Management of Acute Retinal Ischemia: Follow the Guidelines!

Transcriptional responses in a mouse model of silicone wire embolization induced acute retinal artery ischemia and reperfusion

Acute retinal ischemia and ischemia-reperfusion injury are the primary causes of retinal neural cell death and vision loss in retinal artery occlusion (RAO). The absence of an accurate mouse model for simulating the retinal ischemic process has hindered progress in developing neuroprotective agents for RAO. We developed a unilateral pterygopalatine ophthalmic artery occlusion (UPOAO) mouse model using silicone wire embolization combined with carotid artery ligation. The survival of retinal ganglion cells and visual function were evaluated to determine the duration of ischemia. Immunofluorescence staining, optical coherence tomography, and haematoxylin and eosin staining were utilized to assess changes in major neural cell classes and retinal structure degeneration at two reperfusion durations. Transcriptomics was employed to investigate alterations in the pathological process of UPOAO following ischemia and reperfusion, highlighting transcriptomic differences between UPOAO and other retinal ischemia-reperfusion models. The UPOAO model successfully replicated the acute interruption of retinal blood supply observed in RAO. 60 min of Ischemia led to significant loss of major retinal neural cells and visual function impairment. Notable thinning of the inner retinal layer, especially the ganglion cell layer, was evident post-UPOAO. Temporal transcriptome analysis revealed various pathophysiological processes related to immune cell migration, oxidative stress, and immune inflammation during the non-reperfusion and reperfusion periods. A pronounced increase in microglia within the retina and peripheral leukocytes accessing the retina was observed during reperfusion periods. Comparison of differentially expressed genes (DEGs) between the UPOAO and high intraocular pressure models revealed specific enrichments in lipid and steroid metabolism-related genes in the UPOAO model. The UPOAO model emerges as a novel tool for screening pathogenic genes and promoting further therapeutic research in RAO.

Injectable Gel-PEG hydrogels as promising delivery system for intravitreal PACAP release: Novel therapeutics for unilateral common carotid artery occlusion induced retinal ischemia

Retinal ischemia is an ophthalmic emergency often caused by cardiovascular diseases, leading to irreversible vision loss and even blindness. Innovative retinal ischemia treatments are needed due to limited options. The pathological mechanisms involve retinal cell apoptosis and microglial activation. The pituitary adenylate cyclase-activating polypeptide (PACAP) is a well distributed neuropeptide found in both central nervous system and peripheral organs. Though it shows great anti-apoptosis and anti-microglia activation properties, it is rapidly cleared by intravitreal injection. Herein, we established a novel poly(ethylene glycol) (PEG) hydrogel system by cross-linking 4arm-PEG-NHS and 4arm-PEG-NH2 to load PACAP (PACAP@Gel-PEG), which exhibited great fluidity, injectability, structural recovery ability, moderate swelling ratio and drug release ability that were appropriate for drug delivery. Then the safety and effectiveness of the PACAP@Gel-PEG were evaluated in vitro in three retinal cell lines (ARPE-19, 661 W and rRMC) and in vivo using the unilateral common carotid artery occlusion (UCCAO) mice model. The CCK-8 test and live/dead staining demonstrated that PACAP@Gel-PEG exhibited excellent biocompatibility in three retinal cell lines. Furthermore, after PACAP@Gel-PEG treatment, a great anti-apoptotic effect was observed in cells treated by CoCl2. Application of PACAP@Gel-PEG greatly improved the therapeutic efficacy of PACAP in restoring retinal function, maintaining retinal integrity, and suppressing apoptosis and microglia activation in retinal tissues. Moreover, in mice, the biosafety of PACAP@Gel-PEG was confirmed by H&E staining of systemic organs. Taken together, our results demonstrated PACAP@Gel-PEG as a promising therapeutic option for retinal ischemia, providing new strategies for vision restoration.

Position paper on retinal arterial occlusion. SEMI-SERV

The retina is an organ frequently affected by ischemic changes. Retinal arterial occlusion can be considered the equivalent of stroke, in terms of presentation, management and treatment. In addition to a specific ophthalmological treatment systemic management is essential with an appropriate study and control of cardiovascular risk factors considering these patients of a very high cardiovascular risk. In this consensus document we aim to provide an update on this relatively frequent pathology in our practices, considering the importance of an early and systematic action.

Eye stroke protocol in in the emergency department

BACKGROUND

Visual outcomes of acute central and branch retinal artery occlusions (CRAO/BRAO) are poor and acute treatment options are limited by delayed diagnosis. In the hyper-acute setting, the ocular fundus may appear "normal", making recognition challenging, but is facilitated by retinal optical coherence tomography (OCT), which is seldom available in emergency departments (ED). We evaluated the use of non-mydriatic ocular fundus photographs (NMFP) combined with OCT to facilitate ultra-rapid remote diagnosis and stroke alert for patients with acute vision loss presenting to the ED.

METHODS

Prospective evaluation of all CRAO/BRAO between 06/06/2023-06/06/2024 who had NMFP-OCT in our general ED affiliated with a stroke center.

RESULTS

Over 1 year, 22 patients were diagnosed with CRAO, 4 with BRAO. Five patients presented within 4.5 hours of vision loss onset, 6 within 4.5 to ≤12 hours and 15 within >12 to 24 hours. On average, NMFP-OCT was performed within 141 minutes of presentation to the ED (range 27- 422 minutes). Diagnosis of acute RAO was made remotely with NMFP-OCT within 4.5 hours in 4 patients, 2 of whom received intravenous thrombolysis. Of the 9 patients with NMFP-OCT within 12 hours of symptom onset, 5 patients had subtle retinal whitening on color fundus photograph, but all had OCT inner retinal hyper-reflectivity/edema.

CONCLUSION

Implementation of NMFP-OCT in a general ED enables rapid remote diagnosis of CRAO/BRAO and facilitates initiation of an eye stroke protocol in acute patients. OCT complements color fundus photography and provides greater diagnostic accuracy in hyperacute cases with near-normal appearing ocular fundi.

Optometric Practice Patterns for Acute Central and Branch Retinal Artery Occlusion

BACKGROUND

Optometrists are often the first providers to evaluate patients with acute vision loss and are often the first to diagnose a central retinal artery occlusion (CRAO). How quickly these patients present to the optometrist, are diagnosed, and referred for evaluation are major factors influencing the possibility of acute therapeutic intervention. Our aim was to survey the U.S. optometric community to determine current optometric practice patterns for management of CRAO.

METHODS

An anonymous seven-question survey was emailed in 2020 to the 5,101 members of the American Academy of Optometry and the 26,502 members of the American Optometric Association.

RESULTS

Of 31,603 optometrists who were sent the survey, 1,926 responded (6.1%). Most respondents (1,392/1,919, 72.5%) worked in an optometry-predominant outpatient clinic and were less than 30 minutes from a certified stroke center (1,481/1,923, 77.0%). Ninety-eight percent (1,884/1,922) of respondents had diagnosed less than 5 CRAOs in the previous year, and 1,000/1,922 (52.0%) had not diagnosed a CRAO in the prior year. Of the optometrists who diagnosed at least one CRAO in the previous year, 661/922 (71.7%) evaluated these patients more than 4 hours after the onset of vision loss. Optometrists who diagnosed a CRAO or branch retinal artery occlusion referred patients to an emergency department (ED) affiliated with a certified stroke center (844/1,917, 44.0%), an outpatient ophthalmology clinic (764/1,917, 39.9%), an ED without a stroke center (250/1,917, 13.0%), an outpatient neurology clinic (20/1,917, 1.0%), or other (39/1,917, 2.0%); most (22/39, 56.4%) who responded "other" would refer to a primary care physician.

CONCLUSIONS

Optometrists are likely the first providers to evaluate patients with acute vision loss, including from a retinal artery occlusion. However, only 6.1% of optometrists responded to our survey despite 2 reminder emails, likely reflecting the lack of exposure to acute retinal artery occlusions, and a potential lack of interest of optometrists in participating in research. Of the optometrists who reported evaluating a CRAO in the previous year, less than 29% saw the patient within 4 hours of vision loss. In addition, a large portion of optometrists are referring acute CRAO patients to outpatient ophthalmology clinics, delaying appropriate acute management. Therefore, it is imperative that optometrists and ophthalmologists are educated to view acute retinal arterial ischemia as an acute stroke and urgently refer these patients to an ED affiliated with a stroke center. The delay in patient presentation and these referral patterns make future clinical trials for acute CRAO challenging.

Retina-Brain Homology: The Correlation Between Ophthalmic or Retinal Artery Occlusion and Ischemic Stroke

The retina's similar structure and function to the brain make it a unique visual "window" for studying cerebral disorders. Ophthalmic artery occlusion (OAO) or retinal artery occlusion (RAO) is a severe ophthalmic emergency that significantly affects visual acuity. Studies have demonstrated that patients with OAO or RAO face a notably higher risk of future acute ischemic stroke (AIS). However, ophthalmologists often overlook multidisciplinary approach involving the neurologist, to evaluate the risk of AIS and devise clinical treatment strategies for patients with OAO or RAO. Unlike the successful use of thrombolysis in AIS, the application of thrombolysis for OAO or RAO remains limited and controversial due to insufficient reliable evidence. In this review, we aim to summarize the anatomical and functional connections between the retina and the brain, and the clinical connection between OAO or RAO and AIS, compare and review recent advances in the effectiveness and safety of intravenous and intra-arterial thrombolysis therapy in patients with OAO or RAO, and discuss future research directions for OAO or RAO. Our goal is to advance the development of multidisciplinary diagnosis and treatment strategies for the disease, as well as to establish expedited pathways or thrombolysis guidelines for vascular intervention.

Central retinal artery occlusion: a stroke of the eye

Central retinal artery occlusion (CRAO), like a stroke in the brain, is a critical eye condition that requiring urgent medical attention. Patients with CRAO present with acute loss of vision and the visual prognosis is poor with low chance of spontaneous visual recovery. Moreover, the risk of developing ischaemic heart disease and cerebral stroke is increased due to the presence of underlying atherosclerotic risk factors. Currently, there is no officially recommended treatment for CRAO. This review will describe the anatomy, pathophysiology, clinical features of CRAO, as well as exploring existing and potential future approaches for managing the condition.

Optical coherence tomography angiography in the diagnosis of ocular disease

Clinical imaging provided by optical coherence tomography (OCT) and its variant, OCT-angiography (OCT-A), has revolutionised eyecare practice. The imaging techniques allow for the identification and quantification of ocular structures, supporting the diagnosis and prognosis of eye disease. In this review, an overview of the usefulness of OCT-A imaging in the diagnosis and management of a range of ocular conditions is provided when used in isolation or in combination with other imaging modalities and measures of visual function (visual field results). OCT-A imaging has the capacity to identify and quantify ocular vasculature non-invasively, thereby assisting the clinician in the diagnosis or to determine the efficacy of intervention in ocular conditions impacting retinal vasculature. Thus, additional clinically useful information can be obtained in eye diseases involving conditions such as those impacting retinal vessel occlusion, in diabetic retinopathy, inherited retinal dystrophy, age-related macular degeneration, choroidal neovascularisation and optic nerve disorders. Through a clinical case series, various ocular conditions are reviewed, and the impact of OCT-A imaging is discussed. Although OCT-A imaging has great promise and is already used in clinical management, there is a lack of set standards to characterise altered vascular features in disease and consequently for prognostication, primarily due to a lack of large-scale clinical trials and variability in OCT-A algorithms when generating quantitative parameters.

Ocular Manifestations and Complications of Patent Foramen Ovale: A Narrative Review

Patent foramen ovale (PFO) is a prevalent congenital cardiac anomaly associated with a persistent opening between the atrial septum, allowing communication between the left and right atria. Despite often being asymptomatic, PFO can lead to various clinical presentations, including cryptogenic stroke and other embolic events. Transient visual disturbances, alterations in the visual field, migraine with aura, impaired eye movement and endogenous eye infections may prompt patients to seek ophthalmological consultation. Understanding these diverse clinical scenarios is crucial for early detection, appropriate management and mitigating the morbidity burden associated with PFO. This narrative review aims at examining the spectrum of clinical presentations of ocular pictures associated with PFO. The pathophysiology, diagnosis and treatment methods for PFO will be described, emphasizing the importance of a multidisciplinary approach involving ophthalmologists, cardiologists, neurologists and imaging specialists. In the future, prospective studies and clinical trials are warranted to provide further insights into the preventive role and optimal therapeutic strategies for managing PFO-related ocular complications, ultimately guiding clinical decision making and optimizing patient care.

Central retinal artery occlusion or retinal stroke: a neurosonologist's perspective

In central retinal artery occlusion (CRAO) or retinal stroke, which is usually a vision-threatening condition, timely diagnosis is imperative to improve the chances of retinal preservation and to establish adequate secondary prevention measures. Even though retinal strokes have been traditionally assigned to the field of ophthalmology, while considering reperfusion therapy as the only way to avoid permanent vision loss, we suggest prompt evaluation of CRAO causes (primarily related to cardiovascular risk factors) performed by a well-organized interdisciplinary team (ophthalmologist and neurologist) in a neurovascular center with stroke expertise. Therefore, the most suitable adjunct method for rapidly diagnosing non-arteritic CRAO could be target transorbital ultrasound, performed by an experienced neurologist/neurosonologist in the stroke unit. Consequently, after an ophthalmological assessment, a final decision on thrombolytic therapy could be made. We accept that further research is obviously needed to determine whether transorbital ultrasound could replace ophthalmological investigation in the case of a suspected acute retinal stroke. We assert that retinal stroke requires interdisciplinary treatment in cooperation with neurologists and ophthalmologists, with an additive value for each to achieve the best results for the patient.

Transient Monocular Visual Loss (Amaurosis Fugax): How Does Age Impact Diagnosis?

Transient monocular visual loss (TMVL), also known as transient monocular blindness or amaurosis fugax ("fleeting blindness"), is a temporary loss of vision often due to ischemia to the retina. While acute TMVL should be considered an emergency that further requires exhaustive investigation, there are some cases in which TMVL arises secondary to benign causes. Age has a major impact in the diagnosis of ischemia and although the differential diagnosis of TMVL can be broad, timely and appropriate history, examination, diagnostic testing, and treatment can be vision- or life-saving. We review the causes of TMVL and the impact of age on the differential diagnoses and management.

Clinical characteristics of recurrent non-arteritic retinal artery occlusion

OBJECTIVES

To investigate the recurrent non-arteritic retinal artery occlusion (RAO) in the same or opposite eye.

METHODS

We searched the RAO registry at Seoul National University Bundang Hospital and included patients with recurrent RAO in the present study. Ophthalmic and systemic features were analysed to identify risk factors and visual outcomes.

RESULTS

Of the 850 patients in the non-arteritic RAO cohort, 11 (1.3%) experienced a second RAO recurrence, either in the same (5 patients; 0.6%) or opposite (6 patients; 0.7%) eye. The same eye group experienced an earlier recurrence (1-2 months, median 1 month) than the opposite eye group, where the time to recurrence was notably longer (8-66 months, median 22 months). Best corrected visual acuity (BCVA) in the same eye group decreased after the recurrence of RAO. In the same eye group, initial BCVA ranged from 20/200 to counting fingers (CF), while BCVA during RAO recurrence ranged from CF to hand motion. When RAO recurred in the opposite eye, the reduction in visual acuity was less severe than the reduction of the initial episode: initial episode ranged from 20/400 to light perception and recurrent episode ranged from 20/25 to 20/400. Patients exhibited varying degrees of carotid (81.8%) and cerebral (9.1%) artery occlusions. Additionally, one patient in each group (total 2 patients, 18.2%) experienced a stroke 6 months after RAO recurrence.

CONCLUSIONS

Since the RAO recurrences could lead to devastating visual impairment, it is essential to emphasise the importance of risk factor screening to patients while collaborating with neurologists and cardiologists.

Circulating serum fibroblast growth factor 21 as risk and prognostic biomarker of retinal artery occlusion

To evaluate the predictive and prognostic value of fibroblast growth factor 21 (FGF21) levels in retinal artery occlusion (RAO) patients. In this case-control study, serum FGF21 levels were detected by using the ELISA method. Multivariable logistic regression analyses were performed to evaluate the significance of FGF21 in assessing the risk of developing RAO and its impact on vision and concurrent ischemic stroke. Compared with control group, serum FGF21 levels were significantly higher (median [IQR] = 230.90[167.40,332.20] pg/ml) in RAO patients. Multivariate logistic regression analysis showed that elevated serum FGF21 levels were associated with a higher risk of RAO occurrence (P = 0.025, OR [95%CI] = 9.672 [2.573, 36.359]) after adjustment for multiple confounding factors. Higher serum FGF21 levels were negatively associated with visual acuity improvement (P = 0.029, OR [95%CI] = 0.466[0.235, 0.925]) and positively correlated with concurrent ischemic stroke (P = 0.04, OR [95% CI] = 1.944[1.029, 3.672]) in RAO patients. Elevated serum FGF21 levels could promote the development of RAO and indicate worse visual prognosis and increase the risk of concurrent ischemic stroke, which might help clinicians early diagnose and treat RAO patients.

Comparison of vascular risk profile and clinical outcomes among patients with central (branch) retinal artery occlusion versus amaurosis fugax

BACKGROUND

Retinal artery occlusions lead to sudden, painless vision loss, affecting millions globally. Despite their significance, treatment strategies remain unestablished, contrasting with acute ischemic stroke (AIS), where IVT has proven efficacy. Similar to AIS, retinal artery occlusions demand urgent evaluation and treatment, reflecting the principle "time is retina". Even for patients with transient monocular vision loss, also known as amaurosis fugax (AF), pertinent guidelines meanwhile recommend immediate emergency assessment in a specialized facility. However, data on the clinical benefit and comparability with persistent occlusions are missing. This study aimed to compare the results of a comprehensive stroke-workup among patients with persistent retinal artery occlusions (RAO), including both central retinal (CRAO) and branch retinal artery occlusion (BRAO) and those with AF.

METHODS

Conducted at the University Hospital Giessen, Germany, this exploratory cross-sectional study enrolled patients with transient or permanent unilateral vision loss of non-arteritic origin. The primary outcome were differences between the two groups RAO and AF with regard to cardiovascular risk profiles and comorbidities, vascular and pharmacological interventions and clinical neurological and ophthalmological outcomes. Secondary outcome was a sub-group analysis of patients receiving IVT.

RESULTS

Out of 166 patients assessed, 76 with RAO and 40 with AF met the inclusion criteria. Both groups exhibited comparable age, gender distribution, and cardiovascular risk profiles. Notably, RAO patients did not show significantly more severe vascular comorbidities than AF patients. However, AF patients received vascular interventions more frequently. Pharmacological intervention rates were similar across groups. RAO patients had slightly worse neurological outcomes, and IVT did not yield favorable ophthalmological outcomes within any observed patients.

CONCLUSION

The study found similar vascular burden and risk factors in patients with RAO and AF, with implications for clinical workflows. IVT for RAO may only be effective in very early treatment windows. This emphasizes the need for public awareness and collaborative protocols between ophthalmologists and neurologists to improve outcomes.

Thrombolysis in acute retinal ischemia treated with tenecteplase

Central retinal artery occlusion (CRAO), a type of acute retinal arterial ischemia, analogous to an ocular stroke, is a medical emergency that warrants immediate diagnosis and treatment. CRAO usually presents with sudden, painless, monocular vision loss. Ipsilateral carotid artery disease is an important associated finding in these patients. The primary limitation to effective treatment of CRAO is that patients are rarely seen in the acute stage. Moreover, there are no guidelines for effective treatment. We report a patient with right CRAO whose treatment with intravenous thrombolysis with tenecteplase and anterior chamber paracentesis with ocular massage resulted in a good clinical outcome.

Evaluation of Increase in Retinal Thickness as Diagnostic Marker in Central Artery Occlusion

PURPOSE

To evaluate the increase in retinal thickness as a marker in predicting the onset of central retinal artery occlusions.

METHODS

Retrospective clinical study conducted at one Swiss hospital. Electronic records were filtered for patients with artery occlusions. Optical coherence tomography data, including time between the imaging and ischemic event, were reviewed. Increase in relative retinal thickness was measured, defined as an increase in retinal thickness compared to the unaffected partner eye. This was correlated with the time from symptom onset. A cutoff value of relative increase of < 24.5% was applied, as suggested in previous studies. The results were compared to the time gathered from the electronic records, and sensitivity, specificity, positive predictive value as well as negative predictive value were calculated for predicting an ischemia time of < 4.5 h.

RESULTS

Forty-two eyes from 41 patients with central artery occlusions were identified. Fourteen were female. Mean age was 66.4 ± 15.8 years. Initial corrected visual acuity was 2.41 ± 0.68 logMAR, and 2.13 ± 0.87 logMAR at the last follow-up (p > 0.05). Of eyes with a visual acuity of counting fingers (n = 38) or worse, 89.5% showed no improvement during follow-up, while eyes with logMAR 1 or better (n = 4) improved. Thirteen eyes (13 patients) presented within 4.5 h of the ischemic event. Four patients received i. v. thrombolysis, with visual recovery in one. In 12 eyes with an ischemia time of < 4.5 h, relative increase was below 24.5%. In the remaining 29 eyes with > 4.5 h, relative increase was below 24.5% in 4 eyes and above 24.5% in 25 eyes. This yielded a sensitivity of 92.3%, a specificity of 86.2%, with a positive predictive value of 75.0% and a negative predictive value of 96.2%.

CONCLUSION

Central retinal artery occlusion is associated with severe vision loss. There is no current established therapy. Parameters that objectify the presence of a therapeutic window for thrombolysis are gaining in importance as patient history is often imprecise. Relative retinal thickness increase proved a noninvasive imaging parameter demonstrating adequate performance in detecting patients within the therapeutic window of thrombolysis. Further investigation of this parameter in central retinal occlusion is warranted.

Stem cell factor protects against chronic ischemic retinal injury by modulating on neurovascular unit

Retinal ischemia is a significant factor in various vision-threatening diseases, but effective treatments are currently lacking. This study explores the potential of stem cell factor (SCF) in regulating the neurovascular unit as a therapeutic intervention for retinal ischemic diseases. A chronic retinal ischemia model was established in Brown Norway rats using bilateral common carotid artery occlusion (BCCAO). Subsequent SCF treatment resulted in a remarkable recovery of retinal function, as indicated by electroretinogram, light/dark transition test, and optokinetic head tracking test results. Histological examination demonstrated a significant increase in the number of retinal neurons and an overall thickening of the retina. Immunofluorescence confirmed these findings and further demonstrated that SCF treatment regulated retinal remodeling. Notably, SCF treatment ameliorated the disrupted expression of synaptic markers in the control group's BCCAO rats and suppressed the activation of Müller cells and microglia. Retinal whole-mount analysis revealed a significant improvement in the abnormalities in retinal vasculature following SCF treatment. Transcriptome sequencing analysis revealed that SCF-induced transcriptome changes were closely linked to the Wnt7 pathway. Key members of the Wnt7 pathway, exhibited significant upregulation following SCF treatment. These results underscore the protective role of SCF in the neurovascular unit of retinal ischemia rats by modulating the Wnt7 pathway. SCF administration emerges as a promising therapeutic strategy for retinal ischemia-related diseases, offering potential avenues for future clinical interventions.

Peripheral blood transcriptomic analysis identifies potential inflammation and immune signatures for central retinal artery occlusion

Central retinal artery occlusion (CRAO) is an acute retinal ischaemic disease, but early diagnosis is challenging due to a lack of biomarkers. Blood samples were collected from CRAO patients and cataract patients. Gene expression profiles were distinct between arterial/venous CRAO blood (A-V group) and venous CRAO/control blood (V-C group) samples. Differentially expressed genes (DEGs) were subjected to GO and KEGG enrichment analyses. Hub genes were identified by Cytoscape and used to predict gene interactions via GeneMANIA. Immune cell infiltration was analysed by CIBERSORT. More than 1400 DEGs were identified in the A-V group and 112 DEGs in the V-C group compared to controls. The DEGs in both groups were enriched in the ribosome pathway, and those in the V-C group were also enriched in antigen processing/MHC pathways. Network analysis identified ribosomal proteins (RPS2 and RPS5) as the core genes of the A-V group and MHC genes (HLA-F) as the core genes of the V-C group. Coexpression networks showed ribosomal involvement in both groups, with additional immune responses in the V-C group. Immune cell analysis indicated increased numbers of neutrophils and T cells. Ribosomal and MHC-related genes were identified as potential CRAO biomarkers, providing research directions for prevention, diagnosis, treatment and prognosis.

Aetiology, Diagnosis and Treatment of Arterial Occlusions of the Retina-A Narrative Review

Arterial occlusions of the retina are potentially sight-threatening diseases which often result in profound visual loss. The aim of this narrative review is to provide an overview of the aetiology, discuss major risk factors, describe the management and systemic assessments and evaluate existing therapies. For this review, an extensive literature search in PubMed was performed. Emboli from the heart or the carotid arteries can cause ophthalmic artery occlusion (OAO), central retinal artery occlusion (CRAO) and branch retinal artery occlusion (BRAO). Most patients with arterial occlusions have vascular risk factors such as arterial hypertension, hyperhomocysteinaemia, carotid stenosis and atrial fibrillation, which also increase the risk of cerebral stroke and myocardial infarction. Therapies such as ocular massage, thrombolysis and anterior chamber paracentesis have been suggested but are still equivocal. However, it is evident that retinal artery occlusion should be immediately treated and accompanied by interdisciplinary collaboration, since early diagnosis and the proper treatment of possible risk factors are important to reduce the risk of further damage, recurrences, other vascular diseases and mortality.

Incidence rates of retinal vascular occlusive diseases from 2011 to 2020 in South Korea: a nationwide cohort study

BACKGROUND

Retinal vascular occlusions, including retinal vein occlusion and retinal artery occlusion, are common causes of visual impairment. In order to evaluate the national medical burden and help improve ophthalmic health care policy planning, we investigated the incidence of retinal vascular occlusive diseases from 2011 to 2020 in Korea.

METHODS

This study is a nationwide population-based retrospective study using data from the Korea national health claim database of the Health Insurance Review and Assessment (HIRA) service. We identified retinal vascular occlusive diseases registered from January 1, 2009, to December 31, 2020, according to the retinal vascular occlusion code (H34) and its sub-codes from international classification of disease, tenth revision diagnosis code. We used data from the entire Korean population based on the 2015 census of the population in Korea to calculate standardized incidence rates.

RESULTS

We identified 348,775 individuals (male, 161,673 [46.4%]; female, 187,102 [53.6%]) with incident retinal vascular occlusion (H34), 10,451 individuals (males, 6,329 [60.6%]; females, 4,122 [39.4%]) with incident central retinal artery occlusion (H34.1), and 252,810 individuals (males, 114,717 [45.4%]; females, 138,093 [54.6%]) with incident retinal vein occlusion (H34.8) during the 10-year study period. The weighted mean incidence rate of retinal vascular occlusion was 70.41 (95% CI, 70.18-70.65) cases/100,000 person-years. The weighted mean incidence rate of central retinal artery occlusion was 2.10 (95% CI, 2.06-2.14) cases/100,000 person-years. The weighted mean incidence rate of retinal vein occlusion was 50.99 (95% CI, 50.79-51.19) cases/100,000 person-years.

CONCLUSION

The total retinal vascular occlusion and retinal vein occlusion showed a decreasing trend until 2020. However, the central retinal artery occlusion decreased until 2014 and remained stable without a significant further decline until 2020. The incidence of total retinal vascular occlusion and retinal vein occlusion was higher in females than in males, while the incidence of central retinal artery occlusion was higher in males. All retinal vascular occlusive diseases showed an increasing incidence with older age; the peak age incidence was 75-79 years for total retinal vascular occlusion and retinal vein occlusion, and 80-85 years for central retinal artery occlusion.

Improved visual outcomes of central retinal artery occlusion with local intra-arterial fibrinolysis beyond the conventional time window

Local intra-arterial fibrinolysis (LIF) is a promising therapeutic option for CRAO. However, the narrow time window of 6 h has greatly limited the application of LIF. In this study, we explored the efficacy of LIF beyond the conventional time windows and compared the result with conservative therapy. This prospective study included 179 CRAO patients with baseline visual acuity (VA) ≤ 20/400 treated at Renmin Hospital of Wuhan University. The mean time from vision loss to presentation was 5.5 days. 58 patients received conventional standard therapy (CST) alone.121 patients underwent LIF. Main outcome was VA improvement ≥ 0.3 logMAR. Secondary outcome was a favorable VA outcome of 20/200 or better. Logistic regressions were performed to identify predictors of visual improvement. 43% patients in the LIF group experienced VA improvement versus 19% with CST (P = 0.002). LIF was associated with 4.0-fold higher likelihood of visual improvement compared to CST (P = 0.001). Poor baseline VA (light perception or no light perception) and shortened prothrombin time (PT) were associated with greater chance of visual improvement with LIF. However, LIF showed no significant advantage over CST for favorable VA outcomes. No major complications occurred. LIF beyond the therapeutic time window improved vision in functionally blind CRAO patients and showed better efficacy when compared with CST. PT may be a potential predictor of visual outcome after LIF. Our findings could complement existing time-based treatment guidelines and potentially allow for personalized decisions on the use of LIF beyond time windows.

Risk factors for ischemic cerebral stroke in patients with acute amaurosis fugax

OBJECTIVE

The National Stroke Association and the American Heart Association consider retinal ischemia, as in the case of amaurosis fugax (AF), to be a stroke event. The purpose of this study was to evaluate the risk factors for ischemic cerebral stroke in patients hospitalized for acute AF.

METHODS

The National Inpatient Sample Database from 2002 to 2014 was used to identify patients 21 years of age and older with a primary admission diagnosis of AF with the ICD-9 code 362.34. Comorbidity measures and in-hospital events were extracted using relevant ICD-9 codes. Statistical analyses were performed using IBM SPSS 25 and R package.

RESULTS

A weighted total of 12,142 patients was identified. The most common comorbidities in this cohort with AF included hypertension, dyslipidemia, tobacco use, coronary artery disease (CAD), and diabetes mellitus. Multivariable regression analysis showed comorbidities of hypercoagulable state, systemic vasculitis, CAD, and atherosclerosis to be independent risk factors for ischemic stroke in patients with AF. In contrast, dyslipidemia was associated with a decreased risk. Asian/Pacific Islander race conferred a 5-fold increased risk compared with Whites.

CONCLUSION

Ischemic stroke and myocardial infarction were diagnosed in 0.3%-0.9% of hospitalized acute AF cases. Presence of hypercoagulable state, systemic vasculitis, CAD, and atherosclerosis each individually increased the risk of ischemic stroke by more than 3-fold; patients with these risk factors and acute AF should be closely monitored for developing acute systemic thrombotic events.

Single-Cell Transcriptomic Sequencing Reveals Tissue Architecture and Deciphers Pathological Reprogramming During Retinal Ischemia in Macaca fascicularis

Purpose

Acute retinal arterial ischemia diseases (ARAIDs) are ocular emergencies that require immediate intervention within a restricted therapeutic window to prevent blindness. However, the underlying molecular mechanisms contributing to the pathogenesis of ARAIDs remain enigmatic. Herein, we present the single-cell RNA sequencing (scRNA-seq) alterations during ischemia in the primate retina as a preliminary endeavor in understanding the molecular complexities of ARAIDs.

Methods

An ophthalmic artery occlusion model was established through ophthalmic artery ligation in two Macaca fascicularis. scRNA-seq and bioinformatics analyses were used to detect retinal changes during ischemia, which are further validated by immunofluorescence analysis. Western blot and flow cytometry assays were performed to measure the microglia polarization status.

Results

The findings of this study reveal notable changes in the retina under acute ischemic conditions. Particularly, retinal ischemia compromised mitochondrial functions of rod photoreceptors, partly leading to the rapid loss of healthy rods. Furthermore, we observed a noteworthy transcriptional alteration in the activation of microglia induced by ischemia. The targeted correction of the proinflammatory cytokine CXCL8 effectively suppresses microglia M1 polarization in retinal ischemia, ultimately reducing the proinflammatory transformation in vitro. In addition, retina ischemia induced the apoptotic inclination of endothelial cells and the heightened interaction with microglia, which signifies the influence of microglia in disrupting the retinal-blood barrier.

Conclusions

Our research has successfully identified and described the pathologic alterations occurring in several cell types during a short period of ischemia. These observations provide valuable insights for ameliorating retinal damage and promoting the restoration of vision.

Retinal arterial occlusion and patent foramen ovale: A case study-based review

PURPOSE

To identify all reported cases of retinal artery occlusion (RAO) associated with patent foramen ovale (PFO) in the literature and present a similar case of CRAO from our clinic.

METHODS

PubMed database was searched for studies reporting RAO in individuals with PFO. Relevant data were tabulated and reviewed. We estimated each case's Risk of Paradoxical Embolism (RoPE) score.

RESULTS

23 cases of CRAO (n=10; including ours), BRAO (n=10), and CILRAO (n=3) were reviewed. Most cases were under 50 years of age (78.3%). The reported predisposing factors were: hypertension (26.1%), migraine (17.3%), smoking (13.0%), recent immobilization (13.0%), strenuous exertion (8.7%), pregnancy (8.7%), and diabetes (4.3%). A high RoPE score (≥7; suggestive of paradoxical embolism via PFO) was estimated for 71.4% of patients. In most cases, the neurological and cardiovascular examinations, laboratory studies, and imaging were unremarkable, except for the PFO±atrial septal aneurysm (present in 21.7%). In only 28.6% of cases, transthoracic echocardiography (TTE) (± saline contrast) could visualize the PFO; transesophageal echocardiography (TEE) was necessary to detect the PFO in 71.4%. Approximately one-half of the patients underwent percutaneous closure of the PFO; no complications or subsequent acute ischemic events ensued. The visual prognosis was poorer for CRAO than for BRAO or CILRAO.

CONCLUSION

Timely diagnosis, acute management, and ensuring urgent initiation of stroke workup in cases with RAO or transient monocular vision loss are crucial. Clues to a possible paradoxical embolism as the cause include the absence of known cardiovascular risk factors, young age, migraine, recent immobility, vigorous exercise, and pregnancy.

Prevalence and risk factors of ischemic monocular vision loss and concurrent brain ischemia

INTRODUCTION

We performed a retrospective cohort study to identify predictors of concurrent asymptomatic brain ischemia in patients with ischemic monocular vision loss.

PATIENTS AND METHODS

An inpatient database research of admissions to the Helios University Hospital Wuppertal, Germany between 01/2016 and 12/2020 was conducted. Inclusion criteria were confirmed diagnosis of transient monocular vision loss (MVL), retinal artery occlusion (RAO), and magnetic resonance imaging (MRI) of the brain within 10 days of MVL. Silent brain ischemia (SBI) was defined as diffusion restrictions with corresponding reduced apparent diffusion coefficient in MRI and an absence of neurological deficits besides those complying with MVL in clinical examination. The prevalence and cardiovascular predictors of SBI were analyzed with logistic regression and an artificial neural network.

RESULTS

One hundred fourteen out of 475 patients treated with monocular vision loss were included in this study. The mean age was 67.7 ± 13.6 years. 48.2% were male and 47.4% had RAO. MRI scan of the brain was performed after 3.9 ± 2.3 days and detected SBI in 17%. Age ⩾67 years, cardiac etiology of MVL, and cerebral ischemia in medical history were revealed as predictors of SBI in MRI.

CONCLUSIONS

Patients older than 66 years, with a suspected cardiac embolism as the cause of RAO and previous cerebral ischemia, are more likely to present SBI in cerebral MRI. Therefore, MR imaging, particularly in these patients, can be useful.

Statin Treatment on Cardiovascular Risk After Retinal Artery Occlusion: A Historical Cohort Study

INTRODUCTION

Retinal artery occlusion (RAO) is a major cause of acute visual loss and patients with RAO have an increased risk for subsequent cardiovascular events. However, there is little evidence of whether the use of statins is associated with the prevention of cardiovascular events in patients with RAO. We investigated whether statin treatment in patients with RAO is associated with a lower risk of cardiovascular events.

METHODS

This study was a historical cohort study with nested case-control analysis. Using the nationwide health insurance claims database in Korea, we retrospectively established a cohort of newly diagnosed RAO patients without prior cardiovascular events between January 2008 and March 2020. We defined the case group as those who had cardiovascular events (stroke or myocardial infarction) and the control group as RAO patients without primary outcome matched by sex, age, comorbidities, and duration of follow-up (1:2 incidence density sampling). Conditional logistic regression was performed.

RESULTS

Among 13,843 patients newly diagnosed with RAO, 1030 patients had cardiovascular events (mean follow-up period of 6.4 ± 3.7 years). A total of 957 cases were matched to 1914 controls. Throughout the study period, the proportion of patients taking statin was less than half. Statin treatment after RAO was associated with a low risk of cardiovascular events (adjusted OR, 0.637; 95% CI 0.520-0.780; P < 0.001). A longer duration of statin exposure was associated with a lower cardiovascular risk.

CONCLUSIONS

In patients with newly diagnosed RAO, treatment with statins, particularly long-term use, was associated with a low risk of future cardiovascular events.

[Internistic clarification of retinal vascular occlusions]

Retinal vascular occlusions require close cooperation of different medical disciplines to ensure optimal care of the affected patients. The medical clarification between arterial and venous occlusions is comparable but in the case of retinal arterial occlusions it should be carried out immediately. The most important associated diagnoses are arterial hypertension, diabetes mellitus, dyslipidemia, and atrial fibrillation. In younger patients and in the absence of risk factors, a search for rarer causes should be carried out giant cell arteritis in particular should be excluded. In both types of occlusions a causative glaucoma must also be considered.

Paracentral acute middle maculopathy in systemic sclerosis and subsequent branch retinal artery occlusion

Purpose

We report a case of systemic sclerosis-associated paracentral acute middle maculopathy (PAMM) in a young woman who subsequently developed branch retinal artery occlusion.

Observations

A 22-year-old woman presented with a paracentral scotoma. Optical coherence tomography (OCT) revealed bilateral paracentral acute middle maculopathy. Upon systemic examination, she was diagnosed with systemic sclerosis (SSc). She subsequently developed branch retinal artery occlusion despite vasodilator medications. After the prescription of aspirin, she did not experience a new event for one year.

Conclusion and importance

This case illustrates that SSc may affect the retinal vascular system and vision and cause PAMM. The optimal prophylaxis for patients with recurrent retinal events should be investigated in future studies.

Retinal Findings and Cardiovascular Risk: Prognostic Conditions, Novel Biomarkers, and Emerging Image Analysis Techniques

Many retinal diseases and imaging findings have pathophysiologic underpinnings in the function of the cardiovascular system. Myriad retinal conditions, new imaging biomarkers, and novel image analysis techniques have been investigated for their association with future cardiovascular risk or utility in cardiovascular risk prognostication. An intensive literature search was performed to identify relevant articles indexed in PubMed, Scopus, and Google Scholar for a targeted narrative review. This review investigates the literature on specific retinal disease states, such as retinal arterial and venous occlusions and cotton wool spots, that portend significantly increased risk of future cardiovascular events, such as stroke or myocardial infarction, and the implications for personalized patient counseling. Furthermore, conditions diagnosed primarily through retinal bioimaging, such as paracentral acute middle maculopathy and the newly discovered entity known as a retinal ischemic perivascular lesion, may be associated with future incident cardiovascular morbidity and are also discussed. As ever-more-sophisticated imaging biomarkers and analysis techniques are developed, the review concludes with a focused analysis of optical coherence tomography and optical coherence tomography angiography biomarkers under investigation for potential value in prognostication and personalized therapy in cardiovascular disease.

Nationwide trends in emergency department utilisation for acute retinal ischaemia in the USA, 2011-2018

BACKGROUND

Guidelines recommend urgent evaluation for transient monocular vision loss (TMVL) and retinal artery occlusion (RAO), but emergency department (ED) utilisation for these conditions is unknown.

METHODS

We performed a retrospective longitudinal cross-sectional analysis of the Nationwide Emergency Department Sample (2011-2018), a database of all ED visits from a representative 20% sample of US hospital-based EDs. We identified patients aged 40 and older with a primary diagnosis of TMVL or RAO and calculated the weighted number of total visits and admission rate by year. We used joinpoint regression to analyse time trends and logistic regression to measure differences according to demographic characteristics and comorbidities.

RESULTS

There were an estimated 2451 ED visits for TMVL and 2472 for RAO annually in the USA from 2011 to 2018. Approximately 36% of TMVL and 51% of RAO patients were admitted. The admission rate decreased by an average of 4.9% per year for TMVL (95% CI -7.5% to -2.3%) and 2.2% per year for RAO (95% CI -4.1% to -0.4%), but the total number of ED visits did not change significantly over time. Elixhauser Comorbidity Index and hyperlipidaemia were associated with increased odds of hospital admission for both TMVL and RAO. There were also differences in admission rate by insurance payer and hospital region.

CONCLUSION

Of the estimated 48 000 patients with TMVL or RAO annually in the USA, few are evaluated in the ED, and admission rates are less than for transient ischaemic attack or ischaemic stroke and are decreasing over time.

Analysis of the Association between Retinal Artery Occlusion and Acute Ischaemic Stroke/ST-Elevation Myocardial Infarction and Risk Factors in Hungarian Patients

Background and Objectives: We aimed to analyse data on retinal artery occlusion (RAO) patients to explore correlations with acute ischaemic stroke (AIS), ST-elevation myocardial infarction (STEMI), and cardio/cerebrovascular comorbidities. Patients and Methods: Our retrospective cohort study included 169 RAO and 169 age- and gender-matched control patients. We examined the association of AIS, STEMI, and related comorbidities such as hypertension (HT), type 1 and type 2 diabetes (T1DM and T2DM, respectively), hyperlipidaemia, and ischaemic heart disease (IHD) with RAO. We also recorded atrial fibrillation in our RAO patients. Results: Our results demonstrated that RAO patients developed both AIS and STEMI at a significantly higher rate compared to controls (p < 0.001 for both). We also found that RAO patients had a significantly higher prevalence of HT and hyperlipidaemia (p1 = 0.005, p2 < 0.001) compared to controls. Multiple risk factors together significantly increased the odds of developing AIS and STEMI. Conclusions: Our results suggest that through identifying and treating the risk factors for RAO patients, we can reduce the risk of AIS, STEMI, and RAO of the fellow eye. Considering that ophthalmologists are often the first detectors of these cardiovascularly burdened patients, collaboration with colleagues from internal medicine, cardiology, and neurology is essential to achieve secondary prevention.

Retinal Vascular Occlusion and Underlying Generalized Vascular Diseases

Retinal vascular occlusion not only threatens vision loss but is also associated with other systemic risk factors and vascular diseases. Interdisciplinary cooperation is of great importance in these patients. The risk factors hardly differ between arterial and venous retinal occlusions, which is due to the special anatomy of retinal vessels. Major underlying conditions associated with retinal vascular occlusion include arterial hypertension, diabetes mellitus, dyslipidemia, cardiac disease, particularly atrial fibrillation, or vasculitis of large- and middle-sized arteries. Every new diagnosed retinal vascular occlusion should therefore be taken as an occasion to search for risk factors and possibly adjust an already existing therapy in order to prevent further vascular events.

DeepDrRVO: A GAN-auxiliary two-step masked transformer framework benefits early recognition and differential diagnosis of retinal vascular occlusion from color fundus photographs

Retinal vascular occlusion (RVO) are common causes of visual impairment. Accurate recognition and differential diagnosis of RVO are unmet medical needs for determining appropriate treatments and health care to properly manage the ocular condition and minimize the damaging effects. To leverage deep learning as a potential solution to detect RVO reliably, we developed a deep learning model on color fundus photographs (CFPs) using a two-step masked SwinTransformer with a Few-Sample Generator (FSG)-auxiliary training framework (called DeepDrRVO) for early and differential RVO diagnosis. The DeepDrRVO was trained on the training set from the in-house cohort and achieved consistently high performance in early recognition and differential diagnosis of RVO in the validation set from the in-house cohort with an accuracy of 86.3%, and other three independent multi-center cohorts with the accuracy of 92.6%, 90.8%, and 100%. Further comparative analysis showed that the proposed DeepDrRVO outperforms conventional state-of-the-art classification models, such as ResNet18, ResNet50d, MobileNetv3, and EfficientNetb1. These results highlight the potential benefits of the deep learning model in automatic early RVO detection and differential diagnosis for improving clinical outcomes and providing insights into diagnosing other ocular diseases with a few-shot learning challenge. The DeepDrRVO is publicly available on https://github.com/ZhouSunLab-Workshops/DeepDrRVO.

Quantitative Wide-Field Swept-Source Optical Coherence Tomography Angiography and Visual Outcomes in RAO

Purpose

Retinal artery occlusion (RAO) is an ophthalmic emergency that can lead to poor visual outcomes and is associated with an increased risk of stroke and cardiovascular events. Wide-field swept-source OCT-A (WF SS-OCTA) can provide quick and non-invasive angiographic information with a wide field of view. Here, we looked for associations between OCT-A vascular imaging metrics and vision in RAO patients.

Methods

Patients with diagnoses of central (CRAO) or branched retinal artery occlusion (BRAO) were included. 6mm × 6mm Angio and 15mm × 15mm AngioPlex Montage OCT-A images were obtained for both eyes in each patient using Zeiss Plex Elite 9000 WF SS-OCTA device. Each 6mm × 6mm image was divided into nine Early Treatment Diabetic Retinopathy Study (ETDRS) subfields. Non-perfusion area (NPA) was manually measured using 15mm × 15mm images. A linear regression model was utilized to identify correlation between imaging metrics and vision. P-values less than 0.05 were considered as statistically significant.

Results

Twenty-five subjects were included. For RAO eyes, there was a statistically significant inverse correlation between retinal thickness as well as superficial capillary plexus (SCP) vessel density (VD) and vision. An inverse correlation was found between deep capillary plexus (DCP) VD and vision without statistical significance. There was a positive correlation between choroidal thickness as well as choroidal volume and vision without statistical significance. No significant correlation was found between the metrics and vision in contralateral eyes. For NPA and vision, no significant correlation was identified.

Conclusion

This is the first study to investigate the utility of WF SS-OCTA in RAO and to demonstrate correlations between retinal vascular imaging metrics and visual outcomes. The results of this study provide a basis to understand the structural changes involved in vision in RAO and may guide management of RAO and prevention of cerebral stroke and cardiovascular accidents.

Altered Spontaneous Brain Activity and Its Predictive Role in Patients with Central Retinal Artery Occlusion Using fMRI and Machine Learning

Objective

To investigate spontaneous neuronal activity changes in patients with central retinal artery occlusion (CRAO) using the resting-state functional magnetic resonance imaging (fMRI) and detect whether these brain functional alterations can represent an objective biomarker of clinical response using a machine learning algorithm.

Methods

Eighteen patients with CRAO and eighteen healthy controls (HCs) were recruited. The regional homogeneity (ReHo) method of resting-state fMRI was conducted to evaluate the synchronous brain activity alterations between two groups. Differences of ReHo values between two groups were compared using the independent two-sample t-test. The support vector machine algorithm was to distinguish patients of CRAO from HCs based on the two groups' whole-brain ReHo patterns. The accuracy, sensitivity, and specificity for the classification were calculated. The classification performance was evaluated using the non-parametric permutation test.

Results

Compared to HCs, individuals with CRAO showed significantly lower ReHo in the right cerebellum and precuneus. Meanwhile, significant higher ReHo values were observed in the left superior temporal gyrus, postcentral gyrus, and precentral gyrus in the CRAO group compared to HCs. Furthermore, our results suggested that 77.78% individuals with CRAO could be successfully distinguished from HCs by the machine learning, with a sensitivity of 72.22% and a specificity of 83.33%, respectively. The area of receiver operating characteristic curve was calculated to be 0.85.

Conclusion

This study uncovered individuals with CRAO exhibited disturbed synchronous neuronal activities in multiple brain areas using neuroimaging techniques. The ReHo variability could distinguish individuals with CRAO from HCs with high accuracy.

High prevalence of thrombophilic risk factors in patients with central retinal artery occlusion

INTRODUCTION

Central retinal artery occlusion (CRAO) is a common cause of blindness and visual morbidity. In the majority of cases, it is related to thrombotic embolism. Nevertheless, the role of inherited or acquired thrombophilic risk factors in CRAO pathogenesis has not been comprehensively studied.

METHODS

In 126 CRAO patients (66 [52.4%] men, median age 55 [range: 18-80] years) and 107 matched controls (56 [52.3%] men, median age 53 [range: 34-78] years) we evaluated classical atherosclerotic risk factors, including serum lipid profile and glucose level, analyzed intima-media complex thickness (IMT) of external carotid arteries, and performed transthoracic echocardiography. Furthermore, we established the prevalence of inherited and acquired thrombophilic risk factors, such as factor V Leiden (FVL) and prothrombin 20210 G/A genetic variants, plasma activity of factor (F) VIII, protein C and antithrombin activity, and free protein S levels. We also assessed the presence of antiphospholipid antibodies (APLA) and evaluated blood homocysteine in all enrolled subjects. Additionally, we estimated the occurrence of Val34Leu polymorphism of the A subunit of coagulation factor XIII (FXIII-A) in both groups as a potential thrombosis-protecting factor.

RESULTS

Among traditional atherosclerotic risk components, obesity/overweight and hypercholesterolemia were the most common in the CRAO group and occurred in 103 (81.7%) and 85 (67.5%) patients, respectively. CRAO patients also had elevated IMT and altered echocardiographic parameters, indicating diastolic cardiac dysfunction. In thrombophilia investigations, at least one laboratory risk factor occurred in 72.2% (n = 91) of CRAO patients, with APLA as the most frequent, detected in 38.1% (n = 48) of them (almost seven times more frequent than in controls, p < 0.001). Deficiencies in protein C activity and free protein S levels were also common in the CRAO group, reported in 17.5% (n = 22) and 19.8% (n = 25) of patients, respectively. Interestingly, among two analyzed prothrombotic genetic variants, only the FVL was related to CRAO, with the allelic frequency 2.4 times more prevalent than in controls (p = 0.044). Finally, the CRAO group was characterized by hyperhomocysteinemia, almost twice as common as in controls (p = 0.026). Antithrombin deficiency, elevated FVIII, and FXIII-A Val34Leu polymorphism were not associated with CRAO.

CONCLUSIONS

Our findings suggest that thrombophilia plays a vital role in the pathogenesis of CRAO. Thus, proper laboratory screening should be considered in the primary and secondary prevention of those episodes, with implementing appropriate therapy as needed.

Successful Mechanical Thrombectomy for Isolated Internal Carotid Artery Occlusion in a Patient with Monocular Blindness: A Case Report

We report a rare case of isolated internal carotid artery occlusion complicated by central retinal artery occlusion that was successfully treated with mechanical thrombectomy for internal carotid artery occlusion. A 59-year-old man visited the emergency room because of right monocular blindness. Magnetic resonance imaging showed multiple acute small embolic infarctions in the right frontal lobe, and magnetic resonance angiography revealed right internal carotid artery occlusion without the associated occlusion of the circle of Willis, which indicates the patency of the anterior and middle cerebral arteries. An electrocardiogram showed atrial fibrillation. Therefore, we performed mechanical thrombectomy with a stent retriever under continuous manual aspiration with a balloon-guiding catheter and confirmed complete recanalization, anterograde flow in the right ophthalmic artery, and retinal brush. The procedure was completed without complications, and the patient noticed an improvement in visual acuity immediately after the procedure. When a patient with atrial fibrillation complains of monocular blindness, it is important to consider internal carotid artery occlusion due to cardioembolism, to perform an examination promptly, and to consider early treatment, including mechanical thrombectomy.

Methods to measure blood flow and vascular reactivity in the retina

Disturbances of retinal perfusion are involved in the onset and maintenance of several ocular diseases, including diabetic retinopathy, glaucoma, and retinal vascular occlusion. Hence, knowledge on ocular vascular anatomy and function is highly relevant for basic research studies and for clinical judgment and treatment. The retinal vasculature is composed of the superficial, intermediate, and deep vascular layer. Detection of changes in blood flow and vascular diameter especially in smaller vessels is essential to understand and to analyze vascular diseases. Several methods to evaluate blood flow regulation in the retina have been described so far, but no gold standard has been established. For highly reliable assessment of retinal blood flow, exact determination of vessel diameter is necessary. Several measurement methods have already been reported in humans. But for further analysis of retinal vascular diseases, studies in laboratory animals, including genetically modified mice, are important. As for mice, the small vessel size is challenging requiring devices with high optic resolution. In this review, we recapitulate different methods for retinal blood flow and vessel diameter measurement. Moreover, studies in humans and in experimental animals are described.

Trends in Utilization of Vitreoretinal Services Following the Initial Phase of the 2020 COVID-19 Pandemic

BACKGROUND

To identify vitreoretinal practice patterns in the months following the initial 2020 national shutdown due to the COVID-19 pandemic in the United States (US).

STUDY DESIGN

Retrospective analysis of vitreoretinal practice patterns from multiple retinal centers across the US from January 1, 2018 to December 31, 2020.

RESULTS

The lowest utilization of retina care occurred during the week of March 23, 2020, after which utilization returned to pre-pandemic levels by July 2020. Patients with retinal detachments (RDs) presented with worse visual acuity during March, April, and May 2020 compared to the same time periods of 2018 and 2019 (P values < 0.05). However, only comparing eyes that presented in March 2018 to March 2020, was the year 1 vision significantly worse (P = 0.008).

CONCLUSION

The COVID-19 pandemic significantly impacted vitreoretinal care. The vision of patients with RDs may not have been affected by the delayed presentation. [Ophthalmic Surg Lasers Imaging Retina 2023;54:15-23.].

Recent Practice Patterns in Acute Retinal Artery Occlusions in the United States

PURPOSE

To determine how to practice patterns for work-up of incident retinal artery occlusion (RAO) compare to the American Academy of Ophthalmology (AAO) guidelines.

METHODS

In this cohort study, patients receiving a new diagnosis of RAO, either central (CRAO) or branch (BRAO), were identified between 2002 and 2020 from a large US medical claims database. Claims were reviewed for diagnostic tests specified by the AAO as essential components of an RAO work-up including carotid ultrasound, echocardiogram, magnetic resonance imaging (MRI) and emergency department (ED) referral. Outcomes included rates of and time to completion of work-up.

RESULTS

18697 new outpatient diagnoses of RAO (11348 BRAO, 7349 CRAO) were analyzed. 15.9% and 30.4% of patients received carotid ultrasounds within 7 and 30 days, respectively. 9.4% and 21.1% of patients received echocardiograms within 7 and 30 days, respectively. 4.9% and 8.1% of patients received a brain MRIs within 7 and 30 days, respectively. Only 4.1% of patients were referred to the ED within a day of diagnosis. Ophthalmologists diagnosed the majority (78.7%) of RAOs compared to neurologists (0.6%). Patients diagnosed by ophthalmologists were significantly more likely to have carotid ultrasound within 7 days, but those diagnosed by neurologists were more likely to have echocardiogram, MRI, and ED referral (p < .01 for all comparisons). The rates of adherence to the AAO care guidelines increased significantly between 2002 and 2020 (p < .01).

CONCLUSIONS

The referral and work-up practices demonstrated in this new RAO diagnosis patient cohort have improved with time but are still far below the standard recommended by the AAO.

Evaluation of Risk Scores as Predictive Tools for Stroke in Patients with Retinal Artery Occlusion: A Danish Nationwide Cohort Study

Purpose  We investigated the 1-year risk of stroke in patients with retinal artery occlusion and evaluated the predictive and discriminating abilities of contemporary risk stratification models for embolic stroke. Methods  This register-based cohort study included 7,906 patients with retinal artery occlusion from Danish nationwide patient registries between 1995 and 2018. The study population was stratified according to the number of points obtained in the stroke risk scores: the CHA ₂ DS ₂ -VASc score and the ESSEN Stroke Risk score. The 1-year risk of stroke within strata was evaluated and compared using the cox proportional hazards model. Furthermore, the discrimination of the risk scores as predictive tools for stroke risk assessment was investigated using C-statistics, Brier score, and the index of prediction accuracy. Results  The stroke event rate in patients with retinal artery occlusion increased as the score increased for both risk scores, ranging from 3.62 (95% confidence interval [CI]: 2.46-5.31) per 100 person-years to 13.25 (95% CI: 11.78--14.89) per 100-person-years for increasing levels of the CHA ₂ DS ₂ -VASc score and from 3.97 (95% CI: 2.97-5.32) per 100 person-years to 16.43 (95% CI: 14.01-19.27) per 100 person-years for increasing levels of the ESSEN Stroke Risk score. Using a risk score of 0 as a reference, the difference was statistically significant for retinal artery occlusion patients with a CHA ₂ DS ₂ -VASc score of 2 or above and for all levels of the ESSEN Stroke Risk score. The C-statistics for the risk scores was 61% (95% CI: 58%-63%) and 62% (95% CI: 59-64%) for the CHA ₂ DS ₂ -VASc score and ESSEN Stroke Risk score, respectively. Conclusion  The results suggested that the use of the CHA ₂ DS ₂ -VASc score and the ESSEN Stroke Risk score was applicable for risk stratification of stroke in patients with retinal artery occlusion, but discrimination was poor due to low specificity.

Acute retinal ischaemia associated with paracentral acute middle maculopathy detected on multimodal imaging: a premonitory sign of severe carotid occlusive disease

A man in his 60s presented with a subacute paracentral scotoma and preserved visual acuity in the left eye. He was found to have a very subtle area of deep retinal whitening at the macula and multiple retinal cholesterol emboli. Optical coherence tomography (OCT) with En face imaging revealed globular paracentral acute middle maculopathy (PAMM). A diagnosis of PAMM associated with branch artery occlusion was made and the patient was immediately transferred to the nearest stroke centre. Investigations revealed severe carotid occlusive disease for which the patient underwent carotid endarterectomy. Paracentral scotomas in patients with little clinical findings on fundus examination should raise the suspicion for PAMM, which is easily identifiable on OCT. Eye care professionals must recognise PAMM as a possible sign of acute retinal arterial ischaemia-an ocular and systemic emergency that requires immediate referral to specialised stroke centres.

Risk Factors and Treatment Strategy for Retinal Vascular Occlusive Diseases

Retinal occlusive diseases are common diseases that can lead to visual impairment. Retinal artery occlusion and retinal vein occlusion are included in the clinical entity, but they have quite different pathophysiologies. Retinal artery occlusion is an emergent eye disorder. Retinal artery occlusion is mainly caused by thromboembolism, which frequently occurs in conjunction with life-threatening stroke and cardiovascular diseases. Therefore, prompt examinations and interventions for systemic vascular diseases are often necessary for these patients. Retinal vein occlusion is characterized by retinal hemorrhage and ischemia, which may impair visual function via several complications such as macular edema, macular ischemia, vitreous hemorrhage, and neovascular glaucoma. Even though anti-vascular endothelial growth factor therapy is the current established first-line of treatment for retinal vein occlusion, several clinical studies have been performed to identify better treatment protocols and new therapeutic options. In this review, we summarize the current findings and advances in knowledge regarding retinal occlusive diseases, particularly focusing on recent studies, in order to provide an update for a better understanding of its pathogenesis.

Similarities and differences in systemic risk factors for retinal artery occlusion and retinal vein occlusion: A nationwide case-control study

BACKGROUND

To investigate the relationship between risk factors for retinal artery occlusion (RAO) and retinal vein occlusion (RVO) and thereby identify similarities and differences between the two types of retinal vascular occlusions.

METHODS

In this case-control study, 5708 patients with RAO were included and matched with three patients with RVO each. The patients with RVO were matched on sex and age at index date. All patients, personal information, diagnoses, and prescriptions were obtained from the Danish nationwide registries. Adjusted conditional logistic regression was used to investigate the association of RAO and RVO with the included risk factors.

RESULTS

RAO was stronger associated with arterial hypertension, heart failure, ischemic heart disease, peripheral artery disease, and stroke than RVO, with effect measures ranging from 1.10 to 2.21. RVO was associated with cataract and glaucoma with effect measures of 0.80 (95% CI 0.73-0.87) and 0.65 (95% CI 0.56-0.76), respectively.

CONCLUSION

Differences in the level of associations with the included risk factors suggests differences in the pathophysiologies of the two diseases. The main pathophysiology associated with RAO was atherosclerosis, whereas the main pathophysiology associated with RVO was changes in the pressure gradients of the eyes.

Silencing of circular RNA‑ZYG11B exerts a neuroprotective effect against retinal neurodegeneration

Ischemic retinal diseases are the major cause of vision impairment worldwide. Currently, there are no available treatments for ischemia‑induced retinal neurodegeneration. Circular RNAs (circRNAs) have emerged as important regulators of several biological processes and human diseases. The present study investigated the role of circRNA‑ZYG11B (circZYG11B; hsa_circ_0003739) in retinal neurodegeneration. Reverse transcription quantitative polymerase chain reaction (RT‑qPCR) demonstrated that circZYG11B expression was markedly increased during retinal neurodegeneration in vivo and in vitro. Cell Counting Kit‑8, TUNEL and caspase‑3 activity assays revealed that silencing of circZYG11B was able to protect against oxidative stress‑ or hypoxic stress‑induced retinal ganglion cell (RGC) injury. Furthermore, immunofluorescence staining and hematoxylin and eosin staining revealed that silencing of circZYG11B alleviated ischemia/reperfusion‑induced retinal neurodegeneration, as indicated by reduced RGC injury and decreased retinal reactive gliosis. In addition, luciferase reporter, biotin‑coupled miRNA capture and RNA immunoprecipitation assays revealed that circZYG11B could regulate RGC function through circZYG11B/microRNA‑620/PTEN signaling. Clinically, RT‑qPCR assays demonstrated that circZYG11B expression was markedly increased in the aqueous humor of patients with glaucoma. In conclusion, circZYG11B may be considered a promising target for the diagnosis and treatment of retinal ischemic diseases.

Retinal Artery Occlusion and Its Impact on the Incidence of Stroke, Myocardial Infarction, and All-Cause Mortality during 12-Year Follow-Up

The aim of the study was to evaluate the incidence of ischemic stroke, myocardial infarction, and all-cause mortality in patients with retinal artery occlusion (RAO). This single-center retrospective study included 139 patients diagnosed with RAO between 2009 and 2020. The control group included 139 age- and sex-matched patients without RAO who underwent cataract surgery. The year of the surgery corresponded to the year of RAO onset. During the 12-year follow-up, patients with RAO had a shorter time to death (49.95 vs. 15.74 months; p = 0.043), a higher all-cause mortality rate (log-rank p = 0.026, and a higher rate of the composite endpoint, including ischemic stroke, myocardial infarction, and all-cause mortality (log-rank p = 0.024), as compared with controls. Patients with RAO younger than 75 years showed a higher risk of cerebral ischemic stroke (log-rank p = 0.008), all-cause mortality (log-rank p = 0.023), and the composite endpoint (log-rank p = 0.001) than controls. However, these associations were not demonstrated for patients aged 75 years or older. Our study confirms that patients with RAO have a higher risk of all-cause mortality than those without RAO. Moreover, patients with RAO who are younger than 75 years are significantly more likely to experience ischemic stroke, death, or the composite endpoint after an occlusion event, as compared with individuals without RAO.