Mechanistic Evaluation of Panretinal Photocoagulation Versus Aflibercept in Proliferative Diabetic Retinopathy: CLARITY Substudy

Anti-vascular endothelial growth factor therapy and retinal non-perfusion in diabetic retinopathy: A meta-analysis of randomised trials

PURPOSE

Retinal non-perfusion (RNP) is fundamental to disease onset and progression in diabetic retinopathy (DR). Whether anti-vascular endothelial growth factor (anti-VEGF) therapy can modify RNP progression is unclear. This investigation quantified the impact of anti-VEGF therapy on RNP progression compared with laser or sham at 12 months.

METHODS

A systematic review and meta-analysis of randomised controlled trials (RCTs) were performed; Ovid MEDLINE, EMBASE and CENTRAL were searched from inception to 4th March 2022. The change in any continuous measure of RNP at 12 months and 24 months was the primary and secondary outcomes, respectively. Outcomes were reported utilising standardised mean differences (SMD). The Cochrane Risk of Bias Tool version-2 and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines informed risk of bias and certainty of evidence assessments.

RESULTS

Six RCTs (1296 eyes) and three RCTs (1131 eyes) were included at 12 and 24 months, respectively. Meta-analysis demonstrated that RNP progression may be slowed with anti-VEGF therapy compared with laser/sham at 12 months (SMD: -0.17; 95% confidence interval [CI]: -0.29, -0.06; p = 0.003; I2  = 0; GRADE rating: LOW) and 24-months (SMD: -0.21; 95% CI: -0.37, -0.05; p = 0.009; I2  = 28%; GRADE rating: LOW). The certainty of evidence was downgraded due to indirectness and due to imprecision.

CONCLUSION

Anti-VEGF treatment may slightly impact the pathophysiologic process of progressive RNP in DR. The dosing regimen and the absence of diabetic macular edema may impact this potential effect. Future trials are needed to increase the precision of the effect and inform the association between RNP progression and clinically important events.

PROSPERO REGISTRATION

CRD42022314418.

Retinal vein changes in patients with high-risk proliferative diabetic retinopathy treated with conbercept and panretinal photocoagulation co-therapy: a cohort study

Objective

This study aimed to observe and compare retinal vein diameter changes and other essential indicators in patients with high-risk proliferative diabetic retinopathy (PDR) treated with intravitreal injection of conbercept (IVC) combined with panretinal photocoagulation (PRP) versus PRP monotherapy.

Methods

A retrospective analysis was conducted on data from patients with high-risk PDR who received specific treatment and were followed up for 24 months. Among 82 patients with high-risk PDR, 50 eyes received PRP combined with IVC, whereas 32 eyes received PRP alone. During the 24-month follow-up period, changes in best-corrected visual acuity (BCVA), central foveal thickness (CFT), retinal vein diameter, number of microaneurysms (MA), neovascularization (NV) area, hard exudate (HE) area, size of the foveal avascular zone (FAZ), superficial capillary plexus (SCP) blood flow density, and adverse effects were recorded and compared between the two groups at baseline and at 6, 12, 18, and 24 months after treatment. The relationship between each observation index and vein diameter was also analyzed.

Results

During the 24-month follow up, significant improvements in the BCVA, CFT, retinal vein diameter, number of MAs, NV area, HE area, FAZ, and SCP were observed in the IVC+PRP group after treatment. The PRP group only showed significant reductions in NV and HE areas. The IVC+PRP group showed significant superiority over the PRP group in improving the vein diameter, number of MA, and HE area. However, no statistically significant difference in NV area reduction was found between the groups.

Conclusion

In the treatment of high-risk PDR, IVC+PRP therapy has a significant advantage over PRP monotherapy. IVC+PRP therapy may reverse diabetes-induced retinal vein changes, restoring morphology and function.

Determining the Superiority of Vitrectomy vs Aflibercept for Treating Dense Diabetic Vitreous Hemorrhage: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

This review aimed to systematically compare the efficacy and safety of intravitreal aflibercept (IVA) and vitrectomy for treating severe vitreous hemorrhage (VH) secondary to proliferative diabetic retinopathy (PDR). The review was conducted in accordance with PRISMA guidelines. A search strategy, including the MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and US National Library of Medicine databases, was developed to identify randomized controlled trials (RCTs) that compared vitrectomy and IVA for managing VH due to PDR (participant age ≥ 18 years). The primary outcome measure was the difference in the mean visual acuity between the two treatment groups at 1, 6, and 24 months. Outcome measures included clearance of VH (in weeks), the incidence of recurrent VH, and the rate of complications. The studies were evaluated using the Cochrane Bias (ROB) tool. We identified 774 articles; six articles met the inclusion criteria, and two were ultimately included (n = 239 eyes). With or without PRP, IVA injections and vitrectomy were performed in 117 and 122 eyes, respectively. The mean BCVA at one month was significantly better in the vitrectomy group (MD=0.22, CI:0.10-0.34, p=0.0003), but no difference was found at six months (MD=0.04, CI: -0.04-0.12, p=0.356). The incidence of recurrent VH was significantly higher in the IVA group (OR=5.05, CI:2.71-9.42, p<0.0001). The probability of recurrent VH was five times greater in the IVA group than that in the vitrectomy group. There were no significant differences in the overall proportions of intra- or postoperative complications (OR=0.64, CI: 0.09-4.85, p=0.669). None of the studies had a low ROB in any of the seven domains. We conclude that IVA can be considered a viable treatment modality for diabetic VH in patients with a good follow-up. Vitrectomy initially provides better visual effect, faster VH recovery, and lower VH recurrence than IVA injections.

Anti-vascular endothelial growth factor for proliferative diabetic retinopathy

BACKGROUND

Proliferative diabetic retinopathy (PDR) is an advanced complication of diabetic retinopathy that can cause blindness. It consists of the presence of new vessels in the retina and vitreous haemorrhage. Although panretinal photocoagulation (PRP) is the treatment of choice for PDR, it has secondary effects that can affect vision. Anti-vascular endothelial growth factor (anti-VEGF), which produces an inhibition of vascular proliferation, could improve the vision of people with PDR.

OBJECTIVES

To assess the effectiveness and safety of anti-VEGFs for PDR and summarise any relevant economic evaluations of their use.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 6); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov, and the WHO ICTRP. We did not use any date or language restrictions. We last searched the electronic databases on 1 June 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing anti-VEGFs to another active treatment, sham treatment, or no treatment for people with PDR. We also included studies that assessed the combination of anti-VEGFs with other treatments. We excluded studies that used anti-VEGFs in people undergoing vitrectomy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data, and assessed the risk of bias (RoB) for all included trials. We calculated the risk ratio (RR) or the mean difference (MD), and 95% confidence intervals (CI). We used GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 15 new studies in this update, bringing the total to 23 RCTs with 1755 participants (2334 eyes). Forty-five per cent of participants were women and 55% were men, with a mean age of 56 years (range 48 to 77 years). The mean glycosylated haemoglobin (Hb1Ac) was 8.45% for the PRP group and 8.25% for people receiving anti-VEGFs alone or in combination. Twelve studies included people with PDR, and participants in 11 studies had high-risk PDR (HRPDR). Twelve studies were of bevacizumab, seven of ranibizumab, one of conbercept, two of pegaptanib, and one of aflibercept. The mean number of participants per RCT was 76 (ranging from 15 to 305). Most studies had an unclear or high RoB, mainly in the blinding of interventions and outcome assessors. A few studies had selective reporting and attrition bias. No study reported loss or gain of 3 or more lines of visual acuity (VA) at 12 months. Anti-VEGFs ± PRP probably increase VA compared with PRP alone (mean difference (MD) -0.08 logMAR, 95% CI -0.12 to -0.04; I2 = 28%; 10 RCTS, 1172 eyes; moderate-certainty evidence). Anti-VEGFs ± PRP may increase regression of new vessels (MD -4.14 mm2, 95% CI -6.84 to -1.43; I2 = 75%; 4 RCTS, 189 eyes; low-certainty evidence) and probably increase a complete regression of new vessels (RR 1.63, 95% CI 1.19 to 2.24; I2 = 46%; 5 RCTS, 405 eyes; moderate-certainty evidence). Anti-VEGFs ± PRP probably reduce vitreous haemorrhage (RR 0.72, 95% CI 0.57 to 0.90; I2 = 0%; 6 RCTS, 1008 eyes; moderate-certainty evidence). Anti-VEGFs ± PRP may reduce the need for vitrectomy compared with eyes that received PRP alone (RR 0.67, 95% CI 0.49 to 0.93; I2 = 43%; 8 RCTs, 1248 eyes; low-certainty evidence). Anti-VEGFs ± PRP may result in little to no difference in the quality of life compared with PRP alone (MD 0.62, 95% CI -3.99 to 5.23; I2 = 0%; 2 RCTs, 382 participants; low-certainty evidence). We do not know if anti-VEGFs ± PRP compared with PRP alone had an impact on adverse events (very low-certainty evidence). We did not find differences in visual acuity in subgroup analyses comparing the type of anti-VEGFs, the severity of the disease (PDR versus HRPDR), time to follow-up (< 12 months versus 12 or more months), and treatment with anti-VEGFs + PRP versus anti-VEGFs alone. The main reasons for downgrading the certainty of evidence included a high RoB, imprecision, and inconsistency of effect estimates.

AUTHORS' CONCLUSIONS

Anti-VEGFs ± PRP compared with PRP alone probably increase visual acuity, but the degree of improvement is not clinically meaningful. Regarding secondary outcomes, anti-VEGFs ± PRP produce a regression of new vessels, reduce vitreous haemorrhage, and may reduce the need for vitrectomy compared with eyes that received PRP alone. We do not know if anti-VEGFs ± PRP have an impact on the incidence of adverse events and they may have little or no effect on patients' quality of life. Carefully designed and conducted clinical trials are required, assessing the optimal schedule of anti-VEGFs alone compared with PRP, and with a longer follow-up.

Complications, Compliance, and 3-Year Outcomes After Endolaserless Vitrectomy With Aflibercept Monotherapy for Proliferative Diabetic Retinopathy-Related Vitreous Hemorrhage

BACKGROUND AND OBJECTIVE

To report the 3-year outcomes for endolaserless vitrectomy with intravitreal aflibercept injection (IAI) monotherapy for proliferative diabetic retinopathy (PDR)-related vitreous hemorrhage (VH).

MATERIALS AND METHOD

Eyes underwent endolaserless vitrectomy and received one preoperative and intraoperative IAI followed by randomization to a q8week or q16week IAI group. Additional IAI was administered as needed.

RESULTS

31/40 eyes were randomized (14 q8week eyes, 17 q16week eyes). Through 152 weeks, q8week and q16week eyes received 18.6 and 12.1 IAI, respectively. Q8week eyes observed a 34 letter visual acuity (VA) increase (P = 0.003) compared to a 27 letter increase in the q16week group (P = 0.013).

CONCLUSIONS

Endolaserless vitrectomy with aflibercept monotherapy for PDR-related VH provides significant long-term visual gains. Frequent IAI is required for fewer proliferative consequences. [Ophthalmic Surg Lasers Imaging Retina 2023;54:89-96.].

Final Outcomes from the Randomized RECOVERY Trial of Aflibercept for Retinal Nonperfusion in Proliferative Diabetic Retinopathy

PURPOSE

Retinal nonperfusion (RNP) is an important biomarker for diabetic retinopathy (DR). Data suggest that consistent anti-VEGF pharmacotherapy can slow RNP development. The RECOVERY trial evaluated the impact of aflibercept (Eylea, Regeneron) on RNP among eyes with proliferative DR (PDR).

DESIGN

Prospective, randomized clinical trial with treatment crossover in the second year.

SUBJECTS

Eyes with PDR and RNP.

METHODS

At baseline, the subjects were randomized 1:1 to monthly (arm 1) or quarterly (arm 2) intravitreal 2 mg aflibercept. At the beginning of year 2, the treatment arms were crossed over so that the monthly-dosed subjects subsequently received quarterly dosing and the quarterly-dosed subjects subsequently received monthly dosing.

MAIN OUTCOME MEASURES

Change in total RNP area (mm²) through year 2. Secondary outcomes included Diabetic Retinopathy Severity Scale (DRSS) scores; best-corrected visual acuity; central subfield thickness; additional measures of RNP, including ischemic index (ISI); and adverse event incidence. Means and 95% confidence intervals were calculated.

RESULTS

Among all subjects, from baseline to year 2, the mean RNP increased from 235 mm² to 402 mm² (P < 0.0001), and the ISI increased from 25.8% to 50.4% (P < 0.0001). Increases in the mean RNP (P < 0.0001) and ISI (P < 0.0001) were also observed from year 1 to year 2. The mean total RNP increased from 264 mm² at baseline to 386 mm² (P < 0.0001) at year 2 in arm 1 and from 207 mm² at baseline to 421 mm² (P < 0.0001) at year 2 in arm 2 (P = 0.023, arm 1 vs. arm 2). Increases in the mean RNP for both treatment arms (P < 0.0001) were also specifically observed within year 2 (P = 0.32, arm 1 vs. arm 2). Compared with baseline, the DRSS scores at the end of year 2 improved in 82% (n = 27) of subjects and remained stable in 18% (n = 6), with no subjects experiencing worsening; at 2 years, the DRSS scores had improved by 2 or more steps in 65% (n = 11) and 81% (n = 13) of subjects in arms 1 and 2, respectively.

CONCLUSIONS

Through year 2 of the RECOVERY trial, both treatment arms experienced significant increases in RNP. Despite the expansion of the RNP area in nearly all subjects, 82% of subjects demonstrated an improvement in DRSS levels from baseline, with no subjects experiencing worsening in DRSS scores.

Harnessing the Neuroprotective Behaviors of Müller Glia for Retinal Repair

Progressive and irreversible vision loss in mature and aging adults creates a health and economic burden, worldwide. Despite the advancements of many contemporary therapies to restore vision, few approaches have considered the innate benefits of gliosis, the endogenous processes of retinal repair that precede vision loss. Retinal gliosis is fundamentally driven by Müller glia (MG) and is characterized by three primary cellular mechanisms: hypertrophy, proliferation, and migration. In early stages of gliosis, these processes have neuroprotective potential to halt the progression of disease and encourage synaptic activity among neurons. Later stages, however, can lead to glial scarring, which is a hallmark of disease progression and blindness. As a result, the neuroprotective abilities of MG have remained incompletely explored and poorly integrated into current treatment regimens. Bioengineering studies of the intrinsic behaviors of MG hold promise to exploit glial reparative ability, while repressing neuro-disruptive MG responses. In particular, recent in vitro systems have become primary models to analyze individual gliotic processes and provide a stepping stone for in vivo strategies. This review highlights recent studies of MG gliosis seeking to harness MG neuroprotective ability for regeneration using contemporary biotechnologies. We emphasize the importance of studying gliosis as a reparative mechanism, rather than disregarding it as an unfortunate clinical prognosis in diseased retina.

Selective Targeting and Tissue Penetration to the Retina by a Systemically Administered Vascular Homing Peptide in Oxygen Induced Retinopathy (OIR)

Pathological angiogenesis is the hallmark of ischemic retinal diseases among them retinopathy of prematurity (ROP) and proliferative diabetic retinopathy (PDR). Oxygen-induced retinopathy (OIR) is a pure hypoxia-driven angiogenesis model and a widely used model for ischemic retinopathies. We explored whether the vascular homing peptide CAR (CARSKNKDC) which recognizes angiogenic blood vessels can be used to target the retina in OIR. We were able to demonstrate that the systemically administered CAR vascular homing peptide homed selectively to the preretinal neovessels in OIR. As a cell and tissue-penetrating peptide, CAR also penetrated into the retina. Hyperoxia used to induce OIR in the retina also causes bronchopulmonary dysplasia in the lungs. We showed that the CAR peptide is not targeted to the lungs in normal mice but is targeted to the lungs after hyperoxia-/hypoxia-treatment of the animals. The site-specific delivery of the CAR peptide to the pathologic retinal vasculature and the penetration of the retinal tissue may offer new opportunities for treating retinopathies more selectively and with less side effects.

Role of Optical Coherence Tomography Angiography Imaging in Patients with Diabetes

PURPOSE OF REVIEW

Ocular manifestations in patients with diabetes mellitus (DM) can present as microvascular changes. These microvascular changes can be challenging to identify on exams, and imaging technologies have commonly aided in the diagnosis and management of patients with DM. Optical coherence tomography angiography (OCTA) provides noninvasive image segmentation of various layers of the retina and choroid. Also, post-processing of images and associated quantitative measurements offer potential clinical enhancements. Our aim is to review the current evidence on the utility of OCTA for patients with DM.

RECENT FINDINGS

Research suggests OCTA to potentially provide potential clinical enhancements and alternative methods in detecting subclinical manifestation of diabetic retinopathy, staging diabetic retinopathy, management of diabetic macular edema, and monitoring of systemic markers in patients with diabetes mellitus. OCTA is a promising but relatively new modality, and differences in terminology, research designs, and image processing techniques provide a difficult landscape to navigate. Standardization within further validation is needed to determine the extent of OCTA's clinical utility, but the current literature suggests the potential for earlier detection of ocular manifestations in patients with DM, additional objective measurements for grading and management, and opportunity for additional biomarkers for treatment outcomes.

Intravitreal Anti-Vascular Endothelial Growth Factor Agents for the Treatment of Diabetic Retinopathy: A Review of the Literature

Background: Diabetic retinopathy (DR) is the leading cause of blindness in the working-age population. The purpose of this review is to gather the existing literature regarding the use of the approved anti-vascular endothelial growth (anti-VEGF) agents in the treatment of DR. Methods: A comprehensive literature review in PubMed engine search was performed for articles written in English language up to 1 July 2021, using the keywords “diabetic retinopathy”, “ranibizumab”, “aflibercept”, and “anti-VEGF”. Emphasis was given on pivotal trials and recent robust studies. Results: Intravitreal anti-VEGF agents have been found to significantly improve visual acuity and reduce retinal thickness in patients with diabetic macular edema (DME) in a long-term follow-up ranging from 1 to 5 years and are considered the standard-of-care in such patients. Regarding DR, intravitreal anti-VEGF agents provided ≥2-step improvement in DR severity on color fundus photography in about 30–35% of patients with NPDR at baseline, in the majority of clinical trials originally designed to evaluate the efficacy of intravitreal anti-VEGF agents in patients with DME. Protocol S and CLARITY study have firstly reported that intravitreal anti-VEGF agents are non-inferior to panretinal photocoagulation (PRP) in patients with proliferative DR (PDR). However, the use of new imaging modalities, such as optical coherence tomography-angiography and wide-field fluorescein angiography, reveals conflicting results about the impact of anti-VEGF agents on the regression of retinal non-perfusion in patients with DR. Furthermore, one should consider the high “loss to follow-up” rate and its devastating consequences especially in patients with PDR, when deciding to treat the latter with intravitreal anti-VEGF agents alone compared to PRP. In patients with PDR, combination of treatment of intravitreal anti-VEGF agents and PRP has been also supported. Moreover, in the specific case of vitreous hemorrhage or tractional retinal detachment as complications of PDR, intravitreal anti-VEGF agents have been found to be beneficial as an adjunct to pars plana vitrectomy (PPV), most commonly given 3–7 days before PPV, offering reduction in the recurrence of vitreous hemorrhage. Conclusions: There is no general consensus regarding the use of intravitreal anti-VEGF agents in patients with DR. Although anti-VEGF agents are the gold standard in the treatment of DME and seem to improve DR severity, challenges in their use exist and should be taken into account in the decision of treatment, based on an individualized approach.

Retinal neovascularization induced by mutant Vldlr gene inhibited in an inherited retinitis pigmentosa mouse model: an in-vivo study

AIM

To explore whether the retinal neovascularization (NV) in a genetic mutant mice model could be ameliorated in an inherited retinitis pigmentosa (RP) mouse, which would help to elucidate the possible mechanism and prevention of retinal NV diseases in clinic.

METHODS

The Vldlr ^-/- mice, the genetic mutant mouse model of retinal NV caused by the homozygous mutation of Vldlr gene, with the rd1 mice, the inherited RP mouse caused by homozygous mutation of Pde6b gene were bred. Intercrossing of the above two mice led to the birth of the F1 hybrids, further inbreeding of which gave birth to the F2 offspring. The ocular genotypes and phenotypes of the mice from all generations were examined, with the F2 offspring grouped according to the genotypes.

RESULTS

The rd1 mice exhibited the RP phenotype of outer retinal degeneration and loss of retinal function. The Vldlr ^-/- mice exhibited the phenotype of retinal NV obviously shown by the fundus fluorescein angiography. The F1 hydrides, with the heterozygote genotype, exhibited no phenotypes of RP or retinal NV. The F2 offspring with homozygous genotypes were grouped into four subgroups. They were the F2-I mice with the wild-type Pde6b and Vldlr genes (Pde6b^+/+ -Vldlr^+/+ ), which had normal ocular phenotypes; the F2-II mice with homozygous mutant Vldlr gene (Pde6b^+/+ -Vldlr^-/- ), which exhibited the retinal NV phenotype; the F2-III mice with homozygous mutant Pde6b gene (Pde6b^-/- -Vldlr^+/+ ), which exhibited the RP phenotype. Specifically, the F2-IV mice with homozygous mutant Vldlr and Pde6b gene (Pde6b^-/- -Vldlr^-/- ) showed only the RP phenotype, without the signs of retinal NV.

CONCLUSION

The retinal NV can be inhibited by the RP phenotype, which implies the role of a hyperoxic state in treating retinal NV diseases.

Characterizing Flow and Structure of Diabetic Retinal Neovascularization after Intravitreal Anti-VEGF Using Optical Coherence Tomography Angiography: A Pilot Study

Background/Aims. This study evaluates changes of flow and structure of diabetic retinal neovascularization (NV) treated with intravitreal antivascular endothelial growth factor (VEGF) agents using optical coherence tomography angiography (OCTA). With OCTA, retinal blood vessels are visualized at high resolution to separately look at flow and structure information without the need for dye injection. We introduce a new measurement method including and combining information of flow and structure. Methods. Retrospective observational case series. Patients with proliferative diabetic retinopathy (PDR) were treated with intravitreal antiVEGF injections. Retinal NV were repeatedly imaged using swept-source OCTA (Zeiss PlexElite 9000) at baseline, after initial treatment block with 3-4 monthly injections, and during a follow-up period of up to 51 weeks. Change of size and flow density of the structural and angio area of NV was assessed. Results. Nine NV in eight eyes of five patients were analyzed with a median follow-up time of 45 weeks. After the initial treatment block, en face structural area regressed, 18.7% ± 39.0% (95% CI 44.2–6.8%, p=0.26), and en face angio area regressed, 51.9% ± 29.5% (95% CI 32.6 to 71.2%, p=0.007). Flow density within the en face structural area decreased by 33% ± 19.2% (95% CI 20.5–45.5%, p=0.0077). Flow density within the en face angio area decreased by mean 17.9% ± 25.2% (95% CI 1.4–34.4%, p=0.066). In two fellow eyes, NV recurrence could be observed before the onset of vitreous bleeding in one. Conclusion. Our study introduces a new quantitative measurement for NV in PDR, combining structure and flow measurement. The structure area remained after treatment, while its flow density and angio area regressed. We propose this measurement method as a more physiological and possibly more comparable metrics.

Case Report: Peripheral Retinal Ischemia and Retinal Neovascularization in von Willebrand Disease

SIGNIFICANCE

Although von Willebrand disease is the most common inherited bleeding disorder, there are only a few published reports of ocular complications. To our knowledge, this is the first case of peripheral retinal ischemia and retinal neovascularization in a patient with von Willebrand disease.

PURPOSE

This study aimed to demonstrate the value of multispecialty care when exploring a diagnosis for bilateral retinopathy.

CASE REPORT

A 55-year-old African American woman presented with peripheral retinal hemorrhages on routine examination. She was asymptomatic and did not have any personal or family history of bleeding disorders. Blood work was ordered, and she was referred to a retinal specialist who found peripheral telangiectasia, retinal ischemia, and leakage on fluorescein angiography, consistent with retinal neovascularization. Laser photocoagulation was performed while numerous specialists were consulted to determine the cause for her retinopathy. Laboratory testing confirmed low-grade type 1 von Willebrand disease. She was monitored without systemic treatment. She remained stable and asymptomatic, but her retinal neovascularization did not regress fully, so laser treatment was repeated.

CONCLUSIONS

This case described a new finding of peripheral retinal ischemia and retinal neovascularization in von Willebrand disease. It was discovered in an asymptomatic patient who did not have a history of bleeding but presented with bilateral retinal hemorrhages. Diagnosis was challenging because of the high degree of variation in this bleeding disorder, requiring extensive testing and careful consideration of the individual's clinical profile. Most people with von Willebrand disease do not know they have the disease because symptoms are mild or absent, so most cases are unreported. The von Willebrand factor is poorly recognized in ocular disease, but given its role in angiogenesis, it may be a valuable target to consider in future research.

A Norrin/Wnt surrogate antibody stimulates endothelial cell barrier function and rescues retinopathy

The FZD4:LRP5:TSPAN12 receptor complex is activated by the secreted protein Norrin in retinal endothelial cells and leads to βcatenin-dependent formation of the blood-retina-barrier during development and its homeostasis in adults. Mutations disrupting Norrin signaling have been identified in several congenital diseases leading to hypovascularization of the retina and blindness. Here, we developed F4L5.13, a tetravalent antibody designed to induce FZD4 and LRP5 proximity in such a way as to trigger βcatenin signaling. Treatment of cultured endothelial cells with F4L5.13 rescued permeability induced by VEGF in part by promoting surface expression of junction proteins. Treatment of Tspan12-/- mice with F4L5.13 restored retinal angiogenesis and barrier function. F4L5.13 treatment also significantly normalized neovascularization in an oxygen-induced retinopathy model revealing a novel therapeutic strategy for diseases characterized by abnormal angiogenesis and/or barrier dysfunction.

Clinical efficacy of intravitreal aflibercept injection versus vitrectomy with panretinal photocoagulation for patients with proliferative diabetic retinopathy: A protocol for systematic review and meta-analysis

BACKGROUND

In the current literature, it is still controversial whether intravitreal aflibercept injection can provide better vision restoration compared with vitrectomy with panretinal photocoagulation (PRP) for proliferative diabetic retinopathy (PDR) patients. Given that there is no high-quality meta-analysis or review to incorporate existing evidence, the purpose of this study is to systematically review the level I evidence in the literature to ascertain whether intravitreal aflibercept injection can provide better vision restoration compared with vitrectomy with PRP for PDR patients.

METHODS

The systematic literature review is structured to adhere to PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses), which include requirements deemed essential for the transparent reporting of results. A systematic search will be performed in Web of Science, Embase, Scopus, Science Direct, Cochrane Library up to and inclusive of March 19, 2021. The method of data extraction will follow the approach outlined by the Cochrane Handbook for Systematic Reviews of Interventions. The primary outcome is change in best-corrected visual acuity. The secondary outcomes are change in area of neovascularization and change in area of retinal nonperfusion. Where disagreement occurs, this will be resolved through discussion. All outcomes are pooled on random-effect model. A P value of < .05 is considered to be statistically significant.

RESULTS

The results of our review will be reported strictly following the PRISMA criteria.

CONCLUSIONS

The hypothesis of the study was that visual acuity recovery would be faster with vitrectomy because the blood is mechanically cleared during surgery.

REGISTRATION NUMBER

10.17605/OSF.IO/NCAXW.

Effect of Intravitreous Anti-Vascular Endothelial Growth Factor vs Sham Treatment for Prevention of Vision-Threatening Complications of Diabetic Retinopathy: The Protocol W Randomized Clinical Trial

Importance

The role of anti-vascular endothelial growth factor injections for the management of nonproliferative diabetic retinopathy (NPDR) without center-involved diabetic macular edema (CI-DME) has not been clearly established.

Objective

To determine the efficacy of intravitreous aflibercept injections compared with sham treatment in preventing potentially vision-threatening complications in eyes with moderate to severe NPDR.

Design, Setting, and Participants

Data for this study were collected between January 15, 2016, and May 28, 2020, from the ongoing DRCR Retina Network Protocol W randomized clinical trial, conducted at 64 US and Canadian sites among 328 adults (399 eyes) with moderate to severe NPDR (Early Treatment Diabetic Retinopathy Study severity level, 43-53), without CI-DME. Analyses followed the intent-to-treat principle.

Interventions

Eyes were randomly assigned to 2.0 mg of aflibercept injections (n = 200) or sham (n = 199) given at baseline; 1, 2, and 4 months; and every 4 months through 2 years. Between 2 and 4 years, treatment was deferred if the eye had mild NPDR or better. Aflibercept was administered in both groups if CI-DME with vision loss (≥10 letters at 1 visit or 5-9 letters at 2 consecutive visits) or high-risk proliferative diabetic retinopathy (PDR) developed.

Main Outcomes and Measures

Development of CI-DME with vision loss or PDR through May 2020, when the last 2-year visit was completed.

Results

Among the 328 participants (57.6% men [230 of 399 eyes]; mean [SD] age, 56 [11] years), the 2-year cumulative probability of developing CI-DME with vision loss or PDR was 16.3% with aflibercept vs 43.5% with sham. The overall hazard ratio for either outcome was 0.32 (97.5% CI, 0.21-0.50; P < .001), favoring aflibercept. The 2-year cumulative probability of developing PDR was 13.5% in the aflibercept group vs 33.2% in the sham group, and the 2-year cumulative probability of developing CI-DME with vision loss was 4.1% in the aflibercept group vs 14.8% in the sham group. The mean (SD) change in visual acuity from baseline to 2 years was -0.9 (5.8) letters with aflibercept and -2.0 (6.1) letters with sham (adjusted mean difference, 0.5 letters [97.5% CI, -1.0 to 1.9 letters]; P = .47).

Conclusions and Relevance

In this randomized clinical trial, among eyes with moderate to severe NPDR, the proportion of eyes that developed PDR or vision-reducing CI-DME was lower with periodic aflibercept compared with sham treatment. However, through 2 years, preventive treatment did not confer visual acuity benefit compared with observation plus treatment with aflibercept only after development of PDR or vision-reducing CI-DME. The 4-year results will be important to assess longer-term visual acuity outcomes.

Trial Registration

ClinicalTrials.gov Identifier: NCT02634333.

Visual Field Changes Over 5 Years in Patients Treated With Panretinal Photocoagulation or Ranibizumab for Proliferative Diabetic Retinopathy

Importance

Preservation of peripheral visual field (VF) is considered an advantage for anti-vascular endothelial growth factor agents compared with panretinal photocoagulation (PRP) for treatment of proliferative diabetic retinopathy. Long-term data on VF are important when considering either treatment approach.

Objective

To further evaluate changes in VF throughout 5 years among eyes enrolled in the Protocol S clinical trial, conducted by the DRCR Retina Network.

Design, Setting, and Participants

Post hoc analyses of an ancillary study within a multicenter (55 US sites) randomized clinical trial. Individuals with eyes with proliferative diabetic retinopathy enrolled in Protocol S were included. Data were collected from February 2012 to February 2018. Analysis began in June 2018.

Interventions

Panretinal photocoagulation or intravitreous injections of 0.5-mg ranibizumab. Diabetic macular edema, whenever present, was treated with ranibizumab in both groups. Panretinal photocoagulation could be administered to eyes in the ranibizumab group when failure or futility criteria were met.

Main Outcomes and Measures

Mean change in total point score on VF testing with the Humphrey Field Analyzer 30-2 and 60-4 test patterns.

Results

Of 394 eyes enrolled in Protocol S, 234 (59.4%) were targeted for this ancillary study. Of these, 167 (71.4%) had VF meeting acceptable quality criteria at baseline (median [interquartile range] age, 50 [43-58] years; 90 men [53.9%]). At 5 years, 79 (33.8%) had results available. The mean (SD) change in total point score in the PRP and ranibizumab groups was -305 (521) dB and -36 (486) dB at 1 year, respectively, increasing to -527 (635) dB and -330 (645) dB at 5 years, respectively (P = .04). After censoring VF results after PRP treatments in the ranibizumab group, the 5-year mean change in total point score was -201 (442) dB. In a longitudinal regression analysis of change in total point score including both treatment groups, laser treatment was associated with a mean point decrease of 208 (95% CI, 112-304) dB for the initial PRP session, 77 (95% CI, 21-132) dB for additional PRP sessions, and 325 (95% CI, 211-439) dB for endolaser. No association was found between change in point score and the number of ranibizumab injections during the previous year (-9 per injection [95% CI, -22 to 3]).

Conclusions and Relevance

The limited data available from Protocol S suggest that there are factors besides PRP associated with VF loss in eyes treated for proliferative diabetic retinopathy. Further clinical research is warranted to clarify the finding.

Trial Registration

ClinicalTrials.gov identifier: NCT01489189.

Efficacy of intravitreal AFlibercept injection For Improvement of retinal Nonperfusion In diabeTic retinopathY (AFFINITY study)

INTRODUCTION

To evaluate the effects of intravitreal aflibercept injection on retinal nonperfusion in patients with diabetic retinopathy (DR) using ultrawide field (UWF) fluorescein angiography (FA).

RESEARCH DESIGN AND METHODS

Thirty-eight eyes of 38 consecutive patients with DR and substantial retinal nonperfusion (nonperfusion index (NPI): nonperfused/total gradable area >0.2) without macular edema were included in this prospective case series. Monthly injections of 2 mg aflibercept were given for 6 months. UWF-fundus photography and UWF-FA images were acquired at baseline, 6 months, and 12 months and evaluated by 2 masked, independent graders for the extent of retinal nonperfusion and vascular leakage. Twenty untreated fellow eyes were analyzed as controls.

RESULTS

Inter-grader agreement was strong (r=0.875) for NPI measurements. NPI was 0.46±0.10 at baseline; NPI was decreased to 0.43±0.08 (p=0.015) after 6 monthly injections of aflibercept and then slightly increased to 0.44±0.09 (p=0.123) after 6 months of observation. Vascular leakage also significantly decreased by 21.0% at 6 months (p=0.010). Untreated fellow eyes did not show significant changes in NPI and vascular leakage during follow-up. Reduction in retinal nonperfusion was associated with severe nonproliferative diabetic retinopathy (NPDR) (vs PDR, OR 19.119, p=0.025) and higher leakage index (per 0.1, OR 15.152, p=0.020).

CONCLUSIONS

Intensive aflibercept treatment was effective in reducing retinal capillary nonperfusion in patients with DR without macular edema. Severe NPDR and profound vascular leakage were significantly associated with retinal reperfusion after aflibercept treatment.

TRIAL REGISTRATION NUMBER

NCT03006081.

Aflibercept ameliorates retinal pericyte loss and restores perfusion in streptozotocin-induced diabetic mice

INTRODUCTION

Anti-vascular endothelial growth factor (VEGF) agents are used worldwide for advanced-stage diabetic retinopathy (DR). In contrast, apart from blood glucose control, there are no specific treatments that can limit the progression of early-stage DR that starts with pericyte loss and the destruction of the blood-retinal barrier. Here, we examined the efficacy of aflibercept, a potent anti-VEGF agent, against early-DR pathologies in a murine model of streptozotocin (STZ)-induced DR.

RESEARCH DESIGN AND METHODS

STZ was intraperitoneally administered in 8-week-old C57BL/6N male mice. After 4 weeks, the mice were divided into aflibercept-treated and saline-treated groups. Eight weeks after the STZ injection, vascular permeability/leakage was measured with fluorescein angiography in live mice. At 4, 6, and 8 weeks after the STZ injection, the eyes were enucleated, flat-mounted, and stained for platelet-derived growth factor receptor-β to assess pericyte abundance, CD45 to assess leukocyte recruitment, and fluorescein isothiocyanate dextran to assess perfusion. VEGF levels were quantified in each group. The effects of aflibercept on pericyte number, perfusion status, and leukocyte recruitment/accumulation on mice with diabetes retina were evaluated.

RESULTS

Our murine model successfully replicated the salient pathologies of DR such as pericytes loss, hyperpermeability, and perfusion blockage. Interestingly, numerous leukocytes and leukocyte clumps were found in diabetic retinal capillaries, especially in the non-perfused border area of the retina, suggesting a possible mechanism for non-perfusion and related pericyte damage. Treatment with aflibercept in mice with diabetes inhibited the upregulation of VEGF and the associated adhesion molecules while reducing the defects in perfusion. Aflibercept also attenuated pericyte loss in the diabetic retina.

CONCLUSION

VEGF inhibition through aflibercept treatment decreased leukocyte recruitment and aggregation, perfusion blockage, retinal hypoperfusion, and hyperpermeability in mice with diabetes and ultimately attenuated pericyte loss. Our findings suggest that anti-VEGF strategies may prove useful as possible therapies for limiting the progression of early-stage DR.

Aflibercept Reduces Retinal Hemorrhages and Intravitreal Microvascular Abnormalities But Not Venous Beading: Secondary Analysis of the CLARITY Study

PURPOSE

Approximately 50% of patients receiving anti-vascular endothelial growth factor (VEGF) therapy show significant improvement in diabetic retinopathy severity score (DRSS), in particular at DRSS level 47 to 53 (moderately severe to severe nonproliferative diabetic retinopathy). Level 47 to 53 consists of 3 main features: deep hemorrhages (DH), venous beading (VB), and intraretinal microvascular abnormalities (IRMAs). It is unclear whether these features respond to anti-VEGF therapies differently.

DESIGN

Post hoc analysis of Intravitreal Aflibercept versus Panretinal Photocoagulation in Patients with Proliferative Diabetic Retinopathy (CLARITY) study.

PARTICIPANTS

Treatment-naïve participants randomized to intravitreal aflibercept.

METHODS

We reanalyzed the fundus images at baseline, week 12, and week 52 to assess the changes of the 3 main features in DRSS level 47 to 53 in those patients who were treatment naïve and had received aflibercept.

MAIN OUTCOME MEASURES

Changes in DH, VB, and IRMA after aflibercept therapy at weeks 12 and 52.

RESULTS

Fifty-five treatment-naïve eyes at baseline that received aflibercept were included in the study. Severe DH and severe IRMA improved in approximately 75% of eyes at week 12 and mostly remained improved at week 52; VB remained unchanged in all eyes at week 12. From 12 weeks, 32 eyes that had received injections showed improved or stable DH compared with 7 eyes that did not receive injections, and DH deteriorated in 6 eyes with no further injections compared with 4 eyes that had received more injections (P = 0.0072). Similarly, 15 eyes that continued to receive injections from week 12 showed improved or stable IRMA compared with 4 who did not receive injections (P = 0.006). Worsening of IRMA was seen in 5 eyes with no further injections compared with 4 eyes that continued to receive injections. The improvements in DH and IRMA are more likely to be maintained if less than 16 weeks have elapsed since the last anti-VEGF injection.

CONCLUSIONS

Aflibercept seems to improve DH and IRMA after just 3 injections. As soon as the frequency of injections were reduced, DH and IRMA can deteriorate again. It is unclear whether these results can be translated to patients without PDR.

Efficacy of conbercept combined with panretinal photocoagulation in the treatment of proliferative diabetic retinopathy

This prospective clinical study was to compare the effect of panretinal photocoagulation (PRP) associated with intravitreal conbercept injections versus PRP alone in the treatment of proliferative diabetic retinopathy (PDR). For each of 15 patients included, one eye was randomly assigned to receive treatment with PRP, and the other eye received conbercept combined PRP. Ophthalmic examinations, optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) were performed at baseline and at each monthly visit until 6 months. Fluorescein angiography (FA) was acquired at baseline, 3 months and 6 months. Between group and within group analysis was done by using generalized estimating equations (GEE). The combination group had a significant decrease of neovascularization (NV) leakage area than the PRP group at month 3 and month 6 after treatment, and a better best-corrected visual acuity (BCVA) during the first three months. Within-group analysis indicated a significant decrease in NV leakage at month 3 and month 6 in both groups, and a significant increase in BCVA at 1 month in the combination group. In summary, the combination of intravitreal injection of conbercept and PRP can significantly reduce the NV of PDR patients and achieve better BCVA during the drug’s lifespan compared with PRP alone.

Relationships among Retinal Nonperfusion, Neovascularization, and Vascular Endothelial Growth Factor Levels in Quiescent Proliferative Diabetic Retinopathy

Purpose: To investigate the relationships among the retinal nonperfusion (NP) area, neovascularization (NV) area, and aqueous humor vascular endothelial growth factor (VEGF) levels in quiescent proliferative diabetic retinopathy (PDR). Methods: Forty-seven eyes from 47 patients with treatment-naïve PDR that did not show macular edema or vitreous hemorrhage were enrolled. NP area, NV number, and NV area were quantitatively measured using ultra-widefield fluorescein angiography in an automated manner. Aqueous humor VEGF level was measured using a bead assay. Results: The NP areas of the total, posterior pole, peripheral retinae, and NV area positively correlated with each other (all p < 0.034). NV number correlated with total NP area, peripheral NP area, and NV area (all p ≤ 0.001). VEGF levels were significantly positively correlated with total, posterior polar, and peripheral NP areas and NV area (r = 0.575, 0.422, 0.558, and 0.362, respectively; all p ≤ 0.012). In eyes with NV in the disc area, the VEGF level was higher compare to eyes without NV in the disc area (208.89 ± 192.77 pg/mL vs. 103.34 ± 132.66, p = 0.010). A multiple linear regression model using NP area, NV area, and NVD demonstrated good prediction for VEGF level (R2 = 0.417, p < 0.001) and revealed a significant contribution of the peripheral NP area in predicting the VEGF level (β = 0.497, p = 0.002). Conclusions: Aqueous humor VEGF levels in quiescent PDR eyes were associated with NP and NV areas, which had positive correlations with each other. In addition, the NP area of the peripheral retina was the most important predictor of VEGF level.

Retinal Nonperfusion Characteristics on Ultra-Widefield Angiography in Eyes With Severe Nonproliferative Diabetic Retinopathy and Proliferative Diabetic Retinopathy

Importance

Threshold of retinal nonperfusion for the development of proliferative diabetic retinopathy (PDR) is unclear.

Objectives

To identify a threshold of retinal nonperfusion for the presence of retinal neovascularization and the distribution and area of retinal nonperfusion in eyes with severe nonproliferative diabetic retinopathy (NPDR), PDR, neovascularization of the optic disc (NVD), and retinal neovascularization elsewhere (NVE).

Design, Setting, and Participants

This cross-sectional image analysis study was performed between September 24, 2018, and October 24, 2018, at a multicenter national study in the United Kingdom. Baseline images were obtained from 2 completed randomized clinical trials (Ranibizumab for Diabetic Macular Edema Panretinal Photocoagulation [RDP] study and Clinical Efficacy of Intravitreal Aflibercept vs Panretinal Photocoagulation for Best Corrected Visual Acuity in Patients With Proliferative Diabetic Retinopathy at 52 Weeks [CLARITY] study). The RDP study recruited eyes with severe NPDR between April 1, 2014, and December 31, 2015, and the CLARITY study recruited eyes with PDR between August 22, 2014, and November 20, 2015. Ultra-widefield angiography images of eyes with no prior panretinal photocoagulation treatment were included.

Main Outcomes and Measures

The total area of retinal nonperfusion, the area of posterior pole retinal nonperfusion, and the area of peripheral retinal nonperfusion were measured.

Results

A total of 92 patients (92 eyes) were included in the study: 59 in the PDR group (mean [SD] age, 42 [15] years; 20 female [33.9%]) and 33 in the NPDR group (mean [SD] age, 63 [10] years; 3 female [9.1%]). Forty eyes had NVE and 19 had NVD with or without NVE. We identified a retinal nonperfusion threshold of 118.3 disc areas (DA) with a specificity of 84.9% (95% CI, 68.1% to 94.9%) for PDR. The median area of retinal nonperfusion was 67.8 DA (95% CI, 44.2 to 107.3 DA) in the NPDR eyes and 147.9 DA (95% CI, 127.4 to 173.5 DA) for eyes with proliferative changes, with a difference of 69.0 DA (95% CI, 42.2 to 97.7 DA; P < .001). No difference was found in the median area of posterior nonperfusion between NPDR and PDR, with a difference of 0 DA (95% CI, -6.7 to 5.2 DA; P = .56). As for peripheral nonperfusion, NPDR eyes measured 64.1 DA and PDR eyes measured 130.6 DA, with a difference of 70.8 DA (95% CI, 48.4 to 94.9 DA; P < .001). Eyes with NVD had the largest total area of retinal nonperfusion, with a difference of 65.1 DA (95% CI, 28.6 to 95.8 DA; P < .001) compared with eyes with only NVE.

Conclusions and Relevance

These findings suggest eyes with at least 107.3 DA of nonperfusion are at risk of proliferative disease, and eyes with NVD have the largest area of retinal nonperfusion.