Efficacy of vitrectomy combined with an intraoperative dexamethasone implant in refractory diabetic macular edema

Bibliometric and visualized analysis of DME from 2012 to 2022

BACKGROUND

Diabetic macular edema (DME) is the main cause of irreversible vision loss in patients with diabetes mellitus (DM), resulting in a certain burden to patients and society. With the increasing incidence of DME, more and more researchers are focusing on it.

METHODS

The papers related to DME between 2012 and 2022 from the Web of Science core Collection were searched in this study. Based on CiteSpace and VOS viewer, these publications were analyzed in terms of spatiotemporal distribution, author distribution, subject classification, topic distribution, and citations.

RESULTS

A total of 5165 publications on DME were included. The results showed that the research on DME is on a steady growth trend. The country with the highest number of published documents was the US. Wong Tien Yin from Tsinghua University was the author with the most published articles. The journal of Retina, the Journal of Retinal and Vitreous Diseases had a large number of publications. The article "Mechanisms of macular edema: Beyond the surface" was the highly cited literature and "Aflibercept, bevacizumab, or ranibizumab for diabetic macular edema" had the highest co-citation frequency. The treatment, diagnosis, pathogenesis, as well as etiology and epidemiological investigation of DME, have been the current research direction. Deep learning has been widely used in the medical field for its strong feature representation ability.

CONCLUSIONS

The study revealed the important authoritative literature, journals, institutions, scholars, countries, research hotspots, and development trends in in the field of DME. This indicates that communication and cooperation between disciplines, universities, and countries are crucial. It can advance research in DME and even ophthalmology.

Persistent diabetic macular edema: Definition, incidence, biomarkers, and treatment methods

Intravitreal antivascular endothelial growth factor (anti-VEGF) treatment has drastically improved the visual and anatomical outcomes in patients with diabetic macular edema (DME); however, success is not always guaranteed, and a proportion of these eyes demonstrate persistent DME (pDME) despite intensive treatment. While standardized criteria to define these treatment-resistant eyes have not yet been established, many studies refer to eyes with no clinical response or an unsatisfactory partial response as having pDME. A patient is considered to have pDME if the retinal thickness improves less than 10-25% after 6 months of treatment. A range of treatment options have been recommended for eyes with pDME, including switching anti-VEGF agents, using corticosteroids and/or antioxidant drugs in adjunct with anti-VEGF therapy, and vitrectomy. In addition, multimodal imaging of DME eyes may be advantageous in predicting the responsiveness to treatment; this is beneficial when initiating alternative therapies. We explore the literature on persistent DME regarding its defining criteria, incidence, the baseline biological markers that may be useful in anticipating the response to treatment, and the available treatment options.

Pharmacotherapy as an adjunct to vitrectomy

Vitreoretinal surgery has advanced extensively from the first days of vitrectomy. During the last decade, new developments in intravitreal pharmacotherapy have created new opportunities to enhance the surgical outcomes of our patients. In this article, we review and discuss some of the supporting evidence of different pharmacotherapies that may be used as an adjunct to vitrectomy for select common etiologies. Triamcinolone acetonide, dexamethasone, and angiogenesis inhibitors are among the most commonly used drugs given their safety profile and proven efficacy. Other pharmaceuticals have also shown promising results in small studies. The adoption of individualized medical treatments prior, during, and after vitrectomy will continue to increase as new evidence supporting the benefit of pharmacotherapy as an adjunct to vitrectomy becomes available.

Three-year outcomes of vitrectomy combined with intraoperative dexamethasone implantation for non-tractional refractory diabetic macular edema

This retrospective, consecutive interventional study investigated the long-term clinical outcomes of combined vitrectomy with intraoperative dexamethasone implants for non-tractional refractory diabetic macular edema (DME). The study included 43 eyes from 39 participants with DME that had continued for more than 6 months despite repeated non-surgical treatment. Postoperative changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT) were evaluated over 3 years. A Kaplan-Meier curve was obtained for any additional non-surgical treatment, and the average number of non-surgical treatments required for DME before and after surgery was compared. Other postsurgical complications were also investigated. The logMAR BCVA improved from 0.526 ± 0.417 (20/67) preoperatively to 0.294 ± 0.374 (20/39) 3 years postoperatively (p < 0.001, generalized estimating equation). The CMT improved from 478 ± 122 μm preoperatively to 314 ± 90 μm 3 years postoperatively (p < 0.001, generalized estimating equation). Additional non-surgical treatment was not required for 29 (67%) eyes. The average number of annual non-surgical treatments decreased from 5.04 times preoperatively to 0.34 times postoperatively. Seventeen (40%) eyes developed temporary ocular hypertension after surgery, which normalized after antihypertensive eye drop instillation. In conclusion, vitrectomy combined with intraoperative dexamethasone implantation provides satisfactory long-term clinical outcomes for non-tractional refractory DME while reducing the number of intraocular injections for DME.

Intravitreal Dexamethasone Implant as a Sustained Release Drug Delivery Device for the Treatment of Ocular Diseases: A Comprehensive Review of the Literature

Drug delivery into the vitreous chamber remains a great challenge in the pharmaceutical industry due to the complex anatomy and physiology of the eye. Intravitreal injection is the mainstream route of drug administration to the posterior segment of the eye. The purpose of this review is to assess the current literature about the widening use of the intravitreal 0.7 mg dexamethasone (Dex) implant, and to provide a comprehensive collection of all the ocular disorders that benefit from Dex administration. Although anti-vascular endothelial growth-factors (VEGFs) have been largely indicated as a first-choice level, the Dex implant represents an important treatment option, especially in selected cases, such as vitrectomized eyes or patients in whom anti-VEGF failed or are contraindicated. In this article, the safety profile as well as the list of the possible complications related to intravitreal Dex injection are also discussed.

Diabetes and diabetic retinopathy in patients undergoing cataract surgery: a prevalence study-DiCat study report #2

PURPOSE

To report on the prevalence of diabetes, diabetic macula oedema (DME) and retinopathy and their respective grading in a large cohort of patients undergoing cataract surgery.

METHODS

Data on previous diagnosis of diabetes, fasting glucose, glycated haemoglobin, presence and type of retinopathy and other maculopathy of 3657 patients over 55 years of age undergoing cataract surgery in 13 centres scattered throughout Italy were analysed.

RESULTS

A total of 20.4% of patients were known diabetics and 27.9% of diabetics showed signs of retinopathy. Haemoglobin A1C was higher than 48 mmol/L (6.5%) in 32% of diabetics and 2.4% non-diabetics. Fasting blood glucose level was higher than 120 mg/dL in 4.3% non-diabetics and 50% diabetics. Duration of diabetes did not significantly correlate with either fasting glucose or glycated haemoglobin, while higher grades of diabetic retinopathy were significantly more prevalent as duration of disease increased. DME was present in almost 40% of diabetics and 22% of patients showed non-diabetic maculopathy.

DISCUSSION

Diabetic retinopathy and DME worsen after cataract extraction thus complicating long-term prognosis and requiring expensive injective therapy. Since unknown diabetics represent 2-4% of the many million cataract candidates and even known diabetics show poor metabolic control and high rates of DME, preoperative medical testing and accurate retinopathy screening may prove both ethically necessary and cost-effective.

Dexamethasone Provides Effective Immunosuppression for Improved Survival of Retinal Organoids after Epiretinal Transplantation

We investigated the efficacy of the immunosuppressants rapamycin (RAP) and dexamethasone (DEX) in improving the survival of retinal organoids after epiretinal transplantation. We first compared the immunosuppressive abilities of DEX and RAP in activated microglia in an in vitro setting. Following this, we used immunofluorescence, real-time polymerase chain reaction, and flow cytometry to investigate the effects of DEX and RAP on cells in the retinal organoids. Retinal organoids were then seeded onto poly(lactic-co-glycolic) acid (PLGA) scaffolds and implanted into rhesus monkey eyes (including a healthy individual and three monkeys with chronic ocular hypertension (OHT) induction) and subjected to different post-operative immunosuppressant treatments; 8 weeks after the experiment, histological examinations were carried out to assess the success of the different treatments. Our in vitro experiments indicated that both DEX and RAP treatments were equally effective in suppressing microglial activity. Although both immunosuppressants altered the morphologies of cells in the retinal organoids and caused a slight decrease in the differentiation of cells into retinal ganglion cells, the organoid cells retained their capacity to grow and differentiate into retinal tissues. Our in vivo experiments indicate that the retinal organoid can survive and differentiate into retinal tissues in a healthy rhesus monkey eye without immunosuppressive treatment. However, the survival and differentiation of these organoids in OHT eyes was successful only with the DEX treatment. RAP treatment was ineffective in preventing immunological rejection, and the retinal organoid failed to survive until the end of 8 weeks. DEX is likely a promising immunosuppressant to enhance the survival of epiretinal implants.