Current epidemiology of diabetic retinopathy and diabetic macular edema

Knowledge, attitudes and eye health-seeking behaviours in a population-based sample of people with diabetes in rural China

AIMS

To assess knowledge of diabetes and acceptance of eye care among people with diabetes in rural China, to improve service uptake.

METHODS

Population-based study of people in Guangdong, China, with glycosylated haemoglobin A1c≥6.5% and/or known history of diabetes. Between August and November 2014, participants answered a questionnaire (based on Delphi process/previous focus groups) on medical history, demographic characteristics, self-rated health and vision, knowledge about diabetes and diabetic retinopathy, quality of local healthcare, barriers to treatment, likely acceptance of eye exams and treatment, and interventions rated most likely to improve service uptake. Presenting visual acuity was assessed, fundus photography performed and images graded by trained graders. Potential predictors of accepting care were evaluated and confounders adjusted for using logistic regression.

RESULTS

A total of 562 people (9.6% (256/5825), mean age 66.2±9.84 years, 207 (36.8%) men) had diabetes, 118 (22.3%) previously diagnosed. 'Very likely' or 'likely' acceptance of laser treatment (140/530=26.4%) was lower than for eye exams (317/530=59.8%, p<0.001). Predictors of accepting both exams and laser included younger age (p<.001) and prior awareness of diabetes diagnosis (p=0.004 and p=0.035, respectively). The leading barrier to receiving diabetes treatment was unawareness of diagnosis (409/454, 97.2%), while interventions rated most likely to improve acceptance of eye exams included reimbursement of travel costs (387/562, 73.0%), video or other health education (359/562, 67.7%) and phone call reminders (346/562, 65.3%).

CONCLUSIONS

Improving diagnosis of diabetes, along with incentives, education and communication strategies, is most likely to enhance poor acceptance of diabetic eye care in this setting.

Systemic and ocular diseases associated with the development of diabetic macular edema among Japanese patients with diabetes mellitus

Background

Diabetic macular edema (DME) causes severe vision loss among patients with diabetes mellitus (DM). We aimed to investigate systemic and ocular diseases associated with the development of DME in a Japanese population.

Methods

A total of 3.11 million Japanese subjects who were registered in the database of the Japan Medical Data Center from 2005 to 2014 were analyzed. Subjects with DM were defined as individuals who had been prescribed any therapeutic medications for DM, and associated diseases were analyzed. The periods assessed were one year before the development of DME among patients with DME and one year before the last visit to an ophthalmic clinic among patients without DME.

Results

A total of 17,403 patients with DM satisfied the inclusion and exclusion criteria, and 420 patients developed DME. Univariate analysis revealed significant associations between 55 diseases, including 39 systemic and 16 ocular diseases, and DME development. Logistic analysis identified 21 systemic diseases and 10 ocular diseases as significant factors associated with DME development.

Conclusion

Various types of systemic and ocular diseases are associated with DME development. Subjects with DM who present these risk factors must be carefully monitored to prevent visual impairment.

Retinal Physiology and Circulation: Effect of Diabetes

In this article, we present a discussion of diabetes and its complications, including the macrovascular and microvascular effects, with the latter of consequence to the retina. We will discuss the anatomy and physiology of the retina, including aspects of metabolism and mechanisms of oxygenation, with the latter accomplished via a combination of the retinal and choroidal blood circulations. Both of these vasculatures are altered in diabetes, with the retinal circulation intimately involved in the pathology of diabetic retinopathy. The later stages of diabetic retinopathy involve poorly controlled angiogenesis that is of great concern, but in our discussion, we will focus more on several alterations in the retinal circulation occurring earlier in the progression of disease, including reductions in blood flow and a possible redistribution of perfusion that may leave some areas of the retina ischemic and hypoxic. Finally, we include in this article a more recent area of investigation regarding the diabetic retinal vasculature, that is, the alterations to the endothelial surface layer that normally plays a vital role in maintaining physiological functions. © 2020 American Physiological Society. Compr Physiol 10:933-974, 2020.

Psychological, social and everyday visual impact of diabetic macular oedema and diabetic retinopathy: a systematic review

AIMS

To synthesize the evidence on the impact of diabetic retinopathy and diabetic macular oedema from the patient perspective.

METHODS

A systematic literature review was conducted using MEDLINE Complete, PsycINFO, EMBASE and AMED. We included articles investigating the impact of the condition on quality of life, symptoms, visual functioning, activities of daily living, well-being, social functioning, and financial status. The studies evaluated were observational, including cross-sectional, prospective cohort and retrospective cohort designs. Outcome data were extracted and synthesized.

RESULTS

Searches yielded 5114 publications. After screening, 85 studies were included, measuring the following outcomes: visual functioning (n=46); quality of life (n=22); well-being (n=16); functional status (n=5); work (n=4); and visual task performance (n=2). Diabetic retinopathy has a considerable impact on visual functioning and this is greater in people with greater disease severity. Diabetic retinopathy significantly limits activities including working, driving, walking and reading, and has the potential to have a negative impact on psychological well-being.

CONCLUSIONS

Diabetic retinopathy is associated with poor self-reported visual functioning, well-being, and health-related quality of life. Ability to perform basic everyday tasks appears to diminish with disease severity. Some studies suggest impaired mobility and problems with work, but there are gaps in this evidence.

A Multicenter, Cross-Sectional Study of the Incidence of Major Macular Diseases That Cause Visual Impairment and Require Therapeutic Intervention in Greece: The ADVICE Study

Purpose

This multicenter, epidemiological, cross-sectional study aimed to estimate the annual cumulative incidence of major macular diseases that cause visual impairment and require therapeutic intervention in the routine care of Greece.

Methods

The study was carried out between December 2012 and May 2015 in 20 ophthalmology clinics. Over a one-year recruitment period per study site, all treatment naïve adult patients newly diagnosed with wet age-related macular degeneration, visual impairment due to diabetic macular edema or macular edema secondary to retinal vein occlusion requiring therapeutic management and who had not been diagnosed or treated for the same disease in the past were enrolled after providing informed consent. Study data were collected during the single study visit.

Results

A total of 1532 incident cases were enrolled. The estimated annual cumulative incidence of wet age-related macular degeneration, diabetic macular edema and macular edema secondary to retinal vein occlusion requiring therapeutic management was 0.82 [95% confidence interval (CI): 0.76, 0.88; n=723], 0.63 (95% CI: 0.58, 0.69; n=559), and 0.29 (95% CI: 0.25, 0.32; n=250) per 10,000 cases, respectively.

Conclusion

The study provides estimates of the incidence of major macular diseases causing visual impairment and requiring treatment in outpatient hospital settings in Greece, indicating a considerable socioeconomic burden to the healthcare system.

Genotypes and Phenotypes: A Search for Influential Genes in Diabetic Retinopathy

Although gene–environment interactions are known to play an important role in the inheritance of complex traits, it is still unknown how a genotype and the environmental factors result in an observable phenotype. Understanding this complex interaction in the pathogenesis of diabetic retinopathy (DR) remains a big challenge as DR appears to be a disease with heterogenous phenotypes with multifactorial influence. In this review, we examine the natural history and risk factors related to DR, emphasizing distinct clinical phenotypes and their natural course in retinopathy. Although there is strong evidence that duration of diabetes and metabolic factors play a key role in the pathogenesis of DR, accumulating new clinical studies reveal that this disease can develop independently of duration of diabetes and metabolic dysfunction. More recently, studies have emphasized the role of genetic factors in DR. However, linkage analyses, candidate gene studies, and genome-wide association studies (GWAS) have not produced any statistically significant results. Our recently initiated genomics study, the Diabetic Retinopathy Genomics (DRGen) Study, aims to examine the contribution of rare and common variants in the development DR, and how they can contribute to clinical phenotype, rate of progression, and response to available therapies. Our preliminary findings reveal a novel set of genetic variants associated with proangiogenic and inflammatory pathways that may contribute to DR pathogenesis. Further investigation of these variants is necessary and may lead to development of novel biomarkers and new therapeutic targets in DR.

Hypoxia-Inducible Factor Inhibitors Derived from Marine Products Suppress a Murine Model of Neovascular Retinopathy

Neovascular retinal degenerative diseases are the leading causes of blindness in developed countries. Anti-vascular endothelial growth factor (VEGF) therapy is commonly used to treat these diseases currently. However, recent reports indicate that long term suppression of VEGF in the eye is associated with chorioretinal atrophy. Therefore, a physiological amount of VEGF is required for retinal homeostasis. Hypoxia-inducible factor (HIF) is a transcriptional factor upstream of VEGF. We previously reported that HIF regulated pathological angiogenesis in the retina of murine models of oxygen-induced retinopathy and laser-induced choroidal neovascularization. Most of the known HIF inhibitors are anti-cancer agents which may have systemic adverse effects in for clinical use; thus, there is a need for safer and less invasive HIF inhibitors. In this study, we screened marine products, especially fish ingredients, and found that six species of fish had HIF inhibitory effects. Among them, administration of Decapterus tabl ingredients significantly suppressed retinal neovascular tufts by inhibiting HIF expression in a murine oxygen-induced retinopathy model. These results indicate that particular fish ingredients can act as anti-angiogenic agents in retinal neovascularization diseases.

Assessment of Training Outcomes of Nurse Readers for Diabetic Retinopathy Telescreening: Validation Study

BACKGROUND

With the high prevalence of diabetic retinopathy and its significant visual consequences if untreated, timely identification and management of diabetic retinopathy is essential. Teleophthalmology programs have assisted in screening a large number of individuals at risk for vision loss from diabetic retinopathy. Training nonophthalmological readers to assess remote fundus images for diabetic retinopathy may further improve the efficiency of such programs.

OBJECTIVE

This study aimed to evaluate the performance, safety implications, and progress of 2 ophthalmology nurses trained to read and assess diabetic retinopathy fundus images within a hospital diabetic retinopathy telescreening program.

METHODS

In this retrospective interobserver study, 2 ophthalmology nurses followed a specific training program within a hospital diabetic retinopathy telescreening program and were trained to assess diabetic retinopathy images at 2 levels of intervention: detection of diabetic retinopathy (level 1) and identification of referable disease (level 2). The reliability of the assessment by level 1-trained readers in 266 patients and of the identification of patients at risk of vision loss from diabetic retinopathy by level 2-trained readers in 559 more patients were measured. The learning curve, sensitivity, and specificity of the readings were evaluated using a group consensus gold standard.

RESULTS

An almost perfect agreement was measured in identifying the presence of diabetic retinopathy in both level 1 readers (κ=0.86 and 0.80) and in identifying referable diabetic retinopathy by level 2 readers (κ=0.80 and 0.83). At least substantial agreement was measured in the level 2 readers for macular edema (κ=0.79 and 0.88) for all eyes. Good screening threshold sensitivities and specificities were obtained for all level readers, with sensitivities of 90.6% and 96.9% and specificities of 95.1% and 85.1% for level 1 readers (readers A and B) and with sensitivities of 86.8% and 91.2% and specificities of 91.7% and 97.0% for level 2 readers (readers A and B). This performance was achieved immediately after training and remained stable throughout the study.

CONCLUSIONS

Notwithstanding the small number of trained readers, this study validates the screening performance of level 1 and level 2 diabetic retinopathy readers within this training program, emphasizing practical experience, and allows the establishment of an ongoing assessment clinic. This highlights the importance of supervised, hands-on experience and may help set parameters to further calibrate the training of diabetic retinopathy readers for safe screening programs.

Can the dexamethasone intravitreal implant Ozurdex be safely administered in an out-of-operating room setting?

Purpose

To describe a standardized protocol of the dexamethasone intravitreal (DEX) implant Ozurdex (Allergan, Dublin, Ireland) performed in a controlled environment surgical cabin (CESC).

Methods

Retrospective and observational study conducted on patients who underwent a DEX implant between May 2011 and June 2019, in a third level University Hospital. The controlled environment surgical cabin (ArcSterile, Imex, Valencia, Spain) used in this study was the MB 20 (2 m width, 1.60 m depth, and 2 m height) with an uninterrupted power system (ARSSAI1) to keep the cabin working for 20 min. The cabin was used in the open mode. A standardized protocol of intravitreal injections in controlled environment surgical cabin was designed.

Results

From May 2011 to February 2015, a total of 454 DEX implants were performed in the operating room, whereas from March 2015 to June 2019, 1054 DEX devices were implanted using the CESC. The mean number of DEX implants/per week was significantly lower in the operating room than in the CESC [2.3 (2.1 to 2.5) versus 3.8 (3.6 to 4.1), mean difference 1.5 (1.2 to 1.8), p < 0.0001]. The incidence of endophthalmitis was similar in the two populations, 0/454 (0.0%; 95% CI 0.0 to 0.81%) and 0/1054 (0.0%; 95% CI 0.0 to 0.35%) in the operating room and in the CESC, respectively.

Conclusions

The CESC may be a good alternative to the conventional operating room for the administration of the intravitreal DEX implant.

From Rust to Quantum Biology: The Role of Iron in Retina Physiopathology

Iron is essential for cell survival and function. It is a transition metal, that could change its oxidation state from Fe²⁺ to Fe³⁺ involving an electron transfer, the key of vital functions but also organ dysfunctions. The goal of this review is to illustrate the primordial role of iron and local iron homeostasis in retinal physiology and vision, as well as the pathological consequences of iron excess in animal models of retinal degeneration and in human retinal diseases. We summarize evidence of the potential therapeutic effect of iron chelation in retinal diseases and especially the interest of transferrin, a ubiquitous endogenous iron-binding protein, having the ability to treat or delay degenerative retinal diseases.

Two Year Visual Acuity and Structural Outcomes in Patients with Diabetic Macular Oedema Treated with Intravitreal Aflibercept - A Retrospective Cohort Study

Purpose

To assess visual and anatomical outcomes of intravitreal aflibercept for clinically significant diabetic macular oedema (DME).

Methods

For this retrospective single-center cohort study at a tertiary referral center, we performed a data warehouse query to identify 117 treatment-naive patients (139 eyes) undergoing intravitreal treatment with aflibercept for DME between January 2014 and May 2018. Changes in best-corrected visual acuity (BCVA) values (as measured with ETDRS letters), central retinal thickness (CRT) and total macular volume (TVOL) are reported over a two-year period at various time-points.

Results

The total number of injections per study eye was 5.5 ± 1.4 after one and 8.7 ± 2.2 injections after two years. Baseline visual acuity (VA) was 60.1 ± 14.5 letters. A gain of 4.8 and 9.2 letters from baseline was observed after one and two years, respectively (both p ≤ 0.01). In comparison to the mean CRT at baseline (419 ± 174 µm), a CRT decrease was observed after one and two years of treatment (298 ± 115 µm and 319 ± 119 µm, respectively; both p ≤ 0.01). Similarly, TVOL decreased from 10.12 ± 2.05 mm³ to 8.96 ± 0.96 mm³ and 9.01 ± 1.29 mm³ (both p ≤ 0.01).

Conclusion

This study demonstrates that treating DME with intravitreal aflibercept yields positive functional and structural outcomes over a two-year period. However, we observed fewer injection numbers, along with inferior VA and structural outcomes than has been reported in randomized clinical trials. Our results show similar results as in patients treated with ranibizumab due to DME in real-life settings.

Bcl-6-directed follicular helper T cells promote vascular inflammatory injury in diabetic retinopathy

Diabetic retinopathy (DR) is a vision-threatening complication of diabetes mellitus characterized by chronic retinal microvascular inflammation. The involvement of CD4+ T cells in retinal vascular inflammation has been considered, but the specific subset and mechanism of T cell-mediated response during the process remains unclear. Here, we aim to investigate the potential role of follicular helper T (Tfh) cells, a newly identified subset of CD4+ T cells in retinal vascular inflammation in DR.

Methods: Patients with DR were enrolled and the PD-1⁺CXCR5⁺CD4⁺ Tfh cells were detected in the peripheral blood by flow cytometry. The streptozotocin (STZ)-induced DR model and oxygen-induced retinopathy (OIR) model were established, and 79-6, an inhibitor of Bcl-6, was injected intraperitoneally to suppress Tfh cells. The Tfh cells-related genes were investigated in the spleen, lymph nodes, and retina of mice by flow cytometry, immunofluorescence, and qPCR.

Results: The Tfh cells expanded in the circulation of patients with DR and also increased in circulation, lymph nodes and retinal tissues from the STZ-induced DR mice and OIR mice. Notably, inhibition of Bcl-6, a critical transcription factor for Tfh cells development, prevented upregulation of Tfh cells and its typical IL-21 cytokine, and ameliorated vascular leakage in DR mice or retinal angiogenesis in OIR mice, indicating that Bcl-6-directed Tfh cells could promote vascular inflammation and angiogenesis.

Conclusions: Our results suggested that excessive Bcl-6-directed Tfh cells represent an unrecognized feature of DR and be responsible for the retinal vascular inflammation and angiogenesis, providing opportunities for new therapeutic approaches to DR.

Disorganization of retinal inner layers as a biomarker in patients with diabetic macular oedema treated with dexamethasone implant

PURPOSE

To investigate disorganization of retinal inner layers (DRIL) as a biomarker in eyes with diabetic macular oedema (DME) treated by intravitreal dexamethasone (DEX) implant.

METHODS

Multicentre, retrospective study including eyes with DME treated with DEX implant and follow-up of 12 months after the first injection. OCT scans were evaluated for the presence of DRIL and other structural features. Best corrected visual acuity (BCVA) and central subfield thickness (CST) were recorded at baseline and at 2, 4, 6 and 12 months after treatment. Correlation between DRIL at baseline and outcomes after DEX treatment and the change in DRIL were analysed.

RESULTS

A total of 177 eyes (177 patients; naïve, n = 131; refractory, n = 46) were included. Patients without DRIL at baseline gained significantly more vision and enjoyed greater reduction in CST over 12 months (both p = 0.03). DRIL at the boundary between the ganglion cell-inner plexiform complex and inner nuclear layer improved in 48/64 eyes (75%, p < 0.001), while DRIL between the inner nuclear layer and outer plexiform layer improved in 27/77 eyes (35%, p = 0.004).

CONCLUSIONS

This is the first study to show that DEX implant has the potential to ameliorate DRIL. Patients without DRIL at baseline have a favourable outcome. DRIL may serve a robust biomarker in DME treated by DEX implant.

Recent Epidemiological Status of Ocular and Other Major Complications Related to Diabetes Mellitus in Japan

PURPOSE

To investigate the epidemiological status of diabetes mellitus (DM)-related complications in Japan.

METHODS

The subjects were 3.11 million Japanese individuals who were registered in the Japanese claim database between 2005 and 2014. Subjects with a diagnosis associated with codes related to DM and/or DM-related complications as classified by the International Classification of Diseases version 10 and those who were prescribed any therapeutic agents for DM were considered to have DM. The status of ocular, renal, and neural complications was investigated.

RESULTS

A total of 66,923 patients with DM were included. The prevalence of subjects with DM was 3.8% in 2005 and 4.2% in 2014. The most frequent complication was diabetic retinopathy (23.6%, 95% CI: 21.7-25.5%), followed by diabetic nephropathy (14.8%, 95% CI: 14.0-15.6%) and diabetic neuropathy (4.9%, 95% CI: 4.5-5.3%). Among the subjects with ocular complications, 1.8% had proliferative diabetic retinopathy, 1.1% had diabetic macular edema (DME), 0.3% had neovascular glaucoma, and 1.5% had vitreous hemorrhage. Only DME significantly increased during the study period. The frequencies of the ocular and neural complications significantly decreased, while that of renal complications significantly increased during the study period.

CONCLUSIONS

Ocular complications were the most common DM-related major complications in Japan. Notably, DME significantly increased in recent years.

Optimization of Diabetic Macular Edema Management in the Real World: A Model of Excellence in Retina Units: The EMUREX Initiative

PURPOSE

To define and develop a model of excellence for the clinical management of diabetic macular edema (DME) patients in a real-world setting.

METHODS

A multidisciplinary joint commission (5 ophthalmologists, 1 nurse, and 1 pharmaceutic) established a series of preliminary recommendations based on clinical guidelines and DME activity results from 8 Pilot Hospitals (PH). These were validated by members of each PH and a group of DME patients in discussion workshops. Thus, the validated guideline (VG) took into consideration different aspects, namely, main core points (ranging 0-100), criteria, and indicators. Finally, each PH own setting was compared to the VG in order to settle down a starting point to clinical excellence.

RESULTS

Mean PH score was 51.5 (range 30-65). As compared to their maximum, main points that showed best scores were Clinical Guidelines and Protocols (78%) and Portfolio of Services (73%). Topics reaching close to 50% scoring included Resources (55%), Innovation (54%), Care Process (53%), Organization (52%), and Leadership (50%). Lowest scores were observed in the Strategic Alliances (46%) and Staff (37%) points.

CONCLUSIONS

Analysis of each PH by the VG delivered a global vision of the starting situation, especially focused in the identification of the different improvement areas. In order to further extend this model into the Public Health System, the effect of implementing it in different hospitals should be assessed to analyze its impact on daily clinical practice and health economics.

NOD-like Receptors in the Eye: Uncovering Its Role in Diabetic Retinopathy

Diabetic retinopathy (DR) is an ocular complication of diabetes mellitus (DM). International Diabetic Federations (IDF) estimates up to 629 million people with DM by the year 2045 worldwide. Nearly 50% of DM patients will show evidence of diabetic-related eye problems. Therapeutic interventions for DR are limited and mostly involve surgical intervention at the late-stages of the disease. The lack of early-stage diagnostic tools and therapies, especially in DR, demands a better understanding of the biological processes involved in the etiology of disease progression. The recent surge in literature associated with NOD-like receptors (NLRs) has gained massive attraction due to their involvement in mediating the innate immune response and perpetuating inflammatory pathways, a central phenomenon found in the pathogenesis of ocular diseases including DR. The NLR family of receptors are expressed in different eye tissues during pathological conditions suggesting their potential roles in dry eye, ocular infection, retinal ischemia, cataract, glaucoma, age-related macular degeneration (AMD), diabetic macular edema (DME) and DR. Our group is interested in studying the critical early components involved in the immune cell infiltration and inflammatory pathways involved in the progression of DR. Recently, we reported that NLRP3 inflammasome might play a pivotal role in the pathogenesis of DR. This comprehensive review summarizes the findings of NLRs expression in the ocular tissues with special emphasis on its presence in the retinal microglia and DR pathogenesis.

Remote Temperature Monitoring in Patients With Visual Impairment Due to Diabetes Mellitus: A Proposed Improvement to Current Standard of Care for Prevention of Diabetic Foot Ulcers

BACKGROUND

Two debilitating sequelae of diabetes are foot ulcerations and vision impairing conditions including retinopathy, open-angle glaucoma, and cataracts. Current standard of care recommends daily visual screening of feet. Despite willingness, many patients are impeded by visual impairment. We investigate whether once-daily remote temperature monitoring can improve self-screening for patients at risk for diabetic foot complications.

METHODS

We followed four male veterans with diabetes mellitus, peripheral neuropathy, impaired visual acuity, and at least one other diabetes-related visual impairment in a high-risk podiatry clinic. Patients received a telemedicine remote temperature monitoring mat and instructed on proper daily use. Each patient developed a "hotspot," defined as a 1.75°C localized temperature difference between matched pedal locations, which resulted in telephone triage outreach.

RESULTS

In three cases, outreach resulted in a sooner appointment where patients were found to have a relevant outcome at the hotspot. Patients in cases 1-3 had University of Texas (UT) 1A ulcerations. The patient in case 4 had inflammation from trauma. All patients had refractive errors plus another vision impairing condition that potentially delayed identification of lesions. Patients in cases 1 and 2 have cataracts, patients in cases 2 and 3 have retinopathy, and patient in case 4 has glaucoma.

CONCLUSIONS

As an adjunct to daily preventative diabetic self-care, once-daily remote temperature monitoring technology can augment self-screening to prompt necessary outreach and treatment and potentially prevent costly and debilitating diabetic foot complications. This case series serves as a pilot study for real-world application of thermometry, where further large-scale research is needed.

Factors associated with the duration of action of dexamethasone intravitreal implants in diabetic macular edema patients

We designed this study to determine the association between the duration of action of intravitreal dexamethasone implants and aqueous humor biomarkers or optical coherence tomography (OCT) findings of diabetic macular edema (DME) patients. We measured the concentrations of interleukin (IL)-1β, -8, -10, -17; placental growth factor; and vascular endothelial growth factor in the aqueous humor, and identified the number of hyperreflective foci (HF), grades of ellipsoid zone disruptions, and baseline central subfield thicknesses (CSTs) using OCT of patients with DME. The average duration of action of dexamethasone implants was 4.32 ± 1.18 months. In multivariate linear regression analyses, the duration of action was associated with aqueous IL-8 levels and the number of HF (β = -0.016, p = 0.037 and β = -0.073, p = 0.035, respectively). Multivariate logistic regression showed that the number of HF (>10) was significantly associated with a shorter duration (<4 months) of action (odds ratio: 17.17, p = 0.010). The duration of action of intravitreal dexamethasone implants in DME patients was associated with the level of aqueous IL-8 and the number of HF using OCT. Specifically, higher number of HF in the OCT was associated with a shorter duration of action.

OCT Angiography Metrics Predict Progression of Diabetic Retinopathy and Development of Diabetic Macular Edema: A Prospective Study

PURPOSE

To prospectively determine the relationship of OCT angiography (OCTA) metrics to diabetic retinopathy (DR) progression and development of diabetic macular edema (DME).

DESIGN

Prospective, observational study.

PARTICIPANTS

A total of 205 eyes from 129 patients with diabetes mellitus followed up for at least 2 years.

METHODS

All participants underwent OCTA with a swept-source OCT device (DRI-OCT Triton, Topcon, Inc, Tokyo, Japan). Individual OCTA images of superficial capillary plexus (SCP) and deep capillary plexus (DCP) were generated by IMAGEnet6 (Basic License 10). After a quality check, automated measurements of foveal avascular zone (FAZ) area, FAZ circularity, vessel density (VD), and fractal dimension (FD) of both SCP and DCP were then obtained.

MAIN OUTCOME MEASURES

Progression of DR and development of DME.

RESULTS

Over a median follow-up of 27.14 months (interquartile range, 24.16-30.41 months), 28 of the 205 eyes (13.66%) developed DR progression. Of the 194 eyes without DME at baseline, 17 (8.76%) developed DME. Larger FAZ area (hazard ratio [HR], 1.829 per SD increase; 95% confidence interval [CI], 1.332-2.512), lower VD (HR, 1.908 per SD decrease; 95% CI, 1.303-2.793), and lower FD (HR, 4.464 per SD decrease; 95% CI, 1.337-14.903) of DCP were significantly associated with DR progression after adjusting for established risk factors (DR severity, glycated hemoglobin, duration of diabetes, age, and mean arterial blood pressure at baseline). Lower VD of SCP (HR, 1.789 per SD decrease; 95% CI, 1.027-4.512) was associated with DME development. Compared with the model with established risk factors alone, the addition of OCTA metrics improved the predictive discrimination of DR progression (FAZ area of DCP, C-statistics 0.723 vs. 0.677, P < 0.001; VD of DCP, C-statistics 0.727 vs. 0.677, P = 0.001; FD of DCP, C-statistics 0.738 vs. 0.677, P < 0.001) and DME development (VD of SCP, C-statistics 0.904 vs. 0.875, P = 0.036).

CONCLUSIONS

The FAZ area, VD, and FD of DCP predict DR progression, whereas VD of SCP predicts DME development. Our findings provide evidence to support that OCTA metrics improve the evaluation of risk of DR progression and DME development beyond traditional risk factors.

Automatic Identification and Intuitive Map Representation of the Epiretinal Membrane Presence in 3D OCT Volumes

Optical Coherence Tomography (OCT) is a medical image modality providing high-resolution cross-sectional visualizations of the retinal tissues without any invasive procedure, commonly used in the analysis of retinal diseases such as diabetic retinopathy or retinal detachment. Early identification of the epiretinal membrane (ERM) facilitates ERM surgical removal operations. Moreover, presence of the ERM is linked to other retinal pathologies, such as macular edemas, being among the main causes of vision loss. In this work, we propose an automatic method for the characterization and visualization of the ERM's presence using 3D OCT volumes. A set of 452 features is refined using the Spatial Uniform ReliefF (SURF) selection strategy to identify the most relevant ones. Afterwards, a set of representative classifiers is trained, selecting the most proficient model, generating a 2D reconstruction of the ERM's presence. Finally, a post-processing stage using a set of morphological operators is performed to improve the quality of the generated maps. To verify the proposed methodology, we used 20 3D OCT volumes, both with and without the ERM's presence, totalling 2428 OCT images manually labeled by a specialist. The most optimal classifier in the training stage achieved a mean accuracy of 91 . 9 % . Regarding the post-processing stage, mean specificity values of 91 . 9 % and 99 . 0 % were obtained from volumes with and without the ERM's presence, respectively.

Conbercept and Retinal Photocoagulation in the treatment of Diabetic Macular Edema

OBJECTIVE

To explore the clinical efficacy of intravitreal injection of conbercept in combination with retinal laser photocoagulation in the treatment of diabetic macular edema.

METHODS

Ninety patients with diabetic macular edema were selected and grouped into an observation group and a control group using random number table, 45 patients (45 eyes) each group. The control group was given retinal laser photocoagulation, while the observation group was given intravitreal injection of Conbercept on the basis of panretinal photocoagulation. The Best Corrected Visual Acuity (BCVA), thickness of retinal nerve fibre layer (RNFL) and macular thickness were measured through relevant examinations before and after treatment. The intraocular pressures of patients in the two groups were evaluated, and moreover the complications were recorded.

RESULTS

The RNFL thickness and macular thickness of the two groups had no statistically significant differences before treatment (P>0.05) and decreased significantly after treatment; the decrease amplitude of the observation group was significantly larger than that of the control group (P<0.05). The BCVA of both groups significantly increased in the 1st, 2nd and 4th week after treatment (P<0.05); the increase amplitude of BCVA of the observation group was more significant than that of the control group at different time points after treatment (P<0.05). The intraocular pressure of the observation group was not significantly different with that of the control group in the 1st, 2nd and 4th week after treatment (P>0.05). There were no severe eye complications and systemic adverse reactions in both groups in the process of follow up.

CONCLUSION

Intravitreal injection of conbercept in combination with retinal laser photocoagulation performs better in improving the BCVA and central macular thickness of patients with diabetic macular edema compared to retinal laser photocoagulation and has high safety.

Proteomic Biomarkers of Retinal Inflammation in Diabetic Retinopathy

Diabetic retinopathy (DR), a sight-threatening neurovasculopathy, is the leading cause of irreversible blindness in the developed world. DR arises as the result of prolonged hyperglycemia and is characterized by leaky retinal vasculature, retinal ischemia, retinal inflammation, angiogenesis, and neovascularization. The number of DR patients is growing with an increase in the elderly population, and therapeutic approaches are limited, therefore, new therapies to prevent retinal injury and enhance repair are a critical unmet need. Besides vascular endothelial growth factor (VEGF)-induced vascular proliferation, several other mechanisms are important in the pathogenesis of diabetic retinopathy, including vascular inflammation. Thus, combining anti-VEGF therapy with other new therapies targeting these pathophysiological pathways of DR may further optimize treatment outcomes. Technological advancements have allowed for high-throughput proteomic studies examining biofluids such as aqueous humor, vitreous humor, tear, and serum. Many DR biomarkers have been identified, especially proteins involved in retinal inflammatory processes. This review attempts to summarize the proteomic biomarkers of DR-associated retinal inflammation identified over the last several years.

Shared Care for Patients with Diabetes at Risk of Retinopathy: A Feasibility Trial

Purpose:

While diabetes is a chronic disease, in many health care systems patients with diabetes at risk of diabetic retinopathy (DR) are managed in hospital settings. Aim of this feasibility study is to assess the quality of care and economic benefits of a shared care model managing patients at risk of DR in a primary eye care clinic (PEC) compared with a current tertiary specialist outpatient clinic (SOC).

Methods:

A randomized trial was performed, to compare a PEC with a SOC in Singapore. The trial patients included those previously seen at the SOC, and having no DR or stable mild non proliferative (NPDR) with no macular edema, no visual and DR deterioration. Primary outcomes were clinical management. Secondary outcomes were patient satisfaction and cost of consultation. Differences analysis used equivalence testing and generalized odds ratios (GOR).

Results:

The trial included 231 patients, 83.1% classified as no DR (PEC: 79.1%; SOC: 87.1%) and 16.9% as stable mild NPDR (PEC: 20.9%; SOC: 12.9%). DR management at PEC was significantly equivalent to that received at the SOC (rate difference 2.56%; CI: (–1.61% to 6.74%)) and 4.29%; CI: (0.14%–8.45%), respectively. Patient satisfaction at the PEC was equally high when compared to SOC (GOR: 1.71; CI: (0.50–2.00)). Direct costs per patient visit was 45% lower at PEC compared to SOC.

Conclusions:

Our feasibility trial showed that patients with diabetes with no or stable DR receive similar clinical care and management at a lower-cost PEC setting, are equally satisfied with the service compared to tertiary eye care. A follow-up study is necessary to validate these findings. Managing patients with diabetes at risk of DR at a PEC may be a safe and effective shared care model to improve accessibility for patients while enhancing professional collaboration between hospital and community settings.

Prevalence and risk factors for diabetic retinopathy in a cross-sectional population-based study from rural southern China: Dongguan Eye Study

RESEARCH QUESTION

The current population-based study aimed to investigate the prevalence of diabetic retinopathy (DR) and risk factors among residents over 40 years old in the rural area of Dongguan, southern China.

STUDY DESIGN

The Dongguan Eye Study was a population-based study from September 2011 to February 2012.

SETTING

The area was set in the rural area of Dongguan, southern China.

PARTICIPANTS

Adult rural population aged 40 or older.

INTERVENTION

Participants underwent haematological, physical, ophthalmic examinations and completed a questionnaire regarding lifestyles and systemic medical conditions.

PRIMARY AND SECONDARY OUTCOME MEASURES

The frequency and risk factors of visual impairment and the major vision-threatening eye diseases.

RESULTS

Of the 8952 Han Chinese, 1500 were diagnosed with type 2 diabetes mellitus (T2DM) with an average age of 59.5±11.1 years, and 1310 participants with fundus photography results were analysed. Standardised prevalence rate of DR was 18.2% for all patients with diabetes, 32.8% for the patients with previously diagnosed diabetes and 12.6% for newly diagnosed patients with T2DM. The prevalence rate of male DR was significantly higher than that of female DR (23.0% vs 14.1%, p<0.001). No significant difference was found in age-specific prevalence of DR. In diabetic patients, the prevalence rates of vision-threatening diabetic retinopathy, diabetic macular oedema and clinically significant macular oedema were 2.5%, 2.8% and 0.9%, respectively. Male gender, higher education level, longer duration of diabetes mellitus (DM), higher systolic blood pressure and glycosylated haemoglobin were independent risk factors for DR development in patients with diabetes.

CONCLUSION

A relatively lower prevalence of DR was found among the participants with T2DM in residents over 40 years in the rural area of southern China. Thus, an ophthalmic examination is recommended, especially for individuals with DM and DR risk factors. There is a need to increase awareness and education on DM and DR, especially in subjects with DR risk factors to reduce the incidence of DR and macular oedema.

Characteristics of diabetic macular edema patients refractory to anti-VEGF treatments and a dexamethasone implant

Purpose

To determine the characteristics of diabetic macular edema (DME) patients refractory to intravitreal bevacizumab (IVB) treatments and an additional dexamethasone implant.

Methods

We classified 119 DME patients according to whether or not they are responsive to 3 consecutive monthly anti-VEGF treatments and/or an additional dexamethasone implant. We compared their concentrations of IL (interleukin)-1β, IL-8, IL-10, IL-17, placental growth factor (PlGF), and vascular endothelial growth factor (VEGF) in the aqueous humor as well as their optical coherence tomography (OCT) findings, and baseline characteristics. We used logistic regression analyses to identify preoperative factors related to refractoriness to treatments.

Results

Of 119 treatment-naïve DME patients, 50 (42.02%) patients showed responsiveness [central subfield thickness (CST) < 300μm] after 3 IVBs, and 59 (49.58%) patients showed responsiveness after an additional dexamethasone implant, but 10 (8.40%) patients showed CST 300 ≥ μm even after both treatments. Refractory DME patients showed significantly higher number of hyperreflective foci (HF) in the OCT and higher average level of aqueous IL-1β at baseline (p<0.001 and p = 0.042, respectively). In the logistic regression analysis, higher number of HF in the OCT was associated with the refractoriness to both treatments (odds ratio [OR]: 7.03, p = 0.007)

Conclusions

Higher number of HF in the OCT at the initial visit was associated with poor responses to IVBs and an additional dexamethasone implant.

Imaging and Biomarkers in Diabetic Macular Edema and Diabetic Retinopathy

PURPOSE OF REVIEW

Diabetic retinopathy (DR) is the leading cause of acquired vision loss in adults across the globe. Early identification and treatment of patients with DR is paramount for vision preservation. The aim of this review paper is to outline current and new imaging techniques and biomarkers that are valuable for clinical diagnosis and management of DR.

RECENT FINDINGS

Ultrawide field imaging and automated deep learning algorithms are recent advancements on traditional fundus photography and fluorescein angiography. Optical coherence tomography (OCT) and OCT angiography are techniques that image retinal anatomy and vasculature and OCT is routinely used to monitor response to treatment. Many circulating, vitreous, and genetic biomarkers have been studied to facilitate disease detection and development of new treatments. Recent advancements in retinal imaging and identification of promising new biomarkers for DR have the potential to increase detection, risk stratification, and treatment for patients with DR.

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.

Primary outcomes of the VIDI study: phase 2, double-masked, randomized, active-controlled study of ASP8232 for diabetic macular edema

Background

ASP8232 is a potent and specific small molecule vascular adhesion protein-1 (VAP-1) inhibitor. This study evaluated the effect of ASP8232 on excess retinal thickness when given alone or in combination with ranibizumab in patients with center-involved diabetic macular edema (CI-DME).

Methods

This was a phase 2a, placebo and sham-injection controlled, double-masked, randomized, parallel-group clinical trial. Participants were patients with CI-DME and central subfield thickness (CST) ≥ 375 µm in the study eye as assessed by spectral domain optical coherence tomography. Eligible patients were randomized to (1) daily oral ASP8232 40 mg monotherapy; (2) combination therapy of daily oral ASP8232 40 mg and monthly intravitreal ranibizumab 0.3 mg; or (3) monthly intravitreal ranibizumab 0.3 mg monotherapy. The treatment period was 12 weeks. CST and best corrected visual acuity (BCVA) were assessed at baseline and at Weeks 2, 4, 8, 12, 16 and 24. The primary outcome was the mean percent change from baseline in excess CST at Week 12. Secondary outcomes were BCVA, safety and tolerability, and pharmacokinetic and pharmacodynamic characteristics of ASP8232.

Results

After 12 weeks, the mean (95% confidence interval) percent change in excess CST was 11.4% (− 15.0%, 37.8%) in the ASP8232 group, − 61.7% (− 86.1%, − 37.2%) in the ASP8232/ranibizumab group, and − 75.3% (− 94.8%, − 55.8%) in the ranibizumab group. The change from baseline in the two ranibizumab arms was statistically significant (P < 0.001) as was the difference between the ranibizumab groups and the ASP8232 group (P < 0.001). Mean (SD) increase in BCVA score from baseline was 3.1 (7.3) in the ASP8232 group, 5.2 (7.1) in the ASP8232/ranibizumab group, and 8.2 (9.5) in the ranibizumab group. The increase from baseline in BCVA score was statistically and clinically significant in the ranibizumab group compared with the ASP8232 group (P = 0.015). ASP8232 resulted in near complete inhibition of plasma VAP-1 activity whilst ranibizumab had no effect.

Conclusions

Near complete inhibition of plasma VAP-1 activity with ASP8232 had no effect on CST in patients with CI-DME. Furthermore, combination therapy did not provide additional benefit to treatment with ranibizumab alone, which significantly reduced CST and improved BCVA.

Trial registration clinicaltrials.gov; NCT02302079. Registered on November 26, 2014

Electronic supplementary material

The online version of this article (10.1186/s40942-019-0178-7) contains supplementary material, which is available to authorized users.

Diabetic retinopathy and age-related macular degeneration: a survey of pharmacoutilization and cost in Calabria, Italy

The aged population is constantly growing, thus fostering an increase in age-dependent diseases. Among these, diabetic retinopathy (DR) along with age-related macular degeneration entails progressive vision loss. Since such conditions are associated with the proliferation of novel vessels, their pharmacotherapeutic management consists of the intravitreal injection of anti-vascular endothelial growth factor drugs, able to hinder the driving of vascular proliferation prompted by vascular endothelial growth factor. The humanized anti-vascular endothelial growth factor monoclonal antibody ranibizumab provided evidence for efficacy in several trials, hence earning approval by the US Food and Drug Administration for therapeutic use in all the stages of DR. Due to the lack of epidemiologic and pharmacoeconomic evaluation in the local Calabria Region context, the present retrospective observational study focused on prevalence of DR and age-related macular degeneration, treatment and cost of therapy with ranibizumab in 870 patients arriving to clinical observation at the "Mater Domini" University Hospital in Calabria, Italy from January 2014 to June 2017. Data were extracted from the database of ophthalmology ward and subjected to statistical analysis. The results suggest that the most frequent retinal diseases are age-related macular degeneration and DR and that the use of ranibizumab has been decreasing over the 4-year study period together with the associated cost per patient which was similar for both disorders. Therefore, appropriateness of treatment with drugs other than ranibizumab needs to be assessed in this setting and deep monitoring of pharmacologic treatment for retinal diseases is necessary to prevent or delay visual acuity decrease and complete vision loss. Study procedures were performed in accordance with the "Mater Domini" University Hospital ethical standards of the responsible committee on human experimentation.

Effect of Intravitreal Anti-Vascular Growth Factor Agents With or Without Macular Photocoagulation on Diabetic Macular Edema: A Systematic Review and Meta-Analysis

INTRODUCTION

Diabetes is a common cause of new sight loss in populations world-wide, and diabetic macular edema (DME) is a major cause of visual deficits in the diabetic populations of developed countries. We have performed a meta-analysis to evaluate whether combined treatment with anti-vascular endothelial growth factor (VEGF) injections and macular photocoagulation (MPC) is more efficacious than primary monotherapy with anti-VEGF injections in patients with DME.

METHODS

We systematically searched the PubMed and Web of Science databases for studies providing sufficient information for a comparison of pre- and post-treatment of central macular thickness (CMT) and best-corrected visual acuity (BCVA) between two groups of patients with DME given interventional therapies (monotherapy with an anti-VEGF agent vs. combination therapy with an anti-VEGF agent and MPC) before January 2019. A meta-analysis was performed to summarize the results of the studies included in the systematic review.

RESULTS

The results of our meta-analysis indicated that post-treatment CMT was significantly lower at 3 months in DME patients receiving combination therapy with bevacizumab, a humanized anti-VEGF antibody, and MPC than in those receiving monotherapy with bevacizumab. The results also showed that post-treatment CMT was lower in DME patients given ranibizumab, an anti-VEGF agent, in combination with MPC at 6, 9 and 12 months than in those treated with ranibizumab alone. However, no significant differences were found in post-treatment BCVA at 1, 3, 6, 9 and 12 months between DME patients receiving combination therapy with an anti-VEGF agent (bevacizumab or ranibizumab) and MPC and those receiving monotherapy with an anti-VEGF agent.

CONCLUSION

In conclusion, the results of our meta-analysis demonstrate a transiently synergistic effect of MPC on CMT when this treatment is combined with anti-VEGF agents, whereas no similar synergistic effect could be detected on the BCVA. A relatively longer follow-up was essential to be able to evaluate the long-term existence of this synergistic effect.

Prevalence, Incidence and Ecological Determinants of Diabetic Retinopathy in Iran: Systematic Review and Meta-analysis

Purpose

To estimate the pooled prevalence and incidence of diabetic retinopathy (DR) in Iran and to investigate their correlations with the Human Development Index (HDI), healthcare access (i.e., density of specialists and sub-specialists), and methodological issues.

Methods

Electronic databases such as PubMed, Embase, Scopus, Web of Science, Google Scholar, and local databases were searched for cohort and cross-sectional studies published prior to January 2018. Prevalence and incidence rates of DR were extracted from January 2000 to December 2017 and random effects models were used to estimate pooled effect sizes. The Joanna Briggs Institute critical appraisal tool was applied for quality assessment of eligible studies.

Results

A total of 55,445 participants across 33 studies were included. The pooled prevalence (95% CI) of DR in diabetic clinics (22 studies), eye clinics (4 studies), and general population (7 studies) was 31.8% (24.5 to 39.2), 57.8% (50.2 to 65.3), and 29.6% (22.6 to 36.5), respectively. It was 7.4% (3.9 to 10.8) for proliferative DR and 7.1% (4.9 to 9.4) for clinically significant macular edema. The heterogeneity of individual estimates of prevalence was highly significant. HDI (P < 0.001), density of specialists (P = 0.004), subspecialists (P < 0.001), and sampling site (P = 0.041) were associated with heterogeneity after the adjustment for type of DR, duration of diabetes, study year, and proportion of diabetics with controlled HbA1C.

Conclusion

Human development and healthcare access were correlated with the prevalence of DR. Data were scarce on the prevalence of DR in less developed provinces. Participant recruitment in eye clinics might overestimate the prevalence of DR.

Dexamethasone implant in the management of diabetic macular edema from clinician's perspective

The aim of this article is to provide an overview of characteristics and principles of use of dexamethasone implant in patients with diabetic macular edema (DME). The condensed information about patient selection, dosing, and postinjection management is provided to make the clinician’s decisions easier in real-life practice. DME is a common complication of diabetes and the leading cause of visual loss in the working-age population. Inflammation plays an important role in the pathogenesis of DME. The breakdown of the blood–retinal barrier involves the expression of inflammatory cytokines and growth factors, including vascular endothelial growth factor (VEGF). Steroids have proved to be effective in the treatment of DME by blocking the production of VEGF and other inflammatory cytokines, by inhibiting leukostasis, and by enhancing the barrier function of vascular endothelial cell tight junctions. Dexamethasone intravitreal implant has demonstrated efficacy in the treatment of DME resistant to anti-VEGF therapy and in vitrectomized eyes. Data from clinical trials suggest that dexamethasone implant can be considered as first-line treatment in pseudophakic eyes. Dexamethasone implant is also the first-line therapy in patients not suited for anti-VEGF therapy, pregnant women, and patients unable to return for frequent monitoring. It has been shown that the maximum effect of dexamethasone implant on visual gain and retinal thickness occurs approximately 2 months after injection. Various treatment regimens are used in real-life situations, and reported reinjection intervals were usually <6 months. The number of retreatments needed decreased over time. Treatment algorithms should be personalized. Postinjection management and follow-up should consider potential adverse events such as intraocular pressure elevation and cataract.

MicroRNA-9 inhibits retinal neovascularization in rats with diabetic retinopathy by targeting vascular endothelial growth factor A

Diabetic retinopathy (DR) is a leading cause of adult visual impairment and loss. This study aims to explore the effects of microRNA-9 (miR-9) on retinal neovascularization during DR by targeting the vascular endothelial growth factor A (VEGFA). DR rat models were successfully established. Retinal microvascular endothelial cells (RMECs) of DR rats were isolated and treated with miR-9 mimic, miR-9 inhibitor or small interfering RNA (siRNA)-VEGFA. The expressions of miR-9, VEGFA, and cluster of differentiation 31 (CD31) of the rats' tissues and cells were examined. The targeting relationship between miR-9 and VEGFA was testified. The tubule formation, the cell proliferation and the periodic distribution and apoptosis were evaluated after transfection. In the retinal tissues of DR rats, miR-9 expression decreased while the expression of VEGFA and CD31 increased. Notably, miR-9 targeted and inhibited VEGFA expression. In response to the treatment of miR-9 mimic and siRNA-VEGFA, a reduction was identified in CD31 expression, tubule formation, and proliferation of RMECs and cell ratio in the S phase, but an increase was observed in apoptosis rate of RMECs. The treatment of miR-9 inhibitor reversed the manifestations. Our study demonstrated that miR-9 could inhibit retinal neovascularization of DR and tubule formation, and promote apoptosis in RMECs by targeting VEGFA.

The Preventive Effect of Oxytocin on Retinopathy in Streptozotocin-Induced Diabetic Rats

Objectives:

The aim of this study was to investigate the impact of intravitreal and intraperitoneal use of oxytocin (OT) on retinopathy in streptozotocin-induced diabetic rats.

Materials and Methods:

Twenty-four 6-8-week-old adult male and female Sprague Dawley rats were used in the study. Diabetes was induced in the rats with a single injection of intraperitoneal streptozotocin. Diabetes was verified after 48 hours by measuring blood glucose levels of 260 mg/dl (14.4 mmol/L) or higher in diabetic rats. The rats were divided into 4 groups and treated as follows: intravitreal physiological saline group (0.01 mL saline weekly), intravitreal OT group (10 μU/μL OT weekly), intraperitoneal physiological saline group (1 mL daily), and intraperitoneal OT group (100 IU/kg OT daily). Hamilton syringes fitted with 27-gauge needles were used for intraperitoneal injections while 31-gauge needles were used for intravitreal injection. After 4 weeks of treatment the rats were euthanized to evaluate outer nuclear layer (ONL) thickness, vascular endothelial growth factor (VEGF) immunoexpression, and plasma VEGF levels from blood samples obtained by cardiac puncture.

Results:

Morphometric analysis of retinal cross-sections showed that intravitreal and intraperitoneal OT significantly increased ONL thickness compared to physiological saline-treated groups. Also, OT treatment significantly decreased VEGF protein expression compared with the physiological saline groups. Plasma VEGF level was significantly higher in the physiological saline treatment group compared to the OT treatment group.

Conclusion:

OT reduces diabetic retinopathy progression, particularly when administered intravitreally. To our knowledge, this is the first attempt to investigate the impact of OT on diabetic retinopathy and may provide a new area for further research.

Baseline Ocular Characteristics of Patients Undergoing Initiation of Anti-Vascular Endothelial Growth Factor Therapy for Diabetic Macular Edema

BACKGROUND AND OBJECTIVES

Patients with diabetic macular edema (DME) have variable anatomic and visual responses to anti-vascular endothelial growth (VEGF) treatments based on their presenting visual acuity (VA). The aim of study is to report the baseline ocular and imaging characteristics of patients presenting with DME who were treatment-naïve and who initiated anti-VEGF in routine clinical practice.

PATIENTS AND METHODS

Single-center, cross-sectional study of 638 patients. Subjects were divided into two VA groups: Early Treatment Diabetic Retinopathy Study (ETDRS) less than 70 and ETDRS greater than 70 and ocular variables were compared between groups.

RESULTS

Average central subfield thickness (CST) was 363.5 μm, cube volume was 11.7 mm³, and cube average thickness (CAT) was 326.1 μm. Additionally, 21.5% had subretinal fluid (SRF), and 50.5% had hard exudates on presentation. Eyes with ETDRS less than 70 had greater CAT (338.5 μm³ vs. 313.2 μm³; P < .001), greater cube volume (12.2 mm³ vs. 11.3 mm³; P < .001), greater CST (383.5 μm vs. 350.0 μm; P < .001), and SRF (25.5% vs. 17.3%; P = .012). Furthermore, 7.64% had glaucoma, 1.3% had dry age-related macular degeneration, 4.5% of patients were vitrectomized, and 28.7% were pseudophakic. Regarding diabetic stage, 37% had proliferative diabetic retinopathy (PDR) and 63% presented with nonproliferative diabetic retinopathy. Patients presenting with ETDRS less than 70 were more likely to have a history of vitrectomy (7.1% vs. 1.9%, P = .002) and presence of PDR (42.3% vs. 31.4%, P = .004).

CONCLUSION

The results describe a population of patients from a routine clinical practice not entirely represented in clinical trials, with key differences in ocular characteristics seen between VA groups. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:69-75.].

A real-world study of effectiveness of intravitreal bevacizumab and ranibizumab injection for treating retinal diseases in Thailand

Background

To evaluate the effectiveness of intravitreal bevacizumab (IVB) and intravitreal ranibizumab (IVR) in actual practice for treating patients with retinal diseases in Thailand.

Methods

A prospective, multi-centre, observational study was conducted among eight hospitals in their ophthalmology outpatient departments. Participants consisted of patients who had previously not received any IVB or IVR treatment between 2013 and 2014. The primary outcome measurement was the change in best-corrected visual acuity (BCVA) at the end of the follow-up period compared to baseline.

Results

There were 1629 treatment-naïve patients for the pro re nata (PRN) treatment pattern and 226 treatment-naive patients for the three-injections (3Inj) treatment pattern. BCVA improvements were found in 35% of the PRN group and 47% of the 3Inj group; however, it was not clinically meaningful between the IVB and IVR groups (P-value = 0.568 for PRN, P-value = 0.103 for 3Inj). A multivariable logistic regression (using the propensity score) showed that positive factors associated with vision improvement for the PRN pattern were the number of drug injections, having retinal vein occlusion, and under 60 years of age, while good BCVA at baseline was a negative predictive factor. For the 3Inj pattern, under 60 years of age and baseline BCVA were statistically significant predictors. Nonetheless, diabetes mellitus (DM) without other comorbidities was a statistically significant predictor of low response to vision improvement compared to DM with other comorbidities.

Conclusions

This study was the first observational, prospective study to evaluate the real-life effectiveness of IVB and IVR in Thailand. The majority of participants who used IVB or IVR showed improvements in BCVA after treatment. Further evaluation such as long-term follow-ups and subsequent comparison of effectiveness between IVB and IVR should be investigated due to the limited sample of IVR patients.

Trial registration

Thai Clinical Trial Registry TCTR20141002001. Registered 02 October 2014 (retrospectively registered).

Pharmacological HIF inhibition prevents retinal neovascularization with improved visual function in a murine oxygen-induced retinopathy model

Neovascular retinal diseases are the leading causes of blindness in advanced countries. To date, anti-VEGF (vascular endothelial growth factor) drugs are clinically effective and widely used for these diseases. However, recent animal and clinical studies reported that potent and long-term VEGF antagonism may induce chorioretinal atrophy. Thus, physiological amount of VEGF is required for the homeostasis in the retina. Hypoxia-inducible factors (HIFs) are transcription factors located upstream of VEGF. We hypothesized that ectopically stabilized HIFs induce pathological amount of VEGF involved with retinal neovascularization. Therefore, HIF inhibition could be an alternative therapeutic candidate targeting the pathological amount of VEGF while holding a physiological amount of VEGF. To test this hypothesis, topotecan and doxorubicin, HIF inhibitors with different mechanisms were administered to the murine oxygen-induced retinopathy (OIR) model. We found that both topotecan and doxorubicin significantly prevented pathological but not physiological neovascularization in OIR. Furthermore, impaired visual function observed in OIR can also be suppressed by administering topotecan. These data suggested that HIF inhibition may be effective for pathological angiogenesis and neurodegeneration of the retina.

Correlation between systemic S100A8 and S100A9 levels and severity of diabetic retinopathy in patients with type 2 diabetes mellitus

AIMS

S100A8 and S100A9 are myeloid-related damage-associated molecular patterns (DAMPs) primarily involved in the modulation of innate immune response to cellular injury. This study evaluated the correlation between circulating concentrations of S100A8 and S100A9 proteins with the severity of diabetic retinopathy (DR) in patients with type 2 diabetes (T2DM).

METHODS

T2DM patients with HbA1c levels >7%, fasting blood glucose >126 mg/dl and history of diabetes were included in this study. DR severity was graded based on ETDRS and Gloucestershire classifications. Plasma samples were evaluated for S100A8 and S100A9 levels using ELISA.

RESULTS

In this comparative study, DR patients (n = 89) had increased plasma S100A8 and S100A9 proteins compared to age-matched T2DM controls (n = 28), which was directly related to the severity of DR. Female DR subjects had increased S100A8 expression compared to their male counterparts. Substantial retention of S100A8 and S100A9 production was seen in DR patients above 50 years of age. Duration of T2DM was not found to affect protein levels, however T2DM onset at >50 years old significantly increased S100A8 and S100A9 concentrations.

CONCLUSIONS

Our findings suggest that systemic circulation levels of S100A8 and S100A9 are correlated with the progression of DR in T2DM patients, indicating their potential role in DR pathogenesis.

Profile of a population-based diabetic macular oedema study: the Liverpool Eye and Diabetes Study (Sydney)

PURPOSE

The population prevalence of diabetic macular oedema (DME) is unclear. Previous estimates have depended on photographic grading of clinically significant macular oedema, which is subjective and has resulted in widely varying estimates. With the advent of optical coherence tomography (OCT), the presence and severity of DME can now be assessed objectively and accurately.

METHODS

The Liverpool Eye and Diabetes Study (LEADS) is a cross-sectional population-based study of patients with type 1 and type 2 diabetes in a multi-ethnic region of Sydney, Australia, to determine the population prevalence of OCT-defined DME, how this varies by ethnicity and association with systemic factors. This report describes the rationale, methodology and study aims.

RESULTS

To date 646 patients out of an expected sample size of 2000 have been recruited. Baseline data are presented for patients with type 1 (n=75, 11.8%) and type 2 (n=562, 88.2%) diabetes recruited to date. Patients with type 1 diabetes were younger (39.5vs60.7 years), with longer duration of diabetes (18.1vs11.7 years), slightly worse glycaemic control (HbA1c 9.0vs8.3), and less likely to have hypertension (30.7vs71.4%), hypercholesterolaemia (33.3vs74.6%) and obesity (31.1vs51.5%, respectively, all p<0.05).

CONCLUSIONS

The LEADS will provide objective estimates of the population prevalence of DME, how this varies with ethnicity and associations with systemic disease.

A comprehensive competitive endogenous RNA network pinpoints key molecules in diabetic retinopathy

Diabetic retinopathy (DR) is a severe microvascular complication of diabetes and the primary cause of vision loss in diabetic patients. Previous research has revealed that long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) play pivotal roles in the pathogenesis of DR. However, the roles of lncRNA-miRNA-mRNA interactions in DR are poorly understood. In the present study, we aimed to compute a global triple network of competitive endogenous RNAs (ceRNAs) in order to pinpoint essential molecules. We found that there were 802 nodes (121 lncRNA nodes, 17 miRNA nodes, and 664 mRNA nodes) and 949 edges in the ceRNA network. Further functional analysis suggested that some molecules were specifically related to DR. Surprisingly, these molecules were involved in visual perception, eye development, and lens development in camera-type eye. In summary, our study highlighted specific lncRNAs and miRNAs related to the pathogenesis of DR, which might be used as potential diagnostic biomarkers and therapeutic targets for DR.

Loss to Follow-up After Intravitreal Anti-Vascular Endothelial Growth Factor Injections in Patients with Diabetic Macular Edema

PURPOSE

To determine the rate of loss to follow-up (LTFU) and associated risk factors in patients with nonproliferative diabetic retinopathy (NPDR) who had diabetic macular edema (DME) and were receiving intravitreal anti-vascular endothelial growth factor (VEGF) injections.

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 2595 NPDR patients with DME who received at least one anti-VEGF injection at a single large retina practice from January 1, 2012, to January 1, 2017.

METHODS

A retrospective review based on billing codes was performed. LTFU was defined as no subsequent office visits within 12 months after an intravitreal injection. Patient demographics and clinical features were evaluated, and logistic regression was used to identify independent predictors for LTFU.

MAIN OUTCOME MEASURES

LTFU rates and potential risk factors.

RESULTS

LTFU was found in 413 (25.3%) of 1632 patients. Examining LTFU by racial groups, 21.3% identified themselves as white, 29.1% as black, 30.6% as Asian, and 35.0% as Hispanic (P < 0.001). A difference in LTFU was also found based on average adjusted gross income (AGI) (P < 0.001) and NPDR stage (P = 0.04). In the multivariate model, factors associated with LTFU included Hispanic (odds ratio [OR] 1.66), American Indian, Pacific Islander, multiple races (OR 2.60), and unknown race (OR 1.59) compared with those who were white. Additional factors included those with an average AGI of $50000 to $75000 (OR 1.37) and <$50000 (OR 1.88) compared with those with an average AGI > $75000. Based on subgroup analysis of patients with available visual acuity data, a significant association was found between decreasing baseline vision and LTFU (P < 0.001).

CONCLUSIONS

Approximately 1 in 4 patients with NPDR who had DME had no follow-up visit for at least 1 year after an anti-VEGF injection. Given the importance of ongoing therapy, these real-world findings may help identify at-risk groups for noncompliance with care.

Sensitivity and Specificity of Smartphone-Based Retinal Imaging for Diabetic Retinopathy: A Comparative Study

PURPOSE

To determine the sensitivity and specificity of a smartphone-based fundus camera, the Remidio Fundus on Phone (FOP; Remidio Innovative Solutions Pvt. Ltd., Bengaluru, India) in detecting diabetic retinopathy (DR) compared with a conventional tabletop fundus camera and clinical examination.

DESIGN

Cross-sectional, single-site, instrument validation study.

PARTICIPANTS

Consecutive patients with diabetes who had no DR (n = 55 eyes), mild to moderate nonproliferative diabetic retinopathy (NPDR; n = 70 eyes), severe NPDR (n = 46 eyes), proliferative diabetic retinopathy (PDR; n = 62 eyes), and diabetic macular edema (DME; n = 44 eyes).

METHODS

All participants underwent a dilated examination to determine the grade of DR. Then all participants had mydriatic 45° fundus photographs obtained from three fields of view with the Remidio FOP and a Topcon tabletop fundus camera (Topcon Medical Systems, Inc., Oakland, NJ). Two masked retina specialists graded images for DR and DME, using National Health Service guidelines as well as for image quality using predefined criteria.

MAIN OUTCOME MEASURE

Sensitivity and specificity of the Remidio FOP for the detection of any DR compared to clinical examination.

RESULTS

One hundred thirty-five subjects (233 eyes) were recruited for the study. Compared with the reference clinical examination, using images from the Remidio FOP, graders 1 and 2 reported a sensitivity of 93.1% (95% confidence interval [CI] = 88.3-96.4) and 94.3% (95% CI = 89.7-97.2) and a specificity of 89.1% (95% CI = 68.2-92.2) and 94.5% (95% CI = 84.9-98.9), respectively, in identifying any DR (κ = 0.55; 95% CI = 0.50-0.57). With images from the Topcon camera, graders reported similar sensitivities and specificities with marginally better agreement (κ = 0.68; 95% CI = 0.67-0.73). The sensitivity of detecting DR gradually increased from R1 to R3 disease using both cameras. Both graders classified significantly fewer images as "ungradable" (2.6%-4.3% for Topcon vs. 1.7%-2.1% for Remidio FOP) and more images as excellent from the Remidio FOP (59%-74%) than the Topcon device (52%-61%).

CONCLUSIONS

The Remidio FOP device was found to have high sensitivity and specificity for the detection of any grade of DR with good agreement between graders. The rate of ungradable images was acceptably low and image quality was marginally better with the Remidio FOP.

Intravitreal injection of a Rho-kinase inhibitor (fasudil) combined with bevacizumab versus bevacizumab monotherapy for diabetic macular oedema: a pilot randomised clinical trial

Background/aims

To compare the efficacy of combined intravitreal injection of bevacizumab and a Rho-kinase inhibitor, fasudil (intravitreal bevacizumab (IVB)/intravitreal fasudil (IVF)), with IVB alone for centre-involving diabetic macular oedema (DME).

Methods

In this prospective randomised clinical trial, 44 eyes with centre-involving DME were randomised into two groups. The combined group received three consecutive injections of IVB (1.25 mg) and IVF (50 µM/L) monthly, while the monotherapy group received only one IVB (1.25 mg) injection per month for 3 months. Changes in best-corrected visual acuity (BCVA) and central macular thickness (CMT) were compared between the two groups at months 3 and 6. The primary outcome measure was the mean change in BCVA at month 6.

Results

Mean BCVA was significantly improved in both groups at month 3 (P<0.001), but it persisted up to month 6 only in the IVB/IVF group. Improvement of BCVA was greater in the IVB/IVF group at both time points (P=0.008, P<0.001). In the IVB/IVF and IVB groups, 54.5% versus 10% of the eyes gained≥15 ETDRS letters at month 6 (P=0.026). Between months 3 and 6, mean BCVA significantly decreased by 5±7 ETDRS letters in the IVB group (P=0.002), while no significant deterioration was observed in the IVB/IVF group. Corresponding with the BCVA changes, CMT was significantly reduced in both groups at month 3 (p=0.006, p<0.001) but this reduction sustained only in the IVB/IVF group up to month 6 (p<0.001).

Conclusion

Adjunctive intravitreal injection of a Rho-kinase inhibitor may enhance and prolong the therapeutic effects of anti-vascular endothelial growth factor drugs for centre- involving DME.

Risk factors for development and progression of diabetic retinopathy in Dutch patients with type 1 diabetes mellitus

Purpose

To investigate risk factors for the development and progression of diabetic retinopathy (DR) and long‐term visual outcomes in Dutch patients with type 1 diabetes mellitus (T1DM).

Methods

Cumulative incidences were calculated for DR, vision‐threatening DR (VTDR), defined as (pre)proliferative DR and diabetic macular oedema, and best‐corrected visual acuity (BCVA) <0.5 and <0.3 at the most recent eye examination. The following factors were assessed: duration of diabetes, age of onset of T1DM, gender, mean HbA1c, HbA1c variability (defined as coefficient of variation of five separate HbA1c measurements), mean arterial blood pressure, body mass index, albuminuria and lipid profile. We used multivariable Cox regression models to identify factors associated with DR development and progression to VTDR.

Results

We found 25‐year cumulative incidences of 63% for DR, 21% for VTDR, 2% for BCVA <0.5, and 1% for BCVA <0.3. Mean HbA1c (HR 1.023, p < 0.001), HbA1c variability (HR 1.054, p < 0.001), age of onset of T1DM (HR 1.024, p < 0.001), HDL cholesterol (HR 0.502, p = 0.002) and total cholesterol (HR 1.210, p = 0.029) showed an independent association with faster development of any form of DR. The mean HbA1c (HR 1.023, p < 0.001) and the presence of albuminuria (HR 2.940, p = 0.028) were associated with faster progression to VTDR.

Conclusion

These data show relatively low cumulative incidences of DR, VTDR and visual impairment. Higher mean HbA1c, HbA1c variability, age of onset of T1DM and total cholesterol were independently associated with the risk of DR development, and a protective association was found for HDL cholesterol in subjects with T1DM. Mean HbA1c and presence of albuminuria were associated with progression of DR.

Effects of microRNA-133b on retinal vascular endothelial cell proliferation and apoptosis through angiotensinogen-mediated angiotensin II- extracellular signal-regulated kinase 1/2 signalling pathway in rats with diabetic retinopathy

PURPOSE

This study aimed to explore the effects of microRNA-133b (miR-133b) on diabetic retinopathy (DR) by targeting angiotensinogen (AGT) through the angiotensin-II (AngII) extracellular signal-regulated kinase 1/2 (ERK1/2) signalling pathway in rats.

METHODS

The DR rat model was established using retinal tissues of DR rats and normal rats. Immunohistochemistry was performed to detect the protein expressions of AGT and CD34 in retinal tissues. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were applied to detect miR-133b expression, AGT, AngII, ERK1/2 mRNA, and protein expressions in tissues and cells after transfection. Retinal vascular endothelial cells were cultured and divided into normal, blank, miR-133b mimics, miR-133b mimics negative control (NC), miR-133b inhibitors, miR-133b inhibitors NC, siRNA NC, siRNA-AGT, and miR-133b inhibitors + siRNA-AGT groups. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was performed to detect cell proliferation. Cell cycle and apoptosis were evaluated using flow cytometry.

RESULTS

Compared with normal rats, AGT and CD34 were expressed more frequently in DR rats. MicroRNA (miR)-133b expression was downregulated but AGT, AngII, ERK1 and ERK2 mRNA expressions were upregulated in retinal tissues of DR rats. When compared to the normal group, all other groups displayed decreased cell proliferation, increased cell number in G0/G1, decreased cell number in S stage, increased cell apoptosis rate and declined miR-133b expression. As well, significant increased expressions of AGT and the AngII-ERK1/2 pathway-related proteins were observed in retinal vascular endothelial cells in all groups except the normal group. The miR-133b mimics and siRNA-AGT groups had increased cell proliferation, decreased cell number in the G0/G1 phase, increased cell number in S stage, decreased cell apoptosis rate and decreased expressions of AGT and AngII-ERK1/2 pathway-related proteins than the miR-133b inhibitors + siRNA-AGT group. The miR-133b inhibitors group exhibited opposite trends compared with the miR-133b mimics and siRNA-AGT groups.

CONCLUSION

The study provides data to suggest that miR-133b induces proliferation and inhibits apoptosis of retinal vascular endothelial cells by targeting AGT through the AngII-ERK1/2 signalling pathway in DR rats.

Dopamine Deficiency Mediates Early Rod-Driven Inner Retinal Dysfunction in Diabetic Mice

Purpose

Electroretinograms (ERGs) are abnormal in diabetic retinas before the appearance of vascular lesions, providing a possible biomarker for diabetic vision loss. Previously, we reported that decreased retinal dopamine (DA) levels in diabetic rodents contributed to early visual and retinal dysfunction. In the current study, we examined whether oscillatory potentials (OPs) could serve as a potential marker for detecting early inner retinal dysfunction due to retinal DA deficiency.

Methods

Retinal function was tested with dark-adapted ERGs, taken at 3, 4, and 5 weeks after diabetes induction with streptozotocin. Electrical responses were analyzed and correlations were made with previously reported retinal DA levels. The effect of restoring systemic DA levels or removing DA from the retina in diabetic mice on OPs was assessed using L-3,4-dihydroxyphenylalanine (L-DOPA) treatments and retina-specific tyrosine hydroxylase (Th) knockout mice (rTHKO), respectively.

Results

Diabetic animals had significantly delayed OPs compared to control animals in response to dim, but not bright, flash stimuli. L-DOPA treatment preserved OP implicit time in diabetic mice. Diabetic rTHKO mice had further delayed OPs compared to diabetic mice with normal retinal Th, with L-DOPA treatment also providing benefit. Decreasing retinal DA levels significantly correlated with increasing OP delays mediated by rod pathways.

Conclusions

Our data suggest that inner retinal dysfunction in early-stage diabetes is mediated by rod-pathway deficits and DA deficiencies. OP delays may be used to determine the earliest functional deficits in diabetic retinopathy and to establish an early treatment window for DA therapies that may prevent progressive vision loss.

EFFECTS OF INTRAVITREAL RANIBIZUMAB AND BEVACIZUMAB ON THE RETINAL VESSEL SIZE IN DIABETIC MACULAR EDEMA

PURPOSE

The goal of this study was to assess the effects of a single injection of intravitreal ranibizumab (RAN) or bevacizumab (BEV) on the retinal vessel size in eyes with diabetic macular edema.

MATERIALS AND METHODS

In total, 32 patients were enrolled in the RAN group, and 30 patients were included in BEV group. Each of these groups was also subdivided into two others groups: a study group and a control group. The study groups were composed of the injected eyes, whereas the noninjected fellow eyes served as the control groups. The patients underwent complete ophthalmic examinations, including optical coherence tomography and fundus fluorescein angiography, and the primary outcome measures included the central retinal artery equivalent, central retinal vein equivalent, and artery-to-vein ratio.

RESULTS

In the RAN study group (n = 32), the preinjection mean central retinal artery equivalent (175.42 μm) decreased to 169.01 μm after 1 week, and to 167.47 μm after 1 month (P < 0.001), whereas the baseline central retinal vein equivalent (235.29 μm) decreased initially to 219.90 μm after 1 week, and to 218.36 μm after 1 month (P < 0.001). In the BEV study group (n = 30), the preinjection central retinal artery equivalent (150.21 μm) decreased to 146.25 μm after 1 week, and to 145.89 μm after 1 month (P < 0.001); whereas the baseline central retinal vein equivalent (211.87 μm) decreased initially to 204.59 μm after 1 week and was 205.24 μm after 1 month (P < 0.001). The preinjection artery-to-vein ratio values changed significantly (P = 0.001) after 1 week and after 1 month in the RAN group, but no significant alteration in the artery-to-vein ratio was observed in the BEV group (P = 0.433). In both the RAN (n = 32) and BEV (n = 30) control groups, none of the 3 parameters changed throughout the study period, when compared with the baseline.

CONCLUSION

The results of this study showed that both RAN and BEV injections significantly constricted the retinal blood vessel diameters.