hours. Expression of glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), X-box binding protein 1 (XBP1), ATF6, and VEGF was examined with immunofluorescence and western blot.

Results

Our data indicated that ERS was found in both high glucose and osmotic control groups. Overexpression or downregulation of UPR pathways effectively increased or reduced the production of GRP78, ATF4, XBP1, ATF6, and VEGF, respectively. These 3 signaling pathways had similar regulatory effects on VEGF.

Conclusion

The 3 UPR-mediated inflammatory pathways were dependent on each other. Inhibition any of these signaling pathways in UPR might be a potential therapeutic target for DR.

Three-dimensional analysis of morphologic changes and visual outcomes in diabetic macular edema

PURPOSE

To investigate the association of retinal fluid volume with the visual and anatomic outcomes of patients with diabetic macular edema (DME) after treatment with bevacizumab.

STUDY DESIGN

Retrospective observational study.

METHODS

We retrospectively analyzed 65 eyes of 58 DME patients treated with bevacizumab. The volumes of the inner intraretinal fluid (IRF) in the inner nuclear layer (INL), outer IRF in the outer plexiform layer (OPL)/outer nuclear layer (ONL), and subretinal fluid (SRF) were calculated. The correlations between the baseline fluid volumes and best-corrected visual acuity (BCVA), area of disorganization of the retinal inner layers (DRIL), disrupted external limiting membrane (ELM), and disrupted ellipsoid zone (EZ) at 12 months after treatment were assessed.

RESULTS

The baseline volume of the inner IRF correlated with poor BCVA at the final visit (r = 0.52, P < .001) whereas the baseline volume of the outer IRF and SRF volume did not show a significant correlation with BCVA at the final visit (P = .07 and P = .61, respectively). The improvement in BCVA correlated with the reduction in the baseline volume of the inner IRF and outer IRF (r = 0.25, P = .04 and r = 0.36, P = .003), but not with the SRF volume (P = .59). The baseline volume of the inner IRF correlated positively with the area of DRIL and the disrupted ELM at the final visit (r = 0.56, P < .001 and r = 0.25, P = .04, respectively). Such relationship remained in each quadrant of the macula (P < .005 for all quadrants).

CONCLUSION

The baseline volume of the inner IRF correlated with a poor visual outcome, an increased DRIL area, and a more disrupted ELM area in patients with DME after treatment with bevacizumab.

Toxic anterior segment syndrome: A review

Toxic anterior segment syndrome is a surgical complication characterized by a noninfectious anterior chamber inflammatory reaction having multiple etiologies. The clinical signs (prominent limbus-to-limbus corneal edema, anterior chamber inflammation) and symptoms (decreased visual acuity, discomfort) generally occur within the first 12-48 hours after intraocular surgery. Most patients achieve good clinical and visual outcomes when there is a prompt clinical diagnosis and adequate treatment. We review the literature on toxic anterior segment syndrome, emphasizing its etiology, pathophysiology, and clinical and surgical management, as well as prognosis and sequelae. Our goal is to reduce the frequency of toxic anterior segment syndrome by highlighting the importance of prevention, early recognition, and distinguishing toxic anterior segment syndrome from infectious endophthalmitis.

Intravitreal dexamethasone implant Ozurdex® in naïve and refractory patients with different subtypes of diabetic macular edema

Background

Diabetic macular edema (DME) can be treated with different alternatives, among them Dexamethasone intravitreal implant 0.7 mg (DEX 0.7) has demonstrated that may improve both central macular thickness (CMT) and best corrected visual acuity (BCVA). This study aimed to evaluate the effect of the intravitreal dexamethasone implant Ozurdex® in patients with different subtypes of diabetic macular edema over a 6-month follow-up period.

Methods

Eighty-four (29 naïve and 55 previously treated) eyes were included in this retrospective study. For each patient, the BCVA [Early Treatment Diabetic Retinopathy Study (ETDRS) charts] and macular thickness on optical coherence tomography (OCT) at baseline visit and within the 2nd, 4th, and 6th months of follow-up were obtained. The main outcomes measurements were the mean change in BCVA and in CMT with respect to the baseline value. The percentage of patients gaining ≥5 letters and ≥ 10 letters in BCVA was also analyzed. Results: A total of 84 eyes, 29 (34.5%) naïve and 55 (65.5%) non-naïve, from 69 patients were included in the study. BCVA at baseline was 58.8 (16.4) and 61.8 (11.6) in naïve and refractory patients, respectively, p = 0.4513. At every visit, BCVA significantly improved from baseline in naïve and non-naïve eyes (p < 0.0001 and p = 0.0003, respectively; Friedman rank sum test). At baseline, the mean CMT was 466.2 (189.7) μm and 448.1 (110.7) μm in the naïve and non-naïve patients, respectively (p = 0.5830); and decreased to 339.3 (92.5) μm and 357.5 (79.1) μm, respectively (p = 0.0004 and p < 0.0001, respectively, Wilcoxon signed-rank test). The proportion of patients gaining ≥10 letters was significantly greater in the naïve group, p = 0.0199.

Conclusion

The intravitreal dexamethasone implant (Ozurdex) is effective for the treatment of diabetic macular edema, even in refractory cases that have failed to respond to previous therapies.

Role of Inflammation in Classification of Diabetic Macular Edema by Optical Coherence Tomography

Diabetic macular edema (DME) is the abnormal accumulation of fluid in the subretinal or intraretinal spaces in the macula in patients with diabetic retinopathy and leads to severely impaired central vision. Technical developments in retinal imaging systems have led to many advances in the study of DME. In particular, optical coherence tomography (OCT) can provide longitudinal and microstructural analysis of the macula. A comprehensive review was provided regarding the role of inflammation using OCT-based classification of DME and current and ongoing therapeutic approaches. In this review, we first describe the pathogenesis of DME, then discuss the classification of DME based on OCT findings and the association of different types of DME with inflammation, and finally describe current and ongoing therapeutic approaches using OCT-based classification of DME. Inflammation has an important role in the pathogenesis of DME, but its role appears to differ among the DME phenotypes, as determined by OCT. It is important to determine how the different DME subtypes respond to intravitreal injections of steroids, antivascular endothelial growth factor agents, and other drugs to improve prognosis and responsiveness to treatment.

Central subfield thickness and cube average thickness as bioimaging biomarkers for ellipsoid zone disruption in diabetic retinopathy

BACKGROUND

To evaluate the association of central subfield thickness (CST) and cube average thickness (CAT) with ellipsoid zone (EZ) disruption on spectral domain optical coherence tomography (SD-OCT) in patients of diabetic retinopathy (DR).

METHODS

Cross sectional study including consecutive patients of type 2 diabetes mellitus [without DR (No DR, n = 97); non-proliferative DR (NPDR, n = 91); proliferative DR (PDR, n = 83)] and healthy controls (n = 82) was undertaken. CST and CAT values were measured using SD-OCT. Data was analyzed using Chi square test, ANOVA and multivariate analysis. Discriminant values of CST and CAT for EZ disruption were evaluated using receiver operator characteristic curve. Area under curve (AUC) was computed.

RESULTS

Mean CAT and CST values in the study subjects showed an incremental trend. Multivariate ordinal logistic regression analysis showed increase in CST (OR = 1.022, p < 0.001) and CAT (OR = 1.029, p < 0.001) as significant independent predictors of EZ disruption. Area under curve showed excellent predictive results of CST (AUC = 0. 943 ± 0.021, 95% CI, 0.902-0.984, p < 0.05) and CAT (AUC = 0.959 ± 0.012, 95% CI 0.936-0.982, p < 0.05), as bioimaging biomarkers, for EZ disruption.

CONCLUSION

Increase in CST and CAT is associated with increased odds of EZ disruption and these macular parameters serve as bioimaging biomarkers for EZ disruption in DR.