Case Of Retinal Vein Occlusion Research Articles

COVID-19 Vaccination and Ocular Adverse Events: A Self-Controlled Case Series Study From the Entire South Korean Population

This study aimed to assess the risk of ocular adverse events, including retinal artery occlusion (RAO), retinal vein occlusion (RVO), noninfectious uveitis (NIU), noninfectious scleritis (NIS), optic neuritis (ON), ischemic optic neuropathy (ION), and ocular motor cranial nerve palsy (OMCNP), following Coronavirus Disease 2019 (COVID-19) vaccination. Population-based self-controlled case series METHODS: This study utilized nationwide claims and vaccination data provided by the Korea National Health Insurance Service and Korea Disease Control and Prevention Agency. From the entire South Korean population of 52 million individuals, patients with incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, or OMCNP between January 2021 and March 2022 were included. The postvaccination risk period was defined as up to 56 days after COVID-19 vaccination. The relative incidence rate ratios (IRRs) for RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, and OMCNP during the risk periods were measured using conditional Poisson regression. The study included 6,590, 70,120, 137,958, 17,921, 15,492, 2,039, 49,089, and 11,312 cases of incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, and OMCNP, respectively. The IRRs (95% confidence interval) during the early risk period (0-28 days) were 0.95 (0.88-1.01), 0.96 (0.94-0.98), 0.93 (0.91-0.94), 0.93 (0.89-0.96), 0.96 (0.92-1.01), 1.04 (0.92-1.18), 0.98 (0.95-1.00), and 0.91 (0.86-0.96), respectively. In the late risk period (29-56 days), the IRRs were 0.96 (0.89-1.03), 0.93 (0.91-0.96), 0.96 (0.95-0.98), 1.00 (0.95-1.04), 0.96 (0.91-1.01), 1.00 (0.87-1.15), 1.01 (0.98-1.04), and 0.95 (0.90-1.01), respectively. COVID-19 vaccination did not increase the risk of incident RAO, RVO, anterior NIU, nonanterior NIU, NIS, ON, ION, or OMCNP during the postvaccination period.

Intraocular pressure, primary open-angle glaucoma and the risk of retinal vein occlusion: A Mendelian randomization mediation analysis.

The etiological connection between intraocular pressure (IOP) and the risk of retinal vein occlusion (RVO) remains elusive, particularly regarding whether this risk emanates from the direct influence of elevated intraocular pressure (IOP), irrespective of the presence of primary open-angle glaucoma (POAG), or if it arises as a consequence of the sequelae of POAG. Therefore, we conducted a Mendelian Randomization (MR) mediation analysis to elucidate the mediating role of POAG in the association between IOP and RVO. We identified 47 single-nucleotide polymorphisms (SNPs) associated with IOP (P-value < 5 × 10-8) leveraging data from a genome-wide association study (GWAS) (N = 97,653) obtained from the UK Biobank and 50 SNPs associated with POAG (P-value < 5 × 10-8) from a GWAS meta-analysis (16,677 cases and 199,580 controls). We related these SNPs with RVO using a GWAS of 775 RVO cases and 376,502 controls from FinnGen. By utilizing univariable and multivariable MR analyses we calculated the total effect of IOP on RVO and estimated the degree to which POAG mediates this association. MR analyses showed that higher IOP is associated with higher RVO risk (odds ratio of RVO per 1 mmHg increase in IOP: 1.53; 95% confidence interval: 1.04 to 2.26; p-value = 0.03). Moreover, our MR mediation analysis suggested that 91.6% of the total effect of IOP on RVO risk was mediated through POAG. The primary results were consistent with estimates of pleiotropy-robust MR methods. Our findings suggest that higher IOP increases the risk of RVO and that the majority of this effect is mediated through POAG.

Demographic profile, prevalence, pattern, and risk factors for retinal vein occlusion in Liberia: A retrospective study.

This study aims to describe the demographic profile, prevalence, pattern, and risk factors for retinal vein occlusion (RVO) in patients over 40 years of age presenting to the Liberia Eye Centre, John F Kennedy Memorial Medical Centre, Monrovia, Liberia. A retrospective study was conducted on patients presenting to Liberia Eye Centre from July 2017 to February 2021. A total of 17506 new patients were examined during this period out of which 10813 patients were over 40 years of age. Data were collected from the electronic medical record system database. The variables in the collected data included age, gender, location, laterality of eye affected, uncorrected visual acuity, best-corrected visual acuity, intraocular pressure, ocular diagnosis, systemic risk factors, and associated complications. Of the 10813 patients, RVO was found in 111 patients with an overall prevalence rate of 1.03% (95% confidence interval 0.80-1.2). Central RVO (CRVO) was more common than branch RVO (BRVO) in the defined population with similar proportions of both genders. The mean age for any RVO was 64.45 ± 12.27 standard deviation (SD) years (P = 0.734). Majority of the cases of RVO were from Lofa (n = 20; 18%). Fifty-five (61.1%) patients had hypertension, 5 (5.6%) had diabetes mellitus, and 6 (6.7%) had dyslipidemia. More than one systemic risk factor was present in 24 (26.7%) patients. However, none of the systemic risk factors were statistically significant. Visual acuity was most affected in patients with CRVO, with a visual acuity of <3/60 in 45 (63.4%) patients compared to 12 (30.0%) in BRVO patients. Glaucoma was present in 34 (30.6%) patients. The most common ocular complication was macular edema (n = 62, 55.8%) followed by vitreous hemorrhage (n = 8, 7.2%). RVO was detected in 1.03% of the study population over the age of 40 years in Liberia, CRVO being more common than BRVO. The clinical presentation of RVO in the Liberian population for the first time provides insight into the burden of the disease and opportunity for further research.

The clinical evaluation of a widefield lens to expand the field of view in optical coherence tomography (OCT-A)

This study aimed to evaluate the clinical benefits of incorporating a widefield lens (WFL) in optical coherence tomography angiography (OCT-A) in patients with retinal vascular diseases in comparison to standard single-shot OCT-A scans. Sixty patients with retinal vascular diseases including diabetic retinopathy (DR) and retinal vein occlusion (RVO) were recruited. OCT-A imaging (PlexElite 9000) with and without WFL was performed in randomized order. The assessment included patient comfort, time, field of view (FoV), image quality and pathology detection. Statistical analysis included paired t-tests, Mann–Whitney U-tests and Bonferroni correction for multiple tests, with inter-grader agreement using the kappa coefficient. Using a WFL did not lead to statistically significant differences in DR and RVO group test times. Patient comfort remained high, with similar responses for WFL and non-WFL measurements. The WFL notably expanded the scan field (1.6× FoV increase), enhancing peripheral retinal visibility. However, image quality varied due to pathology and eye dominance, affecting the detection of peripheral issues in RVO and DR cases. The use of a WFL widens the scan field, aiding vascular retinal disease imaging with minor effects on comfort, time, and image quality. Further enhancements are needed for broader view angles, enabling improved quantification of non-perfused areas and more reliable peripheral proliferation detection.

The protective effect of DNase I in retinal vein occlusion.

Retinal vein occlusion (RVO) ranks as the second most prevalent retinal vascular disease, following diabetic retinopathy. Neutrophil extracellular traps (NETs) play an important role in vascular diseases. This study aimed to elucidate the relationship between NETs and RVO, and to discern the potential role of deoxyribonuclease I (DNase I) in the prevention and treatment of RVO through the modulation of NETs. We analyzed circulating NETs biomarkers, namely cell-free DNA (cf-DNA), myeloperoxidase (MPO)-DNA, and neutrophil elastase (NE), in 30 RVO patients and 30 healthy individuals. We established an RVO mouse model using a retinal laser, and the mice were categorized into two groups: the DNase I group and the control group. Retinal images were taken at predetermined time points, and the state of the retinal vessels was assessed. Both tissue and blood samples were harvested for analysis of NETs expression through methods such as western blotting, immunofluorescence staining, and enzyme-linked immunosorbent assay (ELISA). Our finding indicate an increase in circulating NETs biomarkers in human and mouse RVO cases, while also verifying the presence of NETs in the retinal thrombus of the RVO model. Both in vitro and in vivo tests revealed that DNase I attenuated NETs formation. Moreover, DNase I injections led to diminished NETs biomarker levels and a reduced duration of the thrombus after the RVO model establishment. Consequently, DNase I, a well-established modulator of NETs formation, might exhibit protective properties in the prevention and treatment of RVO.

RETINAL VEIN OCCLUSIONS BEFORE AND DURING THE COVID-19 PANDEMIC: Visual Outcomes and Treatment Patterns in a Country with no Mandatory Lockdown.

To investigate the incidence, treatment patterns, and visual outcomes in patients with branch retinal vein occlusion (RVO) and central RVO before and during the COVID-19 pandemic in a country with no mandatory lockdown. This retrospective study included 788 patients presenting with a RVO during the years 2019 to 2022 at St. Erik Eye Hospital. The control group and study groups consisted of patients presenting before and during the pandemic, respectively. The incidence of diagnosed RVO cases decreased from 281 patients before the pandemic to 236 patients during the first year of the pandemic ( P < 0.05). In patients with branch RVO at the end of follow-up, the best-corrected visual acuity improved 10.3 letters (95% confidence intervals [CI] 7.6-12.9) in the control group compared with 14.3 letters (95% CI 12.6-16.0) in the study groups ( P < 0.05). In patients with central RVO, the best-corrected visual acuity improved 6.3 letters (95% CI 2.7-10.0) in the control group compared with 8.6 letters (95% CI 5.7-11.4) in the study groups (p = NS). Overall, the number of intravitreal anti-vascular endothelial growth factor injections increased from 7.0 (95% CI 6.6-7.3) in the control group to 7.6 (95% CI 7.4-7.8) in the study groups ( P < 0.05). Good visual and anatomical outcomes were sustained, and the number of intravitreal anti-vascular endothelial growth factor injections increased significantly in patients with RVO during the COVID-19 pandemic.

Hemicentral retinal vein occlusion in a patient with a history of coronavirus disease 2019 infection: a case report and review of the literature

BackgroundConsidering the various manifestations of coronavirus disease 2019 and its imperative importance in terms of the right clinical approach and early management, we sought to present a hemicentral retinal vein occlusion case, with a history of heterozygosity of methylenetetrahydrofolate reductase (MTHFR) genes and potential for clotting complications as a late manifestation of coronavirus disease 2019, and provide a brief review of reported retinal vein occlusion cases in patients with coronavirus disease 2019.Case presentationA 35-year-old Iranian patient presented with a visual impairment in the left eye 4 months after recovering from coronavirus disease 2019. He reported a mild blurring of vision in the same eye a few days after admission due to coronavirus disease 2019. The ophthalmic evaluation was compatible with hemicentral retinal vein occlusion. Systemic and laboratory workups were negative except for borderline protein C activity, homocysteine levels, and heterozygosity of MTHFR genes. The patient was scheduled to receive three monthly intravitreal antivascular endothelial growth factor injections.ConclusionWe present a case of inferior hemicentral retinal vein occlusion case with an MTHFR mutation with sequential loss of vision 4 months after coronavirus disease 2019 to make clinicians aware of the possibility of late ocular coronavirus disease 2019 manifestations.

Lamina Cribrosa Thickness in Patients with Branch Retinal Vein Occlusion: A Cross Sectional Comparative Evaluation Using Enhanced Depth Imaging Optical Coherence Tomography

Abstract Background: Retinal vein occlusion (RVO) is one of the most common causes of retinal vascular disease, second to diabetic retinopathy. We aimed to compare the lamina cribrosa thickness (LCT) of patients with unilateral branch RVO (BRVO) versus healthy individuals. Materials and Methods: This was a hospital-based, prospective, cross-sectional, and comparative study. Participants were newly diagnosed RVO cases (n = 25) and apparently normal age-matched healthy controls (n = 25). All the participants underwent systemic and comprehensive ophthalmic examination, including refraction and enhanced depth imaging optical coherence tomography. Relevant parameters were compared between the groups using the independent t-test. Statistical significance thresholds were set at a P &lt; 0.05. Results: The mean age of cases (66.7% female) and controls (52% female) was 55.9 ± 7.4 and 59.4 ± 7.0 years, respectively, (P = 0.089). The mean LCT of the affected eyes in cases (176.6 ± 28.3 μm) was significantly lower compared to the unaffected eyes of cases (200.6 ± 33.1 μm, P = 0.008) and control eye (230.9 ± 36.9 μm, P = 0.001). Conclusions: A thinner lamina cribrosa (LC) was observed in both eyes of unilateral RVO patients compared with healthy, nonglaucomatous subjects’ eyes. The role of LCT as a local mechanical factor in the pathogenesis of BRVO and their relationship to systemic factors merits further investigation.

Treatment outcomes for maculopathy secondary to retinal vein occlusion in Afghanistan.

The objective of this study was to investigate the efficacy of intravitreal antivascular endothelial growth factor (VEGF) therapy in the treatment of macular edema secondary to retinal vein occlusion (RVO) in Afghanistan. A retrospective analysis was conducted of all RVO cases that underwent intravitreal ant-VEGF injection at the two leading hospitals in Kabul. The main outcome measures were visual acuity and central retinal thickness as determined by optical coherence tomography. Information was also collected on the distance traveled by each patient and the frequency of injections. One hundred and twenty-five eyes of 121 patients (86 males) with RVO were identified as having undergone treatment, with a mean age of 53.1 years (range 20-80). The only agent used was bevacizumab. The mean central retinal thickness reduced from 624.2 ± 24.9 μm at the baseline to 257.8 ± 5.7 μm following treatment (P < 0.001). There was a small increase in visual acuity from 1.33 LogMAR at the baseline to 1.13 LogMAR following the most recent injection (P = 0.03, paired t-test). The mean distance traveled by patients was 173.9 km (range 2-447 km). Despite the challenges of health-care provision in Afghanistan, this review shows that the use of intravitreal bevacizumab has provided an effective treatment for macular edema after RVO.

In vivo measurement of T1 in the vitreous humor of patients with ischemic retinal disease.

To demonstrate MR T1 mapping in vivo as a method to non-invasively estimate vitreous oxygen concentration in ischemic eye disease. Patients with ischemic eye disease (central retinal vein occlusion, ocular ischemic syndrome, and proliferative diabetic retinopathy) were prospectively recruited. MRI was performed on each patient before any treatment, with T1 mapping acquired using an inversion recovery TrueFISP sequence at several inversion times, from a single slice positioned through the center of both eyes in the axial oblique plane. A phantom study measuring seven different concentrations of vitronectin, a protein released in ischemic eye disease, was undertaken to determine its potential confounding effect on T1 . Ten participants were recruited (eight central retinal vein occlusion, one ocular ischemic syndrome, and one proliferative diabetic retinopathy). Of the eight central retinal vein occlusion cases, there was a statistically different vitreous T1 in the diseased eye compared to the healthy control eye (4.306 vs. 4.518 s, p = 0.008). T1 times did not significantly alter across the range of vitronectin concentrations. Ischemic eye disease decreases vitreous T1 , potentially implying an increase in vitreous partial pressure of oxygen (pO2 ) concentration given what is known from the relationship between 1/T1 and pO2 . Potential theories for this unexpected result are discussed. This study provides further data on this technique, with potential clinical application in eye disease.

PSORIASIS INCREASES RETINAL VEIN OCCLUSION RISK IN DIABETIC PATIENTS: A Nationwide Population-Based Study.

The objective of this research was to explore how psoriasis is linked to the occurrence of retinal vein occlusion (RVO) in diabetic population. This was a retrospective, nationwide, population-based cohort study that examined medical records from January 2009 to December 2012. The study focused on patients ≥20 years of age who had been diagnosed with Type 2 diabetes mellitus (DM). The authors compared the incidence rate of RVO between a group of patients with psoriasis and a group of patients without psoriasis until December 2018 in all subjects. Of the 2,745,689 Type 2 DM patients, 23,725 patients were classified in the psoriasis group and the rest of the 2,547,121 individuals in the control group. A total of 497 RVO cases occurred in the psoriasis group (3.14/1,000 person-years) and 42,388 RVO cases in the control group (2.44/1,000 person-years). According to multivariable Cox proportional hazard models, individuals with psoriasis had a significantly greater risk of developing RVO compared with control subjects (hazard ratio: 1.216, 95% confidence interval: 1.11-1.33) after adjustments for covariates. This study demonstrated that psoriasis was an independent risk factor for developing RVO in DM patients. Therefore, physicians need to be vigilant for the occurrence of RVO in DM patients who also have psoriasis.

Effect of repeated intravitreal anti-vascular endothelial growth factor drugs on corneal nerves.

To investigate the potential effect of repeated intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) drugs on corneal nerves. A total of 64 patients were treated with intravitreal injection of anti-VEGF drugs. There were 19 cases of neovascular age-related macular degeneration (AMD), 20 cases of diabetic macular edema (DME) and 25 cases of retinal vein occlusion (RVO). Twenty-nine cases were treated with aflibercept (2 mg/0.05 mL) whereas 35 cases were managed with ranibizumab (0.5 mg/0.05 mL). A corneal confocal microscope was used to collect images of corneal subbasal nerve plexus, and Image J was used for image analysis. The changes in corneal nerve were compared between 1 month after each injection and before injection. There were no significant differences in the density and length of corneal nerve at specific time after the surgery in comparison with baseline in patients who were given 3 intravitreal injections. There was no significant correlation between the numbers of injections and the changes of the corneal nerves. After 3rd injection, the nerve length of the DME group was markedly lower than that of AMD and RVO groups, the difference was statistically significant (P < .05). The nerve density of the DME group was not significantly different from that of AMD and RVO groups, whereas the nerve length and nerve density of the AMD and RVO groups were not statistically significant between each other also. The corneal nerve length after the 2nd and 3rd injections of Aflibercept were lower than that before surgery, the difference was statistically significant. There were no significant differences in nerve density and nerve length at each time point after Ranibizumab injection. The length and density of the corneal nerve after multiple injections in contralateral eye displayed no significant changes compared with the baseline. Repeated intravitreal anti-VEGF drug can reduce the length of corneal nerves. For patients who need repeated intravitreal injections of anti-VEGF drugs, especially in DM, attention should be paid on the changes affecting the corneal nerves. It is also needed to strengthen the local anti-inflammatory therapy to avoid infection and to use artificial tears to protect the microenvironment of the ocular surface after the surgery.

Retinal Vascular Occlusion after Severe Acute Respiratory Syndrome Coronavirus Vaccination: A Vaccine Adverse Events Reporting System Database Analysis

To evaluate the cases of retinal vessel occlusion following COVID-19 vaccination and evaluate the onset interval and clinical presentations in patients diagnosed with vaccine associated retinal artery occlusion (RAO) and retinal vein occlusion (RVO). Retrospective study of the cases reported to the Centers for Disease Control and Prevention (CDC) Vaccine Adverse Events Reporting System (VAERS) between December 11, 2020 and July 1, 2022. Patients diagnosed with retinal vessel occlusion following vaccination with BNT162b2, mRNA-1273, and Ad26.COV2.S globally. We performed a descriptive analysis of the patient demographics and clinical presentation in patients with retinal vessel occlusion. The correlation between the vaccines and continuous and categorical variables were assessed. We performed the post-hoc analysis to evaluated the association between RAO and RVO onset post-vaccination, and vaccine and dosage. Finally, a 30-day reverse analysis for RAO and RVO onset following administration of vaccine. A major limitation in the methods of this study is the lack of control group for assessing the risk of retinal vessel occlusive disease in patients who received the vaccine compared to the patients who were unvaccinated. The crude reporting rate of retinal vessel occlusion following SARS-CoV-2 vaccine. The ocular and systemic presentations, onset duration and short term risk of RAO and RVO following vaccination. During the study period, 1351 retinal vessel occlusion cases were reported globally. The crude reporting rates of retinal vessel occlusion for BNT162b2, mRNA-1273, and Ad26.COV2.S were 0.36, 0.41, and 0.69, respectively. The majority of the retinal vessel occlusion cases were reported following BNT162b2 (n=606, 74.17%). The mean age of patients with RVO and RAO was 58.54 ± 16.06 years and 64.63 ± 16.16 years, respectively. In the cohort, 817 and 433 patients were diagnosed with RVO and RAO, respectively. Most cases of RVO (41.12%) and RAO (48.27%) were reported within the first week post-vaccination. We observed that the mean onset interval for RVO was significantly longer in patients who received Ad26.Cov2.S (54.07 ± 88.98 days) compared to BNT162b2 (18.07 ± 28.66 days) and mRNA-1273 (22.85 ± 38.13 days) vaccines (p<0.0001). This was further confirmed by post-hoc analysis, which revealed a significantly longer onset duration for the Ad26.Cov2.S compared to BNT162b2 and mRNA 1273 vaccines (p<0.0001). The reverse Kaplan Meier 30-day risk analysis showed a significant a higher risk of RVO onset following BNT162b2 compared to other vaccines(p<0.0001). The low crude reporting rate highlights a low safety concern for retinal vessel occlusion following SARS-CoV-2 vaccination. This study provides insights into possible temporal association between reported retinal vessel occlusion events with SARS-CoV-2 vaccines, however further insights are needed to understand the underlying immunopathological mechanisms that promote thrombosis of retinal vasculature on vaccine administration.

Retinal vein occlusion in patients with primary angle closure: a prospective case–control study

ObjectifComparer la prévalence de la fermeture de l'angle dans des yeux présentant une occlusion veineuse rétinienne (OVR) et dans des yeux témoins, d'une part, et vérifier s'il existe une association entre la fermeture de l'angle et l'OVR, d'autre part. Patients et méthodesCette étude cas-témoins prospective qui a été réalisée à l'insu regroupait des patients ayant des antécédents d'OVR (cas cliniques) et des sujets témoins appariés pour l’âge et l'erreur de réfraction. Ont été analysées les caractéristiques cliniques des patients et les images des structures de l'angle obtenues par tomographie par cohérence optique (OCT) du segment antérieur. RésultatsAinsi, 88 patients (44 par groupe) ont été inclus dans notre étude. L’âge moyen des sujets dans les groupe OVR et témoin était de 59,8 ± 11,6 ans et de 60,8 ± 9,0 ans, respectivement (p = 0,667). Il n'y avait pas de différence statistiquement significative entre les 2 groupes quant aux caractéristiques cliniques, notamment la pression intraoculaire (p = 0,837) et la classification de Shaffer (p = 0,620). Aucune des caractéristiques des structures de l'angle visibles dans les images de l'OCT du segment antérieur ne différait significativement d'un groupe à l'autre. Le nombre de diagnostics de fermeture de l'angle relevés dans le groupe OVR (1 cas de fermeture primaire de l'angle et 7 suspicions de fermeture primaire de l'angle) et dans le groupe témoin (6 suspicions de fermeture primaire de l'angle) ne différait pas de manière significative (p = 0,560). La profondeur de la chambre antérieure (PCA) était moins prononcée dans les yeux atteints d'OVR (2,72 ± 0,31 mm) que dans les yeux controlatéraux exempts d'OVR (2,76 ± 0,31 mm; p = 0,014). ConclusionsCette étude prospective à l'insu comprenant des cas-témoins appariés n'a pas mis au jour de différence significative quant aux mesures cliniques ni aux images des structures de l'angle obtenues à l'OCT du segment antérieur dans des yeux présentant une OVR, comparativement à des yeux témoins. Cela dit, la PCA était légèrement moins prononcée dans les yeux atteints d'OVR que dans les yeux controlatéraux exempts d'OVR. D'après l'ensemble des résultats obtenus, il est peu probable qu'il existe une association entre les mécanismes à l'origine de la fermeture primaire de l'angle et l'OVR. Cependant, la PCA moins prononcée observée en présence d'OVR pourrait accroître le risque de blocage pupillaire intermittent ou permanent.

A study on oxidized-LDL cholesterol in normolipidemic retinal vein occlusion

Background: Oxidized low-density lipoprotein (ox-LDL) has been implicated in atherosclerotic cardiovascular disease. Arteriolosclerosis is an important causative factor for retinal vein occlusion (RVO). Till, date there is dearth of literature on ox-LDL and RVO. Aims and Objectives: The objectives of this study were to see whether ox-LDL cholesterol is an independent risk factor in RVO with normal lipid profile. Materials and Methods: Lipid profiles and ox-LDL levels were assayed in 122 adult unilateral RVO cases and 142 age and sex matched controls in this 1 year old case–control study. Results: ox-LDL cholesterol levels were significantly elevated in RVO cases than controls (54.5±6.1 in cases vs. 36.6±5.6 in controls, P&lt;0.01), although serum lipid profiles were normal in both cases and controls. Conclusion: The ox-LDL-induced atherosclerosis may be responsible for the retinal venous occlusion in absence of other risk factors. Hence, screening for ox-LDL in RVO patients should be worth considering especially in patients with normal lipid profiles.

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.

Retinal vascular occlusions in COVID-19 infection and vaccination: a literature review.

Abnormal hypercoagulability and increased thromboembolic risk are common in patients with coronavirus disease (COVID-19). COVID-19 has been suggested to cause retinal vascular damage, with several studies on COVID-19 patients with retinal vascular occlusions. We reviewed and investigated studies on retinal vascular occlusions in patients diagnosed with COVID-19 and in those vaccinated for COVID-19. Studies that reported retinal vascular occlusion in COVID-19 patients or in vaccinated people were identified using the terms "retinal occlusion," together with "severe acute respiratory syndrome coronavirus 2", "SARS-CoV-2," "COVID-19," "coronavirus," and "vaccine," through systematic searches of PubMed and Google Scholar databases until January 7, 2022. Thirteen cases of retinal artery occlusion (RAO) and 14 cases of retinal vein occlusion (RVO) were identified among patients diagnosed with COVID-19. Half of the patients with RAO or RVO revealed no systemic disorders except current or past COVID-19, and ocular symptoms were the initial presentation in five cases. Among patients with RAO, most presented with central RAO at 1-14days of COVID-19 diagnosis, with abnormal coagulation and inflammatory markers. Among those with RVO, two-thirds presented with central RVO and one-third with RVO. Eleven cases with acute macular neuroretinopathy (AMN) and/or paracentral acute middle maculopathy (PAMM) were reported among patients with COVID-19, presenting scotoma resolved spontaneously in most cases. Among the 26 cases vaccinated with either mRNA or adenoviral vector vaccines for COVID-19 and presenting retinal vascular occlusions, there were more RVO cases than RAO cases, and ocular symptoms mostly occurred within 3weeks after vaccination. One case presented bilateral AMN and PAMM after COVID-19 vaccination. Retinal vascular occlusions might be a manifestation of COVID-19, although rare, especially in patients at risk of systemic hypercoagulability and thromboembolism. For COVID-19 vaccines, the causal relationship is controversial because there are few case reports of retinal vascular occlusions after COVID-19 vaccination.

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

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

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

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. 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. 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. 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.

Optical Coherence Tomography Angiography (OCTA) Analysis of Perifoveal Capillary Arcade in Patients with Retinal Vein Occlusion Treated with Anti-VEGF

Objective: To evaluate the changes in perifoveal capillary arcade in patients with retinal vein occlusion treated with intravitreal injections of anti-vascular endothelial growth factor for macular edema resulting from retinal vein occlusion with OCTA.&#x0D; Study Design: Quasi-experimental study.Place and Duration of Study: Armed Forces Institute of Ophthalmology, Rawalpindi Pakistan, from Jul 2018 to Jul 2019.&#x0D; Methodology: Patients diagnosed as case of retinal vein occlusion underwent complete eye examination. Optical coherence tomography angiography (OCTA) was done in all the patients. Patients having macular edema were prescribed intravitreal anti-vascular endothelial growth factor inhibitors on monthly basis. OCTA was repeated at the third month.&#x0D; Results: In this study, 50 eyes were evaluated. After treatment patients having perifoveal capillary arcade of less than two quadrants increased from 47.7-68.8% (p&lt;0.002) in the superficial capillary plexus and in deep capillary plexus this number increased from 50% to 88.6% (p&lt;0.05). There was also a significant decrease in the number of macular cysts in the superficial and deep capillary plexus post treatment (p&lt;0.05). Mean En face vascular density in superficial capillary plexus decreased in all the quadrants specially the foveal zone.&#x0D; Conclusion: Optical coherence tomography angiography (OCTA) showed a qualitative improvement in perifoveal arcade disruption and decrease in the number of cystic spaces. Quantitative analysis revealed a significant reduction in vessel density in all quadrants. It enables us to follow up patients with retinal vein occlusion and study the vascular arcade changes with time and treatment.