AMALRIC TRIANGULAR SIGN AND CAROTID DOPPLER ULTRASONOGRAPHIC FINDINGS IN CENTRAL RETINAL ARTERY OCCLUSION.

PURPOSE: The aim of this study was to determine the incidence of the Amalric triangular sign (ATS) in patients with central retinal artery occlusion and investigate its association with visual function and carotid Doppler ultrasonography findings. METHODS: A retrospective chart review was conducted on 21 eyes from 21 patients with complete central retinal artery occlusion. Best-corrected visual acuity and carotid Doppler ultrasonography findings [peak systolic velocity, end-diastolic velocity, and resistance index (RI) = (PSV - EDV)/PSV] were investigated. RESULTS: Three patients (14%) exhibited the ATS. Best-corrected visual acuity at first visit was significantly worse in ATS-positive patients than in ATS-negative patients (P = 0.024). Doppler waveform analysis of the common carotid artery showed that ATS-positive patients had a significantly lower end-diastolic velocity [P = 0.009, median 10 (range 9-10) vs. 17 (13-24) m/second] and significantly higher resistance index [P = 0.021, median 0.80 (range 0.79-0.83) vs. 0.72 (0.66-0.82)] than did ATS-negative. CONCLUSION: The Amalric triangular sign was observed in three patients with central retinal artery occlusion, who showed worse best-corrected visual acuity at the first visit than did those without the ATS. Carotid Doppler ultrasonography revealed that ATS-positive patients had a significantly higher resistance index and lower end-diastolic velocity at the common carotid artery than did ATS-negative, indicating steno-occlusive changes in the internal carotid artery.

Analysis of the Effect of Superselective Ophthalmic Artery Thrombolysis for Central Retinal Artery Occlusion.

INTRODUCTION: The aim of the study was to investigate the clinical efficacy of superselective ophthalmic artery thrombolysis for central retinal artery occlusion (CRAO). METHODS: Retrospective study of CRAO patients who attended the Department of Ophthalmology of Affiliated Hospital of Weifang Medical University from January 2022 to July 2023, 138 CRAO patients with onset time of 1-3 days were selected for the study. Among them, 86 patients refused thrombolytic treatment and chose to adopt traditional treatment, which was categorized as the control group; 52 patients adopted superselective ophthalmic artery thrombolytic treatment, which was categorized as the observation group. The visual acuity of the patients treated with traditional modality on the 4th day after the onset of the disease and the visual acuity of the patients treated with superselective ophthalmic artery thrombolysis on the 1st postoperative day were recorded, and the visual acuity improvement after different modalities of treatment was compared between the two groups. RESULTS: In the control group, 77 (89.5%) of the treated patients had no improvement in visual acuity, 9 (10.5%) had improvement, 0 (0.0%) had significant improvement, and the total improvement was 9 (10.5%); in the observation group, 18 (34.6%) of the treated patients had no improvement in visual acuity, 21 (40.4%) had improvement, 13 (25.0%) had significant improvement, and the total improvement was 34 (65.4%). The total improvement rate of treatment in the observation group was 65.4%, which was significantly higher than the 10.5% in the control group, and the difference was statistically significant (p < 0.05). CONCLUSION: Superselective ophthalmic artery thrombolysis for patients with CRAO is clinically effective, promotes improvement in patient vision, and has a high safety profile.

Spontaneous brain activity in patients with central retinal artery occlusion: a resting-state functional MRI study using machine learning.

Central retinal artery occlusion (CRAO) is a serious eye condition that poses a risk to vision, resulting from the blockage of the central retinal artery. Because of the anatomical connection between the ocular artery, which derives from the internal carotid artery, and the anterior middle cerebral artery, hemodynamic alterations and sudden vision loss associated with CRAO may impact brain functionality. This study aimed to examine alterations in spontaneous neural activity among patients with CRAO by resting-state functional MRI. In addition, we selected the amplitude of low-frequency fluctuation (ALFF) and fractional amplitude of low-frequency fluctuation (fALFF) values as classification features for distinguishing CRAO from healthy controls (HCs) using a support vector machine classifier. A total of 18 patients diagnosed with CRAO and 18 HCs participated in the study. Resting-state brain function images and structural images were acquired from both groups. Aberrant changes in spontaneous brain functional activity among CRAO patients were investigated utilizing ALFF and fALFF analysis methods. Group differences in ALFF/fALFF values were assessed through a two-sample t -test. Subsequently, a machine learning classifier was developed to evaluate the clinical diagnostic potential of ALFF and fALFF values. In comparison to HCs, individuals with CRAO exhibited significantly higher ALFF values in the left cerebellum_6, vermis_7, left superior frontal gyrus, and left inferior frontal gyrus, triangular part. Conversely, the CRAO group displayed notably lower ALFF values in the left precuneus and left median cingulum gyri. Furthermore, higher fALFF values were observed in the left inferior frontal gyrus, triangular part, whereas lower fALFF values were noted in the right cerebellum_Crus2, left precuneus, right angular gyrus, left angular gyrus, right supramarginal gyrus, right superior parietal gyrus, and left precuneus. Utilizing the ALFF/fALFF values, the receiver operating characteristic curves (area under the curve) yielded 0.99 and 0.94 through machine learning analysis techniques. CRAO patients exhibit atypical neural activity in the brain, characterized by ALFF and fALFF values predominantly localized in the frontal, parietal, and cerebellar regions, which are closely linked to visual cognition and motor control impairments. Furthermore, ALFF and fALFF could serve as potential neuroimaging markers beyond the orbit among CRAO.

A Remote Consult Retinal Artery Occlusion Diagnostic Protocol.

PURPOSE: To report a novel protocol for diagnosis of retinal artery occlusions at the point of care using OCT and a remote consult model. DESIGN: Retrospective case series and evaluation of a diagnostic test or technology. PARTICIPANTS: Adult patients who presented with painless monocular vision loss and were diagnosed with a nonarteritic retinal artery occlusion. METHODS: OCT machines were placed in the stroke center or emergency department at 3 hospitals within our health system. Patients who presented with painless monocular vision loss were evaluated by the stroke neurology service and an OCT was acquired. The images were interpreted remotely by the retina service. An in-house ophthalmology consult was not required to make the final treatment decision. Eligible patients were treated with intra-arterial tissue plasminogen activator (IA-tPA). Patients were followed by ophthalmology during their admission when an in-house consultation service was available or otherwise evaluated immediately after discharge. MAIN OUTCOME MEASURES: Visual acuity (VA) before and after treatment with IA-tPA; time from last known well (LKW) to treatment; and time from presentation to treatment. RESULTS: In the first 18 months since the protocol went live, 59 patients were evaluated. Twenty-five patients (42%) had a confirmed retinal artery occlusion based on OCT and follow-up examination. Ten patients were eligible for treatment, and 9 patients received treatment with IA-tPA. There was a statistically significant improvement in mean VA from logarithm of the minimum angle of resolution (logMAR) 2.14 to logMAR 0.7 within 24 hours after treatment (P = 0.0001) and logMAR 1.04 after 4 weeks (P = 0.01). Clinically significant improvement was noted in 66% of patients within 24 hours and maintained through 1 month in 56% of all treated patients. The mean time to treatment from LKW was 543 minutes and from presentation at the stroke center was 146 minutes. CONCLUSIONS: We report the successful implementation of a remote consult protocol using point-of-care automated OCT. This novel paradigm demonstrates the potential utility of remote consult services for the diagnosis of time-sensitive ophthalmic emergencies. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Central Retinal Artery Occlusion: Visual Outcomes from a Large Northern California Cohort.

PURPOSE: To assess visual acuity (VA) outcomes in a large cohort of patients diagnosed with nonarteritic central retinal artery occlusion (CRAO), and to ascertain whether time from symptom onset to presentation, presenting VA, or conservative treatment delivery (anterior chamber paracentesis, ocular massage, intraocular pressure lowering drugs, hyperventilation, or some combination of those) impacted ultimate VA outcomes. DESIGN: Retrospective cohort study. SUBJECTS: The study included 794 patients who presented with CRAO between 2011 and 2020. Within this cohort, 484 individuals presented within 30 days of symptom onset and had comprehensive documentation regarding the details of their presentation, management, and follow-up ≥ 90 days postdiagnosis. METHODS: Retrospective chart review was conducted for all patients with a diagnosis of CRAO initially identified via International Classification of Diseases coding, followed by confirmation of diagnosis by 2 retina specialists. Cases of arteritic CRAO were excluded. MAIN OUTCOME MEASURES: Visual acuity recovery, defined as improvement from ≤ 20/200 or worse at presentation to ≥ 20/100 ≥ 90 days after diagnosis. RESULTS: Of the 794 identified patients, 712 (89.7%) presented with VA of ≤ 20/200. Similarly, 447 (92.4%) of the 484-patient subset that presented within 30 days and had comprehensive documentation presented with VA ≤ 20/200. Of the 441 of those patients with documented follow-up, 380 (86.2%) remained at that level. Of the 244 patients who presented within 4.5 hours of symptom onset, 227 (93%) presented ≤ 20/200 and 201 (92.6%) of the 217 of those with follow-up data did not improve beyond that threshold. There was no significant difference (P < 0.05) in final VA between patients presenting before versus after 4.5 hours from time of vision loss. There was also no significant difference (P < 0.05) in VA outcomes between patients who did or did not receive conservative treatment. CONCLUSIONS: This large retrospective study further highlights the poor visual prognosis for patients with CRAO. Earlier time to presentation did not seem to impact final VA outcome, nor did conservative treatment efforts. Efficacious evidence-based treatment options are needed for this patient population. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) are more prominent in retinal artery occlusion (RAO) compared to retinal vein occlusion (RVO).

AIM: To evaluate the association between the value of neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), monocyte to high-density lipoprotein ratio (MHR) and the development of retinal artery occlusion (RAO) and retinal vein occlusion (RVO). METHODS: This retrospective study assessed 41 RAO, 50 RVO and 50 control (age and gender matched senile cataract) participants. The NLR, PLR and MHR parameters of patients' peripheral blood were analyzed. A receiver operating characteristics (ROC) curve analysis and the best cutoff value were used to specify the predictive value of NLR, PLR and MHR in RAO and RVO. RESULTS: The NLR, PLR and MHR were significantly higher in RAO group compared to the control group (p<0.001, p<0.001 and p = 0.008; respectively). The NLR, PLR and MHR were also significantly higher in the RVO group compared to the control group (p<0.001, p = 0.001 and p = 0.012, respectively). The NLR and PLR were significantly higher in the RAO group compared to the RVO group (p<0.001 and p = 0.022, respectively). The optimal cut-off value of NLR to predict RAO was >2.99, with 90.2% sensitivity and 100% specificity. The PLR to predict RAO was > 145.52, with 75.6% sensitivity and 80.0% specificity. CONCLUSION: Higher NLR, PLR and MHR are related to the occurrence of RAO and RVO. NLR and PLR are more prominent in RAO compared to RVO.

Retinal diffusion restrictions in acute branch retinal arteriolar occlusion.

This study sought to investigate the occurrence of retinal diffusion restrictions (RDR) in branch retinal arteriolar occlusion (BRAO) using standard brain diffusion-weighted imaging (DWI). Two radiologists assessed DWI MRI scans of BRAO patients for RDR in a retrospective cohort study. Inter- and intrarater reliability were calculated using Kappa statistics. Detection rates of RDR were compared among MRI scans with varying field strength, sequence type and onset-to-DWI time intervals. 85 BRAO patients (63.1 ± 16.5 years) and 89 DWI scans were evaluated. Overall sensitivity of RDR in BRAO was 46.1% with visually correlating low ADC signal in 56.1% of cases. Localization of RDR matched distribution of fundoscopic retinal edema in 85% of patients. Inter- and intra-rater agreement for RDR in BRAO was κinter = 0.64 (95% CI 0.48-0.80) and κintra = 0.87 (95% CI 0.76-0.96), respectively. RDR detection rate tended to be higher for 3T, when compared to 1.5T MRI scans (53.7% vs. 34.3%%; p = 0.07). RDR were identified within 24 h up to 2 weeks after onset of visual impairment. RDR in BRAO can be observed by means of standard stroke DWI in a substantial proportion of cases, although sensitivity and interrater reliability were lower than previously reported for complete central retinal artery occlusion.

Acute Central Retinal Artery Occlusion Seen within 24 Hours at a Tertiary Institution.

OBJECTIVE: Acute central retinal artery occlusion (CRAO) is an emergency with poor visual outcome. Intravenous thrombolysis within 4.5 h of vision loss is safe and may improve vision, but is rarely administered because of frequent delays in presentation. We describe a subgroup of CRAO patients presenting within 24 h of vision loss to a tertiary care center affiliated with a comprehensive stroke center. MATERIALS AND METHODS: Retrospective review of 181 consecutive CRAO patients seen at our institution from 2010 to 2020. RESULTS: Out of 181 CRAO patients, 62 (34%) presented within 24 h of vision loss and tended to live closer to the hospital. These patients were more likely to be admitted to the hospital and receive comprehensive stroke work-up compared to patients who presented after 24 h of vision loss. Patients presenting after 24 h did not necessarily receive prior appropriate work-up at outside institutions. Conservative treatments for CRAO were administered to 20/181 patients, and only 3 patients received intravenous thrombolysis. CONCLUSIONS: Patients with CRAO do not present to the emergency department fast enough and diagnosis of CRAO is often delayed. Despite having a protocol in place, only 3/181 patients received IV thrombolysis, emphasizing the difficulty in administering very acute treatments for CRAO. Public education regarding CRAO is necessary to improve presentation times, management, and visual outcomes. Hospitals need to develop accelerated diagnostic pathway protocols for patients with acute vision loss so that CRAO patients may be diagnosed and be considered for potential acute treatments as quickly as possible.

THE NATIONWIDE INCIDENCE OF RETINAL ARTERY OCCLUSION FOLLOWING DIALYSIS AS A RESULT OF END-STAGE RENAL DISEASE: 2004 Through 2013.

PURPOSE: To examine the incidence and risk of retinal artery occlusion (RAO) in patients who have undergone dialysis in Korea. METHODS: A nationwide, population-based study using South Korean national health insurance data from 2004 to 2013 was used for analysis. All patients who began dialysis between 2004 and 2013 and the same number of control subjects were selected via propensity score matching. The incidence of RAO in the dialysis and control cohorts was calculated for 2004 to 2013 using washout data from 2003. The multivariable Cox proportional hazards model was used to evaluate the risk of developing RAO in dialysis patients. Cumulative RAO incidence curves were generated using the Kaplan-Meier method. Whether dialysis modalities influenced the incidence of RAO was also evaluated. RESULTS: Seventy-six thousand seven hundred and eighty-two end-stage renal disease patients on dialysis were included in the dialysis cohort, and 76,782 individuals were included in the control cohort. During the study period, 293 patients in the dialysis cohort and 99 patients in the control cohort developed RAO. The person-years incidence of RAO was significantly higher in the dialysis cohort than in the control cohort (dialysis = 1.1/1,000 person-years; control = 0.3/1,000 person-years; P < 0.001). The incidence of RAO was not significantly different between the two methods of dialysis (hemodialysis vs. peritoneal dialysis; P = 0.25, log-rank test). CONCLUSION: The current study provided epidemiological evidence that undergoing dialysis for end-stage renal disease was associated with an increased risk of developing RAO. The incidence of RAO rapidly increased as the duration of dialysis increased. These results strengthen the significant role of the renal function in retinal vascular disease.

Structural and Functional Imaging of the Retina in Central Retinal Artery Occlusion - Current Approaches and Future Directions.

Central retinal artery occlusion (CRAO) is a form of acute ischemic stroke which affects the retina. Intravenous thrombolysis is emerging as a compelling therapeutic approach. However, it is not known which patients may benefit from this therapy because there are no imaging modalities that adequately distinguish viable retina from irreversibly infarcted retina. The inner retina receives arterial supply from the central retinal artery and there is robust collateralization between this circulation and the outer retinal circulation, provided by the posterior ciliary circulation. Fundus photography can show canonical changes associated with CRAO including a cherry-red spot, arteriolar boxcarring and retinal pallor. Fluorescein angiography provides 2-dimensional imaging of the retinal circulation and can distinguish a complete from a partial CRAO as well as central versus peripheral retinal non-perfusion. Transorbital ultrasonography may assay flow through the central retinal artery and is useful in the exclusion of other orbital pathology that can mimic CRAO. Optical coherence tomography provides structural information on the different layers of the retina and exploratory work has described its utility in determining the time since onset of ischemia. Two experimental techniques are discussed. 1) Retinal functional imaging permits generation of capillary perfusion maps and can assay retinal oxygenation and blood flow velocity. 2) Photoacoustic imaging combines the principles of optical excitation and ultrasonic detection and - in animal studies - has been used to determine the retinal oxygen metabolic rate. Future techniques to determine retinal viability in clinical practice will require rapid, easily used, and reproducible methods that can be deployed in the emergency setting.

Diabetic and Retinal Vascular Eye Disease.

The retinal vasculature is the only neurovascular system directly visible to the human eye, easily evaluated by fundoscopy and many imaging modalities. This window allows physicians to diagnose and treat retinal pathologies and detect systemic diseases including diabetes, hypertension, hypercoagulable/hyperviscosity syndromes, and vasculitis. Diabetic retinopathy is the most common retinal vascular disease, followed by retinal vein and artery occlusion. Patients with these conditions require medical optimization to prevent further damage to the eyes and to the other organs. Both the internists and medical subspecialists play a crucial role in the prevention, detection, evaluation, and management of vision-threatening retinal vascular diseases.

Central retinal artery occlusion after Descemet membrane reposition by intracameral air: A case report.

PURPOSE: To report a case of central retinal artery occlusion after Descemet membrane reposition by intracameral air. METHODS: An otherwise healthy 60-year-old woman presented with white mature cataract in her left eye. Ocular exam of both eyes was within normal limits. After an uneventful topical phacoemulsification, a moderate-grade striate keratopathy and non-planar Descemet membrane detachment was noted on first postoperative day, which was confirmed on anterior segment optical coherence tomography. The Descemet membrane was repositioned within 24 h of cataract extraction by intracameral air tamponade (pneumatic descematopexy) under topical anesthesia, and partial air release was done after 2 h. The patient was evaluated for decreased immediate postoperative vision of perception of light. RESULTS: After pneumatic descematopexy, the stromal edema relatively cleared. The intraocular pressure before releasing the intracameral air was 38 mmHg and antiglaucoma medication was started. Dilated fundus exam showed retinal pallor and a cherry-red spot over the macula. A diagnosis of central retinal artery occlusion was confirmed, and thorough systemic workup was done. Systemic investigations were within normal limits. The patient was managed conservatively, but the final visual acuity remained at 1/60. CONCLUSION: Central retinal artery occlusion is not a reported complication after pneumatic descematopexy for Descemet membrane detachment management. The possible mechanism could be sudden increase in intraocular pressure due to pupil block by air, and thus, ocular surgeries with use of intracameral air for prolonged duration warrants close monitoring of intraocular pressure and its subsequent management.

Management of Acute Central Retinal Artery Occlusion, a "Retinal Stroke": An Institutional Series and Literature Review.

OBJECTIVES: Acute central retinal artery occlusion (CRAO) is an ophthalmologic emergency that often results in permanent vision loss. Over 25% are associated with acute cerebral ischemia. In the absence of existing Level I treatment options, this study aims to examine institutional practice patterns and review the literature to develop a formalized approach to the treatment of CRAO in the era of ischemic stroke protocols. MATERIALS AND METHODS: This is a retrospective review of institutional practices in the workup and treatment of patients diagnosed with acute non-arteritic (NA) CRAO at a single center from January 2017 to August 2020. RESULTS: Of 91 patients managed for acute NA-CRAO, 62.6% were male and average age was 66.4 years. Only 20.9% of patients presented within 4 h of symptom onset. 12.1% of patients had evidence of acute stroke on MRI, and 27.5% had ipsilateral internal carotid artery stenosis >50%. Half (52.7%) did not receive any acute treatment for CRAO, excluding antiplatelet/anticoagulation. 48.5% of patients undergoing acute medical treatment had improved visual acuity compared to 29.4% without treatment (p=0.14). CONCLUSIONS: There is a lack of clear protocol for the management of NA-CRAO. While not reaching statistical significance, our experience mirrors the literature with patients undergoing medical treatment demonstrating improved visual acuity over those without treatment. Given the presence of acute ischemic stroke, carotid disease, and/or stroke risk factors in over 25% of patients with CRAO, multidisciplinary involvement and modern stroke algorithms should be considered for this disease.

Risk of Retinal Artery Occlusion in Patients with Migraine.

PURPOSE: We sought to determine if migraine is associated with increased risk of retinal artery occlusion (RAO). DESIGN: Retrospective cohort study. METHODS: We reviewed a large insurance claims database for patients with migraine and matched control subjects without migraine between 2007 and 2016. Cox proportional hazard regression models were used to investigate the association between migraine and risk of all RAO, central RAO (CRAO), branch RAO (BRAO), and "other" RAO, which includes transient and partial RAO. Primary outcome measures included the incidence of all RAO, including CRAO, BRAO, and other RAO, after first migraine diagnosis. RESULT: There were 418,965 patients with migraine who met the study criteria and were included in the analysis with the appropriate matched control subjects. Among the 418,965 patients with migraine, 1060 (0.25%) were subsequently diagnosed with RAO, whereas only 335 (0.08%) of the patients without migraine were diagnosed with RAO. The hazard ratio (HR) for incident all RAO in patients with migraine compared with those without migraine was 3.48 (95% confidence interval [CI] 3.07-3.94; P < .0001). This association was consistent across all types of RAO, including CRAO (HR 1.62 [95% CI 1.15-2.28]; P = .004), BRAO (HR 2.09 [95% CI 1.60-2.72]; P < .001), and other types of RAO (HR 4.61 [95% CI 3.94-5.38]; P < .001). Patients with migraine with aura had a higher risk for incident RAO compared with those with migraine without aura (HR 1.58 [95% CI 1.40-1.79]; P < .001). This association was consistent for BRAO (HR 1.43 [95% CI 1.04-1.97]; P < .03) and other types of RAO (HR 1.67 [95% CI 1.45-1.91]; P < .001) but was not statistically significant for CRAO (HR 1.18 [95% CI 0.75-1.87]; P = .475). Significant risk factors for this association included increased age, male sex, acute coronary syndrome, valvular disease, carotid disease, hyperlipidemia, hypertension, retinal vasculitis or inflammation, and systemic lupus erythematosus. CONCLUSIONS: Migraine is associated with increased risk of all types of RAO and migraine with aura is associated with increased risk of RAO compared with migraine without aura.

Retinal vascular occlusions.

Acute retinal vascular occlusions are common causes of visual impairment. Although both retinal artery occlusions and retinal vein occlusions are associated with increased age and cardiovascular risk factors, their pathophysiology, systemic implications, and management differ substantially. Acute management of retinal artery occlusions involves a multidisciplinary approach including neurologists with stroke expertise, whereas treatment of retinal vein occlusions is provided by ophthalmologists. Optimisation of systemic risk factors by patients' primary care providers is an important component of the management of these two disorders.