Acute retinal arterial occlusive disorders

Update on central retinal artery occlusion

The medical condition referred to as "central retinal artery occlusion" (CRAO) was first documented by Albrecht von Graefe in 1859. Subsequently, CRAO has consistently been identified as a serious medical condition that leads to substantial visual impairment. Furthermore, it is correlated with vascular complications that have the potential to affect crucial organs such as the brain and heart. A considerable amount of research has been extensively published on the various aspects of this topic, which is marked by notable debates and misconceptions, especially regarding its management and outcomes. The primary aim of this review article is to analyze the latest developments in the understanding of CRAO, which includes its causes, techniques for retinal imaging, systemic evaluation, and therapeutic strategies, such as vitrectomy. This review article offers readers a comprehensive learning experience to gain knowledge on the fundamental principles and recent advancements in CRAO.

Congenital heart disease: types, pathophysiology, diagnosis, and treatment options

Congenital heart disease (CHD) is a structural abnormality of the heart and/or great vessels and patients with CHD are at an increased risks of various morbidities throughout their lives and reduced long-term survival. Eventually, CHD may result in various complications including heart failure, arrhythmias, stroke, pneumonia, and sudden death. Unfortunately, the exact etiology and pathophysiology of some CHD remain unclear. Although the quality of life and prognosis of patients with CHD have significantly improved following technological advancement, the influence of CHD is lifelong, especially in patients with complicated CHD. Thus, the management of CHD remains a challenge due to its high prevalence. Finally, there are some disagreements on CHD among international guidelines. In this review, we provide an update of the pathophysiology, diagnosis, and treatment in most common type of CHD, including patent foramen ovale, atrial septal defect, ventricular septal defect, atrioventricular septal defect, patent ductus arteriosus, coarctation of the aorta, transposition of the great arteries, congenitally corrected transposition of the great arteries, coronary anomalies, left and right ventricular outflow tract obstruction, tetralogy of Fallot and Ebstein anomaly. In particular, we focus on what is known and what is unknown in these areas, aiming to improve the current understanding of various types of CHD.

Retinal artery/arteriole occlusion risks after endovascular treatment for unruptured intracranial aneurysm

BACKGROUND

To evaluate the association between retinal artery/arteriole occlusion (RAO) and unruptured intracranial aneurysm (UIA).

METHODS

Incident UIA patients from a nationwide cohort (n=253 240) were categorised into three groups based on subsequent treatment: observation (n=208 993), microsurgical clipping (n=14 168) and endovascular treatment (EVT) groups (n=30 079). The incidence and the incident time of RAO were analysed. HRs of RAO and associated risk factors were evaluated. Additionally, a hospital cohort comprising 2569 consecutive UIA patients treated at a tertiary hospital was analysed with detailed clinical information of UIAs.

RESULTS

In the nationwide cohort analysis, the incidence of RAO was significantly higher in EVT group than in observation and clipping groups, especially within 60 days (early RAO (within 60 days): HR=4.00, 95% CI: 2.44 to 6.56); delayed RAO (after 60 days): HR=1.74, 95% CI: 1.13 to 2.68). Multivariable analysis showed that the presence of chronic kidney disease (p=0.009) and use of a balloon microcatheter during the procedure (p=0.013) were associated with a higher risk of RAO. In hospital cohort analysis, 11 (0.8%) cases of RAO occurred after EVT, whereas none occurred after microsurgical clipping (p<0.001). Patients with RAO were younger and received balloon microcatheters more frequently than their counterparts. Ten cases of RAO (90.9%) occurred in paraclinoid aneurysms, where EVT was preferred over microsurgical clipping.

CONCLUSIONS

Performing EVT for UIA may increase the risk of subsequent RAO. Care should be taken when treating paraclinoid aneurysms with balloon microcatheters.

Efficacy and safety of hyperbaric oxygen therapy monitored by fluorescein angiography in patients with retinal artery occlusion

AIMS

To assess the efficacy and safety of a standardised hyperbaric oxygen therapy protocol (HBOT) monitored by fluorescein angiography (FA) in patients with retinal artery occlusion (RAO).

METHODS

It is a prospective, non-comparative, monocentric study conducted between July 2016 and March 2022. All consecutive patients diagnosed with RAO within 7 days underwent visual acuity measurement, FA, macular optical coherence tomography (OCT) and OCT-angiography. They received two daily HBOT sessions (2.5 atmosphere absolute, 90 min) until revascularisation assessed by FA. Complete ophthalmic follow-up was scheduled at day 14, day 21 and at 1 month. The main outcome measure was a best-corrected visual acuity (BCVA) improvement defined as a decrease ≥0.3 logMAR at 1 month.

RESULTS

Thirty-one patients were included and received a mean number of 33.9 (13-56) HBOT sessions. Retinal revascularisation was observed in 48.4% and 87.1% of patients at days 14 and 21, respectively. The mean BCVA on referral and at 1 month was 1.51 logMAR and 1.10 logMAR, respectively. Fifteen (48.4%) patients achieved the main outcome measure. Six (19.4%) patients experienced minor barotrauma that did not require HBOT discontinuation. The univariate analysis showed that antiplatelet-treated patients (p=0.044) and patients with a poor initial BCVA (p=0.008) were more likely to achieve a BCVA improvement. OCT-angiography was not sensitive enough to diagnose RAO or assess revascularisation.

CONCLUSION

In RAO patients monitored by FA until spontaneous revascularisation of the central retinal artery, HBOT was effective and safe.

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.

Clinical Implications of Alternating Hypointense Bands on OCT Angiography in Retinal Vascular Occlusive Disease

PURPOSE

To demonstrate the relationship between alternating hypointense signal bands on OCT angiography (OCTA), real-time fluorescein angiography (FA), and structural OCT findings in patients with retinal vascular occlusive disease (RVOD).

DESIGN

Retrospective, consecutive case series.

SUBJECTS

Consecutive patients with a clinical diagnosis of acute RVOD and alternating bands of hypointense OCTA flow signal on en face projections.

METHODS

Complete ophthalmic examination and multimodal imaging, including color fundus photography, real-time FA, spectral-domain OCT, and OCTA performed with different instruments having different scan speeds and acquisition protocols.

MAIN OUTCOME MEASURES

The primary outcomes were: hypointense OCTA band characteristics (number, width, orientation, and location), OCTA acquisition characteristics (speed and scan direction), and FA findings including delayed arteriovenous (AV) transit and pulsatile flow. Secondary outcomes were: structural OCT changes including retinal fluid, paracentral acute middle maculopathy (PAMM) lesion, and a prominent middle limiting membrane (p-MLM) sign.

RESULTS

OCT angiography hypointense bands were detected in the superficial and deep vascular plexuses in 9 eyes of 9 patients with either partial central retinal vein occlusion (RVO) or nonischemic RVO. When obtained on the same device, hypointense bands were thinner and more numerous at lower (100 kHz) scan speeds compared with higher (200 kHz) scan speeds. Band orientation was parallel to the OCTA scan direction, and their extent correlated with the area of delayed AV transit on FA. Structural OCT showed multiple PAMM lesions in 78% of cases and a p-MLM sign centered in the fovea in 44% of cases.

CONCLUSIONS

OCT hypointense bands are a novel biomarker in RVOD indicating delayed AV transit and pulsatile filling without the need for dye angiography. Structural OCT often shows PAMM in these eyes and, less commonly, a p-MLM sign.

FINANCIAL DISCLOSURE(S)

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

SUDDEN MONOCULAR VISION LOSS AFTER SNEEZING AS CAPTURED ON WIDEFIELD SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY-ANGIOGRAPHY

PURPOSE

We report an unusual case of likely combined retinal artery occlusion and retinal vein occlusion after a sneeze. Widefield swept-source optical coherence tomography-angiography was used to analyze retinal changes at one-month follow-up.

METHODS

The patient reported visual symptoms in his left eye immediately after sneezing five times in a row. Fundus examination showed an embolus along the superior arcade. Stroke workup revealed moderate carotid artery stenosis and a subtherapeutic INR. At one-month follow-up, fundus photography and swept-source optical coherence tomography-angiography were obtained.

RESULTS

Fundus photography showed superior retinal whitening and arteriole attenuation, an inferior perifoveal cotton wool spot, and inferotemporal intraretinal hemorrhages. Swept-source optical coherence tomography-angiography showed loss of the deep capillary plexus superiorly and inferotemporally, most consistent with combined retinal artery and retinal vein occlusion.

CONCLUSION

We report the first case of sneeze-induced combined retinal artery and retinal vein occlusion. The retina is a uniquely accessible window that provides insight into human physiology, and swept-source optical coherence tomography-angiography is a powerful tool that can give further insight into the pathophysiology of an occlusion.

Retinal Artery Reperfusion After Translumenal YAG Laser Embolysis in a Case of Branch Retinal Artery Occlusion

Purpose: To present a potential treatment for embolic branch retinal artery occlusion (BRAO). Methods: A case and its findings were analyzed. Results: A 75-year-old man with a 5-day history of an acute superior visual field defect in the right eye was found to have a BRAO secondary to a Hollenhorst plaque and was treated with translumenal YAG laser embolysis. Reperfusion of the retinal artery was observed on dislodging the Hollenhorst plaque, and improvements were seen in the patient's superior visual field defect. Conclusions: Translumenal YAG laser embolysis could potentially reverse ischemia secondary to embolic RAOs. This case report and the current literature cited suggest a rationale for treatment and supports further study of this technique.

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.

A Review of Current Literature on Central Retinal Artery Occlusion: Its Pathogenesis, Clinical Management, and Treatment

The ocular analogue of a cerebral stroke is central retinal artery occlusion (CRAO), a medical emergency concerning the eyes. Most patients experience substantial acute vision loss with a visual acuity of 20/400 or worse, resulting in decreased quality of life (QoL) and decreased functional ability. An impending cerebral stroke and ischemic heart disease are also more likely. The four distinct clinical entities that make up CRAO are non-arteritic CRAO, transitory non-arteritic CRAO, non-arteritic CRAO with cilioretinal artery sparing, and arteritic CRAO. Depending on the CRAO type, clinical traits, visual results, and treatment all vary greatly. Contrary to current belief, there is a spontaneous improvement in the optical field and vision, mainly in the first week. The likelihood of instinctive development in optical acuity in the first seven days varies greatly. The pathogenesis, epidemiology, and medical features of CRAO will be described in this review, along with present and potential management future options.

Abnormal retinal vessel filling in central retinal artery occlusion

CLINICAL RELEVANCE

Central retinal artery occlusion (CRAO) is an ophthalmic emergency with a poor prognosis. Several initial CRAO presentation factors can influence the final visual outcome. Fluorescein angiography filling of retinal vessels in CRAO has not been studied in great detail.

BACKGROUND

The aim of this paper is to study the aberrant filling of the retinal vessels on fluorescein angiography in patients with CRAO and understand its clinical relevance.

METHODS

Cases of CRAO diagnosed between June 2017 and May 2022 and who had undergone a fundus fluorescein angiography were included. Comparisons were made between the cases with and without aberrant filling of the retinal vessel.

RESULTS

Twenty-two eyes of 22 patients (14 males and 8 females) with CRAO underwent fluorescein angiography. Ages of the patients ranged from 18 to 73 years, while time interval between development of acute onset vision problems and presentation to the retinal clinic ranged from a minimum of 1 day to a maximum of 30 days. Snellen visual acuity at presentation ranged from perception of light (PL +) to 6/6. On fluorescein angiography, aberrant flow of the fluorescein dye into the retinal vein was observed in four of the 22 (18%) eyes with CRAO. All these cases showed a patient's temporal cilioretinal artery. The cases with aberrant filling of the retinal vessels showed a better presenting visual acuity (6/6-6/60), lesser severity of inner retinal damage and a better final visual acuity (6/6-6/60) compared to CRAO cases without aberrant filling.

CONCLUSION

Aberrant filling of the retinal vein can be seen on fluorescein angiography in eyes with CRAO and a patent temporal cilioretinal artery. Such eyes with aberrant retinal vessel filling have a better visual prognosis.

Infrared images help to identify retinal emboli in hemodynamic retinal artery occlusion

To report a case of stroke with internal carotid artery (ICA) occlusion and retinal artery occlusion (RAO) with multiple emboli identified by infrared images. The patient presented with acute blurred vision and slurred speech since woke up in the morning. Carotid Doppler ultrasonography showed severe left ICA stenosis with the decreased flow. Computed tomography angiography demonstrated left ICA critical stenosis with compensatory flows from the right ICA. There was coexistent RAO with multiple emboli, silver-wiring, and segmentation of the retinal artery. More hyperreflective emboli were uncovered by infrared images of spectral-domain optical coherence tomography. Embolism may accompany with the compensatory flow for ICA occlusion. RAO patients should have thorough carotid evaluations, especially those with multiple retinal emboli.

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.

Central retinal artery occlusion following pediatric blunt ocular trauma

BACKGROUND

To analyze the clinical profile, presentation, possible pathophysiology, and outcomes of central retinal artery occlusion (CRAO) following blunt trauma in pediatric subjects.

METHODOLOGY

The medical charts of subjects aged 18 years or less with a diagnosis of CRAO following blunt ocular trauma were analyzed retrospectively for demography, details of the trauma, ocular findings, additional imaging reports if any, and final outcome. A Medline search was done (key words like central retinal artery occlusion, blunt trauma, children, pediatric subjects, and adolescents) to gather information available in the literature on the subject.

RESULTS

A total of 11 patients (11 eyes), mean age of 14.3 ± 3.4 years, and 100% male preponderance, with an average time duration from trauma to presentation to the hospital of 8.1 days were included. Visual acuity ranged from no light perception (four eyes) to finger count at a 1 m distance. Intraocular pressure was raised in three patients, of which two were suffering from sickle cell disease. In two eyes, the CRAO coexisted with optic nerve avulsion and the cilioretinal artery was spared. Disk pallor was seen in six eyes as early as 12 days from the trauma. None of the cases revealed any bony fracture in the CT scan.

CONCLUSION

CRAO was observed to be an important primary or contributory cause of visual loss in children following blunt trauma, reflex vasospasm being the most common etiology. Early onset disk pallor could suggest an underlying vascular compromise of both retinal and optic disk circulation in addition to direct disk damage.

Microbiome and Retinal Vascular Diseases

The gut microbiome consists of more than a thousand different microbes and their associated genes and microbial metabolites. It influences various host metabolic pathways and is therefore important for homeostasis. In recent years, its influence on health and disease has been extensively researched. Dysbiosis, or imbalance in the gut microbiome, is associated with several diseases. Consequent chronic inflammation may lead to or promote inflammatory bowel disease, obesity, diabetes mellitus, atherosclerosis, alcoholic and non-alcoholic liver disease, cirrhosis, hepatocellular carcinoma, and other diseases. The pathogenesis of the three most common retinal vascular diseases, diabetic retinopathy, retinal vein occlusion, and retinal artery occlusion, may also be influenced by an altered microbiome and associated risk factors such as diabetes mellitus, atherosclerosis, hypertension, and obesity. Direct cause-effect relationships remain less well understood. A potential prevention or treatment modality for these diseases could be targeting and modulating the individual's gut microbiome.

Case report: acute isolated cilioretinal artery occlusion secondary to percutaneous coronary intervention

INTRODUCTION

This case report aims to describe in detail the acute isolated cilioretinal artery occlusion (CLRAO) secondary to complicated therapeutic percutaneous coronary intervention (PCI).

CASE DESCRIPTION

A 68-year-old Chinese man with coronary artery disease (CAD) complained of sudden, sharp chest pain. Coronary angiography revealed severe stenoses of the coronary arteries. The patient was then treated with PCI. One hour after the procedure, the patient presented with a sudden reduction in vision in the right eye. The patient was diagnosed with acute isolated CLRAO and treated with Salvia miltiorrhiza injections.

CONCLUSIONS

This is the report to provide a detailed description of acute isolated CLRAO secondary to therapeutic PCI treated with Salvia miltiorrhiza. The visual prognosis of the untreated patients is poor. Suitable management and prevention are essential for interventional cardiologists to prevent these complications.

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.

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.

Sex differences in major adverse cardiovascular and cerebrovascular event risk among central retinal artery occlusion patients

To estimate the association between central retinal artery occlusion (CRAO) and major adverse cardiovascular and cerebrovascular events (MACCE), including their clinical characteristics, blood markers, and the contribution of CRAO to MACCE, as well as to assess any sex differences. This retrospective cohort study included continuous new-onset CRAO patients and 1:4 controls during the same period. Correlations of CRAO with the incidence of MACCE during follow-up and the sex-related differences were studied. One hundred and twenty-four CRAO patients and four hundred and ninety-six controls were enrolled. Neutrophil-to-lymphocyte ratio (NLR, P = 0.014) and high-sensitivity C-reactive protein (hs-CRP, P = 0.038) were tended to be higher in CRAO patients. After the follow-up period, 78 patients experienced MACCE. Multivariate Cox regression analysis showed that CRAO was a predictor of the occurrence of MACCE (HR 2.321, 95% CI 1.439-3.744, P = 0.001). Sex subgroups indicated that age, diabetes, current smoking, CRAO, NLR and hs-CRP increased the risk factor of MACCE in males (All P < 0.05) and CRAO, NLR, low-density lipoprotein cholesterol (LDL-C) and hs-CRP were independent influencing factors for females (All P < 0.05). New-onset CRAO significantly increases the probability of MACCE and is associated with a poor prognosis. The sex-related differences suggested that effective prevention of the occurrence of MACCE in high-risk patients requires that attention be given to individualized risk factors corresponding to sexes.

Uveal vascular bed in health and disease: uveal vascular bed anatomy. Paper 1 of 2

The uveal vascular bed is the largest vascular system in the eye and has a role in supplying almost every tissue in the eyeball. This makes it the most important ocular vascular system. This is an up-to-date review of the literature of the entire uveal vascular bed in health based on detailed anatomy of the posterior ciliary arteries (PCAs), anterior ciliary arteries, cilioretinal arteries, and vortex veins. Although postmortem injection cast preparations gave us useful information on the morphology of the choroidal vascular bed; in vivo studies showed that they misled us for centuries about the in vivo situation. According to the postmortem cast studies, the uveal vascular bed has no segmental distribution, the uveal vessels anastomose freely with one another, there are inter-arterial and arteriovenous anastomoses in the choroid, and the choriocapillaris form a freely communicating and an uninterrupted vascular bed in the entire choroid.

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.

Aberrant filling of the retinal vein on fluorescein angiography in branch and hemi-central retinal artery occlusion

OBJECTIVE

To study aberrant filling of the retinal vessels on fluorescein angiography (FA) images in patients with branch (BRAO) or hemi-central retinal artery occlusions (hemi-CRAO) and correlate with associated changes on optical coherence tomography (OCT).

METHODS

Cases of acute BRAO or hemi-CRAO having FA and OCT images at presentation between June 2017 to May 2022 were included. Comparisons were made between the cases with and without aberrant filling of the retinal vessel.

RESULTS

Thirty-nine eyes of 39 patients with acute retinal artery occlusions underwent FA and OCT imaging. Seven of the ten cases with either BRAO or hemi-CRAO showed aberrant filling of the retinal vein on FA. No case with CRAO showed aberrant filling on FA. The cases with aberrant filling showed a better presenting visual acuity and lesser severity of retinal ischemia on OCT. Shunts between the retinal artery in the unaffected region and the retinal vein in the affected segment was seen in two eyes. The remaining five eyes showed no arteriovenous anastomosis. Cases with aberrant filling had a better visual function even at the last visit.

CONCLUSION

Aberrant retinal vein filling across the horizontal median raphe in the affected region in BRAO or hemi-CRAO eyes had less severity of retinal ischemia and better presenting and final visual acuities. Reduced perfusion in retinal capillaries with altered retinal vascular anatomy or arteriovenous shunts could be probable reasons for the development of this FA finding. Presence of aberrant filling of the retinal vein could indicate better final visual prognosis.

Progress in central retinal artery occlusion: a narrative review

Central retinal artery occlusion (CRAO) is a catastrophic ophthalmic emergency that severely impairs a patient's visual function, often reducing visual acuity to counting fingers or worse. Progress in CRAO research has provided new information regarding its epidemiological characteristics and led to useful assessments through various ophthalmic examinations. Additional insights about CRAO have been gained through studies of its pathophysiological mechanisms, improving intervention timing and enhancing patient prognosis. Treatment for CRAO has evolved, particularly with assistance from surgical instruments and surgical robots. Although surgical treatment is now possible, this option is not widely recognized by ophthalmologists. Conservative therapies have limited benefits compared with the natural course of disease. Recently, pars plana vitrectomy plus endovascular surgery has received considerable interest among ophthalmologists because of its potential efficacy in the treatment of CRAO. Considering the inconsistencies in rationale and efficacy of CRAO treatment modalities, it is important to distinguish between treatment effects and the natural courses of various CRAO subclasses. This narrative review explores progress in CRAO epidemiology, pathophysiology, ophthalmic examination, and treatment.

Neovascular Glaucoma Complicating Central Retinal Artery Occlusion Despite Cilioretinal Artery Sparing

This case report aims to describe a case of unilateral central retinal artery occlusion (CRAO) with cilioretinal artery sparing, which was complicated by neovascular glaucoma (NVG). A 75-year-old Indian woman with underlying normal tension glaucoma presented with the sudden onset of painless generalized blurring of the right eye's vision for a week. Her right eye vision was hand motion with the presence of a right relative afferent pupillary defect. Fundus examination revealed retinal whitening over the macula sparing the papillomacular bundle with generalized retinal arteriolar attenuation, which was suggestive of right CRAO with cilioretinal artery sparing. Systemic examination revealed high blood pressure (175/75 mmHg) without ocular bruit or audible murmur on auscultation. Optical coherence tomography of the macula showed inner retinal thickening over the temporal macula. Ultrasound carotid Doppler and computed tomography angiography of the carotid showed more than 75% stenosis over the right distal internal carotid artery. Unfortunately, she developed rubeosis iridis over her right eye two weeks after her presentation, which required pan-retinal photocoagulation. She subsequently progressed to NVG, requiring maximum anti-glaucoma medications to stabilize intraocular pressure. In conclusion, CRAO is a sight-threatening medical emergency. Thorough investigations are required to determine the underlying cause so that early intervention can be done to reduce the risk of a similar attack in the fellow eye and the risk of a cerebrovascular event or cardiac ischemia, which could be life-threatening. The presence of a cilioretinal artery does not prevent ocular neovascularization in CRAO. Hence, patients should also be closely monitored after the initial diagnosis to prevent devastating complications such as NVG.

Mid-phase pinpoint hyperfluorescent spots on fundus fluorescein angiography in acute central retinal artery occlusion - a novel imaging finding

PURPOSE

To describe the development and outcome of mid-phase pinpoint hyperfluorescent spots (MPHS) on fundus fluorescein angiography (FFA) in acute (< 7-day symptom onset) central retinal artery occlusion (CRAO) patients.

METHODS

This retrospective study included acute CRAO patients who underwent multimodal imaging utilizing optical coherence tomography (OCT) and FFA between June 2017 and January 2023. The correlation of FFA images with the OCT images in various stages and severity of CRAO were studied.

RESULTS

Twenty-three FFA studies on 23 patients with acute CRAO were included. In 11 (48%) cases, an important finding noted on FFA was the presence of single or multiple MPHS with adjacent minimal late vascular leakage. Of these 11 cases, eight (73%) were males and median age was 41 years (inter quartile range: 33-55 years). Visual acuity ranged from 'light perception' to 6/18, and these patients presented anytime on the same day to seven days after symptom onset. On OCT, three eyes had severe CRAO, seven eyes had moderate CRAO, and one eye had mild CRAO. MPHS were primarily observed at the posterior pole and more frequently observed in moderate CRAO severity. During follow-up, the MPHS and retinal vessel staining on FFA disappeared as the CRAO showed signs of resolution.

CONCLUSION

MPHS at the posterior pole on FFA in acute CRAO patients could indicate a more severe occlusion and poor visual outcomes, even after treatment. This finding is most likely caused by red blood cell aggregation or rouleaux formation.

TRIAL REGISTRATION NUMBER

Not applicable.

An Ocular Emergency Often Ignored

Branch retinal artery occlusion (BRAO) is a relatively rare vascular disorder characterized by the occlusion of one or more branches of the central retinal artery, with an incidence of around 5 per 100,000 persons per year. Its ability to cause permanent vision loss in a specific visual field makes it a significant clinical obstacle that requires careful management. We describe a case of a 77-year-old male patient, a known hypertensive (on medication and whose hypertension was under control), presented with sudden painless loss of vision in the superior field of his right eye. Timely and accurate diagnosis is crucial to initiate appropriate management. Patients with hypertension should be routinely screened for its various micro- and macrovascular complications, and prophylactic therapy/management should be started wherever warranted.

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

Background

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

Materials and Methods

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

Results

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

Conclusion

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

Maxillary artery pseudoaneurysm causing retinal artery occlusion

Purpose

To report a novel case of central retinal artery occlusion in a 44-year-old male caused by emboli from a non-traumatic maxillary artery pseudoaneurysm.

Observations

A 44-year-old male with history of hypertension presented to clinic with painless vision loss in his left eye. He was found to have a central retinal artery occlusion. Ocular massage and intraocular pressure lowering agents were administered and the patient was transferred to the emergency department for cerebrovascular work-up. Remarkably, the patient had rapid symptom improvement from no light perception to 20/70 after ocular massage and IOP agents. Neuroimaging studies discovered a maxillary artery pseudoaneurysm with anastomotic branches to the internal carotid artery via the foramen rotundum and Vidian artery. Endovascular embolization was performed to prevent further thromboembolic event.

Conclusion and Importance

We believe this to be the first reported case of retinal artery occlusion caused by a maxillary artery pseudoaneurysm. This case demonstrates that visual deficits can be the presenting symptom of a non-traumatic maxillary artery pseudoaneurysm.

Neuroprotection for Nonarteritic Central Retinal Artery Occlusion: Lessons from Acute Ischemic Stroke

Nonarteritic central retinal artery occlusion (NA-CRAO) is a variant of acute ischemic stroke (AIS) and is a cause of sudden severe loss of vision. There are guidelines by the American Heart Association and the American Stroke Association for the care of CRAO patients. This review explores the basis of retinal neuroprotection for CRAO and its potential for improving the outcome of NA-CRAO. Recently, there have been significant advances in research into the use of neuroprotection to treat retinal diseases, including retinal detachment, age-related macular degeneration, and inherited retinal diseases. Also, neuroprotective research in AIS has been extensive, and newer drugs tested, including Uric acid, Nerinetide, and Otaplimastat, with promising results. Progress in cerebral neuroprotection after AIS offers hope for retinal neuroprotection after CRAO; and a possibility of extrapolating research findings from AIS into CRAO. Combining neuroprotection and thrombolysis can extend the therapeutic window for NA-CRAO treatment and potentially improve outcomes. Experimented neuroprotection for CRAO includes Angiopoietin (Comp Ang1), KUS 121, Gene therapy (XIAP), and hypothermia. Efforts in the field of neuroprotection for NA-CRAO should focus on better imaging to delineate the penumbra after an acute episode of NA-CRAO (using a combination of high-definition optical coherence angiography and electrophysiology). Also, research should explore details of pathophysiologic mechanisms involved in NA-CRAO, allowing for further neuroprotective intervention, and closing the gap between preclinical and clinical neuroprotection.

Chronic ocular small vessel disease: An overview of diabetic retinopathy and its relationship with cardiovascular health

Diabetic retinopathy (DR) is a potentially blinding disease originating from small vessel damage in the retina in chronic hyperglycemic states. DR has a complex multi-pathway driven pathogenesis resulting in diabetic macular edema and retinal ischemia, the former being the most common cause of vision impairment in DR. Hypoxia induced cytokines stimulate vascular endothelial growth factor (VEGF) production and subsequent angiogenesis with resultant mechanical retinal damage over time. Anti-VEGF therapy is effective for the treatment of center-involving diabetic macular edema. There is evolving evidence showing the effectiveness of anti-VEGF as both adjuvant and monotherapy in the treatment of proliferative DR, however laser photocoagulation continues to remain the standard of care. DR in large cohort studies has been shown to be an independent risk factor for the development of cardiovascular disease and mortality. In addition, changes in retinal vascular caliber ratios may have implications for risk of macrovascular events with a gender discrepancy towards women.

The accumulated oxygen deficit as an indicator of the ischemic retinal insult

We here attempt to improve quantification of the ischemic retinal insult, that is, what is imposed on the retinal tissue by ischemia, especially in experimental models of ischemia. The ischemic retinal insult initiates the ischemic retinal injury (or outcome). Accordingly, it is reasonable to assume that the better the quantification of the insult, the better the correlation with, and thereby estimation of, the injury. The insult seldom has been quantified in terms of the relevant physiological factors, especially in connection with the rate of oxygen delivery (DO2). We here propose the accumulated oxygen deficit (AO2D) as an indicator of the ischemic retinal insult. We hypothesized that AO2D is correlated with the rate of oxygen metabolism measured 1 h after reperfusion following an episode of ischemia (MO2_1_Hr). Previously, we showed that MO2_1_Hr is related to the electroretinogram amplitude and the retinal thickness when they are measured seven days after reperfusion. We studied 27 rats, as well as 26 rats from our published data on retinal ischemia in which we had measurements of DO2 and duration of ischemia (T) of various levels and durations. We also measured DO2 in 29 rats treated with sham surgery. Ischemia was induced by either ipsilateral or bilateral common carotid artery occlusion or by ophthalmic artery occlusion, which gave a wide range of DO2. DO2 and MO2_1_Hr were evaluated based on three types of images: 1) red-free images to measure vessel diameters, 2) fluorescence images to estimate blood velocities by the displacement of intravascular fluorescent microspheres over time, and 3) phosphorescence images to quantify vascular oxygen tension from the phosphorescence lifetime of an intravascular oxygen sensitive phosphor. Loss of oxygen delivery (DO2L) was calculated as the difference between DO2 under normal/sham condition and DO2 during ischemia. AO2D, a volume of oxygen, was calculated as the product DO2L and T. Including all data, the linear relationship between AO2D and MO2_1_Hr was significant (R2 = 0.261, P = 0.0003). Limiting data to that in which T or DO2L was maximal also yielded significant relationships, and revealed that DO2L at a long duration of ischemia contributed disproportionately more than T to MO2_1_Hr. We discuss the potential of AO2D for quantifying the ischemic retinal insult, predicting the ischemic retinal injury and evaluating the likelihood of infarction.

Large-Scale Protein Analysis of Experimental Retinal Artery Occlusion

Retinal artery occlusion (RAO) is a devastating condition with no effective treatment. The management of RAO could potentially be improved through an in-depth understanding of the molecular alterations in the condition. This study combined advanced proteomic techniques and an experimental model to uncover the retinal large-scale protein profile of RAO. In 13 pigs, RAO was induced with an argon laser and confirmed by fluorescein angiography. Left eyes serving as controls received a sham laser without inducing occlusion. Retinal samples were collected after one, three, or six days and analyzed with liquid chromatography-tandem mass spectrometry. In RAO, 36 proteins were differentially regulated on day one, 86 on day three, and 557 on day six. Upregulated proteins included clusterin, vitronectin, and vimentin, with several proteins increasing over time with a maximum on day six, including clusterin, vimentin, osteopontin, annexin-A, signal transducer, and the activator of transcription 3. On day six, RAO resulted in the upregulation of proteins involved in cellular response to stress, hemostasis, innate immune response, and cytokine signaling. Downregulated proteins were involved in transmission across chemical synapses and visual phototransduction. This study identified the upregulation of multiple inflammatory proteins in RAO and the downregulation of proteins involved in visual pathways.

Paracentral Acute Middle Maculopathy as a Specific Sign of Arteritic Anterior Ischemic Optic Neuropathy

PURPOSE

The purpose of this study is to assess the diagnostic accuracy of paracentral acute middle maculopathy (PAMM) in the setting of anterior ischemic optic neuropathy (AION) to distinguish arteritic (A-AION) from nonarteritic (NA-AION) type.

DESIGN

Retrospective cross-sectional diagnostic evaluation.

METHODS

PAMM was evaluated by 3 physicians blinded to diagnosis using macular spectral-domain optical coherence tomography. We studied 45 patients with AION. Of those, 28 had NA-AION and 17 had A-AION. The study was conducted in the Department of Ophthalmology at the Hospital of Marseille-Assistance Publique, France, from January 1, 2018, to March 31, 2022.

RESULTS

PAMM were only found in the A-AION group (N = 4) (P = .0143). As a distinctive sign of A-AION, we found a specificity of 100% (95% IC, 88.06%-100%) and a positive predictive value of 100%. In contrast, sensitivity and negative predictive value were lower, 19.1% (95% IC, 5.5-42.0) and 63.0% (95% CI, 58.1-67.7), respectively.

CONCLUSIONS

The PAMM finding is highly specific for A-AION in the setting of AION. According to our results, macular spectral-domain optical coherence tomography looking for PAMM should be performed with any patient presenting with AION.

Incidence of Retinal Artery Occlusion and Related Mortality in Korea, 2005 to 2018

IMPORTANCE

It remains unclear whether comorbidities in patients with retinal artery occlusion (RAO), a rare retinal vascular disorder, differ by subtype and whether mortality is higher.

OBJECTIVE

To examine the nationwide incidence of clinically diagnosed, nonarteritic RAO, causes of death, and mortality rate in patients with RAO compared with that in the general population in Korea.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective, population-based cohort study examined National Health Insurance Service claims data from 2002 to 2018. The population of South Korea was 49 705 663, according to the 2015 census. Data were analyzed from February 9, 2021, to July 30, 2022.

MAIN OUTCOMES AND MEASURES

The nationwide incidence of any RAO, including central RAO (CRAO; International Statistical Classification of Diseases and Related Health Problems, Tenth Revision [ICD-10] code, H34.1) and noncentral RAO (other RAO; ICD-10 code, H34.2) was estimated using National Health Insurance Service claims data from 2002 to 2018, with 2002 to 2004 as the washout period. Furthermore, the causes of death were evaluated and the standardized mortality ratio was estimated. The primary outcomes were the incidence of RAO per 100 000 person-years and the standardized mortality ratio (SMR).

RESULTS

A total of 51 326 patients with RAO were identified (28 857 [56.2%] men; mean [SD] age at index date: 63.6 [14.1] years). The nationwide incidence of any RAO was 7.38 (95% CI, 7.32-7.44) per 100 000 person-years. The incidence rate of noncentral RAO was 5.12 (95% CI, 5.07-5.18), more than twice that of CRAO (2.25 [95% CI, 2.22-2.29]). Mortality was higher in patients with any RAO than in the general population (SMR, 7.33 [95% CI, 7.15-7.50]). The SMR for CRAO (9.95 [95% CI, 9.61-10.29]) and for noncentral RAO (5.97 [95% CI, 5.78-6.16]) showed a tendency toward a gradual decrease with increasing age. The top 3 causes of death in patients with RAO were diseases of the circulatory system (28.8%), neoplasms (25.1%), and diseases of the respiratory system (10.2%).

CONCLUSIONS AND RELEVANCE

This cohort study found that the incidence rate of noncentral RAO was higher than that of CRAO, whereas SMR was higher for CRAO than noncentral RAO. Patients with RAO show higher mortality than the general population, with circulatory system disease as the leading cause of death. These findings suggest that it is necessary to investigate the risk of cardiovascular or cerebrovascular disease in patients newly diagnosed with RAO.

Synthesizing multi-frame high-resolution fluorescein angiography images from retinal fundus images using generative adversarial networks

BACKGROUND

Fundus fluorescein angiography (FA) can be used to diagnose fundus diseases by observing dynamic fluorescein changes that reflect vascular circulation in the fundus. As FA may pose a risk to patients, generative adversarial networks have been used to convert retinal fundus images into fluorescein angiography images. However, the available methods focus on generating FA images of a single phase, and the resolution of the generated FA images is low, being unsuitable for accurately diagnosing fundus diseases.

METHODS

We propose a network that generates multi-frame high-resolution FA images. This network consists of a low-resolution GAN (LrGAN) and a high-resolution GAN (HrGAN), where LrGAN generates low-resolution and full-size FA images with global intensity information, HrGAN takes the FA images generated by LrGAN as input to generate multi-frame high-resolution FA patches. Finally, the FA patches are merged into full-size FA images.

RESULTS

Our approach combines supervised and unsupervised learning methods and achieves better quantitative and qualitative results than using either method alone. Structural similarity (SSIM), normalized cross-correlation (NCC) and peak signal-to-noise ratio (PSNR) were used as quantitative metrics to evaluate the performance of the proposed method. The experimental results show that our method achieves better quantitative results with structural similarity of 0.7126, normalized cross-correlation of 0.6799, and peak signal-to-noise ratio of 15.77. In addition, ablation experiments also demonstrate that using a shared encoder and residual channel attention module in HrGAN is helpful for the generation of high-resolution images.

CONCLUSIONS

Overall, our method has higher performance for generating retinal vessel details and leaky structures in multiple critical phases, showing a promising clinical diagnostic value.

Retinal Vascular Occlusion Risks in High Blood Pressure and the Benefits of Blood Pressure Control

PURPOSE

This study aimed to evaluate the association of retinal vascular occlusion, including retinal vein occlusion (RVO) and retinal artery occlusion (RAO), with stages of hypertension.

DESIGN

Nationwide, population-based retrospective cohort study.

METHODS

Based on baseline blood pressure (BP) as defined by the 2017 American College of Cardiology/American Heart Association guideline, participants were categorized into 4 BP groups. For the BP change measurement, BP groups were defined based on the combination of baseline and follow-up BP categories. The composite retinal vascular occlusion events and hazard ratios (HRs) of retinal vascular occlusion according to BP groups were estimated.

RESULTS

With normal BP as the reference, multivariate-adjusted HRs for retinal vascular occlusion were significantly higher than in other BP groups, showing much higher HRs in stage 2 hypertension than in stage 1 (HR, 1.10 for elevated BP; 1.07 for stage 1 hypertension; and 1.32 for stage 2 hypertension). Individual disease analysis showed consistent statistical significance in RVO, whereas RAO showed nonsignificant results. Lowering BP significantly decreased the HRs of retinal vascular occlusion in both stage 1 and stage 2 hypertension (HR, 0.88 and 0.73, respectively). However, once hypertension was diagnosed, the risk of retinal vascular occlusion was higher compared to that in the normal BP groups.

CONCLUSIONS

Elevated BP, stage 1 hypertension, and stage 2 hypertension were all associated with higher retinal vascular occlusion risks than was normal BP. Controlling hypertension appears to reduce the risk of subsequent retinal vascular occlusion; however, the incidence rate was still be significantly higher than that in persons who maintained a normal BP.

Retinal Artery Occlusion as an Early Indicator of Macrovascular Complications in Diabetes

BACKGROUND

A characteristic of the retinal circulation is that arterial occlusion is embolic or secondary to vasculitis but rarely or never due to in situ atherosclerosis. Therefore, retinal artery occlusion suggests the presence of cardiac or large-vessel disease outside the eye. This cohort study examined the general risk of macrovascular disease in individuals with diabetes, with or without retinal artery occlusion.

METHODS

We retrieved data on 992 subjects with incident retinal artery occlusion and preexisting diabetes, registered in Denmark between January 1, 2000, and December 31, 2018. Each retinal artery occlusion subject was matched for age, sex, and diabetes duration, with 5 control subjects with diabetes but without retinal artery occlusion. We performed survival analyses to compare the risk of extraocular macrovascular disease between the 2 groups in a 5-year follow-up.

RESULTS

After 1 year, the incidence of macrovascular disease in subjects with retinal artery occlusion was approximately 21 per 100 person-years (95% confidence interval [CI]: 18.11-24.29), compared to 6.25 per 100 patient-years (95% CI: 5.57-7.00) in those without retinal artery occlusion. After 5 years, the cumulative incidences of macrovascular disease were 51.2% (95% CI: 47.9-54.7%) and 29.4% (95% CI: 28.0-30.8%) in patients with diabetes with or without retinal artery occlusion, respectively. Hazard rate ratios were 3.36 (95% CI: 2.79-4.05) after 1 year and 2.27 (95% CI: 2.04-2.53) after 5 years.

CONCLUSION

Among individuals with diabetes, those diagnosed with retinal artery occlusion had a higher general risk of macrovascular complications for at least 5 years after the occlusion event compared with those without retinal artery occlusion.

GCL loss in BRAO

PURPOSE

Our recent publication used optical coherence tomography (OCT) to follow thinning of the retinal ganglion cell layer (GCL) in central retinal artery occlusion (CRAO). Thinning of the inner layers also occurs in patients with branch retinal artery occlusion (BRAO). The mechanism for such thinning may be partially due to proteolysis by a calcium-activated protease called calpain. Calpain inhibitor SNJ-1945 ameliorated the proteolysis in a past series of model experiments. The purposes of the present retrospective study were to: 1) use segmentation analysis of OCT images to follow the loss of retinal layers in BRAO compared to CRAO patients, and 2) predict the number of patients and days of observation needed for a clinical trial of a calpain inhibitor against BRAO.

METHODS

A retrospective, case control study was conducted by computer-aided search in a medical records database for BRAO (ICD10 Code H34.239) with at least one OCT procedure (CPT: 92134). Non-proliferative, co-morbid eye diseases were allowed in the patient data base, and manual correction of auto-segmentation errors was performed. GCL thickness changes were followed over time and Cohen-d/sample size statistics were used to predict minimal patients needed for drug trials.

RESULTS

The thickness of the GCL layer in BRAO decreased rapidly with time as in CRAO, but in more limited quadrants. The data, as fit to a single-phase decay curve, showed that GCL thickness could be used to provide sample size statistics in a clinical trial to test a calpain inhibitor. For example, a 60-day trial with a 60% effective inhibitor would need a minimum of 29 patients.

CONCLUSIONS

Using thickness changes in the GCL layer to monitor the efficacy of potential inhibitors against BRAO and CRAO is practical in human trials requiring a reasonable number of patients and relatively short trial period.

TRANSLATIONAL RELEVANCE

Measurement of GCL thickness would be a useful indicator of amelioration of BRAO and CRAO progression in a clinical trial of a putative inhibitor.

Efficacy and safety of intra-arterial thrombolysis in patients with central retinal artery occlusion: a systematic review and meta-analysis

PURPOSE

To investigate the efficacy and safety of intra-arterial thrombolysis (IAT) in patients with central retinal artery occlusion (CRAO).

METHODS

PubMed and EMBASE were searched for potentially eligible studies that reported IAT in CRAO patients from inception to Nov 8, 2021. Standard mean difference (SMD) was pooled to compare visual acuity (VA) at baseline with final in IAT patients. The rates and odds ratios (OR) were meta-analyzed to compare VA improvement in IAT with non-IAT patients, stratified to different times from onset to procedure, different definitions of VA improvement, and three CRAO stages. Adverse effects were recorded.

RESULTS

Fifteen studies were included, enrolling 507 CRAO patients who received IAT and 296 CRAO patients who did not. VA was significantly improved from baseline to final VA in IAT patients (SMD [LogMAR] 0.70, 95% CI [0.51, 0.90]). VA improvement rate was higher in IAT patients than that in non-IAT (56% vs 32%, OR 3.55, 95%CI [1.74, 7.24]), with greater OR in IAT within 6 h from onset to procedure (OR 4.60, 95%CI [1.24, 16.99]) than that beyond 6 h (OR 3.36, 95%CI [1.43, 7.85]). The benefit remained consistent when VA improvement was defined as ≥ 3 lines on the Snellen chart (OR 4.68, 95%CI [2.10, 10.41]) and was even greater when CRAO was incomplete. Five patients had a symptomatic intracranial hemorrhage and 21 patients had ischemic stroke or transient ischemic attack after IAT.

CONCLUSIONS

IAT treatment has certain potential in ameliorating VA in CRAO patients, which should be balanced against cerebral complications.

Management of ocular arterial ischemic diseases: a review

PURPOSE

To summarize the existing treatment options regarding central retinal artery occlusion (CRAO), branch retinal artery occlusion (BRAO), arteritic anterior ischemic optic neuropathy (AAION), non-arteritic anterior ischemic optic neuropathy (NAION), and ocular ischemic syndrome (OIS), proposing an approach to manage and treat these patients.

METHODS

A systematic literature search of articles published since 1st January 2010 until 31st December 2020 was conducted using MEDLINE (PubMed), Scopus, and Web of Science. Exclusion criteria included case reports, non-English references, articles not conducted in humans, and articles not including diagnostic or therapeutic options. Further references were gathered through citation tracking, by hand search of the reference lists of included studies, as well as topic-related European society guidelines.

RESULTS

Acute ocular ischemia, with consequent visual loss, has a variety of causes and clinical presentations, with prognosis depending on an accurate diagnosis and timely therapeutic implementation. Unfortunately, most of the addressed entities do not have a standardized management, especially regarding their treatment, which often lacks good quality evidence on whether it should or not be used to treat patients.

CONCLUSION

Ophthalmologic signs and symptoms may be a warning sign of cardiovascular or cerebrovascular events, namely stroke. Most causes of acute ocular ischemia do not have a standardized management, especially regarding their treatment. Timely intervention is essential to improve the visual, and possibly vital, prognosis. Awareness must be raised among non-ophthalmologist clinicians that might encounter these patients. Further research should focus on assessing the benefit of the management strategies already being employed .

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.

Received anti-VEGF therapy in a patient with CRAO sparing the CLRA with subretinal fluid: A case report

RATIONALE

Central retinal artery occlusion (CRAO) sparing the cilioretinal artery (CLRA) with severe subretinal fluid and non-characteristic cherry-red spot is uncommon. In the present case, the patient received an intravitreal injection of anti- vascular endothelial growth factor, which is very rare.

PATIENT CONCERNS

A 59-year-old man underwent vitrectomy of the left eye for diabetic retinopathy and vitreous hemorrhage. Six months after the operation, the patient presented with sudden painless visual-acuity decline in his left eye and was diagnosed with CRAO; his best corrected visual acuity was weak light perception. Whole retinal edema was seen on the fundus, and macular gray retinal opacification was present without a characteristic cherry-red spot. Optical coherence tomography revealed subretinal fluid (SRF) in the papillomacular bundle and inner retinal thickening. Fundus fluorescein angiography confirmed that the central retinal artery was not filled at 40 seconds and that the CLRA supplied a part of the macular area. Eight months after the second intravitreal injection of ranibizumab, Optical coherence tomography showed a significant reduction in inner retinal hyperreflectivity and the thickness of the nasal macular retina. The SRF was clearly absorbed, and the visual acuity improved to 1.1 logMAR units.

DIAGNOSIS

Atypical CRAO.

INTERVENTIONS

The patient was treated with intravitreal injection of anti-VEGF in his left eye. The thickness of the nasal macular retina decreased.

OUTCOMES

The SRF was clearly absorbed, and the patient's visual acuity significantly improved.

LESSONS

When CRAO occurs in patients with diabetic retinopathy sparing the CLRA, the non-characteristic cherry-red spot may be due to macular inner retinal edema, SRF and other factors. According to the patient's condition, anti-vascular endothelial growth factor can be administered as appropriate to inhibit choroidal neovascularization, reduce SRF in the macular retina, and save some vision.

Airborne fine particulate matter (PM2.5) damages the inner blood-retinal barrier by inducing inflammation and ferroptosis in retinal vascular endothelial cells

This study was the first to explore the effect of airborne fine particulate matter (PM_2.5) exposure on the inner blood-retinal barrier (iBRB). In this study, retinal vascular permeability and diameter were enhanced in the PM_2.5-exposed animal model (1 mg/mL PM_2.5, 10 μL per eye, 4 times per day, 3 days), together with observable retinal edema and increased inflammation level in retina. PM_2.5-induced cell damage in human retinal microvascular endothelial cells (HRMECs) occurred in a time- and dose-dependent manner. Decreased cell viability, proliferation, migration, and angiogenesis, as well as increased apoptosis and inflammation, were observed. Iron overload and excessive lipid oxidation were also discovered after PM_2.5 exposure (25, 50, and 100 μg/mL PM_2.5 for 24 h), along with significantly altered expression of ferroptosis-related genes, such as prostaglandin-endoperoxide synthase 2, glutathione peroxidase 4, and ferritin heavy chain 1. Moreover, Ferrostatin-1, an inhibitor of ferroptosis, evidently alleviated the PM_2.5-induced cytotoxicity of HRMECs. The present study investigated the in vivo effects of PM_2.5 on retinas, revealing that PM_2.5 exposure induced retinal inflammation, vascular dilatation, and caused damage to the iBRB. The crucial role of ferroptosis was discovered during PM_2.5-induced HRMEC cytotoxicity and dysfunction, indicating a potential precautionary target in air pollution-associated retinal vascular diseases.

Bridging a Century-Old Problem: The Pathophysiology and Molecular Mechanisms of HA Filler-Induced Vascular Occlusion (FIVO)—Implications for Therapeutic Interventions

Biocompatible hyaluronic acid (HA, hyaluronan) gel implants have altered the therapeutic landscape of surgery and medicine, fostering an array of innovative products that include viscosurgical aids, synovial supplements, and drug-eluting nanomaterials. However, it is perhaps the explosive growth in the cosmetic applications of injectable dermal fillers that has captured the brightest spotlight, emerging as the dominant modality in plastic surgery and aesthetic medicine. The popularity surge with which injectable HA fillers have risen to in vogue status has also brought a concomitant increase in the incidence of once-rare iatrogenic vaso-occlusive injuries ranging from disfiguring facial skin necrosis to disabling neuro-ophthalmological sequelae. As our understanding of the pathophysiology of these injuries has evolved, supplemented by more than a century of astute observations, the formulation of novel therapeutic and preventative strategies has permitted the amelioration of this burdensome complication. In this special issue article, we review the relevant mechanisms underlying HA filler-induced vascular occlusion (FIVO), with particular emphasis on the rheo-mechanical aspects of vascular blockade; the thromboembolic potential of HA mixtures; and the tissue-specific ischemic susceptibility of microvascular networks, which leads to underperfusion, hypoxia, and ultimate injury. In addition, recent therapeutic advances and novel considerations on the prevention and management of muco-cutaneous and neuro-ophthalmological complications are examined.