Risk factors for central and branch retinal vein occlusion: a meta-analysis of published clinical data

Deciphering the interplay of gut microbiota and metabolomics in retinal vein occlusion

This study aims to explore the link between retinal vein occlusion (RVO), a blinding ocular condition, and alterations in gut microbiota composition, to offer insights into the pathogenesis of RVO. Fecal samples from 25 RVO patients and 11 non-RVO individuals were analyzed using 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC-MS). Significant differences in the abundance of gut microbial species were noted between RVO and non-RVO groups. At the phylum level, the RVO group showed an elevation in the ratio of Firmicutes to Bacteroidetes. At the genus level, the RVO group showed higher abundance in Escherichia_Shigella (P < 0.05) and less abundance in Parabacteroides (P < 0.01) than the non-RVO group. Functional predictions indicated reduced folate synthesis, biotin metabolism, and oxidative phosphorylation, with an increase in butyric acid metabolism in the RVO group. LC-MS analysis showed significant differences in purine metabolism, ABC transporters, and naphthalene degradation pathways, especially purine metabolism. Pearson correlation analysis revealed significant associations between bacterial genera and fecal metabolites. Enrichment analysis highlighted connections between specific metabolites and bacterial genera. The findings showed that the dysregulation of gut microbiota was observed in RVO patients, suggesting the gut microbiota as a potential therapeutic target. Modulating the gut microbiota could be a novel strategy for managing RVO and improving patient outcomes. Furthermore, the study findings suggest the involvement of gut microbial dysbiosis in RVO development, underscoring the significance of understanding its pathogenesis for effective treatment development.

IMPORTANCE

Retinal vein occlusion (RVO) is a blinding ocular condition, and understanding its pathogenesis is crucial for developing effective treatments. This study demonstrates significant differences in gut microbiota composition between RVO patients and non-RVO individuals, implicating the involvement of gut microbial dysbiosis in RVO development. Functional predictions and metabolic profiling provide insights into the underlying mechanisms, highlighting potential pathways for therapeutic intervention. These findings suggest that modulating the gut microbiota might be a promising strategy for managing RVO and improving patient outcomes.

Risk of stroke development following retinal vein occlusion: A systematic review and meta-analysis

Retinal vein occlusion (RVO) and cerebrovascular disease (CVD) share common risk factors and may be independently associated; however, the strength and nature of this association remain unclear. We conducted a systematic review and meta-analysis, informed by studies from PubMed, Scopus, EMBASE, Web of Science, and Google Scholar until January 6, 2024, aimed to clarify this relationship. Eligible studies included cohorts observing stroke incidence in RVO patients for over a year. Pooled effect estimates were calculated using random-effects models, with subgroup analyses evaluating associations between RVO types (central and branch) and stroke subtypes (ischemic and hemorrhagic). Ten cohort studies with a total of 428,650 participants (86,299 RVO patients) were included. Compared to controls, RVO patients exhibited a significantly increased risk of stroke (pooled risk ratio [RR]=1.38, 95% confidence interval (95%CI)=1.34-1.41). Subgroup analyses indicated elevated risk for both ischemic (RR=1.37, 95%CI=1.32-1.42) and hemorrhagic (RR=1.55, 95%CI=1.08-2.22) strokes in RVO patients. Additionally, both central (RR=1.50, 95%CI=1.27-1.78) and branch (RR=1.41, 95%CI=1.32-1.50) RVO were associated with stroke risk. Sensitivity analyses confirmed consistent results across various criteria, and funnel plots indicated no publication bias. RVO significantly increases the risk of both ischemic and hemorrhagic stroke, regardless of RVO type, suggesting a strong independent association between these conditions.

Disparities in Retinal Vein Occlusion Presentation and Initiation of Anti-VEGF Therapy: An Academy IRIS® Registry Analysis

OBJECTIVE

Investigate disparities in retinal vein occlusion (RVO) presentation and initiation of anti-VEGF treatment.

DESIGN

Retrospective cohort study.

SUBJECTS

Patients in the American Academy of Ophthalmology IRIS® (Intelligent Research in Sight) Registry database (2015-2021) with branch or central RVO and macular edema (ME).

METHODS

The association of demographic characteristics and presenting visual acuity (VA) with anti-VEGF treatment initiation were quantified using multivariable logistic regression.

MAIN OUTCOME MEASURES

Treatment with ≥ 1 anti-VEGF injection within 12 months after RVO diagnosis.

RESULTS

A total of 304 558 eligible patients with RVO and ME were identified. Age at presentation varied by race, ethnicity, sex, and RVO type (all P values < 0.001). Within the first year after RVO presentation, 192 602 (63.2%) patients received ≥ 1 anti-VEGF injection. In a multivariable regression model adjusting for relevant covariates, female (vs. male) patients had lower odds of receiving injections (odds ratio [OR], 0.95; 95% confidence interval [CI], 0.93-0.96; P < 0.0001) as did Black/African American (vs. White) patients (OR, 0.90; 95% CI, 0.88-0.92; P < 0.0001) and Asian (vs. White) patients (OR, 0.95; 95% CI, 0.91-0.99; P = 0.02), whereas older patients (vs. patients aged < 51 years) had higher odds (61-70 years: OR, 1.20; 95% CI, 1.16-1.24; 71-80 years: OR, 1.20; 95% CI, 1.16-1.24; > 80 years: OR, 1.15; 95% CI, 1.11-1.18; all P values < 0.0001). Hispanic (vs. non-Hispanic) patients had a small increased odds of treatment initiation (OR, 1.08; 95% CI, 1.04-1.11; P < 0.0001). Results were similar in the subset of 226 143 patients with VA data. In this subset, patients with presenting VA < 20/40 to 20/200 were most frequently treated in the first year after diagnosis (∼ 70%) and patients with light perception/no light perception (LP-NLP) vision or VA of 20/20 or better were treated least frequently (36.9% and 41.9%, respectively).

CONCLUSIONS

In this large national clinical registry, 37% of RVO patients with ME had no anti-VEGF treatment documented in the first year after diagnosis. Black/African American, Asian, and female patients and patients with VA of LP-NLP were least likely to receive treatment. Awareness of this undertreatment and these disparities highlight the need for initiatives to ensure all RVO patients receive timely anti-VEGF injections for optimized visual outcomes.

FINANCIAL DISCLOSURES

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Early vitrectomy is indicated for both diffuse and dense vitreous haemorrhages of unknown aetiology

BACKGROUND

Early vitrectomy for complete fundus-obscuring vitreous haemorrhage (VH) allows for prompt diagnosis and treatment of the cause.

AIMS

To analyse the causes of VH of unknown aetiology, whether partially fundus-obscuring or dense, and to determine the outcomes of early vitrectomy.

METHODS

A retrospective review of patients who underwent early vitrectomy within 10 days of symptom-onset for partially fundus-obscuring or dense VH of unknown origin. Patients with evidence of proliferative diabetic retinopathy in either eye or any other preoperatively diagnosed aetiology of VH were excluded.

RESULTS

19 patients were included. Intraoperative diagnoses were: retinal tears without rhegmatogenous retinal detachment (RRD) (53%); peripheral localised RRD (32%); neovascularisation secondary to retinal vein occlusion (11%) and posterior vitreous detachment without a retinal break (5%). Patients with diffuse VH were as likely to have a retinal tear diagnosed as those with dense VH (88% vs 82%, respectively; p = 0.7). Mean VA improved from 1.26 LogMAR to 0.23 LogMAR postoperatively (p = 0.001). 1 patient (5%) developed a RRD one-year postoperatively.

CONCLUSIONS

In cases of diffuse or dense VH of unknown aetiology, an occult retinal tear should be suspected. Early vitrectomy should be strongly considered regardless of whether the fundal view is partially or completely obscured, to prevent progression to visually significant RRDs.

Effectiveness of Mp-3 Microperimetric Biofeedback Fixation Training For Low Vision Rehabilitation in Patients Treated With Corticosteroid Ivt in Retinal Vein Occlusions

Background

The success of fixation training using microperimetric biofeedback (MP-3 MBFT) in the realm of visual rehabilitation for patients with central vision loss caused by macular pathologies is well established. This study aimed to assess the effectiveness and safety of visual rehabilitation with microperimetric biofeedback in consolidating the benefits obtained, with the goal of reducing the need for repeated intravitreal injections (IVT). Specifically, the focus is on the eyes of patients with central vision loss treated with slow-release corticosteroid IVT following retinal venous thrombosis (RVO), aiming to enhance and maintain postoperative efficacy.

Methods

This retrospective review involved the examination of 44 eyes affected by macular edema due to RVO associated with central vision loss. Patients were divided into two groups, with only one undergoing ten sessions of 10-minute visual rehabilitation with a microperimeter (MP-3 MBFT) after IVT over a period of 20 weeks.

Results

All the treated patients demonstrated good tolerance to the procedure, with no reported complications. A comparison of best-corrected visual acuity (BCVA), retinal sensitivity recorded with a microperimeter, and pre-IVT fixation stability revealed statistically significant improvements at the end of the first month after IVT. However, the treatment group continued to exhibit superior and more enduring results at four months post-IV.

Conclusion

The synergistic use of MP-3 MBFT rehabilitation after IVT with slow-release corticosteroids has proven particularly effective in improving BCVA and long-term fixation stability. This led to a significant reduction in the number of required IVTs, with no related adverse events. The authors argue that biofeedback utilization represents a noninvasive therapeutic option devoid of contraindications and easy to implement and that it positively contributes to the overall patient experience regarding quality of life in advanced stages of macular diseases.

Influence of Smoking and Controlled Medical Conditions on the Risks of Branch Retinal Vein Occlusion in South Korea: A Population-Based Study

PURPOSE

To evaluate the effect of controlled medical conditions and risk of lifetime smoking history on the prevalence of branch retinal vein occlusion (BRVO) based on the Korea National Health and Nutrition Survey (KNHANES) database from 2017-2021.

METHODS

The study population consisted of individuals aged ≥ 40 years who had completed ophthalmological questionnaires, underwent comprehensive ophthalmological examinations, and had at least one good-quality readable fundus photograph. Age, sex, hypertension status, diabetes status, dyslipidemia status, body mass index status, a history of chronic kidney disease (CKD), a lifetime smoking history of ≥ 100 cigarettes, and glaucoma were subjected to univariate and multivariate logistic regression analyses.

RESULTS

The estimated prevalence (± standard error) of RVO was 0.5% (±0.1%). Significant risk factors were one-year increase in age, female sex, hypertension (stage 1, controlled, uncontrolled, and undiagnosed hypertension), underweight, pre-obesity, history of CKD, lifetime smoking history of ≥ 100 cigarettes, and glaucoma. Controlled diabetes decreased the risk of BRVO by 55% (odds ratio [OR] = 0.45, 95% confidence interval [CI] = 0.22-0.89, p = 0.022) and controlled hyper-high-density-lipoprotein (HDL)-cholesterolemia decreased the risk by 69% (OR = 0.31, 95% CI = 0.13-0.76, p = 0.010).

CONCLUSION

This study, for the first time, reported the association between lifetime smoking history of ≥ 100 cigarettes and BRVO in Korea. The risk of BRVO was lower in participants with controlled diabetes and hypo-HDL-cholesterolemia.

Association of Retinal Vein Occlusion With Serum Osmolality and Hydration Status

BACKGROUND AND OBJECTIVE

The aim of this study was to evaluate serum osmolality and hydration status in patients with retinal vein occlusion (RVO).

PATIENTS AND METHODS

This cross-sectional study consisted of 79 patients with RVO and 81 age- and sex-matched peers without ocular disease. Data were collected from patient records and included a comprehensive ophthalmological examination, laboratory data of fasting blood test results, and internal medicine outpatient examination. Complete blood count and levels of fasting glucose, sodium, blood urea nitrogen (BUN), creatinine, triglyceride, low-density lipoprotein, high-density lipoprotein, HbA1c, and serum osmolality were evaluated. BUN/creatinine ratios were calculated.

RESULTS

Mean serum sodium and serum osmolality levels were 142.53 ± 2.13 and 139.74 ± 2.16 mEq/L and 286.58 ± 4.40 and 280.57 ± 4.39 mOsmol/kg H2O in the RVO and control groups, respectively. Serum osmolality and serum sodium levels, and BUN/creatinine ratio were significantly higher in the RVO group than in controls (P < 0.05 for all).

CONCLUSIONS

We found that serum osmolality, sodium levels, and the BUN/creatinine ratio increased significantly in the RVO group. The results suggest dehydration status may affect the genesis of vessel occlusion in RVO. [Ophthalmic Surg Lasers Imaging Retina 2024;55:130-135.].

Hypertension, hyperlipidaemia and thrombophilia as the most common risk factors for retinal vein occlusion in patients under 50 years

BACKGROUND AND AIMS

Cardiovascular (CV) diseases are the most common risk factors (RFs) for retinal vein occlusion (RVO) development in general. The aim of this study was to identify the most frequent causes of RVO in patients under 50.

METHODS

We retrospectively evaluated a group of patients with RVO under 50 years. The parameters of interest included age and sex, RVO type, presence of arterial hypertension (HT), hyperlipidaemia (HLD), diabetes mellitus (DM), congenital thrombophilic disorder (TD), obstructive sleep apnoea syndrome (OSAS), thyroid eye disease (TED), use of hormone contraception (HC) or hormone replacement therapy (HRT), glaucoma and other potential RFs. Patients with central RVO (CRVO), hemi-central RVO (HRVO), branch RVO (BRVO), impending CRVO and combined arterial-venous (AV) occlusion were included.

RESULTS

The group consisted of 110 eyes of 103 patients. CV disease was the most common systemic abnormality. 55.3% patients had HT, 17.5% had HLD. TD was the third most frequent RF (12.6%). The cohort also included patients with DM (6.8%), glaucoma (6.8%) and women using HC/HRT (26.2% of female patients). There were isolated cases of RVO due to retinal vasculitis, intense exercise, antiphospholipid syndrome and COVID-19 pneumonia. None of the patients had OSAS, TED or a haemato-oncological disease. The etiology remained unexplained in 20.4% patients. No difference was observed in RF occurrence between patients with CRVO and HRVO and those with BRVO.

CONCLUSION

The most common systemic abnormality in our cohort was CV disease, especially HT and HLD. The risk factors for central, hemi-central and branch RVOs were similar.

Acute, Treatment-Naïve Branch Retinal Vein Occlusion in Younger Individuals: Risk Factors and Clinical Outcomes

Purpose: To compare the risk factors and clinical outcomes in patients younger than 50 years with acute, treatment-naïve branch retinal vein occlusion (BRVO) with outcomes in patients 50 years or older. Methods: Patients diagnosed with acute, treatment-naïve BRVO at Duke Eye Center over a 9.5-year period who had BRVO with onset 3 months or less before presentation, BRVO with macular involvement, and 12 months or more of follow-up were included. Demographic data, presenting clinical features, risk factors, treatment patterns, and clinical outcomes were extracted during a retrospective review of medical records. Results: Of 302 patients identified, 23 were younger than 50 years (younger group) and 279 were 50 years or older (older group). Compared with older patients, younger patients had similar rates of hypertension (P = .275), diabetes mellitus (P = 1.000), smokers (P = .787), and open-angle glaucoma (P = .628). The younger group had a lower rate of hyperlipidemia than the older group (35% vs 59%) (P = .028). The 2 groups had similar presenting logMAR visual acuities (VAs) in the BRVO eye (P = .131). At the final follow-up, younger patients had significantly better logMAR VA in the BRVO-affected eye than older patients (mean 0.51 ± 0.65 vs 1.01 ± 1.20) (P = .016). The 2 groups had similar treatment burdens at 1 year (P = .516) and at the final follow-up (P = .782). Conclusions: Younger patients with acute, treatment-naïve BRVO have similar risk factors and treatment patterns as older patients, except for a lower rate of hyperlipidemia. Younger patients with BRVO may have similar presenting VA as older BRVO patients but better final VA, suggesting that age may be a potential prognostic factor.

Evaluation of Central and Peripheral Retinal Vascular Changes in the Fellow Eyes of Patients with Unilateral Retinal Vein Occlusions

Objectives

To evaluate the subtle peripheral retinal and macular vascular changes in the fellow eyes of patients with unilateral retinal vein occlusion (RVO).

Materials and Methods

This retrospective study included 53 patients with unilateral RVO and 44 age-matched controls. The frequency of peripheral retinal vascular pathologies in both eyes was evaluated using high quality ultra-wide field fluorescein angiography (UWFFA). Macular vascular density, flow area, and foveal avascular zone measurements from optical coherence tomography angiography (OCTA) were analyzed together with laser flare photometry values in patients and controls.

Results

Peripheral retinal vascular pathologies were detected on UWFFA in the fellow eyes of 36 (67.9%) patients. No significant central vascular pathologies were detected on OCTA and there was no significant difference in OCTA parameters between the fellow eyes and the controls. Flare values did not differ significantly between the control and the fellow eyes.

Conclusion

Two thirds of the fellow eyes of unilateral RVO patients had subtle peripheral retinal vascular changes, while there was no significant microvascular change detected with OCTA in the macula. This suggests that vascular changes caused by systemic vascular disorders probably first start in the peripheral retina of the fellow eyes of patients with RVO.

Case series of branch retinal vein occlusion secondary to rhegmatogenous retinal detachment and its surgical management

BACKGROUND

To review cases of branch retinal vein occlusion (BRVO) secondary to rhegmatogenous retinal detachment (RRD) and its surgical management and presume their mechanism.

METHODS

Medical records of patients who underwent surgery for RRD between 2015 and 2019 at a single tertiary care center were retrospectively reviewed. New BRVO secondary to RRD or its surgical procedure was diagnosed based on the fundus examination and its clinical course.

RESULTS

A total of 734 RRD surgeries were performed for five years, and six cases of new BRVOs were noticed in the first year after surgery (incidence was 0.68%: six cases of BRVO / 734 cases of surgical RRD); five cases occurred after vitrectomy, and one occurred after scleral buckling. In three cases, retinal veins were presumed to already be partially occluded related due to a kink of the retinal vein seen before surgery. In the other three cases, the retinal veins were presumed to have incurred damage during vitrectomy.

CONCLUSION

In the present cohort, RRD or its related procedures caused BRVO within a year of surgery at an incidence of 0.68%. The proposed mechanisms are kinks of the retinal vein on the detached retina and damage to the retinal vein during vitrectomy.

Ocular venous occlusion in pediatrics: Should thrombophilia investigation and anticoagulant treatment be initiated?

Retinal vein occlusion (RVO) and superior ophthalmic vein thrombosis (SOVT) are rare diseases in the pediatric population; however, the ophthalmic and neurologic morbidity are significant. As published data are scarce for these conditions, we present our experience with pediatric ocular venous thrombosis in four patients, and discuss recommended management for evaluation and treatment. We suggest performing thrombophilia workup for all pediatric patients with RVO or SOVT. In patients with thrombophilia risk factors or patients with additional thrombi, we highly recommend initiating anticoagulation therapy. There is a need for more research in order to determine the optimal management strategy.

Retinal Vein Occlusion Amongst People Vaccinated by mRNA- and Viral Vector- COVID-19 Vaccines: A Systematic Review

Vaccines are highly effective in lowering the mortality due to COVID-19. Although several suspected adverse events or side effects after vaccination including retinal vein occlusion (RVO) have been reported. We conducted a systematic review using PRISMA methods to analyze the occurrence of RVO among people vaccinated by COVID-19 mRNA- vs viral vector- vaccines on 4 databases from 1-1-2021 to 31-12-2022 using specified MeSH terms. All included studies were assessed using JBI critical appraisal tools for eligibility. The final included studies are 31 studies (n=78 cases from 75 patients; 3 of these patients suffered twice). The median age of the patients was 61 years (28 to 96 years old) and most of them were female (52.00%). Thirty-nine patients received the mRNA vaccine (52.00%), while 36 patients received the viral vector vaccine (48.00%) before the event. The RVO diagnoses are based on physical examination confirmed by Fluorescein Angiography (FA), and/or Optical Coherence Tomography (OCT). The median time interval between vaccination and RVO was 6 days in the mRNA vaccine group and 4 days in the viral vector vaccine group. Central retinal vein occlusion (CRVO) and Branch Retinal Vein Occlusion (BRVO) were tied as the most common diagnosis in the mRNA vaccine group (20.51% and 20.51%), whilst in the viral vector vaccine group CRVO was the most common diagnosis (17.94%). Most of these cases had good outcomes with improved visual impairment in one or both eyes. From this review, we could not ascertain that the RVO occurs due to the type of COVID-19 vaccines because of the detailed data on the dosage and the history of illness of each patient. However, the awareness that the RVO could develop after COVID-19 vaccination must be taken into consideration, even though it is rare.

Cardiovascular morbidity and all-cause mortality in patients with retinal vein occlusion: a Danish nationwide cohort study

BACKGROUND/AIMS

Associations between retinal vein occlusion (RVO) and subsequent cardiovascular disease (CVD) or mortality have not been evaluated in a recent cohort, after novel therapeutic options have increased referrals for treatment of the condition. We aimed to evaluate overall and subtype-stratified risk of CVD and all-cause mortality following RVO and assess any alterations after the introduction of angiostatic therapy in Denmark in 2011.

METHODS

This nationwide, registry-based cohort study from 1998 to 2018 evaluated 4 194 781 individuals. Hazard ratios (HRs) were reported for RVO as an overall measure and subclassified as branch and central RVO.

RESULTS

Patients with RVO (n=15 665) were median 71.8 years old at the time of exposure and 50.7% were women. RVO associated with incident CVD (adjusted HR 1.13, 95% CI 1.09 to 1.17) but not mortality (adjusted HR 1.00, 95% CI 0.97 to 1.03). Almost similar risks of CVD were found for patients with branch and central RVO (adjusted HRs 1.14, 95% CI 1.03 to 1.25, and 1.12, 95% CI 1.00 to 1.25, respectively), but only patients with central RVO exhibited increased mortality (adjusted HR 1.12, 95% CI 1.04 to 1.21). Risk of CVD, especially non-ischaemic, was higher for patients diagnosed after 2011 (adjusted HRs 1.24, 95% CI 1.15 to 1.33 vs 1.06, 95% CI 1.01 to 1.12).

CONCLUSION

In a cohort of the Danish population aged 40 years or more, patients with RVO had a 13% increased risk of incident CVD compared with unexposed individuals. Risk of CVD was increased after 2011, when intravitreal angiostatic treatment was introduced and referral practices altered.

Prevalence and systemic associations of retinal vascular occlusions in Sub-Saharan Africa

Background

Retinal vascular occlusions are a common cause of visual impairment. Studies on retinal vascular occlusions in sub-Saharan Africa (SSA) have primarily been retrospective and on retinal vein occlusion (RVO) only. The aim of this study, therefore, was to determine the prevalence and pattern of retinal vascular occlusions and their systemic associations in SSA.

Materials and Methods

This was a hospital-based, cross-sectional study involving all new patients presenting at the general ophthalmic and specialty retina clinics in four hospitals in Nigeria over a 1 year period. All the patients underwent a comprehensive eye examination. The demographic and clinical data of patients with retinal vascular occlusions were entered into an excel sheet and analyzed using the Statistical Package for the Social Sciences (SPSS) software version 22.0. Statistical significance was indicated by P < 0.05.

Results

A total of 8614 new patients were seen, and a diagnosis of retinal vascular occlusion was made in 90 eyes of 81 patients giving a disease prevalence of 0.9%. Eighty-one eyes of 72 (88.9%) patients had RVO, while 9 eyes of 9 (11.1%) patients had retinal artery occlusion (RAO). The mean age of patients with RVO and RAO was 59.5 years and 52.4 years, respectively. Increasing age, hypertension, and diabetes were the significant associations with retinal vascular occlusion with P < 0.0001.

Conclusion

Retinal vascular occlusions are an increasing cause of retinal disease in SSA and tend to occur at an earlier age. They are associated with hypertension, diabetes, and increasing age. Further studies will, however, be required to establish the demographic and clinical profile of patients with RAO in the region.

Novel pharmaceuticals for the management of retinal vein occlusion and linked disorders

INTRODUCTION

Retinal vein occlusion (RVO) is the second leading cause of blindness from retinal vascular disease behind diabetic retinopathy. Anti-vascular endothelial growth factor (VEGF) and glucocorticoid therapy are the cornerstones of pharmaceutical treatment for RVO. There is considerable interest in developing new pharmaceuticals in and out of these two classes to reduce costs, lower injection burden, and treat the occlusion itself, rather than the complications.

AREAS COVERED

In this review, we discuss novel pharmaceuticals for the treatment of RVO outside of current standard of care. We performed a comprehensive literature search encompassing pharmaceuticals that have recently been approved or have shown promising results in early clinical trials or animal models.

EXPERT OPINION

Anti-VEGF therapy remains the most efficacious treatment for RVO with a very favorable side effect profile. New biosimilars reduce costs while maintaining efficacy. Novel glucocorticoids may be a useful therapy in patients for whom anti-VEGF therapy has failed, or as an adjunct. Pharmaceuticals in other drug classes, particularly those with neuroprotective or regenerative properties, as well as those geared toward treating the occlusion itself, represent exciting options for early RVO therapy, but are likely years away from clinical relevance.

Profile of Patients Treated with Intravitreal Anti-Vascular Endothelial Growth Factor Injections in Bhutan

Purpose

Ocular vascular diseases are common causes of visual impairment and blindness, for which anti-vascular endothelial growth factor (anti-VEGF) is the first-line therapy. Current study describes the profile of patients receiving intravitreal anti-VEGF injections (IVI), and gender variation in Bhutan. The study was designed to inform national health policy.

Study Design

Retrospective cross-sectional study.

Methods

We reviewed the surgical registers of the vitreoretinal (VR) units across Bhutan over three years. Patient demography, clinical findings, diagnostic tests performed, and diagnoses or indications for IVI were logged. A descriptive analysis was performed.

Results

Despite limited availability of anti-VEGF, a total of 381 patients received IVI in operating theatres as mandated by the national guidelines. The majority of patients were males (230, 60.4%, p = 0.004). The mean age was 65.2 ± 13.5 years (range 13 years to 90 years), and a median of 69 years. The majority of the treated eyes (117, 30.7%) had BCVA <3/60 to light perception (PL), and another 51 eyes (13.4%) had < 6/60 to 3/60. The most common indication for IVI was neovascular age-related macular degeneration (nAMD) (168 cases, 42.2%), followed by retinal vein occlusion (RVO) (132 cases, 34.6%), diabetic macular oedema (DMO) and retinopathy (DR) (50 cases, 13.1%), and myopic choroidal neovascular membrane (11 cases, 0.03%).

Conclusion

Limited human resources for managing VR diseases in Bhutan are compounded by economic and geographic challenges. With increasing VR diseases such as nAMD and myopia and complications of systemic diseases such as DR, DMO and RVO, there is a need to improve VR services. Currently, anti-VEGF is procured only for a pooled patients requiring IVI, and patients are lost due to longer waiting periods. Bhutan needs to assess if females are reporting less or are not receiving treatment due to cultural barriers and social stigma.

Association between retinal vein occlusion and early-stage hypertension: A propensity score analysis using a large claims database

BACKGROUNDS/OBJECTIVES

The threshold of hypertension was lowered from systolic blood pressure (SBP)/diastolic blood pressure (DBP) 140/90 mmHg to 130/80 mmHg by the 2017 American College of Cardiology/American Heart Association blood pressure (BP) guideline. Thus, we investigated the association between retinal vein occlusion (RVO) occurrence and early-stage hypertension.

SUBJECTS/METHODS

This retrospective cohort study used the JMDC Claims Database (JMDC Inc., Tokyo, Japan) between 2005 and 2020. Individuals undergoing health checkups who had data on BP and did not take antihypertensive medications were included. They were classified into four BP groups: normal BP (SBP < 120 mmHg and DBP < 80 mmHg), elevated BP (SBP 120-129 mmHg and DBP < 80 mmHg), stage 1 hypertension (SBP 130-139 mmHg or DBP 80-89 mmHg), and stage 2 hypertension (SBP ≥ 140 mmHg or DBP ≥ 90 mmHg). Date of RVO occurrence was defined as the first date of diagnosis. We estimated adjusted hazard ratios for RVO and central RVO using weighted Cox regression to adjust for potential confounders.

RESULTS

A total of 2,703,264 individuals were eligible. During a mean follow-up of 1,091 days, 3,526 RVO and 828 central RVO events occurred. The adjusted hazard ratios (95% confidence intervals) were 1.37 (1.19-1.57), 1.95 (1.75-2.18), and 3.33 (2.95-3.76) for RVO and 1.44 (1.07-1.93), 2.17 (1.72-2.73), and 3.76 (2.91-4.86) for central RVO in the elevated BP, stage 1 hypertension, and stage 2 hypertension groups, respectively, compared with the normal BP group.

CONCLUSIONS

Even individuals with early-stage hypertension showed higher risks for RVO and central RVO than individuals with normal BP.

Mendelian randomization indicates a causal contribution of type 2 diabetes to retinal vein occlusion

Background

Retinal vein occlusion (RVO) is a common retinal vascular disease that can cause severe visual impairment. Many observational studies have shown that type 2 diabetes (T2DM) is associated with RVO, but it remains unknown if the association is causal. The present study aimed to perform Mendelian randomization (MR) analyses to evaluate the causal contribution of genetically predicted T2DM to RVO.

Methods

We obtained summary-level data from a genome-wide association study meta-analysis including 48,286 cases and 250,671 controls for T2DM and from a genome wide association study of 372 cases and 182,573 controls in the FinnGen project for RVO. To verify the robustness of the results, an independent validation dataset for T2DM (12,931 cases and 57,196 controls) was used. In addition to the main MR analysis using the inverse variance weighted (fixed effect) approach, sensitivity analyses and multivariable MR adjusting for common risk factors of RVO were conducted.

Results

Genetically predicted T2DM was found to be causally associated with RVO risk (odds ratio (OR)=2.823, 95% confidence interval (CI): 2.072-3.847, P=4.868×10^-11). This association was supported by sensitivity analyses using the weighted median (OR=2.415, 95% CI: 1.411-4.132, P=1.294×10^-3), weighted mode (OR=2.370, 95% CI: 1.321-4.252, P=5.159×10^-3), maximum likelihood (OR=2.871, 95% CI: 2.100-3.924, P=3.719×10^-11), MR-PRESSO (OR=2.823, 95% CI: 2.135-3.733, P=5.150×10^-10), and MR-Egger (OR=2.441, 95% CI: 1.149-5.184, P=2.335×10^-2) methods. In addition, this association persisted in multivariable MR after accounting for common RVO risk factors (OR=1.748, 95% CI: 1.238-2.467, P=1.490×10^-3). The MR analyses using the validation dataset obtained consistent results.

Conclusion

This study indicates that genetically predicted T2DM may have a causal contribution to RVO. Future studies are required to elucidate the underlying mechanisms.

Estimation of Vitamin D Levels in Patients With Retinal Vein Occlusions and a Comparison With Age-Matched Control Groups

Background In the older population, retinal vein occlusion (RVO) is a major contributor to vision loss and blindness. RVO is the second most common form of retinal vascular disease, following diabetic retinopathy. On the other hand, there is a paucity of studies on vitamin D insufficiency and its influence on the causation of RVOs. The goal of this study is to demonstrate a link between vitamin D levels of individuals in rural India who have RVOs. Methods This study is a hospital-based prospective case-control study. All patients aged 18 years and above with RVO visiting the ophthalmology outpatient department at a tertiary care facility in central India and all controls in the same age group were chosen for the study after taking into consideration inclusion and exclusion criteria. Fasting for 12 hours prior to blood sample collection was required of all participants. The total vitamin D concentration in the serum was determined using tandem mass spectrometry after it had been frozen at 20°C. For this study, vitamin D levels were collected from 70 participants. Results The average age is 60, with a standard variation of 10 for both cases and controls. There is a 49% prevalence of central RVO (CRVO), 34% prevalence of inferotemporal branched RVO (IT BRVO), and 17% prevalence of superotemporal BRVO (ST BRVO). Twenty percent of the 35 patients were deficient in vitamin D, and 80% had insufficient levels. No case patient had vitamin D levels within the normal range. No one with vitamin D insufficiency was found among the 35 controls. Twenty-five percent of the patients had adequate vitamin D levels, but only 28.6% of the controls did. The p-value of 0.01 indicates a remarkable difference in vitamin D levels between the diagnosed cases and controls. Cases had mean vitamin D levels of 21.408 +/- 4.947 ng/dl, while controls had mean levels of 37.808 +/- 11.799 ng/dl. Vitamin D levels did not differ significantly across RVO subtypes. The study also shows the association of RVO with hypertension (HTN) and dyslipidemia as the p-value was noted to be significant (p = 0.0147 < p = 0.05) for HTN with an odds ratio of 3.43 (CI, 1.25-9.4) and was significant (p = 0.0404 < p = 0.05) for dyslipidemia with an odds ratio of 4.87 (CI, 0.96-24.97). Diabetes, smoking, hyperhomocysteinemia, dyslipidemia, cardiovascular disease, and cerebrovascular accident are all well-known risk factors, but we found no evidence associating them together. Conclusion  Vitamin D proved to be an important risk factor in the causation of RVOs. Other risk factors like HTN and dyslipidemia also showed significant relation in the study. Vitamin D levels should be advised as a routine investigation in patients who are diagnosed with RVOs along with screening for other risk factors. Vitamin D supplementation should be given as prophylaxis in cases of deficiency.

The risk of retinal vein occlusion among patients with neovascular age related macular degeneration: a large-scale cohort study

PURPOSE

To examine the risk for retinal-vein-occlusion (RVO) in patients with neovascular age-related-macular-degeneration (AMD) as compared to age- and sex-matched controls.

METHOD

This is a population-based, cohort study. The study encompassed 24,578 consecutive patients with neovascular AMD and 66,129 control subjects. Multivariate cox regression analysis was utilized to detect the risk of RVO among patients with neovascular AMD. Predictors of RVO in patients with neovascular AMD were identified using multivariate logistic regression analysis. Mortality of patients was assessed using Kaplan-Meier method.

RESULTS

The incidence rate of RVO was estimated at 1.25 (95% CI, 1.06-1.45) per 1000 person-years among patients with neovascular AMD and 0.25 (95% CI, 0.20-0.31) per 1000 person-years among controls. Patients with neovascular AMD were associated with an increased risk of RVO (adjusted HR, 4.35; 95% CI, 3.34-5.66; P < 0.001). Among patients with neovascular AMD, older age (≥79.0 years) was associated with a decreased risk of RVO (adjusted OR, 0.50; 95% CI, 0.37-0.70; P < 0.001), whilst a history of glaucoma increased the likelihood of RVO (adjusted OR, 2.66; 95% CI, 1.94-3.65; P < 0.001). Patients with neovascular AMD and comorbid RVO had a comparable risk of all-cause mortality relative to other patients with neovascular AMD (HR, 0.90; 95% CI, 0.67-1.22; P = 0.500) CONCLUSIONS: An increased risk of RVO was found among patients with neovascular AMD. Younger age and glaucoma predicted the development of RVO in patients with neovascular AMD. Awareness of this comorbidity is of benefit for clinicians as patients with neovascular AMD might be carefully examined for RVO signs and complications.

A Case of Impending Central Retinal Vein Occlusion Associated With Antiphospholipid Antibody Syndrome Complicated by Paracentral Acute Intermediate Layer Maculopathy

We report a case of impending central retinal vein occlusion (CRVO) due to antiphospholipid syndrome (APS) complicated by paracentral acute middle maculopathy (PAMM). A 42-year-old man with no medical history acutely presented with blurred vision in his right eye. The best-corrected visual acuity was 20/20 in the right eye, but the Goldman visual field test showed a dark spot over the superior nasal region of the right eye. Fundus examination showed dilated and tortuous retinal veins of the right eye with delayed filling of the inferior retinal veins on fluorescein angiography. Optical coherence tomography (OCT) showed a hyperreflective lesion confined to the inner nuclear layer (INL), consistent with PAMM. After several weeks, his symptoms improved, and the dilated retinal vein and the INL hyperreflexia on OCT were reduced. Multiple positive findings for anti-cardiolipin antibodies were confirmed; therefore, he was diagnosed with APS and treated with aspirin. If the impending CRVO is associated with visual impairment, the complication of PAMM should be considered. In the presence of retinal vasculopathy without atherosclerotic factors, APS should be considered.

Highlights on Genetic Polymorphism Associated with Thromboembolic Risk; Implications in Ophthalmic and Autoimmune Disorders—A Review

The present paper explores genetic polymorphism and its association with thromboembolic retinal venous disorders, such as central/hemi-retinal vein occlusion, as well as possible correlations with other ocular findings, such as closed angle glaucoma, but also with autoimmune general disorders. In this review, we are highlighting the importance of establishing a correspondence between all of the above, since they all have complex etiopathogeneses; sometimes, when all coexist together, they could generate effects that may be very difficult to manage. There are studies supporting that genetic polymorphism, such as the variant MTHFR A1298C, may increase the risk for developing glaucoma, especially in the heterozygote model. Being aware of all these aspects may prove to be useful in patients with several associated diseases, as a combined effort between several medical specialties may prove to the benefit of these patients. Our review, completed with an exemplifying clinical case, shows that it is necessary to raise awareness of all aspects of a complex medical situation, including the genetic one, of a patient being at risk for thromboembolic episodes, for preventing them or managing them promptly and properly in the future.

Prevalence and risk factors of retinal vein occlusion in the United States: The National Health and Nutrition Examination Survey, 2005 to 2008

Retinal vein occlusion (RVO) is a rare, vision-threatening vascular disorder. Due to limited recovery associated with RVO, prevention is essential. There is a significant discrepancy in previously reported epidemiological studies in the United States on the prevalence and risk factors of RVO. The purpose of this retrospective, cross-sectional study was to determine the prevalence and risk factors of RVO in adults ≥40 years of age in the US using the National Health and Nutrition Examination Survey (NHANES) 2005-2008. We collected information on the demographic characteristics, medical conditions, and ocular pathology of NHANES participants. We performed weighted analysis to estimate national prevalence rates and multivariate analysis to examine associated risk factors. The main outcome measures were the prevalence of RVO and the odds ratios of associated risk factors. We included 5559 participants and found 33 cases of RVO. The overall prevalence of RVO in the US was 0.50%. Age, per 10-year increase (odds ratio [OR], 1.93; 95% confidence interval [CI], 1.31-2.92) and elevated diastolic blood pressure, per 10 mm Hg increase (OR 1.47; 95% CI, 1.10-2.12) were significant risk factors for RVO. Race, sex, glaucoma, elevated cholesterol, and self-reported history of diabetes, stroke, and heart disease were not significant risk factors. RVO is significantly associated with older age and elevated diastolic blood pressure. Our findings should alert clinicians to identify individuals at risk for RVO.

Relationship Between Retinal Microcirculation and Renal Function in Patients with Diabetes and Chronic Kidney Disease by Laser Speckle Flowgraphy

This study investigated the effect of renal dysfunction categorized by the stage of chronic kidney disease (CKD) on the retinal microcirculation assessed by laser speckle flowgraphy (LSFG) and retinal artery caliber measured by adaptive optics imaging in diabetic patients particularly the early stage of retinopathy and nephropathy. We divided the patients with diabetes into three groups based on the CKD stage (non-CKD (n = 54); CKD stage 1 + 2 (n = 20); CKD stage 3 (n = 41)). The mean blur rate (MBR) of the stage 3 CKD group was significantly lower than that of the no-CKD group (p < 0.015). The total retinal flow index (TRFI) in the stage 3 CKD group was significantly lower than that of the no-CKD group (p < 0.002). Multiple regression analysis demonstrated that CKD stage was independently associated with MBR (β = -0.257, p = 0.031) and TRFI (β = -0.316, p = 0.015). No significant differences were observed in external diameter, lumen diameter, wall thickness, and wall to lumen ratio among the groups. These results indicated that the ONH MBR and TRFI as assessed by LSFG decreases in diabetic patients with stage 3 CKD, but the arterial diameter measured by adaptive optics imaging does not change, suggesting that impaired renal function may be associated with decreased retinal blood flow in early-stage diabetic retinopathy.

Vessel Pulse Amplitude Mapping in Eyes With Central and Hemi Retinal Venous Occlusion

Purpose

The purpose of this study was to describe vessel pulse amplitude characteristics in eyes with central retinal vein occlusion (CRVO), hemiretinal vein occlusion (HVO), normal eyes (N1 N1), and the unaffected contralateral eyes of CRVO and HVO eyes (N1 CRVO and N1 HVO), as well as the unaffected hemivessels of HVO eyes (N2 HVO).

Methods

Ophthalmodynamometry estimates of blood column pulse amplitudes with modified photoplethysmography were timed against cardiac cycles. Harmonic analysis was performed on the vessel reflectance within 0.25 to 1 mm from the disc center to construct pulse amplitude maps. Linear mixed modeling was used to examine variable effects upon the log harmonic pulse amplitude.

Results

One hundred seven eyes were examined. Normal eyes had the highest mean venous pulse amplitude (2.08 ± 0.48 log u). CRVO had the lowest (0.99 ± 0.45 log u, P < 0.0001), followed by HVO (1.23 ± 0.46 log u, P = 0.0002) and N2 HVO (1.30 ± 0.59 log u, P = 0.0005). N1 CRVO (1.76 ± 0.34 log u, P = 0.52) and N1 HVO (1.33 ± 0.37 log u, P = 0.0101) had no significantly different mean amplitudes compared to N1 N1. Arterial amplitudes were lower than venous (P < 0.01) and reduced with venous occlusion (P < 0.01). Pulse amplitude versus amplitude over distance decreased along the N1 N1 vessels, with increasing slopes observed with CRVO (P < 0.01).

Conclusions

Pulse amplitude reduction and attenuation characteristics of arteries and veins in venous occlusion can be measured and are consistent with reduced vessel wall compliance and pulse wave transmission.

Translational Relevance

Retinal vascular pulse amplitudes can be measured, revealing occlusion induced changes, suggesting a role in evaluating the severity and progression of venous occlusion.

Choroidal thickness as a possible predictor of non-response to intravitreal bevacizumab for macular edema after retinal vein occlusion

To evaluate outcomes of intravitreal bevacizumab (IVB) treating macular edema (ME) after retinal vein occlusion (RVO) following pro re nata (PRN) regimen and investigate potential predictors of non-response. Retrospective analysis of 126 treatment-naive eyes with ME after RVO. Eyes were treated initially with IVB of 1.25 mg/ml. Therapy was switched in case of non-response. Outcome measures included best-corrected visual acuity (BCVA) and central macular thickness (CMT), which were recorded over 4 years of treatment. BCVA improved significantly during first 2 years. CMT decreased significantly during the 4-year follow-up period. Switching was required in 42 eyes (33%). 34 eyes (26.9%) were switched to steroids, while 8 eyes (6.3%) were switched to other anti-VEGF due to diagnosed glaucoma. Switching occurred after 12.4 ± 8.3 months and an average of 8 ± 4.1 IVBs. Compared with the treatment-responsive group, the treatment-unresponsive group had significantly worse BCVA, higher CMT and subfoveal choroidal thickness (SFCT) at baseline. Treatment IVB following PRN regimen showed significant functional and anatomic improvement in patients with ME after RVO. Switching was required in more than one third of eyes. Higher baseline SFCT could be considered as predictor for non-response to such therapy and thus an indicator of early switching.

Comparison of Intravitreal Dexamethasone Implant and Intravitreal Ranibizumab Efficacy in Younger Patients with Branch Retinal Vein Occlusion

Objectives

This study aimed to compare the effects of dexamethasone (DEX) implants and ranibizumab (RAN) injections in younger patients with macular edema due to branch retinal vein occlusion (RVO) in a 6-month follow-up.

Methods

The treatment-naive patients with macular edema secondary to branch RVO were included retrospectively. Medical records of patients who were treated with intravitreal RAN or DEX implant were evaluated before and at the 1^st, 3^rd, and 6^th months after the injection. Primary outcome measures were the change in best-corrected visual acuity (BCVA) and central retinal thickness. The level of statistical significance was set at 0.05/3=0.016, according to the Bonferroni correction.

Results

Thirty-nine eyes of 39 patients were included in the study. The mean age of the study population was 53.82±5.08 years. Median BCVA in the DEX group (n=23) at baseline, 1^st, 3^rd, and 6^th month was 1.1, 0.80 (p=0.002), 0.70 (p=0.003), and 1 (p=0.018) logarithm of the minimum angle of resolution (log-MAR), respectively (p<0.05). Median BCVA in the RAN group (n=16) at baseline, 1^st, 3^rd, and 6^th months was 0.90, 0.61, 0.52, and 0.46 logMAR, respectively (p<0.016 for all comparisons). Median central macular thickness (CMT) in the DEX group at baseline, 1^st, 3rd, and 6th months was 515, 260, 248, and 367 μm, respectively (p<0.016 for all comparisons). Median CMT in the RAN group at baseline, 1^st, 3^rd, and 6^th months was 432.5 (p<0.016), 275 (p<0.016), 246 (p<0.016), and 338 (p=0.148) μm.

Conclusion

There is no significant difference in treatment efficacies in both visual and anatomical outcomes at the end of the 6th month. However, RAN can be considered the first choice in younger patients with macular edema secondary to branch RVO because of the lower side effect profile.

A narrative review on the association of high intraocular pressure and glaucoma in patients with retinal vein occlusion

BACKGROUND AND OBJECTIVE

Retinal vein occlusion (RVO) is a major cause of vision loss and elevated intraocular pressure (IOP), high ocular perfusion pressure, and glaucoma are known ophthalmic risk factors for RVO. The aim of this paper is to provide the update on the association and management of high IOP/glaucoma and RVO.

METHODS

A literature review was performed in PubMed and Medline until May 2022 utilizing specific keywords and cross-matched reference lists.

KEY CONTENT AND FINDINGS

The association of RVO with high IOP/glaucoma may be attributed to retinal ganglion cell loss due to retinal ischemia in high IOP and glaucoma. As new modalities showed, decreased optic disc perfusion, reduced density of blood vessels in the optic nerve head of glaucoma patients, changes in the peripapillary microvascular parameters, and decreased retinal nerve fiber layer (RNFL) thickness of the optic nerve head of eyes with RVO suggest a common pathway between RVO and glaucoma. Literature suggests the close follow up for glaucoma development among patients with non-arteriovenous (AV) crossing (optic cup or optic nerve sited) RVO in fellow eye and management of elevated IOP among RVO cases treated with anti-vascular endothelial growth factor (VEGF) antibodies/corticosteroids and those with preexisting primary open angle glaucoma (POAG).

CONCLUSIONS

Determining potential patient responses to treatment and considering therapeutic options are challenging among patients with RVO and glaucoma. However, IOP lowering managements in preventing IOP spikes in patients with preexisting glaucoma and early treatment of macular edema in eyes with RVO is recommended.

Altered synchronous neural activities in retinal vein occlusion patients: A resting-state fMRI study

Objective

Retinal vein occlusion (RVO) is the second most common retinal vascular disorder after diabetic retinopathy, which is the main cause of vision loss. Retinal vein occlusion might lead to macular edema, causing severe vision loss. Previous neuroimaging studies of patients with RVO demonstrated that RVO was accompanied by cerebral changes, and was related to stroke. The purpose of the study is to investigate synchronous neural activity changes in patients with RVO.

Methods

A total of 50 patients with RVO and 48 healthy subjects with matched sex, age, and education were enrolled in the study. The ReHo method was applied to investigate synchronous neural activity changes in patients with RVO.

Results

Compared with HC, patients with RVO showed increased ReHo values in the bilateral cerebellum_4_5. On the contrary, patients with RVO had decreased ReHo values in the bilateral middle occipital gyrus, right cerebelum_crus1, and right inferior temporal gyrus.

Conclusion

Our study demonstrated that patients with RVO were associated with abnormal synchronous neural activities in the cerebellum, middle occipital gyrus, and inferior temporal gyrus. These findings shed new insight into neural mechanisms of vision loss in patients with RVO.

Central retinal vein occlusion in the setting of fibroblast growth factor receptor inhibition

Purpose

To report a case of central retinal vein occlusion (CRVO) in a patient being treated with a fibroblast growth factor receptor (FGFR) inhibitor.

Observations

A 54-year-old female patient with endometrial cancer presented with CRVO and cystoid macular edema while receiving lenvatinib/pembrolizumab combination therapy. The patient received treatment with intravitreal bevacizumab, after which her visual acuity improved markedly, permitting the continuation of her chemotherapy regimen without recurrence of ocular adverse events.

Conclusions and Importance

Like mitogen-activated protein kinase inhibitors, FGFR inhibitors have the potential to be associated with retinal vein occlusion. In this case, visual recovery was possible with intravitreal anti-vascular endothelial growth factor therapy, and toxicity did not recur with drug reinitiation and continuation over five years of follow-up.

Progress and Challenges of Anti-VEGF Agents and Their Sustained-Release Strategies for Retinal Angiogenesis

Currently, the treatment for ocular neovascular diseases, including diabetic macular edema (DME) and age-related macular degeneration (AMD), mainly involves repeated intravitreal injection of anti-vascular endothelial growth factor (VEGF) drugs. Although it can preserve vision, repeated injections are an invasive treatment modality, leading to serious complications and reducing patient adherence to treatment. To reduce the frequency of administration, prolong the time of drug action, and avoid repeated intravitreal injections, the combination of sustained-release materials with anti-VEGF drug therapy has become an emphasis in ophthalmology. In this review, we highlight the current state of anti-VEGF technology, its challenges, and the sustained-release strategies under investigation or being used in clinical practice. Both continuous release and considerable therapeutic effects can be achieved by encapsulating anti-VEGF drugs in sustained-release materials to minimize the number of intravitreal injections. At present, two sustained-release materials are being tested in clinical research, and although basic research shows the strong therapeutic application prospects of extended-release drugs, its challenges mainly involve the discrepancy between the release rates in vitro and the efficiency of the drugs in vivo. Briefly, sustained release of anti-VEGF agents is an advantageous strategy for treating retinal angiogenesis.

Review: The Development of Risk Factors and Cytokines in Retinal Vein Occlusion

Retinal vein occlusion (RVO) is the second most prevalent retinal disease. Despite this, the pathogenic mechanisms and risk factors are not entirely clear. In this article, we review recent publications on the classification, pathogenesis, risk factors, ischemic changes, cytokines, and vital complications of RVO. Risk factors and cytokines are important for exploring the mechanisms and new treatment targets. Furthermore, risk factors are interrelated, making RVO mechanisms more complex. Cytokines act as powerful mediators of pathological conditions, such as inflammation, neovascularization, and macular edema. This review aims to summarize the updated knowledge on risk factors, cytokines of RVO and signaling in order to provide valuable insight on managing the disease.

Association between proteinuria and retinal vein occlusion in individuals with preserved renal function: a retrospective cohort study

PURPOSE

To investigate the association between proteinuria and the incidence of retinal vein occlusion (RVO) in individuals with preserved renal function.

METHODS

We conducted a retrospective cohort study from 2005 to 2020 using the JMDC Claims Database, a large database of health check-ups and administrative claims in Japan. Individuals who underwent annual health check-ups were included. Participants were classified into three groups based on the protein concentration in their urine: negative (≤10 mg/dl), trace (10-30 mg/dl) and positive (≥30 mg/dl). We estimated hazard ratios (HRs) for the development of RVO using Cox regression analyses with adjustment for baseline characteristics by the matching weights calculated from the multiple propensity scores. The cumulative incidence of RVO between the weighted groups was calculated using the Kaplan-Meier estimator.

RESULTS

There were 1 635 212 eligible participants, among whom 2360 developed RVO. The mean follow-up period was 1036 ± 951 days. The adjusted HRs for RVO were 1.10 (95% confidence interval 0.92-1.33) and 1.46 (1.19-1.78) in the groups with trace and positive proteinuria compared with negative proteinuria respectively. The cumulative incidence rates of RVO at 7 years were 0.40%, 0.43% and 0.55% in the groups with negative, trace and positive proteinuria, respectively.

CONCLUSION

Positive proteinuria was independently associated with an increased incidence of RVO in individuals with preserved renal function. Proteinuria may be a novel risk factor for RVO development.

Complete Blood Count-Derived Inflammation Indices and Retinal Vein Occlusion: A Case-Control Study

Introduction

This study evaluated complete blood count-derived inflammation indices in patients with retinal vein occlusion (RVO).

Methods

Participants in this case–control study were 54 patients with RVO and 54 age- and sex-matched control subjects. All participants underwent a thorough ophthalmic examination, as well as blood sample testing for complete blood count. Comparison of all parameters derived from complete blood count as well as calculation of specific indices was performed between patients with RVO and controls.

Results

Patients with RVO presented significantly higher white blood cell count (p = 0.033), neutrophil count (p = 0.003), neutrophil-to-lymphocyte ratio (NLR, p = 0.002), red cell distribution width (RDW, p = 0.009), mean platelet volume (MPV, p = 0.023), and systemic immune-inflammatory index (SII, p = 0.007) compared to controls. Receiver operator characteristic curve (ROC) analysis showed that NLR was superior to other inflammatory indices, having the greatest area under the curve. The optimal cutoff value for NLR to predict RVO was 2.29 with 46.2% sensitivity and 77.8% specificity.

Conclusion

Patients with RVO presented increased NLR, RDW, MPV, and SII, providing evidence that inflammation plays an important role in the pathogenesis of RVO. Complete blood cell count-derived indices can be easily calculated and may serve as an easy, simple, and cost-effective tool to evaluate the degree of systemic inflammation in patients with RVO, so as to potentially guide treatment.

Evaluation of the radial peripapillary capillary density in unilateral branch retinal vein occlusion and the unaffected fellow eyes

Background:

Given that unilateral branch retinal vein occlusion (BRVO) and glaucoma share common systemic vascular risk factors, the fellow eyes of patients with BRVO may be at increased risk of glaucoma.

Objectives:

To analyze the radial peripapillary capillary density (RPCD) in eyes with unilateral BRVO and their unaffected fellow eyes using optical coherence tomography angiography (OCTA).

Design:

Cross-sectional, prospective study.

Methods:

The study included 120 eyes of 80 patients: 40 affected eyes of BRVO, 40 fellow eyes of BRVO, and 40 control eyes. The RPCD, retinal nerve fiber layer thickness (RNFLT) were analyzed using OCTA.

Results:

RPCDs in the whole image, peripapillary region, all the hemispheres, and quadrants were statistically lower in the affected eyes than in both the fellow and control eyes ( p < 0.05 for all). RPCD values in the whole image and the peripapillary region were significantly lower in the fellow eyes than in the control eyes ( p = 0.013, and p = 0.021, respectively). RNFLTs in the peripapillary region, inferior hemisphere and inferior quadrant were significantly lower in the affected eyes than in the control eyes ( p < 0.05 for all). No significant differences were detected between the fellow eyes and the control eyes in term of RNFLT values in any regions ( p > 0.05 for all).

Conclusion:

Lower RPCD values despite similar RNFLT values were observed in the fellow eyes of patients with unilateral BRVO compared with healthy controls. These results may indicate the shared vascular mechanisms and risk factors that account for the development of BRVO and glaucoma.

Comparison of Choroidal Thickness, Foveal Avascular Zone, and Macular Capillary Density in Macular Edema Secondary to Branch Retinal Vein Occlusion Treated with Ranibizumab or Aflibercept-A Prospective Study

This prospective comparative case series aims to compare best-corrected visual acuity (BCVA), retinal microvasculature, and retinal structural changes in patients treated with either ranibizumab or aflibercept for macular edema (ME) secondary to treatment-naïve branch retinal vein occlusion (BRVO) by optical coherence tomography angiography (OCTA). Ten patients were enrolled with macular capillary density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) and foveal avascular zone (FAZ) measured in both eyes before and after treatment. Final central retinal thickness and BCVA improved significantly (p < 0.05), and densities of SCP and DCP of BRVO sectors were significantly lower at baseline than fellow eye counterparts and remained persistently lower during treatment, particularly in the aflibercept group (p < 0.05). SCP density, DCP density of both BRVO sectors (p = 0.0001, p < 0.0001), and non-BRVO sectors (p < 0.0001, p < 0.0001) were significantly correlated with final BCVA for diseased eyes. Using multivariate general linear model analysis, and including OCTA parameters only, but not all of the available clinical data, DCP density of BRVO sectors in both eyes was the most predictive factor for final visual outcome (probability p < 0.0001). OCTA offered further qualitative and quantitative evaluation of treatment-naïve BRVO. Judging by OCTA parameters, not only in the diseased eye but also in the fellow eye, DCP density of BRVO sectors was the most predictive factor of final visual outcome.

Arm-to-retina time predicts visual outcome of anti-vascular endothelial growth factor treatment for macular edema due to central retinal vein occlusion

To explore the factors associated with best-corrected visual acuity (BCVA) after anti-vascular endothelial growth factor (anti-VEGF) treatment for macular edema secondary to central retinal vein occlusion (CRVO). We retrospectively reviewed the medical charts of 22 eyes of 22 treatment-naïve patients with CRVO diagnosed between September 2014 and December 2020. They received anti-VEGF treatment and follow-up for > 12 months. Mean patient age was 64.3 years; 13 (59.1%) were men. Eyes with baseline arm-to-retina (AR) time ≥ 16 s had better BCVA at 12 months (adjusted for baseline BCVA and age; B, − 0.658; 95% confidence interval − 1.058 to − 0.257; P = 0.003), greater mean BCVA change (P = 0.006), lower frequency of residual macular edema at 12 months (P = 0.026) and recurrent and/or unresolved macular edema during 12 months (P = 0.046), and higher frequency of reduction in central retinal thickness ≥ 150 μm at 1 and 12 months (both P = 0.046). Delayed AR time was associated with a better visual outcome and macular edema improvement in CRVO after anti-VEGF treatment regardless of initial BCVA and age. Our results may help understand the pathogenesis and predict the visual prognosis of patients before anti-VEGF therapy initiation.

Metabolite Changes in the Aqueous Humor of Patients With Retinal Vein Occlusion Macular Edema: A Metabolomics Analysis

Macular edema (ME) is the main cause of visual impairment in patients with retinal vein occlusion (RVO). The degree of ME affects the prognosis of RVO patients, while it lacks objective laboratory biomarkers. We aimed to compare aqueous humor samples from 28 patients with retinal vein occlusion macular edema (RVO-ME) to 27 age- and sex-matched controls by ultra-high-performance liquid chromatography equipped with quadrupole time-of-flight mass spectrometry, so as to identify the key biomarkers and to increase the understanding of the mechanism of RVO-ME at the molecular level. Through univariate and multivariate statistical analyses, we identified 60 metabolites between RVO-ME patients and controls and 40 differential metabolites in mild RVO-ME [300 μm ≤ central retinal thickness (CRT) < 400 μm] patients compared with severe RVO-ME (CRT ≥ 400 μm). Pathway enrichment analysis showed that valine, leucine, and isoleucine biosynthesis; ascorbate and aldarate metabolism; and pantothenate and coenzyme A biosynthesis were significantly altered in RVO-ME in comparison with controls. Compared with mild RVO-ME, degradation and biosynthesis of valine, leucine, and isoleucine; histidine metabolism; beta-alanine metabolism; and pantothenate and coenzyme A biosynthesis were significantly changed in severe RVO-ME. Furthermore, the receiver operating characteristic (ROC) curve analysis revealed that adenosine, threonic acid, pyruvic acid, and pyro-L-glutaminyl-l-glutamine could differentiate RVO-ME from controls with an area under the curve (AUC) of >0.813. Urocanic acid, diethanolamine, 8-butanoylneosolaniol, niacinamide, paraldehyde, phytosphingosine, 4-aminobutyraldehyde, dihydrolipoate, and 1-(beta-D-ribofuranosyl)-1,4-dihydronicotinamide had an AUC of >0.848 for distinguishing mild RVO-ME from severe RVO-ME. Our study expanded the understanding of metabolomic changes in RVO-ME, which could help us to have a good understanding of the pathogenesis of RVO-ME.

Ocular ischaemia: signs, symptoms, and clinical considerations for primary eye care practitioners

Ischaemic stroke is a major disease burden as well as a leading cause of death. Early signs of ischaemic stroke can manifest in the eye, placing primary eyecare practitioners in an important position to identify patients at risk of ischaemic stroke and initiate suitable referral pathways. The vascular supply to the brain is reviewed with reference to vision including the various retinal signs and ocular symptoms associated with transient ischaemic attacks and ischaemic stroke. Using a range of clinical cases, the diverse clinical presentations of retinal embolic events, as well as other forms of vascular occlusion, are highlighted and the underlying pathophysiology is discussed. A succinct scheme for the assessment and management of ischaemic events for primary eye care practitioners is provided.

Plasma lipid levels and risk of retinal vascular occlusion: A genetic study using Mendelian randomization

The causal effects of plasma lipid levels and the risk of retinal vascular occlusion (RVO) have not been clearly identified, especially for high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C). Here, we try to identify these causal risk factors using a two-sample Mendelian randomization (MR) analysis. Single nucleotide polymorphisms (SNPs) were chosen as instrumental variables (IVs). We obtained genetic variants associated with lipid exposure at the genome-wide significance (P<5×10^-8) level from a meta-analysis of GWAS from the Global Lipids Genetics Consortium (GLGC) based on 188,577 individuals of mostly European ancestry for MR analyses. Meanwhile, we used lipid GWAS from UK Biobank (UKB) with a sample size of 115,078 individuals as a supplement. We obtained genetic predictors of RVO from a FinnGen biobank study. We conducted both univariable and multivariable MR (MVMR) analyses to identify the causal effects of RVO. Although inverse variance weighted (IVW) was the primary method used for MR analyses, MR-Egger and weighted-median methods were used as supplements to IVW. We determined the heterogeneity of IVs using Cochrane's Q test and I² , and used the MR-Egger intercept and MR-PRESSO Global test to detect horizontal pleiotropy. A leave-one-out sensitivity analysis was conducted by removing a single variant from the analysis. Genetically predicted increased HDL-C level was associated with decreased risk of RVO from GLGC [OR=0.806; 95% CI=(0.659, 0.986); P=0.036], which was consistent with UKB results [OR=0.766; 95% CI=(0.635, 0.925); P=0.005]. MVMR analysis for plasma lipids [adjusted OR=0.639; 95% CI=(0.411, 0.992); P=0.046] or diabetes [adjusted OR=0.81; 95% CI=(0.67, 0.979); P=0.029] suggested that low HDL-C may be an independent risk factor for RVO. However, there was no evidence to support a causal association between LDL-C {GLGC [adjusted OR=1.015; 95% CI=(0.408, 2.523); P=0.975], UKB [OR=1.115; 95% CI=(0.884, 1.407); P=0.359]}, total cholesterol {GLGC [adjusted OR=0.904; 95% CI=(0.307, 2.659); P=0.854], UKB [OR=1.047; 95% CI=(0.816, 1.344); P=0.716]} or triglycerides {GLGC [OR=1.103; 95% CI=(0.883, 1.378); P=0.385], UKB [OR=1.003; 95% CI=(0.827, 1.217); P=0.098]} and RVO. Using two-sample MR analysis, our study suggested that dyslipidemia was a risk factor for RVO. Furthermore, our results indicated that a low HDL-C level may be an independent risk factor for RVO, suggesting that controlling HDL-C level may be effective in RVO development.

The effect of select systemic medications on outcomes in diabetics with central retinal vein occlusion

BACKGROUND

Diabetes mellitus is a risk factor for central retinal vein occlusion (CRVO); however, it is unclear whether certain commonly used medications among diabetics or glycemic control impact visual outcomes in diabetic eyes with CRVO.

PURPOSE

To evaluate the effect of select systemic medications and glycemic control on presenting features, treatment burden, and outcomes in patients with diabetes who develop a central retinal vein occlusion (CRVO).

METHODS

Retrospective longitudinal cohort study at a single tertiary academic referral center from 2009-2017 investigating eyes of patients being treated for diabetes mellitus at CRVO onset. Eyes with a prior history of anti-vascular endothelial growth factor (anti-VEGF) therapy or laser treatment within the year prior to CRVO onset were excluded. Main outcomes and measures were visual acuity (VA), central subfield thickness (CST), cystoid macular edema (CME), and number of intravitreal injections and laser treatment throughout follow-up.

RESULTS

We identified 138 eyes of 138 participants who were diabetic at CRVO onset. Of these, 49% had an ischemic CRVO. Median follow-up time was 25.5 months. Fifty-five eyes (40%) had a HbA1c within 6 months of CRVO presentation. HbA1c was positively correlated with both presenting CST (p = 0.04) and presence of CME (p < 0.01). In all 138 eyes, mean presenting VA was 20/246, and mean final VA was 20/364. Better-presenting VA was significantly associated with aspirin 325 mg use (p = 0.04). Lower CST at presentation was significantly associated with metformin use (p = 0.02). Sitagliptin use at CRVO onset was associated with a lower prevalence of CME at final follow-up (p < 0.01). Lower final CST was significantly associated with glipizide use at CRVO onset (p = 0.01). There were no significant associations between systemic medications or HbA1c and treatment burden or final VA (p > 0.05).

CONCLUSION

Although aspirin 325 mg, metformin, sitagliptin, and glipizide were associated with better-presenting VA, lower-presenting CST, lower prevalence of macular edema at final visit, and lower final CST, respectively, none of these systemic agents or glycemic control were associated with decreased treatment burden or improved visual outcomes in diabetics with CRVO.

The effect of branch retinal vein occlusion on the vascular structure of the choroid

OBJECTIVE

Our aim is to examine choroidal structural changes in eyes with branch retinal vein occlusion (BRVO).

MATERIAL AND METHOD

This retrospective, comparative study included 34 newly diagnosed unilateral BRVO patients and 40 healthy controls. Subfoveal choroidal thickness (SFCT) measurement was performed with enhanced depth imaging optical coherence tomography (EDI-OCT). The images were binarized using the ImageJ software program. Total choroidal area (TCA), stromal area (SA), and luminal area (LA) were calculated from the 1500 µm area. The choroidal vascular index (CVI) was determined as the LA/TCA ratio. All parameter values were compared between the BRVO eye and the fellow eye, and the control group eyes.

RESULTS

Eyes with BRVO had a greater SA compared to both fellow and control eyes; hence, the CVI was lower (p < 0.001). LA did not differ between eyes. TCA, although not statistically significant, was larger in eyes with BRVO than in both fellow and control eyes. SFCT was also greater in eyes with BRVO. No correlation was observed between CVI and SFCT and best-corrected visual acuity (BCVA).

CONCLUSION

BRVO affects the stromal part of the choroid rather than its vascular structure. SA increases due to choroidal exudation that occurs in response to retinal ischemia, and CVI decreases accordingly.

Retinal Vascular Events after mRNA and Adenoviral-Vectored COVID-19 Vaccines-A Case Series

Background: To describe cases of retinal vascular events shortly after administration of mRNA or adenoviral-vectored COVID-19 vaccines. Design: Retrospective, multicenter case series. Methods: Six cases of retinal vascular events shortly after receiving COVID-19 vaccines. Results: A 38-year-old, otherwise healthy male patient presented with branch retinal arterial occlusion four days after receiving his second dose of SARS-CoV-2 vaccination with Comirnaty^® (BioNTech^®, Mainz, Germany; Pfizer^®, New York City, NY, USA). An 81-year-old female patient developed visual symptoms twelve days after the second dose of SARS-CoV-2 vaccination with Comirnaty^® and was diagnosed with a combined arterial and venous occlusion in her right eye. A 40-year-old male patient noticed blurry vision five days after his first dose of SARS-CoV-2 vaccination with Comirnaty^® and was diagnosed with venous stasis retinopathy in his left eye. A 67-year-old male was diagnosed with non-arteritic anterior ischemic optic neuropathy in his right eye four days after receiving the first dose of Vaxzevria^® (AstraZeneca^®, Cambridge, UK). A 32-year-old man presented with a sudden onset of a scotoma two days after receiving the second dose of SARS-CoV-2 vaccination with Spikevax^® (Moderna, Cambridge, UK) and was diagnosed with a circumscribed nerve fiber infarction. A 21-year-old female patient developed an acute bilateral acute macular neuroretinopathy three days after receiving the first dose of SARS-CoV2-vaccine Vaxzevria^® (AstraZeneca^®, Cambridge, UK). Conclusion: This case series describes six cases of retinal vascular events shortly after receiving mRNA or adenoviral-vectored COVID-19 vaccines. The short time span between received vaccination and occurrence of the observed retinal vascular events raises the question of a direct correlation. Our case series adds to further reports of possible side effects with potential serious post-immunization complications of COVID-19 vaccinations.

Pachychoroid disease and its association with retinal vein occlusion: a case-control study

The development of a retinal vein occlusion (RVO) is multifactorial. This study investigates pachychoroid as a risk factor for RVO or as an entity sharing common pathophysiology with RVO. A database screening at the University Eye Hospital, Ludwig-Maximilian University Munich, Germany was performed for patients diagnosed with central or branch RVO (CRVO/BRVO). In every patient a complete ophthalmologic examination was performed, including posterior segment enhanced depth spectral domain optical coherence tomography (EDI-SD-OCT). The SD-OCT scans of respective partner eyes without history of RVO were compared to an age- and refraction-matched, randomly recruited normal control group. In total, 312 eyes of 312 patients were included in this study, with 162 eyes in the RVO and 150 eyes in the control group. A significantly higher subfoveal choroidal thickness (SFCT) was found in the RVO (310.3 ± 72.5 (94 to 583) µm) as compared to the control group (237.0 ± 99.0 (62 to 498); p < 0.00001). Moreover, the RVO group showed a significantly higher prevalence of a symptomatic pachychoroid (22 vs. 9 eyes; odds ratio: 2.46; 95 CI: 1.10 to 5.53; p = 0.029). Since pachychoroid disease represents a bilateral entity, it might be a risk factor for RVO, or share risk factors with RVO.

Systemic antiplatelet agents and anticoagulants in eyes with branch retinal vein occlusion

Purpose

The purpose of this study was to investigate the effect of systemic antiplatelet agents and anticoagulants on the structural and functional outcomes of eyes with branch retinal vein occlusion (BRVO).

Methods

A retrospective longitudinal cohort study was performed on BRVO patients evaluated at a single tertiary care referral center between 2009 and 2017. Medical records were reviewed for antiplatelet agent and anticoagulant use including aspirin, clopidogrel, warfarin, rivaroxaban, apixaban, or dabigatran prior to BRVO onset. In addition, optical coherence tomography (OCT) parameters, clinical outcomes, and treatment patterns were also recorded.

Results

A total of 354 BRVO eyes were identified with a mean follow-up time of 36 months. Antiplatelet or anticoagulant use was associated with presence of cystoid macular edema (CME) at presentation after controlling for potential confounding variables in a multivariate logistic regression. Multivariate regression also revealed an association between foveal hemorrhage at presentation and use of antiplatelet or anticoagulant medications. There were no significant differences in visual acuity or prevalence of CME at the final visit in those with antiplatelet/anticoagulant use compared to those not on these agents.

Conclusion

Although the use of systemic antiplatelet or anticoagulant agents was associated with increased prevalence of CME and foveal hemorrhage at presentation of BRVO, the use of these medications was not associated with different visual or structural outcomes at the final visit.

Optical Coherence Tomography Biomarkers Predicting Visual Acuity Change after Intravitreal Bevacizumab Injections for Macular Edema Secondary to Branch Retinal Vein Occlusion

PURPOSE

This study aimed to identify baseline optical coherence tomography (OCT) factors in branch retinal vein occlusion (BRVO) that predict response to bevacizumab injections.

METHODS

It is a retrospective case series of consecutive patients that underwent OCT at diagnosis, and the central macular thickness (CMT), extent of disorganized retinal inner layers, and outer retinal layers including external limiting membrane, ellipsoid zone (EZ), and cone outer segment tips (COST) were measured. Patients received 3 consecutive monthly injections of bevacizumab followed by pro re nata treatment. The main outcome measure was improvement in best-corrected visual acuity (BCVA) after 1 year. Results are expressed as mean ± SD, and p value <0.05 was considered statistically significant.

RESULTS

Overall, 66 eyes of 66 patients, with an average age of 68.5 ± 11.4 years, were included. The mean BCVA improved significantly from 0.68 logMAR at baseline to 0.50 logMAR at 1 year (p < 0.001). Baseline logMAR BCVA (r = 0.41, p < 0.001) and CMT (r = 0.23, p = 0.04) were associated with improvement while EZ (r = -0.24, p = 0.05) and COST (r = -0.32, p = 0.01) disruption with deterioration in BCVA.

CONCLUSION

In patients with naïve BRVO treated with bevacizumab, BCVA improvement at 1 year can be predicted from baseline BCVA, CMT, extent of COST disruption, and EZ disruption.

A Review of Aflibercept Treatment for Macular Disease

Aflibercept is a fully human recombinant fusion protein that includes the second domain of human VEGF receptor 1 and the third domain of human VEGF receptor 2. Despite the important role played by VEGF in maintaining the physiological condition of the retina under normal conditions, dysregulation of VEGF can result in pathological alterations including hyperpermeability of the retinal capillaries and migration and proliferation of retinal endothelial cells. Over the years, a number of studies have evaluated the use of intravitreal aflibercept in different retinal diseases. In this review, we aim to summarize the scientific evidence and recommendations for use of intravitreal aflibercept in neovascular age-related macular degeneration, diabetic macular oedema, macular oedema associated with retinal vein occlusion, and myopic choroidal neovascularization.