Visual functions and multimodal imaging of patients with idiopathic focal choroidal excavation.

This study aimed to evaluate visual function and perform multimodal imaging on patients with focal choroidal excavation without any chorioretinal disease (idiopathic focal choroidal excavation [iFCE]). Seventeen eyes of 15 patients with iFCE (8 men, 7 women; mean ± standard deviation age, 56.0 ± 10.8 years) were assessed for visual function including visual acuity, metamorphopsia, aniseikonia, and retinal sensitivity. Multimodal imaging included optical coherence tomography (OCT), fundus autofluorescence (FAF), and OCT angiography. This study found that the maximum width and depth of the excavation were 597 ± 330 (238-1809) µm and 123 ± 45 (66-231) µm, respectively, and that FAF showed normal or hypoautofluorescence corresponding to iFCE. The fundus examination findings were stable during the follow-up period (96 ± 48 months). None of the eyes showed any abnormalities in central retinal sensitivity or aniseikonia. Metamorphopsia was detected using Amsler grid testing and M-CHARTS in two eyes. Therefore, this study is the first to quantitatively and qualitatively study metamorphopsia of patients with iFCE. Our results showed that most patients with iFCE did not have visual impairments, despite the presence of morphological changes in the outer retina and choroid.

Tractometry of Human Visual White Matter Pathways in Health and Disease.

Diffusion-weighted MRI (dMRI) provides a unique non-invasive view of human brain tissue properties. The present review article focuses on tractometry analysis methods that use dMRI to assess the properties of brain tissue within the long-range connections comprising brain networks. We focus specifically on the major white matter tracts that convey visual information. These connections are particularly important because vision provides rich information from the environment that supports a large range of daily life activities. Many of the diseases of the visual system are associated with advanced aging, and tractometry of the visual system is particularly important in the modern aging society. We provide an overview of the tractometry analysis pipeline, which includes a primer on dMRI data acquisition, voxelwise model fitting, tractography, recognition of white matter tracts, and calculation of tract tissue property profiles. We then review dMRI-based methods for analyzing visual white matter tracts: the optic nerve, optic tract, optic radiation, forceps major, and vertical occipital fasciculus. For each tract, we review background anatomical knowledge together with recent findings in tractometry studies on these tracts and their properties in relation to visual function and disease. Overall, we find that measurements of the brain's visual white matter are sensitive to a range of disorders and correlate with perceptual abilities. We highlight new and promising analysis methods, as well as some of the current barriers to progress toward integration of these methods into clinical practice. These barriers, such as variability in measurements between protocols and instruments, are targets for future development.

New-Onset Vision Impairment in Children: Magnetic Resonance Imaging Findings by Age Groups.

INTRODUCTION: Non-traumatic visual impairment is rare in the pediatric population, but early diagnosis and treatment of the cause is crucial to prevent long-term consequences affecting children's neurocognitive development. The authors aim to determine the most common causes of non-traumatic visual impairment in pediatric patients according to age groups by magnetic resonance imaging (MRI). METHODS: Images of patients who underwent contrast-enhanced cranial and orbital MRI for new-onset visual impairment between June 2019 and June 2022 were retrospectively reviewed. MRI findings were categorized as tumors, idiopathic intracranial hypertension, demyelinating disorders, infections, isolated optic neuritis, and others. The patients were grouped according to age as preschoolers, schoolchildren, and adolescents. Demographic features of patients and MRI findings were collected and compared among age groups. RESULTS: One hundred seventeen of the 238 patients had pathologic MRI findings. The most common pathologies were tumors (26.4%), idiopathic intracranial hypertension (24.7%), demyelinating disorders (18.8%), infections (11.1%), and isolated optic neuritis (7.6%). Tumors (69.2%) in preschool children, idiopathic intracranial hypertension (36.3%) in schoolchildren, and demyelinating disorders (32.7%) in adolescents were the most common cause of vision impairment by age group. CONCLUSION: Children with acute vision impairment could have severe pathologies. Tumors in preschool children, idiopathic intracranial hypertension in schoolchildren, and demyelinating disorders in adolescents were the most common causes of new-onset vision impairment detected with MRI. Because of the difficulty of performing optimal ophthalmologic and neurologic examinations, especially in young children, cranial and orbital MRI should be considered to detect life-threatening pathologies.

Understanding Visual Disorders through Correlation of Clinical and Radiologic Findings.

Patients presenting with visual disturbances often require a neuroimaging approach. The spectrum of visual disturbances includes three main categories: vision impairment, ocular motility dysfunction, and abnormal pupillary response. Decreased vision is usually due to an eye abnormality. However, it can also be related to other disorders affecting the visual pathway, from the retina to the occipital lobe. Ocular motility dysfunction may follow disorders of the cranial nerves responsible for eye movements (ie, oculomotor, trochlear, and abducens nerves); may be due to any abnormality that directly affects the extraocular muscles, such as tumor or inflammation; or may result from any orbital disease that can alter the anatomy or function of these muscles, leading to diplopia and strabismus. Given that pupillary response depends on the normal function of the sympathetic and parasympathetic pathways, an abnormality affecting these neuronal systems manifests, respectively, as pupillary miosis or mydriasis, with other related symptoms. In some cases, neuroimaging studies must complement the clinical ophthalmologic examination to better assess the anatomic and pathologic conditions that could explain the symptoms. US has a major role in the assessment of diseases of the eye and anterior orbit. CT is usually the first-line imaging modality because of its attainability, especially in trauma settings. MRI offers further information for inflammatory and tumoral cases. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

The relation between neuroimaging and visual impairment in children and adolescents with cerebral palsy: A systematic review.

OBJECTIVE: The structure-function relation between magnetic resonance imaging (MRI) and visual impairment (VI) in children with cerebral palsy (CP) has not been fully unravelled. The present systematic review aims to summarize the relation between brain lesions on MRI and VI in children and adolescents with CP. METHODS: PubMed, Embase, Web of Science Core Collection, and Cochrane Database were systematically searched according to the PRISMA checklist. A total of 45 articles met the inclusion criteria. RESULTS: White matter lesions were most frequently associated with VI. Only 25 studies described lesions within specific structures, mainly in the optic radiations. Only four studies reported on the thalamus. 8.4% of children with CP showed no brain abnormalities on MRI. Diffusion-weighted MRI studies showed that decreased structural connectivity in the optic radiations, superior longitudinal fasciculus, posterior limb of the internal capsule, and occipital lobe is associated with more severe VI. CONCLUSIONS: All types of brain lesions lead to visual dysfunctions, arguing for a comprehensive visual assessment in all children with CP. Whereas white matter damage is a well-known contributor, the exact contribution of specific visual structures requires further investigation, to enable early prediction, detection, and intervention.

Immune-related visual dysfunction in thyroid eye disease: a combined orbital and brain neuroimaging study.

OBJECTIVES: To investigate the pathological interplay between immunity and the visual processing system (VPS) in thyroid eye disease (TED). METHODS: A total of 24 active patients (AP), 26 inactive patients (IP) of TED, and 27 healthy controls (HCs) were enrolled. Orbital magnetic resonance imaging (MRI) and resting-state functional MRI (rs-fMRI) were conducted for each participant. Multiple MRI parameters of the intraorbital optic nerve (ON) were assessed. The amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) were calculated. Correlation analyses were carried out on the above parameters and clinical characteristics. RESULTS: Visual functioning scores differentiated between the AP and IP groups. The ON subarachnoid space and ON sheath diameter were significantly higher in AP than in IP. Six vision-related brain regions were identified in TED patients compared with HCs, including right calcarine (CAL.R), right cuneus (CUN.R), left postcentral gyrus (PoCG.L), right middle temporal gyrus (MTG.R), left superior frontal gyrus (SFG.L), and left caudate (CAU.L). The brain activity of MTG.R, SFG.L, and CAU.L differentiated between the AP and IP groups. The correlation analysis revealed a close association among the vision-related brain regions, MRI parameters of ON, and clinical characteristics in AP and IP, respectively. CONCLUSIONS: Combined orbital and brain neuroimaging revealed abnormalities of the VPS in TED, which had a close correlation with immune statuses. Vision-related brain regions in TED might be possibly altered by peripheral immunity via a direct or indirect approach. CLINICAL RELEVANCE STATEMENT: The discovery of this study explained the disparity of visual dysfunction in TED patients with different immune statuses. With the uncovered neuroimaging markers, early detection and intervention of visual dysfunction could be achieved and potentially benefit TED patients. KEY POINTS: • Patients with different immune statuses of thyroid eye disease varied in the presentation of visual dysfunction. • The combined orbital and brain neuroimaging study identified six altered vision-related brain regions, which had a significant correlation with the MRI parameters of the intraorbital optic nerve and immunological characteristics. • Peripheral immunity might possibly give rise to alterations in the central nervous system part of the visual processing system via a direct or indirect approach.

MRI features of idiopathic intracranial hypertension are not prognostic of visual and headache outcome.

BACKGROUND: In idiopathic intracranial hypertension (IIH), certain MRI features are promising diagnostic markers, but whether these have prognostic value is currently unknown. METHODS: We included patients from the Vienna-Idiopathic-Intracranial-Hypertension (VIIH) database with IIH according to Friedman criteria and cranial MRI performed at diagnosis. Presence of empty sella (ES), perioptic subarachnoid space distension (POSD) with or without optic nerve tortuosity (ONT), posterior globe flattening (PGF) and transverse sinus stenosis (TSS) was assessed and multivariable regression models regarding visual outcome (persistent visual impairment/visual worsening) and headache outcome (headache improvement/freedom of headache) were fitted. RESULTS: We included 84 IIH patients (88.1% female, mean age 33.5 years, median body mass index 33.7). At baseline, visual impairment was present in 70.2% and headache in 84.5% (54.8% chronic). Persistent visual impairment occurred in 58.3%, visual worsening in 13.1%, headache improvement was achieved in 83.8%, freedom of headache in 26.2%. At least one MRI feature was found in 78.6% and 60.0% had ≥3 features with POSD most frequent (64.3%) followed by TSS (60.0%), ONT (46.4%), ES (44.0%) and PGF (23.8%). In multivariable models, there was no association of any single MRI feature or their number with visual impairment, visual worsening, headache improvement or freedom. Visual impairment at baseline predicted persistent visual impairment (odds ratio 6.3, p<0.001), but not visual worsening. Chronic headache at baseline was significantly associated with lower likelihood of headache freedom (odds ratio 0.48, p=0.013), but not with headache improvement. CONCLUSIONS: MRI features of IIH are neither prognostic of visual nor headache outcome.

Traumatic Brain Injury and Vision.

Traumatic brain injury disrupts the complex anatomy of the afferent and efferent visual pathways. Injury to the afferent pathway can result in vision loss, visual field deficits, and photophobia. Injury to the efferent pathway primarily causes eye movement abnormalities resulting in ocular misalignment and double vision. Injury to both the afferent and efferent systems can result in significant visual disability.

Association between visual impairment and psychosis: A longitudinal study and nested case-control study of adults.

BACKGROUND: Theories propose that visual impairment might increase the risk of psychosis, and vice versa. We aimed to investigate the relationship between visual impairment and psychosis in the UK Biobank cohort. STUDY DESIGN: In a nested case control study of ~116,000 adults, we tested whether a Schizophrenia Spectrum Disorder (SSD) diagnosis as exposure was associated with visual impairment. We also tested longitudinally whether poorer visual acuity, and thinner retinal structures on Optical Coherence Tomography (OCT) scans in 2009 were associated with psychotic experiences in 2016. We adjusted for age, sex, depression and anxiety symptoms; and socioeconomic variables and vascular risk factors where appropriate. We compared complete case with multiple imputation models, designed to reduce bias potentially introduced by missing data. RESULTS: People with visual impairment had greater odds of SSD than controls in multiply imputed data (Adjusted Odds Ratio [AOR] 1.42, 95 % Confidence Interval [CI] 1.05-1.93, p = 0.021). We also found evidence that poorer visual acuity was associated with psychotic experiences during follow-up (AOR per 0.1 point worse visual acuity score 1.06, 95 % CI 1.01-1.11, p = 0.020; and 1.04, 95 % CI 1.00-1.08, p = 0.037 in right and left eye respectively). In complete case data (15 % of this cohort) we found no clear association, although confidence intervals included the multiple imputation effect estimates. OCT measures were not associated with psychotic experiences. CONCLUSIONS: Our findings highlight the importance of eye care for people with psychotic illnesses. We could not conclude whether visual impairment is a likely causal risk factor for psychosis.

The yield of neuroimaging in patients presenting to the emergency department with isolated neuro-ophthalmological complaints: A retrospective chart review.

Neuro-ophthalmological emergencies require prompt assessment and management to avoid vision or life-threatening sequelae. The decision to perform a neuroimaging procedure is based on the clinical judgment of the medical team, without defined indications. This study aims to identify presenting symptoms and physical exam findings associated with relative positive findings on neuroimaging studies. Electronic medical records of patients presenting to the emergency department (ED) with isolated neuro-ophthalmologic complaints between January 1, 2013 and September 30, 2019 were reviewed. We collected data on the clinical presentation, neuroimaging procedures and results, consults, and diagnoses. Two hundred eleven patients' charts were reviewed. Most presented with unilateral eye complaints (53.6%), and the most common symptoms were blurred vision (77.3%) and headaches (42.2%). A total of 126 imaging procedures were performed of which 74.6% were normal, while 25.4% showed relevant abnormal findings. Complaining of blurry vision (P = .038) or visual field changes (P = .014) at presentation as well as having a visual field defect (P = .016), abnormal pupil reactivity (P = .028), afferent pupillary defect (P = .018), or abnormal optic disc exam (P = .009) were associated with positive findings on imaging. Neuroimaging is more likely to yield positive findings in patients presenting to the ED with visual field irregularities, afferent pupillary defects, or abnormal optic discs. These findings - when combined with the proper clinical setting - should lower the threshold to proceed with neuroimaging in the emergency department. Based on our results, larger-scale studies might lead to a well-structured algorithm to be followed by ED physicians in decision making.

Neurovascular Compression in the Anterior Visual Pathway: A Case Series.

A retrospective review of 29 patients with neurovascular compression syndrome (NVCS) involving the anterior visual pathway was conducted. Various patterns of NVCS and visual defects were identified, most commonly involving the optic nerve and internal carotid artery. Most patients were stable, except one with progressive visual field defects. Although mostly asymptomatic, NVCS can rarely cause compressive optic neuropathy. NVCS should be kept in the differential diagnosis of normal tension glaucoma, especially with progressive visual loss despite treatment. Patients with progressive visual loss may require decompression surgery. Non-contrast computed tomography scan may miss NVCS, and magnetic resonance imaging is diagnostic.

RETINAL THICKNESS AND FOVEAL HYPOPLASIA IN ADULTS BORN PRETERM WITH AND WITHOUT RETINOPATHY OF PREMATURITY: The Gutenberg Prematurity Eye Study.

PURPOSE: This study analyses whether prematurity, retinopathy of prematurity (ROP), and associated factors lead to altered foveal shape in adulthood and whether these alterations are associated with visual acuity. METHODS: The Gutenberg Prematurity Eye Study is a German cohort study with a prospective ophthalmologic examination (participants aged 18-52 years) of individuals born preterm and full-term that were examined with spectral domain optical coherence tomography. Participants were grouped according to gestational age (GA) and postnatal ROP status. Multivariable linear regression analyses for foveolar retinal thickness, foveal hypoplasia, and posterior vitreous status were performed. RESULTS: A total of 755 eyes of 414 preterm and full-term individuals were included (aged 28.6 ± 8.6 years, 233 female individuals). Central foveal retinal thickness increased as GA decreased. The prevalence of foveal hypoplasia was 2% (control group), 9% (GA 33-36), 18% (GA 29-32), 48% (GA ≤28), 50% (ROP without treatment), and 82% of eyes (with ROP requiring treatment). In multivariable analyses, central foveal thickness was independently associated with GA and advanced stages of ROP requiring treatment while foveal hypoplasia was only associated with GA. Posterior vitreous was more frequently visible as partially detached in full-term than in preterm individuals. Lower distant-corrected visual acuity correlated with increased foveolar thickness (rho = 0.08; P = 0.03) and with foveal hypoplasia (rho = 0.15, P < 0.001). CONCLUSION: Our findings indicate that there are fetal origins affecting foveal shape, resulting in foveal hypoplasia potentially affecting the visual acuity in adulthood.

Choroidal macrovessel and persistent metamorphopsia after epiretinal membrane surgery.

We report the case of a 59-year-old man with decreased visual acuity and metamorphopsia in both eyes in the context of bilateral epiretinal membrane (ERM) who underwent retinovitreal surgery (chromovitrectomy plus peeling of internal limiting membrane). He recovered visual acuity in his left eye. However, the visual results of his right eye were not satisfactory, with persistence of metamorphopsia in that eye. The multimodal imaging study that included color and red filter retinographies, enhanced depth imaging optical coherence tomography (EDI-OCT), fluorescein angiography (FA), indocyanine green angiography (ICGA), OCT angiography (OCTA) and OCT en face, were useful to diagnose a choroidal macrovessel. This ran from the fovea to the temporal macula. EDI-OCT revealed that the choroidal macrovessel generated a foveal deformation of both the ellipsoid zone (EZ) and the retinal pigment epithelium (RPE). This paper discusses whether structural changes in the fovea generated by the choroidal macrovessel are related to persistent metamorfopsia in the affected eye.

The effect of prolonged spaceflight on cerebrospinal fluid and perivascular spaces of astronauts and cosmonauts.

Long-duration spaceflight induces changes to the brain and cerebrospinal fluid compartments and visual acuity problems known as spaceflight-associated neuro-ocular syndrome (SANS). The clinical relevance of these changes and whether they equally affect crews of different space agencies remain unknown. We used MRI to analyze the alterations occurring in the perivascular spaces (PVS) in NASA and European Space Agency astronauts and Roscosmos cosmonauts after a 6-mo spaceflight on the International Space Station (ISS). We found increased volume of basal ganglia PVS and white matter PVS (WM-PVS) after spaceflight, which was more prominent in the NASA crew than the Roscosmos crew. Moreover, both crews demonstrated a similar degree of lateral ventricle enlargement and decreased subarachnoid space at the vertex, which was correlated with WM-PVS enlargement. As all crews experienced the same environment aboard the ISS, the differences in WM-PVS enlargement may have been due to, among other factors, differences in the use of countermeasures and high-resistive exercise regimes, which can influence brain fluid redistribution. Moreover, NASA astronauts who developed SANS had greater pre- and postflight WM-PVS volumes than those unaffected. These results provide evidence for a potential link between WM-PVS fluid and SANS.

Brain microstructural antecedents of visual difficulties in infants born very preterm.

Infants born very preterm (VPT) are at risk of later visual problems. Although neonatal screening can identify ophthalmologic abnormalities, subtle perinatal brain injury and/or delayed brain maturation may be significant contributors to complex visual-behavioral problems. Our aim was to assess the micro and macrostructural antecedents of early visual-behavioral difficulties in VPT infants by using diffusion MRI (dMRI) at term-equivalent age. We prospectively recruited a cohort of 262 VPT infants (≤32 weeks gestational age [GA]) from five neonatal intensive care units. We obtained structural and diffusion MRI at term-equivalent age and administered the Preverbal Visual Assessment (PreViAs) questionnaire to parents at 3-4 months corrected age. We used constrained spherical deconvolution to reconstruct nine white matter tracts of the visual pathways with high reliability and performed fixel-based analysis to derive fiber density (FD), fiber-bundle cross-section (FC), and combined fiber density and cross-section (FDC). In multiple logistic regression analyses, we related these tract metrics to visual-behavioral function. Of 262 infants, 191 had both high-quality dMRI and completed PreViAs, constituting the final cohort: mean (SD) GA was 29.3 (2.4) weeks, 90 (47.1%) were males, and postmenstrual age (PMA) at MRI was 42.8 (1.3) weeks. FD and FC of several tracts were altered in infants with (N = 59) versus those without retinopathy of prematurity (N = 132). FDC of the left posterior thalamic radiations (PTR), left inferior longitudinal fasciculus (ILF), right superior longitudinal fasciculus (SLF), and left inferior fronto-occipital fasciculus (IFOF) were significantly associated with visual attention scores, prior to adjusting for confounders. After adjustment for PMA at MRI, GA, severe retinopathy of prematurity, and total brain volume, FDC of the left PTR, left ILF, and left IFOF remained significantly associated with visual attention. Early visual-behavioral difficulties in VPT infants are preceded by micro and macrostructural abnormalities in several major visual pathways at term-equivalent age.

Epileptic manifestations, pathophysiology, and imaging characteristics of non-ketotic hyperglycaemia: a review of the literature and a report of two cases with irreversible cortical vision loss.

The purpose of this review is to create more awareness regarding the epileptic manifestations of non-ketotic hyperglycaemia, which are not widely recognised, and to assist understanding of the pathophysiology involved. Given that type II diabetes is one of the common causes of morbidity worldwide, it is important to appreciate the various neurological manifestations of non-ketotic hyperglycaemia.Here, I present two cases and review the existing literature. Both patients developed irreversible vision loss, which is a novel finding because only transient visual defects have previously been reported. The review includes a detailed discussion of the pathophysiology and characteristic magnetic resonance imaging (MRI) findings of patients with defects in cerebral lobar regions, which were associated with a variety of clinical manifestations. These manifestations can be ascribed to epileptic phenomena involving various parts of the cerebrum.Hyperglycaemia can lead to the irreversible loss of vision. Early diagnosis and treatment on the basis of the clinical features and characteristic MRI findings are important to avoid an epilepsia partialis continua-like state and irreversible visual impairment.

Resting-state Functional Connectivity After Occipital Stroke.

BACKGROUND: Resting-state functional magnetic resonance imaging (rsfMRI) reflects spontaneous activation of cortical networks. After stroke, these networks reorganize, both due to structural lesion and reorganization of functional connectivity (FC). OBJECTIVE: We studied FC in chronic phase occipital stroke patients with homonymous visual field defects before and after repetitive transorbital alternating current stimulation (rtACS). METHODS: This spin-off study, embedded in the randomized, sham-controlled REVIS trial, comprised 16 chronic occipital stroke patients with visual field defect and 12 healthy control subjects. The patients underwent rsfMRI at baseline, after two weeks of rtACS or sham treatment, and after two months of treatment-free follow-up, whereas the control subjects were measured once. We used a multivariate regression connectivity model to determine mutual prediction accuracy between 74 cortical regions of interest. Additionally, the model parameters were included into a graph to analyze average path length, centrality eigenvector, centrality degree, and clustering of the network. The patients and controls at baseline and the two treatment groups were compared with multilevel modeling. RESULTS: Before treatment, the patients and controls had similar whole-network prediction accuracy and network parameters, whereas centrality eigenvector differed in perilesional regions, indicating local modification in connectivity. In line with behavioral results, neither prediction accuracy nor any network parameter changed systematically as a result of rtACS rehabilitation compared to sham. CONCLUSIONS: Whole-network FC showed no difference between occipital stroke patients and healthy population, congruent with the peripheral location of the visual network in relation to the high-density cortical core. rtACS treatment in the given setting did not affect FC.

Influence of postoperative ectopic inner foveal layer on visual function after removal of idiopathic epiretinal membrane.

PURPOSE: To investigate the functional and anatomical parameters and their postoperative changes according to the ectopic inner foveal layer (EIFL) staging scheme for idiopathic epiretinal membrane (ERM). METHODS: In this prospective study, patients with idiopathic ERM underwent pars plana vitrectomy and ERM removal, and were followed-up for 6 months. The associations of EIFL with pre- and postoperative functional and anatomical parameters were analyzed. RESULTS: A total of 84 eyes (84 patients) were included: 39 (46.4%), 33 (39.3%), and 12 (14.3%) as EIFL stages 2, 3, and 4, respectively. At 6 months after surgery, the mean best-corrected visual acuity (BCVA) significantly improved in all EIFL stages (P ≤ 0.003); however, metamorphopsia improved only in eyes with EIFL stage 2 (P = 0.039) and 3 (P = 0.011). The aniseikonia and foveal avascular zone (FAZ) area showed no significant postoperative changes in any of the EIFL stages. Both preoperatively and during 6 months after surgery, the EIFL stage showed a significant correlation with BCVA (P ≤ 0.033), metamorphopsia (P ≤ 0.008), central macular thickness (P < 0.001), and FAZ parameters (P ≤ 0.016) at each time point, but not with aniseikonia. Significant correlations of EIFL thickness with BCVA (P = 0.028) and metamorphopsia (P = 0.006) before surgery were not persistent after surgery. CONCLUSION: Both pre- and postoperatively, the staging of EIFL, rather than its thickness, is a simple and adequate surrogate marker for visual acuity and metamorphopsia in eyes with idiopathic ERM.