Advances in the management of diabetic macular oedema based on evidence from the Diabetic Retinopathy Clinical Research Network

[Diabetic Macular Edema]

Diabetic macular edema (DME) is a chronic retinal disease, which requires intensive clinical monitoring. Within the last ten years the intravitreal anti-VEGF (vascular endothelial growth factor) therapy has become the standard of care to improve and stabilize vision in patients with centre involving DME. Long-acting intravitreal corticosteroids can achieve similar visual results with fewer injection rates. Because of steroid-induced side effects (progression of cataract, glaucoma) these drugs are regarded as second-line medication. Since the introduction of anti-VEGF-medication the focal laser photocoagulation is no longer considered as first-line therapy for DME. However, a focal laser treatment can sometimes be a possible alternative in specific situations. In patients with proliferative diabetic retinopathy and DME, the intravitreal anti-VEGF therapy is approved for both conditions. In ischemic maculopathy the functional outcome is restricted. For the indication of anti-VEGF-treatment for DME with accompanying central ischemia not only visual acuity and optical coherence tomography parameters should be considered, the amount of ischemia seen on fluorescein angiography should also be taken into account. In tractional macular edema due to epiretinal membranes and vitreomacular adhesions a pars-plana vitrectomy with membrane peeling is indicated.

Diabetisches Makulaödem

Das diabetische Makulaödem (DMÖ) ist für den Großteil der Visusminderungen bei Diabetikern verantwortlich. Eine Reduktion der Sehschärfe durch ein DMÖ kann schon im milden nicht-proliferativen Stadium der diabetischen Retinopathien (DR) auftreten 1. Der chronische Verlauf der diabetischen Makulopathie erfordert ein intensives klinisches Monitoring über einen langen Zeitraum. Dieser Beitrag gibt einen Überblick über das diagnostische und therapeutische Management beim Vorliegen eines DMÖ.

Visual Acuity Gain Profiles and Anatomical Prognosis Factors in Patients with Drug-Naive Diabetic Macular Edema Treated with Dexamethasone Implant: The NAVEDEX Study

Brief Summary Statement

NAVEDEX (NAive diabetic macular Edema treated by DEXamethasone implant) study is a real-life multi-center study on drug-naive diabetic macular edema treated by Dexamethasone-implant. Two different visual acuity gain (VA) profiles were identified, based on baseline visual acuity (VA). Baseline disorganization of retinal inner layers or ellipsoid zone alterations (EZAs) negatively influence final VA but has no impact on VA gain.

Abstract

The purpose of this study is to evaluate the visual acuity (VA) gain profiles between patients with drug-naive diabetic macular edema (DME) treated by dexamethasone implant (DEX-implant) and assess the baseline anatomical and functional factors that could influence the response to the treatment in real-life conditions. A retrospective, multi-center observational study included 129 eyes with drug-naive DME treated by DEX-implant. The Median follow-up was 13 months. Two groups of VA gain trajectories were identified—Group A, with 71% (n = 96) of patients whose average VA gain was less than five letters and Group B, with 29% (n = 33) of patients with an average gain of 20 letters. The probability of belonging to Group B was significantly higher in patients with baseline VA < 37 letters (p = 0.001). Ellipsoid zone alterations (EZAs) or disorganization of retinal inner layers (DRILs) were associated with a lower final VA (53.0 letters versus 66.4, p = 0.002) but without a significant difference in VA gain (4.9 letters versus 6.8, p = 0.582). Despite a low baseline VA, this subgroup of patients tends to have greater visual gain, encouraging treatment with DEX-implant in such advanced-stage disease. However, some baseline anatomic parameters, such as the presence of EZAs or DRILs, negatively influenced final vision.

Effectiveness of Intravitreal Ranibizumab in Nonvitrectomized and Vitrectomized Eyes with Diabetic Macular Edema: A Two-Year Retrospective Analysis

The aim of this study was to compare the effectiveness of intravitreal ranibizumab (IVR) injections for the treatment of diabetic macular edema (DME) in eyes with and without previous vitrectomy. The medical records of 28 eyes (11 vitrectomized and 17 nonvitrectomized) of 28 patients (mean age, 59.0 ± 9.6 years; male to female ratio 1 : 1) who were diagnosed with DME and had received IVR treatment were reviewed retrospectively. The indications of vitrectomy in 11 vitrectomized eyes were intravitreal hemorrhage (n = 8) and epiretinal membrane (n = 3). The best-corrected visual acuity (BCVA), central macular thickness (CMT), and total macular volume (TMV) were measured at baseline and at months 6, 12, 18, and 24 of the follow-up. The number of IVR injections, the duration between diagnosis of DME and IVR injection, and the hemoglobin A1c (HbA1c) level at baseline were also recorded. Baseline demographics, HbA1c, BCVA, CMT, and TMV values were similar between two groups (p>0.05). The duration between diagnosis of DME and IVR injections was similar in both groups (16 ± 5 months vs. 13 ± 4 months, respectively; p=0.11). IVR injection was performed 6.3 times in vitrectomized eyes and 6.1 times in nonvitrectomized eyes during the 24-month period (p>0.05). The mean BCVA improved significantly during the 24-month period in both groups. The improvements in BCVA, in CMT, and in TMV were more significant at month 6 (p=0.036) group, at month 12 (p=0.013), at month 12 (p=0.021), and month 24 (p=0.021) in nonvitrectomized eyes, respectively, while there was no difference in improvements of BCVA, CMT, and TMV in vitrectomized group at each visit. Treatment effected by time in terms of BCVA, CMT, and TMV values in all groups (p=0.0004, p<0.0001, p<0.0001, respectively), not by time-group interaction and group (all p values >0.05). In conclusion, IVR treatment for DME is equally effective in both groups. However, the response to treatment is seen earlier in nonvitrectomized eyes compared to vitrectomized eyes.

Rebound Phenomenon after Intravitreal Injection of Triamcinolone Acetonide for Macular Edema

INTRODUCTION

The aim of this article was to report on a rebound phenomenon after intravitreal triamcinolone acetonide (IVTA) injection for macular edema secondary to diabetic retinopathy (DR) and central or branch retinal vein occlusion (CRVO/BRVO).

METHODS

The data were analyzed retrospectively. Complete ophthalmic examinations, including spectral domain optical coherence tomography, were performed before and 2 months after IVTA injection. The incidence of a rebound phenomenon was defined as an increase in central retinal thickness of >10% from baseline at 2 months after IVTA injection.

RESULTS

This retrospective study included 211 consecutive patients (268 eyes). One hundred ninety (71.2%), 39 (14.6%), and 39 (14.6%) eyes had macular edema (ME) due to DR, CRVO, and BRVO. In total, 9.7% of the eyes showed a rebound phenomenon (DR: 9.5%, CRVO: 5.2%, BRVO: 15.4%). The mean number of prior injections of vascular endothelial growth factor inhibitor or corticosteroid agent was statistically significantly higher in the rebound group (6.8 vs. 5.3) than in the nonrebound group (p = 0.01).

CONCLUSION

Our study shows that 9.7% of the eyes with ME secondary to DR and RVO developed a rebound phenomenon following IVTA injection, limiting its therapeutic effect. We found an increased number of prior intravitreal pharmacotherapy to be a risk factor for a rebound phenomenon.

Correlations of blood lipids with early changes in macular thickness in patients with diabetes

PURPOSE

This study aimed to investigate the correlations of blood lipids with changes in macular volume and thickness in patients with diabetes.

METHODS

Central subfield macular thickness (CSMT) and central subfield macular volume (CSMV) were measured in 85 patients with type 2 diabetes (DM2) using spectral-domain optical coherence tomography (SD-OCT). In addition, serum creatinine (Cr), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC), glycated hemoglobin (HbA1c), and proteinuria were measured in all patients.

RESULTS

The mean CSMT of the 85 patients was 272.8±16.9μm, and CSMV was 215.1±14.6×10^-3mm³. TC, LDLC, HbA1c, and proteinuria were closely correlated to CSMT, and HDLC, HbA1c, and proteinuria were correlated to CSMV. After adjustment for sex, age, DM2 course, proteinuria, and HbA1c, LDLC was significantly correlated to CSMT (95% confidence interval (CI), 1.93-11.05, P=0.008) and CSMV (95% CI, 0.92-8.41, P=0.021); however, HDLC, TC, and TG showed no significant correlation with CSMT or CSMV.

CONCLUSIONS

Increased LDLC was closely correlated to changes in CSMT and CSMV in early diabetic patients, and increased CSMT was also accompanied by increased LDLC; therefore, this type of patient would be more likely to develop macular edema.

Burden Of Treatment Among Patients Undergoing Intravitreal Injections For Diabetic Macular Oedema In Australia

AIM

The incidence and prevalence of diabetes mellitus (DM) in Australia is increasing. Thus, it is essential that practitioners appreciate the impending effect that increasing incidence of diabetes has on patients and the wider community. Accordingly, this study examines the humanistic burden of intravitreal injections for the treatment of diabetic macular oedema (DMO) among several health variables.

METHODS

Survey data from a representative sample of Australian adults undergoing treatment for DMO were examined. Respondents participated via an online survey recruited by means of a national online consumer panel and the New South Wales and Victorian Diabetes Foundations. The online survey included questions relating to the humanistic burden of disease, such as the emotional and physical impact of intravitreal injection therapy; the practical impacts of injection therapy; and to identify potential improvements to treatment regimens.

RESULTS

Sixty-five participants took part in the online survey. Of these, 49% had their most recent injection <1 month prior to completing the survey. The mean age was 52.5 years, with the majority of patients in full-time work. A substantial proportion of participants had several comorbidities, with a significantly high Charlson comorbidity index of 2.7. Participants reported the main burden of DMO care was the direct cost of medical treatment and the time burden demanded upon their carers. Results suggest that the overall burden is significant for those with diabetes and increases as additional complications of diabetes occur.

CONCLUSION

These results suggest that treatment strategies for DMO should consider clinical, humanistic and economic burden and patients should be educated on the roles of complications in disease outcomes. Less frequent treatment regimens could also reduce the economic burden and assist in decreasing the effect on health care resources, relevant to the escalation in the prevalence of diabetes.

Simulation of panretinal laser photocoagulation using geometric methods for calculating the photocoagulation index

PURPOSE

To establish geometrically based methods for simulating panretinal laser photocoagulation (PRP) for the photocoagulation index.

METHODS

A formula for calculating the curved surface area of a spherical dome was used for the simulation. If the radius of the dome is c and the height of the dome is h, then the curved surface area (S) of the dome is S = π (c2 + h2). We calculated the area of the whole retina using this formula and the anatomical dimensions of the standard eyeball. To simulate PRP with a 400-μm spot on the retina with 1-spot spacing, we drew 400-μm-diameter circles, separated by 400 μm, on a retinal map. We calculated the ratio of the total retinal photocoagulated area to the whole retina, termed the photocoagulation index, in order to investigate the impact of the extent of the photocoagulated area and the pulse duration on PRP.

RESULTS

The whole retinal area was 1,092 mm2. The numbers of spots in the scattered and full-scattered PRP were 1,222 and 1,814, respectively. The photocoagulation index was 14.1% and 20.9% for scattered and full-scattered PRP, respectively. These values changed to 14.3% (5.6%) and 21.3% (8.3%), respectively, for PRP with a 100-ms pulse or a 20-ms pulse.

CONCLUSIONS

This method will be useful for investigating the impact of various PRP parameters (duration, spacing, intensity of burns, extent of photocoagulated area, etc.) on the photocoagulation index.

Novel strategies for the treatment of diabetic macular edema

Macular edema such as diabetic macular edema (DME) and diabetic retinopathy are devastating back-of-the-eye retinal diseases leading to loss of vision. This area is receiving considerable medical attention. Posterior ocular diseases are challenging to treat due to complex ocular physiology and barrier properties. Major ocular barriers are static (corneal epithelium, corneal stroma, and blood-aqueous barrier) and dynamic barriers (blood-retinal barrier, conjunctival blood flow, lymph flow, and tear drainage). Moreover, metabolic barriers impede posterior ocular drug delivery and treatment. To overcome such barriers and treat back-of-the-eye diseases, several strategies have been recently developed which include vitreal drainage, laser photocoagulation and treatment with biologics and/or small molecule drugs. In this article, we have provided an overview of several emerging novel strategies including nanotechnology based drug delivery approach for posterior ocular drug delivery and treatment with an emphasis on DME.

Enface Thickness Mapping and Reflectance Imaging of Retinal Layers in Diabetic Retinopathy

Purpose

To present a method for image segmentation and generation of enface thickness maps and reflectance images of retinal layers in healthy and diabetic retinopathy (DR) subjects.

Methods

High density spectral domain optical coherence tomography (SDOCT) images were acquired in 10 healthy and 4 DR subjects. Customized image analysis software identified 5 retinal cell layer interfaces and generated thickness maps and reflectance images of the total retina (TR), inner retina (IR), outer retina (OR), and the inner segment ellipsoid (ISe) band. Thickness maps in DR subjects were compared to those of healthy subjects by generating deviation maps which displayed retinal locations with thickness below, within, and above the normal 95% confidence interval.

Results

In healthy subjects, TR and IR thickness maps displayed the foveal depression and increased thickness in the parafoveal region. OR and ISe thickness maps showed increased thickness at the fovea, consistent with normal retinal anatomy. In DR subjects, thickening and thinning in localized regions were demonstrated on TR, IR, OR, and ISe thickness maps, corresponding to retinal edema and atrophy, respectively. TR and OR reflectance images showed reduced reflectivity in regions of increased thickness. Hard exudates appeared as hyper-reflective spots in IR reflectance images and casted shadows on the deeper OR and ISe reflectance images. The ISe reflectance image clearly showed the presence of focal laser scars.

Conclusions

Enface thickness mapping and reflectance imaging of retinal layers is a potentially useful method for quantifying the spatial and axial extent of pathologies due to DR.