Panretinal Photocoagulation: A Review of Complications

Characterization of the visually impaired patients with diabetes mellitus in Japan

AIMS/INTRODUCTION

To conduct a multicenter survey of visually impaired patients with diabetes mellitus (DM) and to identify the physical and ocular characteristics that lead to blindness in Japan.

MATERIALS AND METHODS

Visually impaired patients with diabetes mellitus in Japan were divided into blind and low-vision groups according to the World Health Organization classification. Data on parameters related to diabetes mellitus and ocular complications in the right and left eyes were collected from 19 highly advanced medical facilities and compared between the two groups.

RESULTS

Among 408 visually impaired persons (blind group: 257, low-vision group: 151), 72.1% were under 70 years of age. The rates of neovascular glaucoma (NVG) (right eye, P = 0.041; left eye, P = 0.0031) or proliferative diabetic retinopathy (PDR) (right eye: P = 0.014, left eye: P = 0.0047) and the rate of proliferative membrane beyond half of the retinal area (right eye: P = 0.0263, left eye: P = 0.037) were significantly higher in the blind group. The direct cause of visual impairment was retinal atrophy, common in both groups. Neovascular glaucoma and diabetic macular edema were equally prevalent in the blind and low-vision groups, respectively.

CONCLUSIONS

In Japan, blind patients with diabetes mellitus are characterized by severe conditions such as neovascular glaucoma and progressive proliferative diabetic retinopathy upon their initial visit to an advanced care facility. These results highlight the importance of monitoring retinopathy through regular ophthalmological examinations, internal medicine, and appropriate therapeutic intervention.

Photoreceptor loss does not recruit neutrophils despite strong microglial activation

In response to central nervous system (CNS) injury, tissue resident immune cells such as microglia and circulating systemic neutrophils are often first responders. The degree to which these cells interact in response to CNS damage is poorly understood, and even less so, in the neural retina which poses a challenge for high resolution imaging in vivo. In this study, we deploy fluorescence adaptive optics scanning light ophthalmoscopy (AOSLO) to study fluorescent microglia and neutrophils in mice. We simultaneously track immune cell dynamics using label-free phase-contrast AOSLO at micron-level resolution. Retinal lesions were induced with 488 nm light focused onto photoreceptor (PR) outer segments. These lesions focally ablated PRs, with minimal collateral damage to cells above and below the plane of focus. We used in vivo (AOSLO, SLO and OCT) imaging to reveal the natural history of the microglial and neutrophil response from minutes-to-months after injury. While microglia showed dynamic and progressive immune response with cells migrating into the injury locus within 1-day after injury, neutrophils were not recruited despite close proximity to vessels carrying neutrophils only microns away. Post-mortem confocal microscopy confirmed in vivo findings. This work illustrates that microglial activation does not recruit neutrophils in response to acute, focal loss of photoreceptors, a condition encountered in many retinal diseases.

The application of functional imaging in visual field defects: a brief review

Visual field defects (VFDs) represent a prevalent complication stemming from neurological and ophthalmic conditions. A range of factors, including tumors, brain surgery, glaucoma, and other disorders, can induce varying degrees of VFDs, significantly impacting patients' quality of life. Over recent decades, functional imaging has emerged as a pivotal field, employing imaging technology to illustrate functional changes within tissues and organs. As functional imaging continues to advance, its integration into various clinical aspects of VFDs has substantially enhanced the diagnostic, therapeutic, and management capabilities of healthcare professionals. Notably, prominent imaging techniques such as DTI, OCT, and MRI have garnered widespread adoption, yet they possess unique applications and considerations. This comprehensive review aims to meticulously examine the application and evolution of functional imaging in the context of VFDs. Our objective is to furnish neurologists and ophthalmologists with a systematic and comprehensive comprehension of this critical subject matter.

Porous Se@SiO2 nanospheres alleviate diabetic retinopathy by inhibiting excess lipid peroxidation and inflammation

BACKGROUND

Lipid peroxidation is a characteristic metabolic manifestation of diabetic retinopathy (DR) that causes inflammation, eventually leading to severe retinal vascular abnormalities. Selenium (Se) can directly or indirectly scavenge intracellular free radicals. Due to the narrow distinction between Se's effective and toxic doses, porous Se@SiO2 nanospheres have been developed to control the release of Se. They exert strong antioxidant and anti-inflammatory effects.

METHODS

The effect of anti-lipid peroxidation and anti-inflammatory effects of porous Se@SiO2 nanospheres on diabetic mice were assessed by detecting the level of Malondialdehyde (MDA), glutathione peroxidase 4 (GPX4), decreased reduced/oxidized glutathione (GSH/GSSG) ratio, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and interleukin (IL) -1β of the retina. To further examine the protective effect of porous Se@SiO2 nanospheres on the retinal vasculopathy of diabetic mice, retinal acellular capillary, the expression of tight junction proteins, and blood-retinal barrier destruction was observed. Finally, we validated the GPX4 as the target of porous Se@SiO2 nanospheres via decreased expression of GPX4 and detected the level of MDA, GSH/GSSG, TNF-α, IFN-γ, IL -1β, wound healing assay, and tube formation in high glucose (HG) cultured Human retinal microvascular endothelial cells (HRMECs).

RESULTS

The porous Se@SiO2 nanospheres reduced the level of MDA, TNF-α, IFN-γ, and IL -1β, while increasing the level of GPX4 and GSH/GSSG in diabetic mice. Therefore, porous Se@SiO2 nanospheres reduced the number of retinal acellular capillaries, depletion of tight junction proteins, and vascular leakage in diabetic mice. Further, we identified GPX4 as the target of porous Se@SiO2 nanospheres as GPX4 inhibition reduced the repression effect of anti-lipid peroxidation, anti-inflammatory, and protective effects of endothelial cell dysfunction of porous Se@SiO2 nanospheres in HG-cultured HRMECs.

CONCLUSION

Porous Se@SiO2 nanospheres effectively attenuated retinal vasculopathy in diabetic mice via inhibiting excess lipid peroxidation and inflammation by target GPX4, suggesting their potential as therapeutic agents for DR.

Insights Into Visual Rehabilitation: Pan-Retinal Photocoagulation for Proliferative Diabetic Retinopathy

This review comprehensively explores pan-retinal photocoagulation (PRP) as a pivotal intervention in visually rehabilitating individuals afflicted with proliferative diabetic retinopathy (PDR). The review begins by elucidating the significance of PDR within the spectrum of diabetic retinopathy (DR), emphasizing the progressive nature of the disease and the consequential impact on visual health. A detailed analysis of PRP follows, encompassing its definition, purpose, and historical development, shedding light on the procedural intricacies and mechanisms of action. The postoperative care and follow-up section underscores the necessity of vigilant monitoring for complications, visual recovery, and the importance of regular ophthalmic check-ups. The subsequent discussion delves into patient education and counseling, stressing the need to manage expectations, encourage lifestyle modifications, and highlight the significance of follow-up appointments. The review concludes with insights into future directions, including advancements in laser technology and emerging therapies, offering a glimpse into the evolving landscape of DR management. By addressing ongoing challenges and embracing innovative approaches, this review provides a comprehensive guide for clinicians, researchers, and healthcare practitioners who visually rehabilitate individuals struggling with PDR.

Lens epithelial cell-derived exosome inhibits angiogenesis in ocular pathological neovascularization through its delivery of miR-146a-5p

Abnormal ocular neovascularization, a major pathology of eye diseases, leads to severe visual loss. The role of lens epithelial cell (LEC)-derived exosomes (Lec-exo) is largely unknown. Thus, we aimed to investigate whether Lec-exo can inhibit abnormal ocular neovascularization and explore the possible mechanisms. In our study, we proved the first evidence that exosomes derived from LECs attenuated angiogenesis in both oxygen-induced retinopathy and laser-induced choroidal neovascularization mice models. Further in vitro experiments proved that Lec-exo inhibited proliferation, migration, and tube formation capability of human umbilical vein endothelial cells in high glucose condition. Further high-throughput miRNAs sequencing analysis detected that miR-146a-5p was enriched in Lec-exo. Mechanistically, exosomal miR-146a-5p was delivered to endothelial cells and bound to the NRAS coding sequence, which subsequently inactivated AKT/ERK signaling pathway. We successfully elucidated the function of Lec-exo in inhibiting abnormal ocular neovascularization, which may offer a promising strategy for treatment of abnormal ocular neovascularization.

Short-Term Outcomes of Trabeculectomy With or Without Anti-VEGF in Patients With Neovascular Glaucoma: A Systematic Review and Meta-Analysis

Objectives

The aim of this study was to compare the safety and efficacy of trabeculectomy alone or combined with intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) agents for the treatment of neovascular glaucoma.

Methods

We conducted a systematic review and meta-analysis to compare the effects of trabeculectomy alone or combined with intravitreal injections of anti-VEGF agents for the treatment of neovascular glaucoma. We searched four databases (PubMed, Cochrane Library, Embase, and Web of Science) up to January 2023 and extracted data on three surgical outcomes: postoperative intraocular pressure, success rate and complications. We used a random-effects model to calculate pooled relative risk (RR) or standardized mean difference (SMD) estimates and 95% confidence intervals (CIs). We assessed publication bias using Begg and Egger tests.

Results

We included seven studies with 353 eyes. Compared to trabeculectomy alone, trabeculectomy with anti-VEGF had a lower risk of postoperative complications (RR, 0.60; 95% CI, 0.41-0.89) and higher success rate (RR, 1.19; 95% CI, 1.02-1.40). The intraocular pressure reduction was significantly greater in the trabeculectomy with anti-VEGF augmentation group than the trabeculectomy group from 1 week (SMD, -1.36; 95% CI, -2.76 to 0.04) to 6 months (SMD, -0.79; 95% CI, -1.50 to -0.07) after surgery.

Conclusions

According to current evidence, adding intravitreal injection of anti-VEGF agents to trabeculectomy may improve the short time outcomes of patients with neovascular glaucoma.

ADAMTS5 promotes neovascularization via autophagic degradation of PEDF in proliferative diabetic retinopathy

Proliferative diabetic retinopathy (PDR) adversely affects visual function. Extracellular matrix proteins (ECM) contribute significantly to the development of PDR. A Disintegrin and Metalloproteinase with Thrombospondin motifs 5 (ADAMTS5) is a member of ECM proteins. ADAMTS5 participates in angiogenesis and inflammation in diverse diseases. However, the role of ADAMTS5 in PDR remains elusive. Multiplex beam array technology was used to analyze vitreous humor of PDR patients and normal people. ELISA and Western blot were used to detect the expression of ADAMTS5, PEDF and autophagy related factors. Immunofluorescence assay was used to mark the expression and localization of ADAMTS5 and PEDF. The neovascularization was detected by tube formation test. Our results revealed that ADAMTS5 expression was increased in the vitreous humor of PDR patients and oxygen-induced retinopathy (OIR) mice retinas. Inhibiting ADAMTS5 alleviated pathological angiogenesis and upregulated PEDF expression in the OIR mice. In addition, ADAMTS5 inhibited PEDF secretion in ARPE-19 cells in vitro studies, thereby inhibiting the migration of HMEC-1. Mechanically, ADAMTS5 promoted the autophagic degradation of PEDF. Collectively, inhibition of ADAMTS5 during OIR suppresses pathological angiogenesis. Our study provides a new approach for resolving pathological angiogenesis in PDR.

Advances in development of exosomes for ophthalmic therapeutics

Exosomes contain multiple bioactive molecules and maintain the connection between cells. Recent advances in exosome-based therapeutics have witnessed unprecedented opportunities in treating ophthalmic diseases, including traumatic diseases, autoimmune diseases, chorioretinal diseases and others. Utilization of exosomes as delivery vectors to encapsulate both drugs and therapeutic genes could yield higher efficacy and avoid the unnecessary immune responses. However, exosome-based therapies also come with some potential ocular risks. In this review, we first present a general introduction to exosomes. Then we provide an overview of available applications and discuss their potential risks. Moreover, we review recently reported exosomes as delivery vectors for ophthalmic diseases. Finally, we put forward future perspectives to grapple with its translation and underlying issues.

FULL-THICKNESS MACULAR HOLE FORMATION FOLLOWING PANRETINAL PHOTOCOAGULATION FOR PROLIFERATIVE DIABETIC RETINOPATHY

PURPOSE

To report two patients who developed full-thickness macular holes following panretinal photocoagulation for proliferative diabetic retinopathy.

METHODS

Case series.

RESULTS

Case 1 was a 58-year-old woman with Type 1 diabetes mellitus and proliferative diabetic retinopathy and Case 2, a 72-year-old man with Type 2 diabetes mellitus and proliferative diabetic retinopathy. Before panretinal photocoagulation, each patient had an epiretinal membrane and an irregular foveal contour noted on optical coherence tomography. At 2 months follow-up, each patient showed foveal floor thinning and Case 2 also had a lamellar macular hole. At 6 months follow-up, each patient had a full-thickness macular hole. Each were successfully repaired with vitrectomy, membrane peeling, and gas tamponade.

CONCLUSION

The relationship between hole formation and previous panretinal photocoagulation in the patients reported here is unclear and possibly coincidental.

The evolving therapeutic landscape of diabetic retinopathy

INTRODUCTION

Diabetic retinopathy (DR) is a leading cause of blindness worldwide. Recent decades have seen rapid progress in the management of diabetic eye disease, evolving from pituitary ablation to photocoagulation and intravitreal pharmacotherapy. The advent of effective intravitreal drugs inhibiting vascular endothelial growth factor (VEGF) marked a new era in DR therapy. Sustained innovation has since produced several promising biologics targeting angiogenesis, inflammation, oxidative stress, and neurodegeneration.

AREAS COVERED

This review surveys traditional, contemporary, and emerging therapeutics for DR, with an emphasis on anti-VEGF therapies, receptor tyrosine kinase inhibitors, angiopoietin-Tie2 pathway inhibitors, integrin pathway inhibitors, gene therapy 'biofactory' approaches, and novel systemic therapies. Some of these investigational therapies are being delivered intravitreally via sustained release technologies for extended durability. Other investigational agents are being delivered non-invasively via topical and systemic routes. These strategies hold promise for early and long-lasting treatment of DR.

EXPERT OPINION

The evolving therapeutic landscape of DR is rapidly expanding our toolkit for the effective and durable treatment of blinding eye disease. However, further research is required to validate the efficacy of novel therapeutics and characterize real world outcomes.

CD40 Upregulation in the Retina of Patients With Diabetic Retinopathy: Association With TRAF2/TRAF6 Upregulation and Inflammatory Molecule Expression

Purpose

CD40 is upregulated in the retinas of diabetic mice, drives pro-inflammatory molecule expression, and promotes diabetic retinopathy. The role of CD40 in diabetic retinopathy in humans is unknown. Upregulation of CD40 and its downstream signaling molecules TNF receptor associated factors (TRAFs) is a key feature of CD40-driven inflammatory disorders. We examined the expression of CD40, TRAF2, and TRAF6 as well as pro-inflammatory molecules in retinas from patients with diabetic retinopathy.

Methods

Posterior poles from patients with diabetic retinopathy and non-diabetic controls were stained with antibodies against von Willebrand factor (labels endothelial cells), cellular retinaldehyde-binding protein (CRALBP), or vimentin (both label Müller cells) plus antibodies against CD40, TRAF2, TRAF6, ICAM-1, CCL2, TNF-α, and/or phospho-Tyr783 phospholipase Cγ1 (PLCγ1). Sections were analyzed by confocal microscopy.

Results

CD40 expression was increased in endothelial and Müller cells from patients with diabetic retinopathy. CD40 was co-expressed with ICAM-1 in endothelial cells and with CCL2 in Müller cells. TNF-α was detected in retinal cells from these patients, but these cells lacked endothelial/Müller cell markers. CD40 in Müller cells from patients with diabetic retinopathy co-expressed activated phospholipase Cγ1, a molecule that induces TNF-α expression in myeloid cells in mice. CD40 upregulation in endothelial cells and Müller cells from patients with diabetic retinopathy was accompanied by TRAF2 and TRAF6 upregulation.

Conclusions

CD40, TRAF2, and TRAF6 are upregulated in patients with diabetic retinopathy. CD40 associates with expression of pro-inflammatory molecules. These findings suggest that CD40-TRAF signaling may promote pro-inflammatory responses in the retinas of patients with diabetic retinopathy.

A Useful Method for the Practice of Pneumatic Retinopexy: Slit-Lamp Laser Photocoagulation through the Gas Bubble

This study aimed to demonstrate the laser retinopexy method through the gas bubble under a slit-lamp biomicroscope using a wide-field contact lens to treat rhegmatogenous retinal detachment (RRD) with pneumatic retinopexy (PR) and report its anatomical and functional results. This single-center, retrospective case series included RRD patients treated with PR using sulfur hexafluoride (SF₆). The demographics, preoperative factors, and anatomical and functional outcomes were collected from the patient files. The single-procedure success rate of PR at postoperative 6th months was 70.8% (17/24 eyes), and the final success rate after secondary surgeries was 100%. The BCVA was better in the successful PR eyes at postoperative 3rd (p = 0.011) and 6th month (p = 0.016) than in failed eyes. No single preoperative factor was associated with PR success. The single-procedure success rate of PR using the laser retinopexy method through the gas bubble with a wide-field contact lens system seems comparable to the PR literature.

Update on the Management of Diabetic Retinopathy: Anti-VEGF Agents for the Prevention of Complications and Progression of Nonproliferative and Proliferative Retinopathy

Diabetic retinopathy (DR) is a microvascular disease caused by poorly controlled blood glucose, and it is a leading cause of vision loss in people with diabetes. In this review we discuss the current management of DR with particular focus on the use of intraocular anti-vascular endothelial growth factor (anti-VEGF) agents. Intraocular anti-VEGF agents were first studied in the 1990s, and now several of these agents are either FDA approved or used off-label as first-line treatments for DR. Recent evidence shows that anti-VEGF agents can halt the progression of markers of DR severity, reduce the risk of DR worsening, and reduce the onset of new macular edema. These significant benefits have been demonstrated in patients with proliferative DR and the milder nonproliferative DR (NPDR). A wealth of evidence from recent trials and meta-analyses has detailed the intraoperative and postoperative benefits of adjunctive anti-VEGF therapy prior to pars plana vitrectomy (PPV) for proliferative DR with vitreous hemorrhage. In this review, we also discuss literature comparing various anti-VEGF injection regimens including monthly, quarterly, as-needed, and treat and extend protocols. Combination protocols with panretinal photocoagulation (PRP) or PPV are also discussed. Current evidence suggests that anti-VEGF therapies are effective therapy for NPDR and PDR and may also provide significant benefits when used adjunctively with other DR treatment modalities such as PRP or PPV.

Development and Preliminary Validation of an Instrument to Measure Symptoms and Impacts in Patients with Proliferative Diabetic Retinopathy

INTRODUCTION

Following a review of patient-reported outcome (PRO) instruments in the literature, existing PRO instruments may not adequately capture the experience of receiving treatment for proliferative diabetic retinopathy (PDR). Therefore, this study aimed to develop a de novo instrument to comprehensively assess the patient experience of PDR.

METHODS

This qualitative, mixed-methods study comprised item generation for the Diabetic Retinopathy-Patient Experience Questionnaire (DR-PEQ), content validation in patients with PDR, and preliminary Rasch measurement theory (RMT) analyses. Adult patients with diabetes mellitus and PDR who received aflibercept and/or panretinal photocoagulation within 6 months of study initiation were eligible for participation. The preliminary DR-PEQ comprised four scales: Daily Activities, Emotional Impact, Social Impact, and Vision Problems. DR-PEQ items were generated using existing knowledge of patient experiences in PDR and conceptual gaps identified from existing PRO instruments. Patients indicated the level of difficulty conducting daily activities and frequency experiencing emotional impacts, social impacts, and vision problems attributed to diabetic retinopathy and its treatment in the past 7 days. Content validity was evaluated in two rounds of in-depth, semi-structured patient interviews. Measurement properties were investigated via RMT analyses.

RESULTS

The preliminary DR-PEQ comprised 72 items. Overall, mean (SD) patient age was 53.7 (14.7) years. Forty patients completed the first interview; of these, 30 completed the second interview. Patients reported that the DR-PEQ was easily understood and relevant to their experience. Minor revisions, including removal of the Social Impact scale and addition of a Treatment Experience scale, were implemented to generate 85 items spanning four scales: Daily Activities, Emotional Impact, Vision Problems, and Treatment Experience. RMT analyses provided preliminary evidence that the DR-PEQ performed as intended.

CONCLUSION

The DR-PEQ evaluated a broad spectrum of symptoms, functional impacts, and treatment experiences relevant to patients with PDR. Additional analyses are warranted to evaluate psychometric properties in a larger patient population.

NOVEL OPTICAL COHERENCE TOMOGRAPHY FINDINGS IN SEROUS MACULAR DETACHMENT AFTER PANRETINAL PHOTOCOAGULATION

PURPOSE

To describe a novel optical coherence tomography finding in a case of macular serous retinal detachment after pars plana vitrectomy and panretinal photocoagulation.

METHODS

Retrospective case report.

RESULTS

A 52 year old male with diabetes underwent uncomplicated pars plana vitrectomy with panretinal photocoagulation for non-clearing vitreous hemorrhage, Postoperative course was complicated by significantly decreased vision and a macular serous retinal detachment that was characterized on optical coherence tomography by a reticular network of hyperreflective bands in the subretinal space. Fluid and hyperreflective material in the subretinal space resolved by postoperative Week 6 with standard postoperative eye drops. However, persistent ellipsoid zone disruption was seen up to postoperative Week 20.

CONCLUSION

Extensive subretinal bands can be seen after panretinal photocoagulation. This novel finding can pose diagnostic and management challenges but may resolve with conservative medical management.

The Patient Experience with Diabetic Retinopathy: Qualitative Analysis of Patients with Proliferative Diabetic Retinopathy

INTRODUCTION

Few qualitative studies have explored the patient experience of daily life with proliferative diabetic retinopathy (PDR) and associated treatments. Herein, a conceptual model was developed to comprehensively examine symptoms, functional impacts, and treatment experiences in PDR.

METHODS

A qualitative, mixed-methods study comprising a literature search and semi-structured interviews with clinicians and patients was conducted. Published literature and online patient resources were searched to identify concepts relevant to patients, including symptoms, functional impacts, and treatment experiences of PDR. Semi-structured interviews with experienced clinicians were conducted to identify symptoms and impacts reported by patients with PDR and to receive feedback regarding concepts identified from the literature search. A preliminary conceptual model was then developed based on findings from the literature search and clinician interviews. Patients with PDR participated in two rounds of semi-structured interviews to identify additional concepts relevant to the patient experience in PDR and associated treatments, which informed revisions to the conceptual model. Saturation of patient interviews was assessed.

RESULTS

Findings from the literature search and clinician interviews yielded 109 concepts that were included in a preliminary conceptual model with three overarching domains: symptoms, impacts, and managing the disease. Clinicians confirmed concepts identified from the literature search. During interviews, patients reported a broad spectrum of symptoms (e.g., red vision); functional impacts relating to activities of daily living (e.g., reading), emotional functioning (e.g., loss of independence), and social functioning (e.g., problems recognizing faces); and treatment experiences (e.g., improves eye problems, no change) associated with PDR. Additional concepts elicited in patient interviews informed revisions to the conceptual model. Saturation was achieved in the patient sample.

CONCLUSIONS

A wide variety of symptoms, functional impacts, and treatment experiences that significantly affect health-related quality of life were identified in patients with PDR. These insights are critical for understanding PDR symptomology and assessing treatment response.

Cross Talks between Oxidative Stress, Inflammation and Epigenetics in Diabetic Retinopathy

Diabetic retinopathy, one of the most devastating complications of diabetes, is a multifactorial progressing disease with a very complex etiology. Although many metabolic, molecular, functional and structural changes have been identified in the retina and its vasculature, the exact molecular mechanism of its pathogenesis still remains elusive. Sustained high-circulating glucose increases oxidative stress in the retina and also activates the inflammatory cascade. Free radicals increase inflammatory mediators, and inflammation can increase production of free radicals, suggesting a positive loop between them. In addition, diabetes also facilitates many epigenetic modifications that can influence transcription of a gene without changing the DNA sequence. Several genes associated with oxidative stress and inflammation in the pathogenesis of diabetic retinopathy are also influenced by epigenetic modifications. This review discusses cross-talks between oxidative stress, inflammation and epigenetics in diabetic retinopathy. Since epigenetic changes are influenced by external factors such as environment and lifestyle, and they can also be reversed, this opens up possibilities for new strategies to inhibit the development/progression of this sight-threatening disease.

Advances in targeted retinal photocoagulation in the treatment of diabetic retinopathy

AIM

Targeted retinal photocoagulation (TRP) is an emerging laser technology for retinal targeted therapy. TRP can specifically act on unperfused retinal capillaries and retinal intermediate ischemic areas, reduce damage to tissue perfusion areas and panretinal photocoagulation (PRP) complications or adverse events. In this regard, this review discusses the treatment options, efficacy, and latest progress of TRP for diabetic retinopathy (DR) based on randomized controlled trial (RCT), meta-analysis, case review, and other existing studies.

METHODS

In-depth research was conducted on articles about the proposal and development of TRP, its simple application in DR, and combined therapy. In order to review the new progress, application methods, effects, and prospects of TRP in the treatment of DR, the articles related to TRP in the databases of PubMed and Web Of Science since this century were comprehensively analyzed.

RESULTS

TRP is effective in treating DR and may become a substitute for PRP in the future. In addition, the treatment regimen of TRP combined with intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) drugs can also be used as a new therapeutic approach to expand the treatment regimen for the treatment of DR, and this combination therapy also has effects on other retinal vascular diseases.

CONCLUSIONS

With the advancement of technology, TRP has been continuously applied in clinical practice, and its potential benefits have opened up broad prospects for the treatment of DR. The combination therapy of TRP and anti-VEGF is expected to become a new option for patients with DR an retinal diseases.

Intravitreal anti-vascular endothelial growth factor, laser photocoagulation, or combined therapy for diabetic macular edema: A systematic review and network meta-analysis

PURPOSE

To conduct a network meta-analysis (NMA) comparing the efficacy of anti-vascular endothelial growth factor (VEGF) therapy alone versus laser photocoagulation (LP) therapy alone or anti-VEGF therapy combined with LP therapy for diabetic macular edema (DME).

METHODS

PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials were systematically searched for studies comparing anti-VEGF therapy alone versus LP therapy alone or anti-VEGF therapy combined with LP therapy for DME. Primary outcomes were mean best-corrected visual acuity (BCVA) and central macular thickness (CMT) change. Relevant data were collected and pooled using NMA.

RESULTS

A total of 13 randomized controlled trials were included in our NMA. Anti-VEGF therapy significantly improved BCVA the most compared to the combined (mean difference [MD] = 1.5; 95% confidence interval [CI]: 0.084, 2.7) and LP (MD = 6.3; 95% CI: 5.1, 7.6) therapies at six months, while there was no difference in reducing CMT at six months between the anti-VEGF and combined therapies (MD = -16; 95% CI: -46, 13). At 12 months, no significant difference was found between the anti-VEGF and combined therapy in terms of BCVA (MD = 0.1; 95% CI: -1.7, 1.5) and CMT (MD = 21; 95% CI: -3.0, 44).

CONCLUSION

There was no significant difference between the anti-VEGF therapy and combined therapy. For the long-term treatment of patients with DME, combined therapy is recommended.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD42022376401.

Rhegmatogenous retinal detachment after retinopathy of prematurity laser treatment

Purpose

Rhegmatogenous retinal detachment (RRD) after retinopathy of prematurity (ROP) laser is rare but has been reported to occur at the border of heavy laser or in combination with tractional retinal detachment (TRD). We describe a rare case of a RRD that developed during treatment for ROP with both laser and intravitreal injections.

Observations

The retinal detachment resolved with scleral buckling surgery with residual macular atrophy.

Conclusions and Importance

This case highlights the importance of retinal imaging, careful funduscopic examination, and consideration of the risk of RRDs after intravitreal injections and laser in neonates with ROP.

Quantification of macular perfusion following panretinal photocoagulation for diabetic retinopathy: An optical coherence tomography angiography study

PURPOSE

To assess the effects of panretinal photocoagulation (PRP) on the microvascular structure of the macula and central thickness of the macula and choroid via optical coherence tomography angiography (OCTA).

METHODS

In this prospective clinical study, 43 eyes of 31 patients with severe non-proliferative diabetic retinopathy or early proliferative diabetic retinopathy were included. Before and at the third and sixth months after PRP, the foveal avascular zone (FAZ) area, acircularity index (AI), foveal density (FD), and vascular density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were evaluated using OCTA. The central macular thickness (CMT) and subfoveal choroidal thickness (SCT) were also measured after PRP.

RESULTS

There was no difference between the FAZ area, AI, FD, and vessel density of the SCP and DCP before and at the third and sixth months after PRP (all p>0.05). The CMT value was higher at the third and sixth months than at baseline (p = 0.002 and p = 0.001, respectively). The SCT value was lower at the third and sixth months than at baseline (p = 0.002 and p = 0.001, respectively).

CONCLUSION

PRP is a beneficial and reliable method that supports the integrity of the macular microvascular structure. After PRP, the CMT increases, and the SCT decreases.

Effect of peripheral laser photocoagulation retinopexy on macular morphology and optic nerve fiber layer thickness; a prospective case series

PURPOSE

The goal of the research was to determine the incidence of microstructural alterations in the macula and optic nerve head (ONH) occurred in eyes treated with peripheral laser photocoagulation retinopexy.

METHODS

Patients with retinal breaks, retinal holes, retinal dialysis, and lattice degenerations who required peripheral laser photocoagulation retinopexy were recruited in this prospective case series investigation. We performed preoperative and postoperative evaluations, including best corrected visual acuity (BCVA), slit lamp examination, intraocular pressure (IOP) measurement, funduscopic examination, and macular and ONH optical coherence tomography (OCT).

RESULTS

Thirty-three eyes of the twenty-three patients enrolled in this study, 14 of which were female. The mean age of the sample was 45.12 ± 9.12 years. The mean refractive error was - 2.45 ± 1.12 Diopters (D). The most prevalent reason for peripheral laser photocoagulation retinopexy was retinal thinning with symptomatic lattice degeneration (90%), followed by retinal hole and break (7%) and retinal dialysis (3%). Between preoperative and postoperative (6-month) evaluation, there was no statistically significant difference in BCVA (P = 0.82), IOP (P = 0.54), central foveal thickness in macular OCT (P = 0.39), or global retinal nerve fiber layer (RNFL) thickness (P = 0.51). There was no association between changes in central foveal thickness and global RNFL thickness and total laser spot numbers (r = - 0.17 P = 0.21, r = 0.06 P = 0.60, respectively). None of patients developed cystoid macular edema (CME) or macular epiretinal membrane (ERM) .

CONCLUSION

We found that OCT parameters were not significantly affected by laser retinopexy in patients with high-risk peripheral retinal lesions, also none of our patients had developed ERM, vitromacular traction or CME at 6 months follow up periods.

Laser Treatment Modalities for Diabetic Retinopathy

Diabetes is a chronic progressive metabolic disorder that is caused by the body's inability to regulate blood glucose levels. If uncontrolled, it can lead to various complications. Among its various complications, long-term diabetes leads to diabetic retinopathy (DR). It is a disease involving blood vessels and the destruction of retinal nerves. It is usually classified into two types: proliferative diabetic retinopathy (PDR) and nonproliferative diabetic retinopathy (NPDR). It progresses and causes loss of vision. The leading cause of loss of vision is diabetic macular edema (DME). The argon laser is used as a modality in the management of PDR. There are various types of laser photocoagulation, such as peripheral retinal laser photocoagulation, focal macular laser photocoagulation, and grid photocoagulation. DR results in various adverse consequences such as vitreous hemorrhage, fibrosis, traction, detachment of the retina, and glaucoma. To assess DR, a detailed fundus examination with a slit lamp biomicroscope needs to be done. Seven-standard field stereoscopic-color fundus photography needs to be done for documentation and follow-up. Patients with diabetes mellitus (DM) type 1 have a greater risk of suffering from DR. Another major complication of the condition is DME, which is characterized by an increase in the permeability of vessels and the thickening of the central part of the retina along with the accumulation of hard exudates on the macula. This article discusses various laser therapy modalities for the treatment of DR, their types, mechanisms, and aims. Clinical features of DR include abnormal dilatation of capillaries, and outpouchings in the form of microaneurysm from the capillary wall are one of the earliest and most dangerous changes; later, non-perfusion of the retina occurs, which is associated with cotton wool spots and blot hemorrhages. In patients suffering from PDR and maculopathy, peripheral retinal laser photocoagulation is used as a mode of intervention.

Systemic Administration of Pegylated Arginase-1 Attenuates the Progression of Diabetic Retinopathy

Diabetic retinopathy (DR) is a serious complication of diabetes that results from sustained hyperglycemia, hyperlipidemia, and oxidative stress. Under these conditions, inducible nitric oxide synthase (iNOS) expression is upregulated in the macrophages (MΦ) and microglia, resulting in increased production of reactive oxygen species (ROS) and inflammatory cytokines, which contribute to disease progression. Arginase 1 (Arg1) is a ureohydrolase that competes with iNOS for their common substrate, L-arginine. We hypothesized that the administration of a stable form of Arg1 would deplete L-arginine’s availability for iNOS, thus decreasing inflammation and oxidative stress in the retina. Using an obese Type 2 diabetic (T2DM) db/db mouse, this study characterized DR in this model and determined if systemic treatment with pegylated Arg1 (PEG-Arg1) altered the progression of DR. PEG-Arg1 treatment of db/db mice thrice weekly for two weeks improved visual function compared with untreated db/db controls. Retinal expression of inflammatory factors (iNOS, IL-1β, TNF-α, IL-6) was significantly increased in the untreated db/db mice compared with the lean littermate controls. The increased retinal inflammatory and oxidative stress markers in db/db mice were suppressed with PEG-Arg1 treatment. Additionally, PEG-Arg1 treatment restored the blood–retinal barrier (BRB) function, as evidenced by the decreased tissue albumin extravasation and an improved endothelial ZO-1 tight junction integrity compared with untreated db/db mice.

A Paradigm Shift in the Management Approaches of Proliferative Diabetic Retinopathy: Role of Anti-VEGF Therapy

Diabetic retinopathy (DR) is considered one of the leading causes of vision loss globally. It principally causes upregulation of pro-angiogenic, proinflammatory, and vascular permeability factors such as vascular endothelial growth factor (VEGF), leading to neovascularisation. The advanced stage of DR or proliferative diabetic retinopathy (PDR) is of more concern, as it leads to vitreous haemorrhage and traction retinal detachment. Various risk factors associated with PDR include hyperglycemia, hypertension, neuropathy, dyslipidemia, anaemia, nephropathy, and retinal complications of drugs used for diabetes. Current management approaches for PDR have been stratified and involve pan-retinal photocoagulation, vitrectomy, and anti-VEGF agents. Given the emerging role of anti-VEGF agents as a favourable adjunct or alternative therapy, they have a critical role in the management of PDR. The review emphasises current management approaches for PDR focusing on anti-VEGF therapy. The review also highlights the risk/benefit evaluation of the various approaches employed for PDR management in various clinical scenarios.

Dry eye disease in patients with type II diabetes mellitus: A retrospective, population-based cohort study in Taiwan

Purpose

To investigate the risk and protective factors of dry eye disease (DED) in patients with type II diabetes mellitus (DM).

Design

A retrospective cohort study using Chang- Gung research database collecting data from 2005 to 2020.

Methods

Patients with type II DM were included, and those with previous ocular diseases were excluded. Ten thousand twenty nine developed DED (DED group), and 142,491 didn't (non-DED group). The possible risk and protective factors were compared and analyzed using the logistic regression model.

Results

A majority of the DED group were female with significantly higher initial and average glycated hemoglobin levels, and higher incidence of diabetic neuropathy and retinopathy. In conditional logistic regression model, advanced age was a risk factor. After adjusting for sex, age, and DM duration; average glycated hemoglobin level, diabetic neuropathy, retinopathy, and nephropathy with eGFR 30 ~ 59 and intravitreal injection, vitrectomy, pan-retinal photocoagulation, and cataract surgery were contributing factors of DED. Considering antihyperglycemic agents, DPP4 inhibitor, SGLT2 inhibitor, GLP-1 agonist, and insulin monotherapy and dual medications combining any two of the aforementioned agents were protective factors against DED compared with metformin alone. In the monotherapy group, SLGT2 inhibitor had the lowest odds ratio, followed by GLP1 agonist, DPP4 inhibitor, and insulin.

Conclusions

DED in patients with DM is associated with female sex, advanced age, poor diabetic control, microvascular complications and receiving ocular procedures. GLP-1 agonist, SGLT-2 inhibitor, DPP4 inhibitor, and insulin are superior to metformin alone in preventing DM-related DED. A prospective randomized control trial is warranted to clarify our results.

Current Trends in Clinical Characteristics, Diagnosis, and Treatment of Polypoidal Choroidal Vasculopathy: A Perspective from Vietnam

Polypoidal choroidal vasculopathy (PCV) is a common choroidal disease in the Asian population including Vietnam and is characterized by subretinal red-orange nodules, pigmented epithelium detachment, and massive subretinal hemorrhage. The recent focus on PCV in Vietnam can be attributed to advancements in PCV diagnosis and treatment. However, there is a scarcity of published literature and clinical data on PCV in the Vietnamese population, highlighting a key knowledge gap in this region. In order to address this gap, we gathered the opinions of experienced clinicians and retinal experts in Vietnam and reviewed available medical literature with the aim of: (i) providing an overview of PCV in the Vietnamese population—in terms of epidemiology, clinical characteristics, and management; (ii) tailoring international/national guidelines for the diagnosis and management of PCV, in line with available resources and medical equipment in Vietnam; and (iii) identifying gaps in clinical data in order to guide future PCV research in Vietnam and other countries with similar clinical conditions. The present review will enable healthcare providers and researchers to gain insight into current clinical practices and the limitations of PCV management in Vietnam and provide optimal and effective solutions.

mTOR inhibition as a novel gene therapeutic strategy for diabetic retinopathy

In addition to laser photocoagulation, therapeutic interventions for diabetic retinopathy (DR) have heretofore consisted of anti-VEGF drugs, which, besides drawbacks inherent to the treatments themselves, are limited in scope and may not fully address the condition’s complex pathophysiology. This is because DR is a multifactorial condition, meaning a gene therapy focused on a target with broader effects, such as the mechanistic target of rapamycin (mTOR), may prove to be the solution in overcoming these concerns. Having previously demonstrated the potential of a mTOR-inhibiting shRNA packaged in a recombinant adeno-associated virus to address a variety of angiogenic retinal diseases, here we explore the effects of rAAV2-shmTOR-SD in a streptozotocin-induced diabetic mouse model. Delivered via intravitreal injection, the therapeutic efficacy of the virus vector upon early DR processes was examined. rAAV2-shmTOR-SD effectively transduced mouse retinas and therein downregulated mTOR expression, which was elevated in sham-treated and control shRNA-injected (rAAV2-shCon-SD) control groups. mTOR inhibition additionally led to marked reductions in pericyte loss, acellular capillary formation, vascular permeability, and retinal cell layer thinning, processes that contribute to DR progression. Immunohistochemistry showed that rAAV2-shmTOR-SD decreased ganglion cell loss and pathogenic Müller cell activation and proliferation, while also having anti-apoptotic activity, with these effects suggesting the therapeutic virus vector may be neuroprotective. Taken together, these results build upon our previous work to demonstrate the broad ability of rAAV2-shmTOR-SD to address aspects of DR pathophysiology further evidencing its potential as a human gene therapeutic strategy for DR.

Biochemical mechanism underlying the pathogenesis of diabetic retinopathy and other diabetic complications in humans: the methanol-formaldehyde-formic acid hypothesis

Hyperglycemia in diabetic patients is associated with abnormally-elevated cellular glucose levels. It is hypothesized that increased cellular glucose will lead to increased formation of endogenous methanol and/or formaldehyde, both of which are then metabolically converted to formic acid. These one-carbon metabolites are known to be present naturally in humans, and their levels are increased under diabetic conditions. Mechanistically, while formaldehyde is a cross-linking agent capable of causing extensive cytotoxicity, formic acid is an inhibitor of mitochondrial cytochrome oxidase, capable of inducing histotoxic hypoxia, ATP deficiency and cytotoxicity. Chronic increase in the production and accumulation of these toxic one-carbon metabolites in diabetic patients can drive the pathogenesis of ocular as well as other diabetic complications. This hypothesis is supported by a large body of experimental and clinical observations scattered in the literature. For instance, methanol is known to have organ- and species-selective toxicities, including the characteristic ocular lesions commonly seen in humans and non-human primates, but not in rodents. Similarly, some of the diabetic complications (such as ocular lesions) also have a characteristic species-selective pattern, closely resembling methanol intoxication. Moreover, while alcohol consumption or combined use of folic acid plus vitamin B is beneficial for mitigating acute methanol toxicity in humans, their use also improves the outcomes of diabetic complications. In addition, there is also a large body of evidence from biochemical and cellular studies. Together, there is considerable experimental support for the proposed hypothesis that increased metabolic formation of toxic one-carbon metabolites in diabetic patients contributes importantly to the development of various clinical complications.

Novel Therapeutics for Diabetic Retinopathy and Diabetic Macular Edema: A Pathophysiologic Perspective

Diabetic retinopathy (DR) and diabetic macular edema (DME) are retinal complications of diabetes that can lead to loss of vision and impaired quality of life. The current gold standard therapies for treatment of DR and DME focus on advanced disease, are invasive, expensive, and can trigger adverse side-effects, necessitating the development of more effective, affordable, and accessible therapies that can target early stage disease. The pathogenesis and pathophysiology of DR is complex and multifactorial, involving the interplay between the effects of hyperglycemia, hyperlipidemia, hypoxia, and production of reactive oxygen species (ROS) in the promotion of neurovascular dysfunction and immune cell polarization to a proinflammatory state. The pathophysiology of DR provides several therapeutic targets that have the potential to attenuate disease progression. Current novel DR and DME therapies under investigation include erythropoietin-derived peptides, inducers of antioxidant gene expression, activators of nitric oxide/cyclic GMP signaling pathways, and manipulation of arginase activity. This review aims to aid understanding of DR and DME pathophysiology and explore novel therapies that capitalize on our knowledge of these diabetic retinal complications.

[Internal ophthalmoplegia after retinal laser photocoagulation]

Laser photocoagulation of the retina is a highly effective technique for preventing visual loss in patients with a wide range of eye fundus diseases. The procedure involves creating thermal burns in the eye fundus accompanied by tissue coagulation, but unfortunately it can lead to possible side-effects and potential complications in the future. Some of the rare complications following retinal laser photocoagulation discussed in this article are accommodative weakness and pupil dilation with eventual transitory myopia and corneal sensitivity impairment. This literature review aims to provide an objective summary of global scientific literature on the issue of internal ophthalmoplegia developing after retinal laser photocoagulation, and describes in detail the current state of the problem including reported occurrences, inciting factors and underlying pathophysiology.

Novel Treatments for Diabetic Macular Edema and Proliferative Diabetic Retinopathy

PURPOSE OF REVIEW

Diabetic retinopathy (DR), a common cause of vision loss, is projected to increase worldwide, and is associated with significant morbidity. The current standard-of-care treatments can preserve and significantly improve vision in many patients affected by DR. However, challenges such as heavy treatment burden and refractory disease remain. The purpose of this review is to highlight and discuss investigative agents in development for the treatment of DR.

RECENT FINDINGS

There are several novel agents with unique mechanisms that may offer greater durability and efficacy compared to existing drugs. Some target new pathways, others leverage a slow-release delivery system, and some modify gene expression through a single-dose treatment. While unfavorable adverse events, such as intraocular inflammation, have been observed with longer-durability agents, many investigational products show excellent efficacy and safety profiles. The outcomes of ongoing and future trials may revolutionize the current treatment paradigm for DR.

Polymyositis and dermatomyositis: ocular manifestations and potential sight-threatening complications

Dermatomyositis (DM) and polymyositis (PM) are idiopathic inflammatory myopathies characterized by progressive, symmetric, mainly proximal muscle weakness. DM is also characterized by cutaneous involvement. However, other clinical features, systemic involvement, histopathological findings, response to treatment, and prognosis, differ significantly. Although uncommon, ocular manifestations in DM and PM may potentially affect any structure within the eye. Notwithstanding being generally mild, ocular involvement in DM and PM may result in significant morbidity. Left untreated, significant retinal inflammation associated with hemorrhage and detachment may occur, leading to significant vision loss. This review aims to present an up-to-date overview for rheumatologists about the ocular involvement and potential complications of DM and PM and when to refer to the ophthalmologist to avoid sight-threatening complications.

Intravitreal anti-vascular endothelial growth factors, panretinal photocoagulation and combined treatment for proliferative diabetic retinopathy: a systematic review and network meta-analysis

PURPOSE

To conduct a systematic review with network meta-analysis (NMA) of randomized clinical trials (RCTs) comparing panretinal photocoagulation (PRP) versus anti-vascular endothelial growth factor (VEGF) treatment alone or in combination with PRP, for proliferative diabetic retinopathy (PDR).

METHODS

PubMed, Medline and Embase databases were searched for RCTs comparing PRP versus intravitreal anti-VEGF therapy and/or combined PRP and intravitreal anti-VEGF for PDR. The primary outcome measures were the mean best corrected visual acuity (BCVA) change and the regression of neovascularization. Mean change of central macular thickness (CMT), the subgroup analyses of patients without diabetic macular oedema (DME) and the rate of vitreous haemorrhage and vitrectomy were secondary outcomes. Frequentist NMAs were performed.

RESULTS

Twelve RCTs were included. For the 12-month mean BCVA change, NMA showed a better visual outcome in both the anti-VEGF group and combined group compared to PRP [anti-VEGF vs PRP, mean difference (MD) = 3.42; standard error (SE) = 1.5; combined vs PRP, MD = 3.92; SE = 1.65], with no difference between combined group and anti-VEGF (MD = -0.50; SE = 1.87). No difference in neovascularization regression was found between PRP and anti-VEGF alone or in combination with PRP, but there was significant inconsistency (p = 0.016). Subgroup analyses in patients without DME yielded no difference for the 12-month visual outcome between the three interventions, but with significant inconsistency (p = 0.005).

CONCLUSION

This NMA showed limited evidence of comparable efficacy in terms of neovascularization regression between PRP and anti-VEGF therapy alone or in combination with PRP, but better visual outcomes were associated with anti-VEGF use. Intravitreal anti-VEGF therapy could be a valid therapeutic option in association with PRP.

Effect of pattern scanning laser on macular thickness in diabetic retinopathy

Purpose:

This study investigates the effect of pattern scanning laser (PASCAL) panretinal photocoagulation (PRP) on central macular thickness (CMT) and visual acuity (VA) in patients with proliferative diabetic retinopathy (PDR).

Methods:

This retrospective non-randomized comparative case series included 262 eyes (163 with macular edema) of 177 patients with PDR. Treatment was PRP alone (137), PRP + anti-vascular endothelial growth factor (VEGF) (69), PRP + focal laser (28), or all three (89). CMT and central macular volume 3 and 6 mm from fovea were analyzed before and 1, 3, and 6 months after PRP. Spot number was plotted against CMT, and linear regression analysis was performed.

Results:

For each treatment group and time point, there was a non-significant relationship between spot number and CMT. In eyes receiving all three treatment modalities, a significant negative relationship was found between spot number and 3-mm volume at 6 months (p = 0.04) and 6-mm volume at 1 month (p = 0.002) and 6 months (p = 0.011). There was no significant change in VA in any treatment group at the 6-month time point.

Conclusion:

PASCAL PRP ± focal laser or anti-VEGF was not associated with increased development of macular edema or change in VA. PASCAL PRP with focal laser and anti-VEGF may result in a decrease in macular edema.

Evaluation of Intravitreal Aflibercept for the Treatment of Severe Nonproliferative Diabetic Retinopathy: Results From the PANORAMA Randomized Clinical Trial

Question

Does treatment of moderately severe to severe nonproliferative diabetic retinopathy (NPDR) with intravitreal aflibercept injections result in 2-step or greater improvement on the Diabetic Retinopathy Severity Scale in more eyes, fewer vision-threatening complications, and fewer center-involved diabetic macular edema events from baseline through 100 weeks compared with sham injections?

Findings

In this randomized clinical trial of 402 patients with moderately severe to severe NPDR without diabetic macular edema, more eyes treated with intravitreal aflibercept injections showed a 2-step or greater improvement on the Diabetic Retinopathy Severity Scale at 24, 52, and 100 weeks, with significantly fewer vision-threatening complications and center-involved diabetic macular edema events. No differences in mean change in best-corrected visual acuity at weeks 52 and 100 were observed.

Meaning

In this study, anatomic improvement was more likely to occur in eyes with moderately severe to severe NPDR that were treated with intravitreal aflibercept injections; in year 2, fixed dosing appeared necessary to maintain anatomic benefit.

Importance

Proactive treatment of nonproliferative diabetic retinopathy (NPDR) reduces the risk of progression to vision-threatening complications.

Objective

To evaluate vascular endothelial growth factor blockade therapy with intravitreal aflibercept injections in eyes with severe NPDR without diabetic macular edema (DME).

Design, Setting, and Participants

The Study of the Efficacy and Safety of Intravitreal Aflibercept for the Improvement of Moderately Severe to Severe Nonproliferative Diabetic Retinopathy (PANORAMA) was a double-masked 100-week randomized clinical trial conducted in multiple centers worldwide. The study included 402 adults with Diabetic Retinopathy Severity Scale (DRSS) level 47 or 53 with no DME and best-corrected visual acuity of 20/40 or better.

Interventions

Intravitreal injections of aflibercept, 2 mg, every 16 weeks after 3 initial monthly doses and one 8-week interval (aflibercept 2q16 group); intravitreal injections of aflibercept, 2 mg, every 8 weeks after 5 initial monthly doses, with pro re nata (PRN) dosing beginning at week 56 (aflibercept 2q8/PRN group); or sham injections (control group).

Main Outcomes and Measures

Proportions of eyes with a 2-step or greater improvement in DRSS level, vision-threatening complications, and center-involved DME from baseline to weeks 24, 52, and 100.

Results

Among 402 participants (1 eye per participant), the mean (SD) age was 55.7 (10.5) years; 225 (56.0%) were male, and 310 (77.1%) were White. A total of 135 were randomized to the aflibercept 2q16 group, 134 to the aflibercept 2q8/PRN group, and 133 to the control group. At 24 weeks, treatment with aflibercept resulted in a 2-step or greater improvement in DRSS level in 157 of 269 eyes (58.4%) in the combined aflibercept groups vs 8 of 133 eyes (6.0%) in the control group (adjusted difference, 52.3%; 95% CI, 45.2%-59.5%; P < .001). At 52 weeks, 88 of 135 eyes (65.2%) in the aflibercept 2q16 group (adjusted difference, 50.1%; 95% CI, 40.1%-60.1%) and 107 of 134 eyes (79.9%) in the aflibercept 2q8/PRN group (adjusted difference, 64.8%; 95% CI, 55.8%-73.9%) compared with 20 of 133 eyes (15.0%) in the control group (P < .001 for both comparisons) showed a 2-step or greater improvement in DRSS level. Fewer eyes treated with aflibercept vs sham injections developed vision-threatening complications and/or center-involved DME through week 100 (22 of 135 eyes [16.3%] in the 2q16 group [adjusted difference, −34.2%; 95% CI, −44.6 to −23.8] and 25 of 134 eyes [18.7%] in the 2q8/PRN group [adjusted difference, −31.7%; 95% CI, −42.5 to −20.9] compared with 67 of 133 eyes [50.4%] in the control group; P < .001 for both comparisons). No new safety signals were identified.

Conclusions and Relevance

In this study, significantly more eyes with moderately severe to severe NPDR that were treated with aflibercept showed a 2-step or greater improvement in DRSS level at 24, 52, and 100 weeks, and significantly fewer eyes treated with aflibercept vs sham developed vision-threatening complications and center-involved DME. Outcomes on the DRSS between year 1 and 2 emphasize the need for ongoing vascular endothelial growth factor suppression and adherence.

Trial Registration

ClinicalTrials.gov Identifier: NCT02718326

Add-on effect of Ayurvedic treatment protocol for diabetic retinopathy: A randomized controlled clinical study

Background

Diabetic retinopathy (DR), the leading cause of visual disability in diabetics, is a significant complication of diabetes mellitus. Currently available conventional treatments for DR have certain limitations, considering which Ayurvedic treatment protocol was designed.

Aim

The aim of this study was to evaluate the clinical efficacy of the Ayurvedic treatment protocol for DR.

Materials and methods

This was a randomized, controlled, black box design clinical study conducted from April 2016 to September 2017 by the department of Shalakya Tantra of a tertiary academic hospital in Western India. A hundred patients of DR in the age group 30-70 years were randomly divided into two groups by simple random sampling using computer-generated random number tables. In the trial group (n = 70), the preparatory phase included Dipana-Pachana (stomachic and digestant), Koshtha Shodhana (mild therapeutic purgation), and Shiro Virechana (eliminative nasal medication). The treatment phase included Marsha Nasya (nasal medication) and Pratimarsha Nasya (nasal medication of mild dose) with Durvadi Ghrita, Takra Dhara (pouring medicated buttermilk over the scalp) with Siddha Takra, and intake of Rasayana Yoga (treatment duration - 3 months). In the control group (n = 30), patients were kept under conservative treatment and observed during the trial period of 3 months. Patients of both groups continued with their treatment for diabetes and DR if any. Two follow-ups were done at an interval of 15 days. The primary outcomes were objective signs like best-corrected visual acuity (BCVA); ophthalmoscopic signs such as superficial hemorrhages, dot-blot hemorrhages, hard exudates, cotton wool spots, neovascularization disc, neovascularization elsewhere, and fibrovascular proliferation; subjective symptoms such as diminished vision, blurred vision, frequent changes in presbyopia glasses, perception of flashes of light, floaters, and problem for dark adaptation. The secondary outcomes were fasting blood sugar (FBS), postprandial blood sugar (PPBS), urine sugar, serum cholesterol, hemoglobin (Hb), glycosylated HbA1C, liver function test, and renal function test outcomes were assessed before and after the treatment.

Results

Ninety participants were included in the analysis of the primary outcome (62 in the trial and 28 in the control group). The trial group provided better results which were statistically significant on dot-blot hemorrhages, superficial hemorrhages, hard exudates, BCVA, FBS, and serum cholesterol. Both the groups provided almost similar effects in PPBS, Hb, HbA1C, and urine sugar which were statistically insignificant. Adverse effects were not reported in any of the patient among either groups.

Conclusion

Ayurvedic treatment protocol is safe and effective in DR.

Large-Area Photoreceptor Degeneration Model in Rabbits by Photocoagulation and Oxidative Stress in the Retina

Photocoagulation is used for the treatment of retinal ischemic disease. However, due to the invasive nature of photocoagulation and variety of melanin concentrations between individuals, it is challenging to avoid damaging the adjacent photoreceptors and inducing several side effects. Previous studies indicate the role of laser power, duration, and spot size on retinal lesions, but the effect of interspot distance of the laser pulses needs to be considered in panretinal photocoagulation. In this study, we examine different parameters of photocoagulation on lesions of the retina in rabbit, finding that the lesion level of the outer nuclear layer of the retina depended on the pulse duration and laser spot size, and decreasing interspot distance could completely abolish the photoreceptor layer. The degeneration of the photoreceptor by photocoagulation occurred in 24 h and was not restored afterward. We then conducted panretinal photocoagulation in rabbit and found that oxidative stress was decreased in the inner nuclear layer of the retina, and pupillary light reflex and ERG signals were impaired. Our study could provide a rabbit model to explore the mechanism of photoreceptor degeneration and therapies for the side effects after photocoagulation.

Panretinal laser photocoagulation decreases large foveal avascular zone area in non-proliferative diabetic retinopathy: A prospective OCTA study

PURPOSE

To analyze the macular microvascular changes after panretinal photocoagulation (PRP) in patients with non-proliferative diabetic retinopathy (NPDR) and a large foveal avascular zone area, using optical coherence tomography angiography.

METHODS

Twenty-four eyes of 24 patients with peripheral ischemia, superficial foveal avascular zone (FAZ) area of larger than 0.350 mm², naive severe NPDR, and no clinically significant diabetic macular edema were included in this prospective study. The PRP was applied in 360-degree in a single session. The main outcome measures of the study were the difference in best-corrected visual acuity, central macular thickness, superficial and deep vascular plexus vessel densities, FAZ features, choroidal and outer retinal flow areas at the baseline versus at one and six months after PRP treatment.

RESULTS

The study group consisted of 13 men and 11 women with a mean age of 68.11 ± 6.47 years. The baseline FAZ area was higher than at one and six months after PRP (0.416 ± 0.70, 0.399 ± 0.065 and 0.407 ± 0.066 mm²; p = 0.001 and p = 0.002, respectively). At one month after PRP, deep capillary plexus vascular density in perifoveal region was statistically significantly lower than at six months after PRP and the baseline. (45.43 ± 4.27, 47.91 ± 4.26 and 49.04 ± 5.64 %; p = 0.001 and p = 0.001, respectively).

CONCLUSION

The PRP effects retinal microvascular morphology in patients with NPDR and a large FAZ area.

Effect of 532 nm argon laser pan retinal photocoagulation on corneal thickness and corneal endothelial cell parameters among proliferative diabetic retinopathy patients

Background

Laser photocoagulation has been the mainstay treatment for diabetic retinopathy (DR). However, the applied laser light must pass through multiple ocular structures such as the cornea to reach the retina, potentially causing thermal injury to non-target tissues. The purpose of this study was to examine the effects of 532 nm Argon laser pan-retinal photocoagulation (PRP) on corneal thickness and corneal endothelial cell parameters by comparing central corneal thickness (CCT), endothelial cell density (ECD), and endothelial cell area coefficient of variation (CoV) before and after PRP for proliferative diabetic retinopathy (PDR). The effect of laser PRP on these corneal parameters may help in adapting treatment protocols to reduce corneal damage and thereby improve patient outcome.

Methods

This was a prospective cohort study involving newly diagnosed PDR patients. All patients underwent specular microscopy examination (CCT, ECD and endothelial cell area CoV) both pre-PRP and at 1-week and 6-weeks after the final PRP session (post-PRP). A Carl Zeiss Visulas Argon laser (532 nm) was used to perform PRP.

Results

A total of 33 newly diagnosed PDR patients were included in this study. There were no significant differences in mean CCT, ECD, and endothelial cell area CoV at 1-week and 6-weeks following PRP compared to pre-treatment baseline (p > 0.05). Further, there were no significant correlations between laser energy delivered and CCT, ECD and endothelial cell area CoV at either post-PRP examination time.

Conclusion

Argon laser (523 nm) energy delivered within recommended ranges for PRP had no adverse effects on corneal structure.

Intravitreal anti-vascular endothelial growth factor versus panretinal LASER photocoagulation for proliferative diabetic retinopathy: a systematic review and meta-analysis

OBJECTIVE

To systematically review and perform a meta-analysis on the available evidence for anti-vascular endothelial growth factor (anti-VEGF) monotherapy versus panretinal photocoagulation (PRP) for proliferative diabetic retinopathy (PDR).

DESIGN

Systematic review and meta-analysis PARTICIPANTS: Randomized clinical trials included participants ≥18 years old with clinical or angiographic evidence of PDR. Interventions included were anti-VEGF monotherapy and PRP. Excluded studies were those with potentially biased treatment allocation and those offering combination therapies.

METHODS

The primary outcome was mean change in best-corrected visual acuity. Secondary outcomes were the proportion of patients developing severe (<6/60) or moderate (6/24-6/60) vision loss, rates of vitrectomy or vitreous hemorrhage, worsening macula edema, and reduced visual field indices.

RESULTS

Five studies of varying quality met the inclusion criteria (n = 632). The anti-VEGF intervention arm had a mean difference of -0.08 logMAR or 4 Early Treatment Diabetic Retinopathy Study (EDTRS) letters gained (p = 0.02) when compared with PRP at 12 months. The difference in rates of vitrectomy and vitreous hemorrhage favoured anti-VEGF over PRP (risk difference [RD] -0.10, p = < 0.001 and RD -0.10, p = 0.003 respectively).

CONCLUSIONS

This meta-analysis of the available evidence in patients with early PDR demonstrates a potential benefit for anti-VEGF over PRP alone. However, these benefits must be weighed against the relative costs of treatment and the potential risks of loss to follow-up.

EFFECT OF PANRETINAL PHOTOCOAGULATION ON CORNEAL SENSATION AND TEAR FUNCTION IN PATIENTS WITH DIABETIC RETINOPATHY

PURPOSE

To evaluate the early effects of panretinal photocoagulation (PRP) on corneal sensation and dry eye signs in patients with diabetic retinopathy.

METHODS

Fifty patients with Type 2 diabetes mellitus and very severe nonproliferative or non-high-risk proliferative diabetic retinopathy who required PRP for the treatment of their retinal condition were enrolled. All patients were treated using a pattern PRP device. Esthesiometry, tear breakup time test, Schirmer test, and corneal staining pattern were evaluated at baseline and 2 months after the last session of PRP.

RESULTS

Data from 88 eyes of 50 patients (41 right eyes and 47 left eyes) were analyzed. The mean tear breakup time test (right eyes) was decreased from 9.51 at baseline to 7.66 seconds after PRP (P < 0.001). The post-PRP eyes showed more advanced grades of corneal staining than pre-PRP assessment (P < 0.001). The average value of Schirmer test was 14.39 versus 12.29 mm (without anesthesia; P < 0.001) and 8.17 versus 7.15 mm (with anesthesia, P < 0.001) for baseline versus post-PRP measurements, respectively. The corneal sensation also showed decrease after laser therapy (4.93 versus 4.31 cm; P < 0.001).

CONCLUSION

This study demonstrates that decreased corneal sensation and signs of dry eye are more common immediately after PRP for diabetic retinopathy. These conditions should be discussed with the patient preoperatively and managed postoperatively.

Saudi Arabia Guidelines for diabetic macular edema: A consensus of the Saudi Retina Group

Diabetes mellitus (DM) and its complications are major public health burdens in Saudi Arabia. The prevalence of diabetic retinopathy (DR) is 19.7% and the prevalence of diabetic macular edema (DME) is 5.7% in Saudi Arabia. Diabetic macular edema is a vision-threatening complication of DR and a major cause of vision loss worldwide. Ocular treatments include retinal laser photocoagulation, anti-vascular endothelial growth factor (anti-VEGF) agents, intravitreal corticosteroids, and vitreoretinal surgery when necessary. The present consensus was developed as a part of the Saudi Retina Group's efforts to generate Saudi guidelines and consensus for the management of DME, including recommendations for its diagnosis, treatment, and best practice. The experts' panel stipulates that the treatment algorithm should be categorized according to the presence of central macula involvement. In patients with no central macular involvement, laser photocoagulation is recommended as the first-line option. Patients with central macular involvement and no recent history of cardiovascular (CVS) or cerebrovascular disorders can be offered anti-VEGF agents as the first-line option. In the case of non-responders (defined as an improvement of <20% in optical coherence tomography or a gain of fewer than 5 letters in vision), switching to another anti-VEGF agent or steroids should be considered after 3 injections. Within the class of steroids, dexamethasone implants are recommended as the first choice. In patients with a recent history of CVS events, the use of anti-VEGF agents is not recommended, regardless of their lens status. The experts' panel recommends that a future study be conducted to provide a cut-off point for early switching to steroid implants in pseudo-phakic eyes.

Photo-Mediated Ultrasound Therapy for the Treatment of Corneal Neovascularization in Rabbit Eyes

Purpose

Corneal neovascularization (CNV) is the invasion of new blood vessels into the avascular cornea, leading to reduced corneal transparency and visual acuity, impaired vision, and even blindness. Current treatment options for CNV are limited. We developed a novel treatment method, termed photo-mediated ultrasound therapy (PUT), that combines laser and ultrasound, and we tested its feasibility for treating CNV in a rabbit model.

Methods

A suture-induced CNV model was established in New Zealand White rabbits, which were randomly divided into two groups: PUT and control. For the PUT group, the applied light fluence at the corneal surface was estimated to be 27 mJ/cm² at 1064-nm wavelength with a pulse duration of 5 ns, and the ultrasound pressure applied on the cornea was 0.43 MPa at 0.5 MHz. The control group received no treatment. Red-free photography and fluorescein angiography were utilized to evaluate the efficiency of PUT. Safety was evaluated by histology and immunohistochemistry. For comparison with the PUT safety results, conventional laser photocoagulation (LP) treatment was performed with standard clinical parameters: 532-nm continuous-wave (CW) laser with 0.1-second pulse duration, 450-mW power, and 75-µm spot size.

Results

In the PUT group, only 1.8% ± 0.8% of the CNV remained 30 days after treatment. In contrast, 71.4% ± 7.2% of the CNV remained in the control group after 30 days. Safety evaluations showed that PUT did not cause any damage to the surrounding tissue.

Conclusions

These results demonstrate that PUT is capable of removing CNV safely and effectively in this rabbit model.

Translational Relevance

PUT can remove CNV safely and effectively.

An allosteric peptide inhibitor of HIF-1α regulates hypoxia-induced retinal neovascularization

Retinal neovascularization (NV), a leading cause of vision loss, results from localized hypoxia that stabilizes the hypoxia-inducible transcription factors HIF-1α and HIF-2α, enabling the expression of angiogenic factors and genes required to maintain homeostasis under conditions of oxygen stress. HIF transcriptional activity depends on the interaction between its intrinsically disordered C-terminal domain and the transcriptional coactivators CBP/p300. Much effort is currently directed at disrupting protein-protein interactions between disease-associated transcription factors like HIF and their cellular partners. The intrinsically disordered protein CITED2, a direct product of HIF-mediated transcription, functions as a hypersensitive negative regulator that attenuates the hypoxic response by competing allosterically with HIF-1α for binding to CBP/p300. Here, we show that a peptide fragment of CITED2 is taken up by retinal cells and efficiently regulates pathological angiogenesis in murine models of ischemic retinopathy. Both vaso-obliteration (VO) and NV were significantly inhibited in an oxygen-induced retinopathy (OIR) model following intravitreal injection of the CITED2 peptide. The CITED2 peptide localized to retinal neurons and glia, resulting in decreased expression of HIF target genes. Aflibercept, a commonly used anti-VEGF therapy for retinal neovascular diseases, rescued NV but not VO in OIR. However, a combination of the CITED2 peptide and a reduced dose of aflibercept significantly decreased both NV and VO. In contrast to anti-VEGF agents, the CITED2 peptide can rescue hypoxia-induced retinal NV by modulating the hypoxic response through direct competition with HIF for CBP/p300, suggesting a dual targeting strategy for treatment of ischemic retinal diseases and other neovascular disorders.

Retinal laser photocoagulation in management of eales' disease

Eales’ disease is an idiopathic occlusive inflammatory vasculopathy resulting in peripheral retinal ischemia, neovascularization, recurrent hemophthalmos, and proliferative tissue formation. It is often complicated by tractional retinal detachment, secondary glaucoma, and central retinal vein occlusion. The management of patients with Eales’ disease includes mainly glucocorticosteroid therapy, the use of angiogenesis inhibitors, vitreoretinal surgery and laser photocoagulation. The clinical case reported demonstrates the potential of retinal laser photocoagulation for treatment of the Eales’ disease in the ischemic and proliferative stages. The results of retinal laser photocoagulation used as monotherapy demonstrate the clinical and functional indices improvement: enhanced visual acuity, stabilized central retinal sensitivity value, restored clarity to the ocular media, regression of neovascularization and macular edema in the patient’s eye being in the proliferative (3b) stage, and the process stabilization in the eye being in the ischemic (2a) stage of the disease.

Electroretinogram Changes Following Sequential Panretinal Photocoagulation for Proliferative Diabetic Retinopathy

Purpose

To evaluate changes in electroretinogram (ERG) response over the course of multiple sessions of panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PRP).

Methods

A prospective cohort study of 11 patients with PDR who required PRP was conducted. PRP was completed over three sessions. Each patient had five ERGs done: baseline, 1 week after each PRP session, and 6 weeks after the last session of PRP. Dark-adapted 0.01 ERG, Dark-adapted 3 ERG, Dark-adapted 10 ERG, Light- adapted 3 ERG, and Light-adapted 30 Hz flicker ERG were done. The mean change in a- and b-wave amplitudes as well as implicit times compared to baseline was analyzed.

Results

A significant reduction in peak amplitudes of both a- and b-waves and delay in latencies were observed in all responses (p<0.05). The absolute amplitude reduction and delay in latency were higher for scotopic b-waves (p<0.05). The root mean square (RMS) of Dark-adapted 10.0 ERG (p<0.05) and total mean amplitude changes of a- and b-waves (p<0.001) were reduced after each laser session; however, the magnitude of change was not different between the first, second, or third sessions of PRP, and each session showed a similar deterioration rate of ERG parameters comparing to each other (p=0.4 for RMS and p=0.2 for total mean amplitude changes). In addition, the results indicated recovery of the amplitude and latency of ERG waves after 6 weeks from the final treatment (p<0.001) although not to baseline levels.

Conclusion

ERG findings following PRP show reduced retinal function after each session which partially recovers by 6 weeks after the completion of therapy. Clinicians should be mindful of these changes when planning the treatment course for patients with PDR.

Association of Statin Therapy With Prevention of Vision-Threatening Diabetic Retinopathy

Importance

Diabetic retinopathy is the leading cause of blindness in working-age adults. Studies have suggested that statins may reduce the risk of developing diabetic retinopathy.

Objective

To investigate the association between statin therapy and the development of diabetic retinopathy in patients with diabetes and dyslipidemia.

Design, Setting, and Participants

This population-based cohort study, conducted among 37 894 Taiwanese patients between January 1, 1998, and December 31, 2013, used the National Health Insurance Research Database to identify patients with type 2 diabetes and dyslipidemia. Outcomes were compared between those taking statins and those not taking statins. Statistical analysis was performed from May 1 to 31, 2018.

Exposure

Statin therapy with a medication possession rate of 80% or more with no other lipid-lowering medications.

Main Outcomes and Measures

Any stage of diabetic retinopathy and treatments for vision-threatening diabetic retinopathy.

Results

Of 1 648 305 patients with type 2 diabetes, 219 359 were eligible for analysis over the study period, including 199 760 patients taking statins and 19 599 patients not taking statins. After propensity score matching, there were 18 947 patients in the statin group (10 436 women and 8511 men; mean [SD] age, 61.5 [10.8] years) and 18 947 patients in the nonstatin group (10 430 women and 8517 men; mean [SD] age, 61.0 [11.0] years), with a mean follow-up of 7.6 years for the statin group and 7.3 years for the nonstatin group. During the study period, 2004 patients in the statin group (10.6%) and 2269 patients in the nonstatin group (12.0%) developed diabetic retinopathy. Patients in the statin group had a significantly lower rate of diabetic retinopathy (hazard ratio [HR], 0.86; 95% CI, 0.81-0.91), nonproliferative diabetic retinopathy (HR, 0.92; 95% CI, 0.86-0.99), proliferative diabetic retinopathy (HR, 0.64; 95% CI, 0.58-0.70), vitreous hemorrhage (HR, 0.62; 95% CI, 0.54-0.71), tractional retinal detachment (HR, 0.61; 95% CI, 0.47-0.79), and macular edema (HR, 0.60; 95% CI, 0.46-0.79) than the nonstatin group, as well as lower rates of interventions such as retinal laser treatment (HR, 0.71; 95% CI, 0.65-0.77), intravitreal injection (HR, 0.74; 95% CI, 0.61-0.89), and vitrectomy (HR, 0.58; 95% CI, 0.48-0.69), along with a smaller number of the interventions (retinal lasers: rate ratio, 0.61; 95% CI, 0.59-0.64; intravitreal injections: rate ratio, 0.68; 95% CI, 0.61-0.76; and vitrectomies: rate ratio, 0.54; 95% CI, 0.46-0.63). Statin therapy was also associated with lower risks of major adverse cardiovascular events (HR, 0.81; 95% CI, 0.77-0.85), new-onset diabetic neuropathy (HR, 0.85; 95% CI, 0.82-0.89), and new-onset diabetic foot ulcers (HR, 0.73; 95% CI, 0.68-0.78).

Conclusions and Relevance

Statin therapy was associated with a decreased risk of diabetic retinopathy and need for treatments for vision-threatening diabetic retinopathy in Taiwanese patients with type 2 diabetes and dyslipidemia.