Correlation between cerebral visual impairment and magnetic resonance imaging in children with neonatal encephalopathy

Cerebral/Cortical Visual Impairment Classification and Categorization Using Eye Tracking Measures of Oculomotor Function

Purpose

Cerebral/cortical visual impairment (CVI) is a leading cause of pediatric visual impairment and is frequently associated with abnormal ocular motility. Eye tracking has previously been used to characterize oculomotor function in CVI. The purpose of this study was to evaluate the utility of eye tracking in diagnosis, categorization, and prognostication of CVI.

Design

Prospective longitudinal study.

Participants

Thirty-nine children with CVI and 41 age-matched controls.

Methods

Children with CVI underwent 4 eye tracking sessions over 1 year, and age-matched controls completed 1 eye tracking session. Fixations and saccades were labeled by the eye tracking software and used to compute 9 oculomotor features. In children with CVI, unsupervised data-driven clustering analysis using these 9 features was performed to identify 3 CVI eye tracking oculomotor groups. Clinical and demographic characteristics of eye tracking oculomotor groups were compared.

Main Outcome Measures

(1) Area under the curve (AUC) for eye tracking oculomotor features in classifying patients with CVI and controls; (2) differences between 3 CVI eye tracking oculomotor groups on clinical and demographic characteristics; and (3) change in visual acuity (VA) over 1 year in 3 CVI eye tracking oculomotor groups.

Results

Six oculomotor features (fixation and saccade latency, frequency, and off-screen proportion) had an AUC ≥0.90 in classifying children with CVI and controls (P < 0.0001). Cerebral/cortical visual impairment eye tracking oculomotor groups had significantly different VA (P < 0.0001) and change in VA over 1 year (P = 0.049). Patients in group B, who had the greatest improvement in VA, were younger and had higher rates of term hypoxic ischemic encephalopathy.

Conclusions

Eye tracking measures of oculomotor function accurately distinguish between children with CVI and age-matched controls. Clustering analysis revealed 3 CVI eye tracking oculomotor groups with prognostic significance. Eye tracking shows promise as an objective, quantitative measure of oculomotor function in CVI that may in future be useful in both clinical practice (for longitudinal assessment, prognostication, and guiding individualized interventions) and research (as an outcome measure or method to stratify patients in clinical trials).

Financial Disclosures

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

Natural history of cerebral visual impairment in children with cerebral palsy

AIM

To longitudinally evaluate the natural history of cerebral visual impairment (CVI) in children with cerebral palsy (CP) and identify which early visual signs or symptoms are associated with cognitive visual disorders (CVDs) at school age.

METHOD

Fifty-one individuals with CP and CVI underwent an ophthalmological, oculomotor, and basic visual function evaluation at three time points: T0 (6-35 months old); T1 (3-5 years old); and T2 (≥6 years old). We also performed a cognitive visual evaluation at T2. Logistic regression fitted using a generalized estimation equation (binary) and cumulative link models (ordinal) were used to model the outcomes of interest.

RESULTS

Ophthalmological deficits were stable over time, except for ocular fundus abnormalities (T1-T0, p = 0.01; T2-T1, p = 0.02; T2-T0, p < 0.01) and strabismus, whose frequency increased with age (T2-T0, p= 0.02 with T2-T0, p = 0.05). Conversely, fixation (T1-T0, T2-T0, p < 0.01), smooth pursuit (T2-T1, T2-T0, p < 0.01), saccades (T1-T0, T2-T1, T2-T0, p < 0.01), as well as visual acuity, contrast sensitivity, and visual field (T1-T0, T2-T0, p < 0.01) all improved over time. Early oculomotor dysfunction was associated with CVD at T2.

INTERPRETATION

Although a diagnosis of CVI was confirmed in all children at each time point, several visual signs and symptoms improved over time; in some cases, they reached complete recovery at T1 and T2. These results emphasize the 'permanent' but 'not unchanging' nature of the CVI associated with CP during development.

Special Commentary: Cerebral/Cortical Visual Impairment Working Definition: A Report from the National Institutes of Health CVI Workshop

Cerebral/cortical visual impairment (CVI), a brain-based condition, has emerged as a leading cause of pediatric visual impairment in the United States and other industrialized nations. The National Eye Institute (NEI) recognized CVI as a priority area for research as part of their 2021 NEI Vision for the Future Strategic Plan and partnered with the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institute of Neurologic Disorders and Stroke within the National Institutes of Health (NIH) to sponsor a CVI Workshop in November 2023. A panel consisting of a group of clinicians with expertise in diagnosing CVI convened to draft a working definition for this condition. Five key elements were identified: (1) CVI encompasses a spectrum of visual impairments caused by an underlying brain abnormality that affects the development of visual processing pathways and is characterized by deficits in visual function and functional vision; (2) the visual dysfunction in CVI is greater than expected by any comorbid ocular conditions alone; (3) the visual dysfunction in CVI may manifest as lower-order or higher-order afferent visual deficits, or both, leading to characteristic behaviors in affected individuals; (4) although CVI may be comorbid with other neurodevelopmental disorders, CVI is not primarily a disorder of language, learning, or social communication; and (5) the underlying neurologic insult of the developing brain may go unrecognized or undiagnosed until later in life. Future work is needed to achieve consensus on nomenclature, diagnostic criteria, and strategies for early identification and intervention. The NIH is developing a CVI registry to collect relevant demographic and clinical data prospectively and longitudinally to help inform future research questions and to provide insight into considerations for future clinical trials in the field of CVI.

Current perspective: Cerebral visual impairment-The impending doom

Cerebral visual impairment (CVI) has emerged as an important cause of morbidity in young children. CVI children often have a large number of visual symptoms along with motor abnormalities. It is the need of the hour to build an integrated approach towards their management. This article aimed to provide a comprehensive view of the manifestations, evaluation, and management of children with CVI.

Parent-Reported Visual Concerns in Children with Cerebral Visual Impairment Presenting to a Pediatric Neurology Clinic

Purpose

Children with cerebral visual impairment (CVI) present with delayed developmental milestones. Pediatricians and pediatric neurologists are usually the first point of contact, and eye exam largely remains referral based. This study documented the visual concerns reported by parents of children with CVI visiting a pediatric neurology clinic. Additionally, we investigated the association between visual concerns, functional vision measures and visual functions.

Patients and Methods

A cross-sectional study was undertaken in children with CVI (chronological age range: 7 months-7 years). Visual concerns reported by the parents/caregivers were documented as open-ended statements. Additionally, a functional vision assessment was conducted using the CVI Range instrument with phase 1, 2 and 3 indicating low, moderate and high visual functioning, respectively. Grating acuity and contrast sensitivity were measured using Teller acuity cards-II and Ohio contrast cards respectively.

Results

A total of 73 children (mean age of 2.84 ± 1.87 years) were recruited. Sixty-eight parents reported visual concerns that were broadly grouped into 14 unique concerns. Nineteen parents (27.9%) reported more than one visual concern. Difficulty maintaining eye contact and recognizing faces were the top two visual concerns in phases 1 and 2. Missing objects in the lower visual field was the top concern in phase 3. A larger number of visual concerns were reported in phase 1 (43%) than phase 2 (40.6%) and phase 3 (16.2%). Multiple regression analysis revealed that grating acuity, contrast sensitivity and chronological age were able to predict the functional vision, F (3, 55) = 63.0, p < 0.001, r² = 0.77.

Conclusion

Targeted questions enquiring about eye contact and face recognition can be included in history elicitation in children with CVI in pediatric neurology clinics. In the presence of visual concerns, it will be important to assess grating acuity and contrast sensitivity. A poor functional vision score requires referral for eye examination and vision rehabilitation services.

Development of an integrated telerehabilitation model in children with cerebral visual impairment in South India during the COVID-19 pandemic - A pilot study

Purpose

Coronavirus disease 2019 (COVID-19) pandemic affected the in-person rehabilitation/habilitation services in families with children with cerebral visual impairment (CVI) in India. This study aimed to develop a structured and family-centered telerehabilitation model alongside conventional in-person intervention in children with CVI to observe its feasibility in the Indian population.

Methods

This pilot study included 22 participants with a median age of 2.5 years (range: 1-6) who underwent a detailed comprehensive eye examination followed by functional vision assessment. The visual function classification system (VFCS) was administered to the children and the structured clinical question inventory (SCQI) to the parents. Every participant underwent 3 months of telerehabilitation including planning, training, and monitoring by experts. At 1 month, the parental care and ability (PCA) rubric was administered to the parents. After 3 months, in an in-person follow-up, all the measures were reassessed for 15 children.

Results

After 3 months of Tele-rehabilitation there were significant improvements noted in PCA rubric scores (P<0.05). Also, statistically significant improvements were noted in functional vision measured using SCQI and VFCS scores (P<0.05) compared to baseline.

Conclusion

The outcomes of the study provide the first steps towards understanding the use of a novel tele-rehabilitation model in childhood CVI along-side conventional face-to-face intervention. The added role of parental involvement in such a model is highly essential.

Longitudinal neurological analysis of moderate and severe pediatric cerebral visual impairment

Introduction

Cerebral visual impairment (CVI) results from damage to cerebral visual processing structures. It is the most common cause of pediatric visual impairment in developed countries and rising in prevalence in developing nations. There is currently limited understanding on how neurologic, developmental, and ophthalmic factors predict outcome for pediatric CVI.

Method

A retrospective manual chart review of pediatric CVI patients seen at the tertiary pediatric hospital neurology and neuro-ophthalmology service between 2010 and 2019 was conducted. Patients were stratified into severity groups (based on a custom CVI grading score), and followed over time to identify outcome predictors. Collected baseline characteristics included perinatal, genetic, developmental, and neurologic history, along with neuroimaging and fundoscopic findings on examination. Longitudinal data collected included age, seizure control, and type of therapy received. Linear mixed-effect models were used for longitudinal CVI grade outcome analysis.

Results

A total of 249 individuals spanning 779 patient visits were identified. Mean age at diagnosis was 18.8 ± 16.8 months (2–108 months). About 64.3% were born at term age. Perinatal history revealed hypoxic ischemic encephalopathy (HIE) in 16.5%, intraventricular hemorrhage (IVH) in 11.6%, and seizures in 21.7%. At presentation, 60.3% had a diagnosis of cerebral palsy and 84.7% had developmental delay. Among all subjects, 78.6% had epilepsy; 33.8% had an epileptic encephalopathy, with spasms/hypsarrhythmia being most common. Abnormal neuroimaging was present in 93.8%. Genetic anomalies were present in 26.9%. Baseline visual examination revealed no blink-to-light (BTL) in 24.5%; only BTL in 34.5%, fixation/tracking in 26.5%, and optokinetic drum follow in 14.4%. Longitudinal data analysis showed that perinatal history of HIE, a positive epilepsy history, using multiple (≥3) epilepsy medications, cerebral palsy, and abnormal fundoscopic findings were all negatively associated with CVI grade change over time. After controlling for significant confounders, receiving any type of therapy [early childhood intervention (ECI), physical and occupational therapy (PT/OT), refractive error correction or glasses] was significantly associated with longitudinal improvement in CVI grade compared to patients who did not receive any therapy, with glasses yielding the largest benefit.

Conclusion

This study offers extensive insights into neurologic, developmental and ophthalmologic features in patients with moderate to severe CVI. In concordance with previous findings, aspects of perinatal history and epilepsy/seizure control may help inform severity and prognosis in the general neurology or ophthalmology clinic. Conversely, these aspects, as well as genetic and specific epilepsy traits may alert vision health care providers in the clinic to pursue visual evaluation in at-risk individuals. Longitudinal follow-up of CVI patients showed that interventional therapies demonstrated vision function improvement greater than no therapy and maturational development.

The Multidisciplinary Guidelines for Diagnosis and Referral in Cerebral Visual Impairment

Introduction

Cerebral visual impairment (CVI) is an important cause of visual impairment in western countries. Perinatal hypoxic-ischemic damage is the most frequent cause of CVI but CVI can also be the result of a genetic disorder. The majority of children with CVI have cerebral palsy and/or developmental delay. Early diagnosis is crucial; however, there is a need for consensus on evidence based diagnostic tools and referral criteria. The aim of this study is to develop guidelines for diagnosis and referral in CVI according to the grade method.

Patients and Methods

We developed the guidelines according to the GRADE method 5 searches on CVI (children, developmental age ≤ 18 years) were performed in the databases Medline, Embase, and Psychinfo, each with a distinct topic.

Results

Based on evidence articles were selected on five topics: 1. Medical history and CVI-questionnaires 23 (out of 1,007). 2. Ophthalmological and orthoptic assessment 37 (out of 816). 3. Neuropsychological assessment 5 (out of 716). 4. Neuroradiological evaluation and magnetic resonance imaging (MRI) 9 (out of 723). 5. Genetic assessment 5 (out of 458).

Conclusion

In medical history taking, prematurity low birth weight and APGAR (Appearance, Pulse, Grimace, Activity, Respiration) Scores (<5) are important. Different questionnaires are advised for children under the age of 3 years, older children and for specific risk groups (extremely preterm). In ophthalmological examination, eye movements, specially saccades, accommodation, crowding, contrast sensitivity and visual fields should be evaluated. OCT can show objective signs of trans-synaptic degeneration and abnormalities in fixation and saccades can be measured with eye tracking. Screening of visual perceptive functioning is recommended and can be directive for further assessment. MRI findings in CVI in Cerebral Palsy can be structured in five groups: Brain maldevelopment, white and gray matter lesions, postnatal lesions and a normal MRI. In children with CVI and periventricular leukomalacia, brain lesion severity correlates with visual function impairment. A differentiation can be made between cortical and subcortical damage and related visual function impairment. Additional assessments (neurological or genetic) can be necessary to complete the diagnosis of CVI and/or to reveal the etiology.

Ocular and cerebral causes of visual impairment in young children and a new scoring system to evaluate visual function

PURPOSE

Childhood blindness is important cause contributing to the burden of blindness. It is necessary to identify the most frequently observed diseases in different populations. We aimed to demonstrate clinical features of low vision children and to evaluate the factors affecting visual function by a new visual function scoring system.

METHODS

Two hundred forty nine children between the age of 6 months and 3 years were included. Visual function was scored from 0 to 15 according to; response to threat, light, object, presence of fixation, duration of fixation, following of light and object in horizontal, vertical, oblique, and circular gazes, optokinetic nystagmus. Patients were classified according to neurological diagnosis and cranial magnetic resonance imaging findings. Correlation between visual function score and ocular and neurologic findings were evaluated.

RESULTS

While 136 patients (54.6%) had cerebral visual impairment (CVI), 89 (35.7%) had ocular pathology, 24 patients (9.6%) had combined pathology. The most common ocular and cerebral pathologies were oculocutaneous albinism (23.9%) and hypoxic ischemic encephalopathy (HIE) (27.5%), respectively. Patients with CVI had lower visual function than ocular pathologies. Neurological structural disorders and HIE had worse visual function. Widespread involvement of brain had lower visual function score. Seizure negatively affected visual function.

CONCLUSIONS

Cerebral causes were found in approximately half of infants and children with low vision who were referred to our center for visual habilitation. The visual function scoring system we developed in this study will provide an opportunity to be objective in the follow-up of babies and in evaluating the effectiveness of visual habilitation programs.

Exploratory Investigation of Brain MRI Lesions According to Whole Sample and Visual Function Subtyping in Children With Cerebral Visual Impairment

Background: There is limited research on brain lesions in children with cerebral visual impairment (CVI) of heterogeneous etiologies and according to associated subtyping and vision dysfunctions. This study was part of a larger project establishing data-driven subtypes of childhood CVI according to visual dysfunctions. Currently there is no consensus in relation to assessment, diagnosis and classification of CVI and more information about brain lesions may be of potential diagnostic value.

Aim: This study aimed to investigate overall patterns of brain lesions and associations with level of visual dysfunction and to compare the patterns between the classification subgroups in children with CVI.

Methods: School-aged children with CVI received ophthalmological and neuro-psychological/developmental assessments to establish CVI-related subtyping. Other pediatric information was collected from medical records. MRI scans were coded according to a semi-quantitative template including brain regions (right hemisphere, left hemisphere, visual pathways) and summed for total scores. Non-parametric analyses were conducted.

Results: 28 children had clinical brain MRI scans available [44% of total sample, Group A (lower severity of visual dysfunctions) n = 16, Group B (higher severity) n = 12]. Total brain scores ranged between 0 and 18 (Group A mdn = 7, IQR = 0.8–10.0, Group B mdn = 10, IQR = 6.5–11.8) and were widespread across regions. 71 per cent had post-geniculate visual pathway damage. The median total brain and hemisphere scores of Group B were higher than subgroup A but differences did not reach statistical significance. No statistically significant associations were found between brain scores and vision variables (acuity, contrast sensitivity).

Conclusion: This study found a spread of lesions across all regions on the brain scans in children with congenital CVI. The majority had damage in the postgeniculate visual pathways and visual cortex region suggesting this is an area of interest and potentially informative for diagnosis. However the subtyping classification did not show differences in number or region of lesions though the trend was higher toward Group B. This study confirms the complex diffuse and variable nature of brain lesions in children with congenital CVI, many of whom have other neurological impairments.

Study of the Characteristic Mental Development Features of Primary School Students with Visçion Impairments

Severe vision impairments are an obstacle to the adequate cognitive and social development of the child. The educational response to priority problems that occur with vision disorders requires appropriate training of vision impairment specialists. For this purpose, they need basic knowledge related to the classification of vision impairments and the main aspects of the development and education of this category of children. This study aimed to analyse the main features of educational activities of children with vision impairments using special diagnostic methods and to search for effective methods for correcting the cognitive activity of children with vision impairments. During the study, an experiment was conducted with children with vision impairments (15 children). To conduct the experiment, the study used methods proposed by V.V. Tarasun and adapted them to the contingent of children with vision impairments. In particular, the following methods: the method of motivational preferences "Three wishes", the method of "Memorising 10 words", and the method of "What, why, how". The depth and time of vision impairment are considered as a primary defect, which has corresponding secondary consequences and requires corrective action under the guidance of an experienced vision impairment specialist.

What assessments are currently used to investigate and diagnose cerebral visual impairment (CVI) in children? A systematic review

PURPOSE

Cerebral visual impairment (CVI) is the leading cause of childhood visual impairment in the developed world. Despite this, there are no agreed clinical guidelines for the investigation and diagnosis of the condition. Before development of such guidelines can commence, it is important to recognise which approaches are currently employed. This systematic review evaluated the literature to identify which methods of assessment are currently used to investigate and diagnose childhood CVI.

METHODS

Medline, Embase, CINAHL, Scopus and the Cochrane Library databases were systematically searched in January 2020 using defined search terms. Articles were included if they: (i) were research papers, conference abstracts or research protocols published in peer-reviewed scientific journals, or relevant textbooks; (ii) included a clinical investigation of CVI in children; (iii) provided an explanation or criteria to diagnose CVI and (iv) were specifically investigating cerebral/cortical visual impairment. Methods used to a) assess and b) diagnose CVI were extracted from included articles. 'Assessment scores' were assigned for each method employed by researchers to investigate and diagnose CVI to quantify and compare approaches between articles. A quality grading was also applied to each article.

RESULTS

Of 6454 identified articles, 45 met the inclusion criteria. From these, 10 categories of assessment utilised within included articles were identified: (1) Medical history, (2) Vision assessment/ophthalmologic examination, (3) Neuroimaging, (4) Visual behaviour and direct observation, (5) Structured history-taking, (6) Visual perception tests, (7) Ocular movement and posture assessment, (8) Intelligence/IQ assessment, (9) Clinical electrophysiology and (10) Neurodevelopmental tests. In terms of diagnostic criteria, the most commonly reported approach was one of exclusion, i.e., CVI was diagnosed when visual dysfunction could not be attributed to abnormalities detected in the anterior visual pathway.

CONCLUSION

There is a lack of common practice in the approaches used by clinicians to investigate and diagnose CVI in children. At present, a 'diagnosis of exclusion' remains the most common means to diagnose CVI. Development of clinical guidelines for assessment and diagnosis are necessary to ensure consistency in the diagnosis of CVI and the timely implementation of support to alleviate the impact of CVI on the child's daily living.

Spectral-domain OCT changes in retina and optic nerve in children with hypoxic-ischaemic encephalopathy

Purpose

To evaluate the effect of neonatal hypoxic–ischaemic injury on the retina and the optic nerve and to correlate ocular damage with systemic parameters, laboratory tests, neurological imaging and therapeutic hypothermia at birth.

Methods

Forty-one children with hypoxic–ischaemic encephalopathy (HIE) at birth (9.09 ± 3.78 years) and a control group of 38 healthy subjects (9.57 ± 3.47 years) were enrolled in a cohort study. The HIE population was divided into three subgroups, based on the degree of encephalopathy according to Sarnat score and the treatment with therapeutic hypothermia (TH): Sarnat score I not treated with hypothermia, Sarnat score II-III treated with TH and Sarnat score II-III not subjected to TH. Total macular thickness, individual retinal layers and peripapillary nerve fibre layer thickness were measured with spectral-domain optical coherence tomography. Clinical data of perinatal period of HIE children were collected: APGAR score, pH and base excess of funiculus blood at birth, apnoea duration, brain ultrasound, cerebral MRI ischaemic lesions and blood chemistry tests.

Results

Children with Sarnat score I did not show a reduction of peripapillary nerve fibres and ganglion cell layer compared to the control group (p = 0.387, p = 0.316). Peripapillary nerve fibre layer was 109.06 ± 7.79 μm in children with Sarnat score II-III treated with TH, 108.31 ± 7.83 μm in subjects with Sarnat score II-III not subjected to TH and 114.27 ± 6.81 μm in the control group (p = 0.028, p = 0.007). Ganglion cell layer was thinner in children with Sarnat score II-III treated with TH (50.31 ± 5.13 μm) compared to the control group (54.04 ± 2.81 μm) (p = 0.01). Inner retinal layers damage correlated with C-reactive protein and lactate dehydrogenase increase, while higher levels of total bilirubin were protective against retinal impairment (p < 0.05). Cerebral oedema was related to peripapillary nerve fibre layer damage (p = 0.046).

Conclusions

Thickness reduction of inner retinal layer and peripapillary nerve fibre impairment was related to encephalopathy severity. Ocular damage was associated with inflammation and cerebral oedema following hypoxic–ischaemic damage.

Cerebral Visual Impairment and Clinical Assessment: The European Perspective

This paper summarizes the multidisciplinary pediatric assessment methods of 3 European centers for identifying and assessing cerebral visual impairment in childhood. It describes a comprehensive neurodevelopmental assessment evaluation in which visual aspects play an important part. Developmental trajectories and the heterogeneity of the clinical picture are emphasized. Multidisciplinary ophthalmology and neurodisability/neurology teamwork together with the parent and teachers, to reach an integrated and individualized perspective for the individual child, are described. This comprehensive assessment is the starting point for habilitation programs and interventions, that can support and meet the child's needs and help them reach their optimal potential. Future developments in classification of the cerebral visual impairment conditions, building on the child's individual assessment profile, will further enhance the direction of clinical, educational, and research progress.

Utility of Magnetic Resonance Imaging (MRI) in Children With Strabismus

PURPOSE

Magnetic resonance imaging (MRI) of the brain can provide valuable information about structural abnormalities in strabismus. The aim of this study was to evaluate the utility of MRI in this regard and to identify risk factors for abnormal MRI results in children with strabismus.

METHODS

A retrospective analysis of children <18 years of age presenting with strabismus, who underwent brain MRI at Pusan National University Hospital (Busan, Korea) between January 2012 and March 2017, was performed. Clinical characteristics, MRI results, and ophthalmologic findings were reviewed. Findings were classified as normal or abnormal according to MRI results. Additionally, patients were divided according to age to compare characteristics of infantile and childhood strabismus.

RESULTS

A total of 90 patients (47 [52.2%] male, 43 [47.8%] female; mean age, 2.19 ± 0.53 years) were enrolled. Of those, 64 (71.1%) presented with normal and 26 (28.9%) with abnormal MRI results. The age at presentation was lower and abnormal findings on fundus examination were more common in the abnormal MRI group (P = .002 and P = .008, respectively). Among the patients, 46 (51.1%) had infantile strabismus and 44 (48.9%) had childhood strabismus. Global developmental delays, speech delays, and MRI abnormalities were more common in patients with infantile than in those with childhood strabismus. Ptosis and headaches were more common in patients with childhood strabismus (P = .025, P = .025, respectively).

CONCLUSION

Brain MRI was helpful for accurate diagnosis and treatment of strabismus in younger children, those with abnormal findings on fundus examination, and infants with developmental, especially speech, delays.

Is there consensus in defining childhood cerebral visual impairment? A systematic review of terminology and definitions

The childhood condition of visual difficulties caused by brain damage, commonly termed cortical or cerebral visual impairment (CVI), is well established but has no internationally accepted definition. Clarification of its core features is required to advance research and clinical practice. This systematic review aimed to identify the definitions of childhood CVI in the original scientific literature to describe and critically appraise a consensual definition of the condition. MEDLINE, EMBASE, PsychINFO, CINAHL and AMED databases were searched in January 2017. Studies were included if they (1) were published original research, (2) contained a childhood CVI sample, (3) contained a definition of CVI and (4) described their CVI identification/diagnostic method. Thematic analysis identified concepts within definitions and narrative synthesis was conducted. Of 1150 articles, 51 met inclusion criteria. Definitions were subdivided according to detail (descriptive definition, description not reaching definition status and diagnostic/operationalising criteria). Three themes concerning visual deficits, eye health and brain integrity were identified (each containing subthemes) and analysed individually across definitions. The most common themes were ‘visual impairment’ (n=20), ‘retrochiasmatic pathway damage’(n=13) and ‘normal/near normal eye health’ (n=15). The most consensual definition identified here may not be the best quality for advancing our understanding of CVI. We argue for the alternative definition: CVI is a verifiable visual dysfunction which cannot be attributed to disorders of the anterior visual pathways or any potentially co-occurring ocular impairment. We propose reporting guidelines to permit comparison across studies and increase the evidence base for more reliable clinical assessment and diagnosis.

Vision Assessments and Interventions for Infants 0-2 Years at High Risk for Cerebral Palsy: A Systematic Review

We performed a systematic review and evaluated the level of evidence of vision interventions and assessments for infants at high risk for or with a diagnosis of cerebral palsy from zero to two years of age. Articles were evaluated based on the level of methodologic quality, evidence, and clinical utilization. Thirty publications with vision assessments and five with vision interventions met criteria for inclusion. Assessments included standard care neuroimaging, electrophysiology, and neuro-ophthalmologic examination techniques that are utilized clinically with any preverbal or nonverbal pediatric patient. The overall level of evidence of interventions was strong for neuroprotective interventions such as caffeine and hypothermia but weak for surgery, visual training, or developmental programs. There are few evidence-based interventions and assessments that address cerebral/cortical visual impairment-related needs of infants and toddlers at high risk for or with cerebral palsy. Recommendation guidelines include the use of three types of standard care methodologies and two types of protective interventions.

The relationship between visual orienting responses and clinical characteristics in children attending special education for the visually impaired

We recently introduced a method based on quantification of orienting responses toward visual stimuli to assess the quality of visual information processing in children. In the present study, we examined the relationship between orienting responses and factors that are associated with visual processing impairments in current clinical practice. Response time and fixation quality to visual features such as form, contrast, motion, and color stimuli were assessed in 104 children from 1 to 12 years attending special education for the visually impaired. Using regression analysis, we investigated whether these parameters were affected by clinical characteristics of children. Response times significantly depended on stimulus type. Responses to high-contrast cartoons were significantly slower in children with a clinical diagnosis of cerebral visual impairment. Fixation quality was significantly affected by visual acuity and nystagmus. The results suggest that the quantitative measurement of orienting responses is strongly related to cerebral visual impairment in children.

Uniplanar Nystagmus Associated with Perceptual and Cognitive Visual Dysfunction due to Presumed Focal Ischemic Occipital Cortical Atrophy: A Missed Diagnosis and New Observation

Uniplanar nystagmus has been described in relation to pathology of the brain stem, retina, optic nerve, sensory visual deprivation, periventricular leucomalacia, and drug toxicity. This paper describes a case of uniplanar nystagmus associated with features of higher visual dysfunction and a presumed focal insult to the occipital lobes following an episode of neonatal apnea.

Visual perception in preterm children: what are we currently measuring?

Over the past two decades, cerebral visual impairment has been recognized as a principal deficit in preterm children, and in particular those with cerebral palsy. We review the current knowledge of visual processing deficits in these children, and provide an overview of the tools for assessing cerebral visual impairment. Commercially available instruments are usually directed at evaluating visuospatial skills rather than detecting object recognition difficulties. Particularly in children aged 3 years or younger and in children with multiple handicaps, cerebral visual impairment is difficult to diagnose. This difficulty may be attributable to limitations specific to the instrument, such as a test that is inappropriate for age, or to child-specific limitations such as motor impairment or speech delay. We therefore include an overview of relevant neuroimaging findings reported in these children, focusing on the most recent imaging modalities. Novel techniques such as diffusion tensor imaging may provide sensitive markers of cerebral visual impairment in situations where clinical diagnosis is difficult, and such approaches may allow for early intervention.

Outcomes after central grey matter injury in term perinatal hypoxic-ischaemic encephalopathy

Central grey matter damage following perinatal hypoxia-ischaemia frequently leads to death or motor abnormality often with deficits in other developmental domains. Predicting these different outcomes is difficult yet very important for early management, planning and providing for needs on discharge and later and not least for parents to know how their children will be affected. The best single predictor of the pattern of outcomes for an individual infant is an early MRI scan. We present a guide for predicting outcome at 2 years in different developmental domains based on the severity of injury seen in the basal ganglia and thalami (BGT) on neonatal MRI.

Neurodevelopmental evolution of West syndrome: a 2-year prospective study

OBJECTIVE

The aim of this study was to evaluate the epileptic and developmental evolution in infants with West syndrome.

METHODS

A prospective study of 21 infants was performed, with a follow-up at 2 years. Serial assessment included long-term EEG monitoring, visual and auditory evaluation and assessment of neurodevelopment.

RESULTS

Neurosensory and developmental impairments at the spasm onset were transitory in seven cases, including four cryptogenic forms. In all other cases, there was a progressive worsening in neurosensory and developmental impairments. The epileptic evolution was generally better: in 11 of the 16 infants without seizures at outcome, spasms had already disappeared by 2 months after disease onset. Statistic analysis of results showed a correlation between neurosensory impairment and development throughout the whole follow-up. In addition, visual function at T1 resulted significant predictor of developmental outcome. Among the epileptic features, disorganization of slow sleep was an unfavorable prognostic factor.

CONCLUSION

Some forms of West syndrome are confirmed to have a benign evolution: among them there are not only cryptogenic cases but also symptomatic ones without significant neurodevelopmental impairment. Abnormalities of sleep organization, expression of the pervasive epileptic disorder, seem to play a role in determining a developmental deterioration. Neurosensory impairment since the onset of the disease could be a relevant cause of the developmental disorder.

Brain injury and the eye

Visual loss associated with brain damage is the single greatest cause of visual impairment in children in developed countries. Damage may occur in any of five separate visual systems: primary visual cortex, visual associative cortex area, optic radiations, optic nerves, and visual attention pathways. Improving our understanding of the pathophysiology of these causes for visual loss may lead to better rehabilitation and educational strategies for these children.

The development of vision

Disorders of visual function are common findings in children with neonatal brain lesions of antenatal and perinatal onset. In the last few years the development of age appropriate batteries for assessing visual function in the first years and the combined use of neuroimaging and neurophysiological techniques have allowed to achieve better understanding of the mechanisms underlying development of vision in low risk infants and in those with brain lesions. We will review the main models of visual development and the tests available to assess visual function in infancy, focusing on the recently described battery of tests for assessing early visual abilities in preterm and full term infants.

Longitudinal Quantitative Assessment of Vision Function in Children with Cortical Visual Impairment

PURPOSE

Cortical visual impairment (CVI) is bilateral visual impairment caused by damage to the posterior visual pathway, the visual cortex, or both. Current literature reports great variability in the prognosis of CVI. The purpose of this study was to evaluate change in vision function in children with CVI over time using a quantitative assessment method.

METHODS

The visual acuity and contrast sensitivity of children with CVI were retrospectively assessed using the sweep visual evoked potential (VEP). Thirty-nine children participated in the visual acuity assessment and 34 of the 39 children participated in the contrast threshold assessment. At the time of the first VEP, the children ranged in age from 1 to 16 years (mean: 5.0 years). The time between measures ranged from 0.6 to 13.7 years (mean: 6.5 years).

RESULTS

Forty-nine percent of the children studied showed significant improvement of visual acuity. The average improvement was 0.43 log unit (mean change: 20/205 to 20/76) in those who improved. The initial visual acuity was worse in those who improved compared with those who did not improve (p < 0.001). Forty-seven percent of the children studied showed significant improvement of contrast threshold. In those who improved, the average amount of improvement was 0.57 log unit (10 to 2.6% Michelson). The initial contrast threshold was significantly worse in those who improved compared with those who did not improve (p = 0.001). Also, the change in contrast threshold was related to age of the child (p = 0.017).

CONCLUSIONS

Significant improvement in vision function can occur over time in children with CVI. In the present study, approximately 50% of the children improved and the remainder remained stable. No relation was found between etiology and improvement. Further investigation is warranted to better understand the prognosis for visual recovery in children with CVI.

Spectrum of visual disorders in children with cerebral visual impairment

Cerebral visual impairment is a visual function deficit caused by damage to the retrogeniculate visual pathways in the absence of any major ocular disease. It is the main visual deficit in children in the developed world. Preperinatal hypoxic-ischemic damage is the most frequent cause of cerebral visual impairment, but the etiology is variable. The authors set out to evaluate the presence of visual disorders not attributable to any major ocular pathology in a sample of children with central nervous system disease and to describe the clinical picture of cerebral visual impairment in this cohort. One hundred twenty-one patients with central nervous system damage and visual impairment underwent a protocol developed at the authors' center that included neurologic, neurophthalmologic, and neuroradiologic assessments (brain magnetic resonance imaging). Reduced visual acuity was found in 105 of 121 patients, reduced contrast sensitivity in 58, abnormal optokinetic nystagmus in 88, and visual field deficit in 7. Fixation was altered in 58 patients, smooth pursuit in 95, and saccadic movements in 41. Strabismus was present in 88 patients, and abnormal ocular movements were found in 43 patients. Of the 27 patients in whom they could be assessed, visual-perceptual abilities were found to be impaired in 24. Fundus oculi abnormalities and refractive errors were frequently associated findings. This study confirms that the clinical expression of cerebral visual impairment can be variable and that, in addition to already well-documented symptoms (such as reduced visual acuity, visual field deficits, reduced contrast sensitivity), the clinical picture can also be characterized by oculomotor or visual-cognitive disorders. Cerebral visual impairment is often associated with ophthalmologic abnormalities, and these should be carefully sought. Early and careful assessment, taking into account both the neurophthalmologic and the ophthalmologic aspects, is essential for a correct diagnosis and the development of personalized rehabilitation programs.

Thalamic atrophy in infants with PVL and cerebral visual impairment

The aim of this retrospective study was to establish the presence and severity of cerebral visual impairment in preterm infants with PVL. We also wished to establish whether abnormalities of visual function are related to brain MRI findings and more specifically not only to the involvement of optic radiations and occipital cortex but also to changes in the thalami, that are often affected in infants with PVL. Twelve infants with cystic PVL were assessed at 1 year (+2) corrected age with a battery of tests specifically designed to assess various aspects of visual function in infancy, such as ocular movements, visual acuity, visual fields and fixation shift. All infants also had a brain MRI. Eleven of the 12 had involvement of the optic radiations: all had some abnormalities of visual function and visual impairment was more severe in infants with more extensive involvement of the optic radiations. The child with normal optic radiations had normal visual function. Six of the 12 infants also had obvious signs of atrophy of the thalami and all had severe and wide-ranging abnormalities of visual function in all testing domains. Two children had equivocal atrophy of the thalami, both had some abnormalities of visual function. Four children had normal thalami and had normal visual function or only minor abnormalities on one of the visual tests. Our results suggest that the atrophy of the thalami may play an additional role in the abnormal development of visual function in infants with PVL and abnormal optic radiations.

Cognitive assessment in epilepsy surgery of children

INTRODUCTION

Although the neurocognitive assessment in children as in the adults is an important step before and after surgery, in the literature, the data about pre- and postoperative neurocognitive evaluations in children are very few.

OBJECTIVE

The purpose of this paper is to consider some peculiar aspects of the neurocognitive assessment during development, and report literature data about neuropsychological outcome of epileptic children treated with focal resection and hemispherectomy.

RESULTS AND DISCUSSION

The second section concerns our personal experience about a cohort of 45 children with refractory epilepsy operated on before 7 years. The results suggest that early surgical treatment is generally effective for seizure control and behavior improvement in children with refractory epilepsy. Concerning cognitive outcome, we found that the neurocognitive level was unchanged in the majority of the patients.

CONCLUSION

We underline the importance of multicentric studies with standardized neuropsychological assessments in large series of young children.

Cryptic cerebral visual impairment in children

AIM

To review the medical records of seven children with a delayed diagnosis of cerebral visual impairment.

METHODS

The charts of a consecutive series of children examined in a university based ophthalmology clinic with a delayed diagnosis of cerebral visual impairment were reviewed. Their neuroimaging studies were evaluated by a paediatric neuroradiologist.

RESULTS

The seven patients ranged in age from 2 years to 10 years at the time of presentation and had acuities ranging from 20/40 to 20/400. Their visual fields ranged from full visual fields to homonymous hemianopias. Neuroimaging findings ranged from subtle occipital lobe abnormalities to obvious cerebral volume loss.

CONCLUSIONS

Cerebral visual impairment can be cryptic in children with mild visual impairment. Neuroimaging studies and visual field testing can help to differentiate this condition from other causes of visual impairment.

Neurodevelopmental follow-up after preterm birth: follow up after two years

Marked differences are seen in neurological and health status, intellectual functioning, school performance and behaviour between children born prematurely and those born at term. Assessment in later childhood has identified more subtle problems than the severe disability or sensory deficits readily identifiable at two years. These problems include learning disabilities, specific neuropsychological deficits in executive function, difficulties in visual-motor integration and perception, selective language impairment, motor coordination disorders, behaviour problems, attention deficit hyperactivity disorder (ADHD), and reduced educational achievement. Follow-up to school entry and beyond is thus required to determine the true prevalence and nature of the neurodevelopmental problems arising from preterm birth. Consensus about the assessment used, definitions of disability and health status, age of assessment and who undertakes it are necessary and should allow comparison across populations; this may help to maximise outcomes for children clearly at biological risk. Assessment of outcome for children born preterm beyond two years is required for counselling parents, planning health and education provision, for evaluation of services and to facilitate understanding of the longer term effects of preterm birth on brain development.

Abnormal cerebral structure is present at term in premature infants

BACKGROUND

Long-term studies of the outcome of very prematurely born infants have clearly documented that the majority of such infants have significant motor, cognitive, and behavioral deficits. However, there is a limited understanding of the nature of the cerebral abnormality underlying these adverse neurologic outcomes.

AIM

The overall aim of this study was to define quantitatively the alterations in cerebral tissue volumes at term equivalent in a large longitudinal cohort study of very low birth weight premature infants in comparison to term-born infants by using advanced volumetric 3-dimensional magnetic resonance imaging (MRI) techniques. We also aimed to define any relationship of such perinatal lesions as white matter (WM) injury or other potentially adverse factors to the quantitative structural alterations. Additionally, we wished to identify the relationship of the structural alterations to short-term neurodevelopmental outcome.

METHODS

From November 1998 to December 2000, 119 consecutive premature infants admitted to the neonatal intensive care units at Christchurch Women's Hospital (Christchurch, New Zealand) and the Royal Women's Hospital (Melbourne, Australia) were recruited (88% of eligible) after informed parental consent to undergo an MRI scan at term equivalent. Twenty-one term-born infants across both sites were recruited also. Postacquisition advanced 3-dimensional tissue segmentation with 3-dimensional reconstruction was undertaken to estimate volumes of cerebral tissues: gray matter (GM; cortical and deep nuclear structures), WM (myelinated and unmyelinated), and cerebrospinal fluid (CSF).

RESULTS

In comparison to the term-born infants, the premature infants at term demonstrated prominent reductions in cerebral cortical GM volume (premature infants [mean +/- SD]: 178 +/- 41 mL; term infants: 227 +/- 26 mL) and in deep nuclear GM volume (premature infants: 10.8 +/- 4.1 mL; term infants: 13.8 +/- 5.2 mL) and an increase in CSF volume (premature infants: 45.6 +/- 22.1 mL; term infants: 28.9 +/- 16 mL). The major predictors of altered cerebral volumes were gestational age at birth and the presence of cerebral WM injury. Infants with significantly reduced cortical GM and deep nuclear GM volumes and increased CSF volume volumes exhibited moderate to severe neurodevelopmental disability at 1 year of age.

CONCLUSIONS

This MRI study of prematurely born infants further defines the nature of quantitative cerebral structural abnormalities present as early as term equivalent. The abnormalities particularly involve cerebral neuronal regions including both cortex and deep nuclear structures. The pattern of cerebral alterations is related most significantly to the degree of immaturity at birth and to concomitant WM injury. The alterations are followed by abnormal short-term neurodevelopmental outcome.

Imaging of early brain injury and cortical plasticity

The human brain undergoes complex organizational changes during development in and ex utero. Pathogenic events affecting the developing brain cause abnormalities or lesions, the patterns of which depend on the stage of brain development. During the first and second trimester, cortical neurogenesis predominantly takes place, characterized by proliferation, migration, and organization of neuronal cells. Brain pathology is characterized by maldevelopments. During the third trimester, growth and differentiation events are predominant, which persist into postnatal life. Disturbances of brain development during this period mainly cause lesions. During the early third trimester, periventricular white matter is especially affected, whereas toward the end of the third trimester, gray matter, either cortical or deep gray matter, appears to be more vulnerable. These patterns of brain maldevelopments or lesions offer excellent models to study mechanisms of organization and reorganization in the developing brain. Evidence for superior brain plasticity is well established for language function after early left-sided lesions. Some evidence exists for higher compensatory potential within in the motor system; maintenance of ipsilateral tracts seems to play a certain, but only incomplete functional role after unilateral lesions in early and mid gestation. The visual system seems to have limited compensatory potential.

Defining the nature of the cerebral abnormalities in the premature infant: a qualitative magnetic resonance imaging study

OBJECTIVES

The aim of this study was to define qualitatively the nature and extent of white and gray matter abnormalities in a longitudinal population-based study of infants with very low birth weight. Perinatal factors were then related to the presence and severity of magnetic resonance imaging (MRI) abnormalities.

METHODS

From November 1998 to December 2000, 100 consecutive premature infants admitted to the neonatal intensive care unit at Christchurch Women's Hospital were recruited (98% eligible) after informed parental consent to undergo an MRI scan at term equivalent. The scans were analyzed by a single neuroradiologist experienced in pediatric MRI, with a second independent scoring of the MRI using a combination of criteria for white matter (cysts, signal abnormality, loss of volume, ventriculomegaly, corpus callosal thinning, myelination) and gray matter (gray matter signal abnormality, gyration, subarachnoid space). Results were analyzed against individual item scores as well as the presence of moderate-severe white matter score, total gray matter score, and total brain score.

RESULTS

The mean gestational age was 27.9+/-2.4 weeks (range, 23-32 weeks), and mean birth weight was 1063+/-292 g. The greatest univariate predictors for moderate-severe white matter abnormality were lower gestational age (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.1-1.7; P<.01), maternal fever (OR, 2.2; 95% CI, 1.1-4.6; P<.04), proven sepsis in the infant at delivery (OR, 1.8; 95% CI, 1.1-3.6; P=0.03), inotropic support (OR, 2.7; 95% CI, 1.5-4.5; P<.001), patent ductus arteriosus (OR, 2.2; 95% CI, 1.2-3.8; P=.01), grade III/IV intraventricular hemorrhage (P=.015), and the occurrence of a pneumothorax (P=.05). There was a significant protective effect of intrauterine growth restriction (OR, 0.51; 95% CI, 0.23-0.99; P=.04). Gray matter abnormality was highly related to the presence and severity of white matter abnormality. A unique pattern of cerebral abnormality consisting of significant diffuse white matter atrophy, ventriculomegaly, immature gyral development, and enlarged subarachnoid space was found in 10 of 11 infants with birth gestation <26 weeks. Given the later outcome of these infants, this pattern may have very high risk for later global neurodevelopmental disability.

CONCLUSIONS

This MRI study confirms a high incidence of cerebral white matter abnormality at term in an unselected population of premature infants, which is predominantly a result of noncystic injury in the extremely immature infant. We confirm that the major perinatal risk factors for white matter abnormality are related to perinatal infection, particularly maternal fever and infant sepsis, and hypotension with inotrope use. We have defined a distinct pattern of diffuse white and gray matter abnormality in the extremely immature infant.

Visual function in the brain-damaged child

The essential role of the primary visual cortex in visual processing has been extensively studied over the last century or more. Injuries to the visual cortex in adult humans can produce blindness, referred to as "cortical blindness". In children some degree of visual recovery has been noted in comparable injuries and for that reason the term "cortical visual impairment" has been suggested as a more appropriate diagnosis in children. This term is, however, inaccurate as a significant number of children with visual loss and neurologic damage have injuries to the noncerebral pathways (for example--optic radiations in children with periventricular leukomalacia). In this study we compare visual outcomes and recovery in children with primary visual cortex lesions vs those with periventricular leukomalacia. We suggest that the poorer outcomes of children with periventricular leukomalacia could have been predicted based on studies of the mechanisms of visual recovery in infant animals following visual cortex ablation.

Perinatal cortical and subcortical visual loss: mechanisms of injury and associated ophthalmologic signs

PURPOSE

To determine whether term and preterm injuries to the retrogeniculate visual system are associated with recognizable patterns of ophthalmologic abnormalities and whether these patterns can be attributed to cortical (gray matter) or subcortical (white matter) injury.

DESIGN

A retrospective case series.

PARTICIPANTS

One hundred children with clinical and neuroimaging signs of perinatal posterior visual pathway injury who were examined at Arkansas Children's Hospital Eye Clinic between 1989 and 1999.

METHODS

We reviewed magnetic resonance images or computed tomographic scans from 50 children with cortical (predominantly or exclusively involving cortical gray matter) and 50 children with subcortical (predominantly or exclusively involving subcortical white matter) perinatal injury to the retrogeniculate visual system. Ophthalmologic abnormalities were analyzed retrospectively in each group.

MAIN OUTCOME MEASURES

Conjugate gaze deviation, type of strabismus, abnormal eye movements, and optic disc morphology.

RESULTS

Horizontal conjugate gaze deviation, exotropia, and a normal optic disc appearance were significantly more common in cortical than in subcortical visual loss. Tonic downgaze, esotropia, and optic nerve hypoplasia (with or without coexisting pallor) were significantly more common in subcortical than in cortical visual loss.

CONCLUSIONS

Perinatal cortical and subcortical visual loss produce differing profiles of ophthalmologic dysfunction. A reclassification of periventricular leukomalacia and other forms of retrogeniculate white matter injury as subcortical visual loss would increase diagnostic specificity.

The variety of visual perceptual impairments in pre-school children with perinatal brain damage

To study the selectivity of visual perceptual impairment in children with early brain injury, eight visual perceptual tasks (L94), were administered to congenitally disabled children both with and without risk for cerebral visual impairment (CVI). The battery comprised six object-recognition and two visuoconstructive tasks. Seven tasks were newly designed. For these normative data are presented (age 2.75-6.50 years). Because the recognition tasks required object naming, each item included a canonical control drawing and visual perceptual ability was evaluated relative to the non-verbal intelligence level, instead of chronological age. In 22 multiple disabled children with no indications of CVI, the frequency of impairment did not exceed that in the reference sample for any L94 task. In contrast, in 57 5-year-old children who were at risk for CVI due to pre-maturity or birth asphyxia, a significant increase in the frequency of impairment was seen on six L94 tasks (range 12-38%). However, only five children had more than two impairments, indicating that the deficits were selective, not pervasive. We conclude that early brain lesions interfere with the functioning of particular visual subsystems, yet leave other subsystems intact and functioning within the normal range.

Correlation between visual function, neurodevelopmental outcome, and magnetic resonance imaging findings in infants with periventricular leucomalacia

AIM

To evaluate the correlation between visual function and neurodevelopmental outcome in children with periventricular leucomalacia at 1 and 3 years.

METHOD

Visual acuity, visual field, ocular motility, and optokinetic nystagmus were tested in 29 infants with periventricular leucomalacia by brain magnetic resonance imaging. All infants also had a structured neurological examination and a Griffiths developmental assessment.

RESULTS

21 of the infants showed at least one abnormality of visual function. The degree of visual impairment-that is, the number of visual tests showing abnormal results-correlated well with the results on developmental assessment at both ages.

CONCLUSION

Multivariate analysis showed that visual impairment was the most important variable in determining the neurodevelopmental scores of these infants, more than their motor disability and the extent of their lesions on magnetic resonance imaging.

Chronic cortical visual impairment in children: aetiology, prognosis, and associated neurological deficits

BACKGROUND/AIMS

To evaluate prevalence, aetiology, prognosis, and associated neurological and ophthalmological problems in children with cortical visual impairment (CVI).

METHODS

The records of 7200 outpatients seen in the paediatric ophthalmology practice over the past 15 years were reviewed in order to compile data concerning CVI. In addition, the authors devised and applied a system for grading visual recovery in order to assess prognosis.

RESULTS

CVI occurred in 2.4% of all patients examined. The four most common causes of CVI were perinatal hypoxia (22%), cerebral vascular accident (14%), meningitis (12%), and acquired hypoxia (10%). Most children with CVI had associated neurological abnormalities. The most common were seizures (53%), cerebral palsy (26%) hemiparesis (12%), and hypotonia (5%). Associated ophthalmological problems were esotropia (19%), exotropia (18%), optic nerve atrophy (16%), ocular motor apraxia (15%), nystagmus (11%), and retinal disease (3%). On average, CVI patients improved by two levels as measured by the authors' scale.

CONCLUSION

The majority of children with CVI showed at least some recovery. In this group of children, CVI is often accompanied by additional ophthalmological problems and is nearly always associated with other, serious neurological abnormalities.

Visual function in term infants with hypoxic-ischaemic insults: correlation with neurodevelopment at 2 years of age

AIMS

To determine if there is any association between the findings of visual assessment performed at the age of 5 months and neurodevelopmental outcome at the age of 2 years in children who have sustained hypoxic-ischaemic insults.

METHODS

Twenty nine term infants with hypoxic-ischaemic encephalopathy and/or brain lesions on neonatal magnetic resonance imaging (MRI) were prospectively evaluated. At 5 months of age all the infants had their visual function assessed using the Atkinson Battery of Child Development for Examining Functional Vision, which includes the assessments of optokinetic nystagmus (OKN), acuity, visual fields, fixation shift and phase and orientation reversal visual evoked potentials. At 2 years of age the children had a structured neurological evaluation and a Griffiths developmental assessment.

RESULTS

There was good correlation between the extent of the early detected visual impairment and both neuromotor and global development. Children with more than three out of five abnormal visual tests at 5 months of age tended to have abnormal neurological examination results and abnormal developmental quotients. Children with three or fewer abnormalities tended to have developmental quotients in the normal range; the level of their performance, however, was still related to the number of visual tests passed.

CONCLUSIONS

Individual visual tests can provide important prognostic information. While abnormal OKN and acuity were always associated with abnormal outcome, normal results on visual evoked potentials and fixation shift tended to be associated with normal outcome.

Visual outcome at 5 years of newborn infants at risk of cerebral visual impairment

Visual development at 5 years of age was tested in a group of 39 children who had shown severe neonatal encephalopathy or perinatal brain lesions, documented by medical history, cranial ultrasound, or MRI. In all children, grating acuity was tested during the first 2 years of life. The assessment protocol at 5 years included various visual functions (grating and resolution acuity, visual field size, depth perception, optokinetic nystagmus, and ocular motility), and neurological and cognitive development. The majority of the children showed visual disorders of different type and degree, which were not due to ophthalmological abnormalities. Visual defects correlated well with the results of early visual assessment and of neuroimaging. Visual outcome could be predicted by grating acuity at 1 to 2 years in 27 of the 39 children, by neonatal cranial ultrasound in 26 of the 32 cases examined by this technique, and by later MRI in 23 out of 27. Moreover, a significant correlation was found between visual, motor, and cognitive impairment.

Cerebral visual impairment in preterm infants with periventricular leukomalacia

Neonatal brain lesions are the main cause of cerebral visual impairment in infancy, i.e., of a visual deficit caused by damage to posterior visual pathways. Visual outcome of preterm infants with periventricular leukomalacia (PVL) was investigated in 14 subjects affected by severe cystic PVL, another 34 with moderate PVL (prolonged periventricular echodensities), and 18 control preterm infants. All cases with significant ocular abnormalities (such as retinopathy of prematurity state III or upwards, optic nerve atrophy, or major refraction problems) were excluded. Visual acuity, visual field, eye alignment, fixation and following, optokinetic nystagmus, and visual threat were tested at 1 year of corrected age. A high incidence of cerebral visual impairment, consisting mainly of low visual acuity, severe oculomotor disorders, and reduced visual field, was found in infants with severe PVL. Visual defects were less frequent and less severe in the moderate PVL group, and very rare in the control group. The results of neuroimaging, and especially of magnetic resonance imaging, correlated with the visual outcome and indicate lesions at the level of optic radiations as the main anatomic substrate of the visual impairment. All infants with PVL need a visual follow-up, from the first months of life, the results of which are important both for visual and motor rehabilitation of these cases and for their daily care.

Basal ganglia damage and impaired visual function in the newborn infant

AIM

To examine the effects of early lesions in the visual pathway on visual function; and to identify early prognostic indicators of visual abnormalities.

METHODS

The visual function of 37 infants with perinatal brain lesions on magnetic resonance imaging was assessed using behavioural and electrophysiological variables.

RESULTS

Normal visual behaviour was observed in most infants with large bilateral occipital lesions, but all the infants with associated basal ganglia involvement had abnormal visual function. Visual abnormalities were also present in six infants with isolated basal ganglia lesions.

CONCLUSIONS

These observations suggest that basal ganglia may have an integral role in human visual development and that their presence on neonatal MRI could be an early marker of abnormal visual function.

Cortical visual impairment following perinatal hypoxia: clinicoradiologic correlation using magnetic resonance imaging

PURPOSE

To evaluate the value of magnetic resonance imaging (MRI) in the visual prognosis of cortical visual impairment following perinatal hypoxia.

METHODS

MRI findings of 19 babies with the diagnosis of a perinatal hypoxic-ischemic insult and cortical visual impairment (CVI) were reviewed. Two groups of patients based on gestational age were compared. Babies with a gestational age > or = 34 weeks were included in group 1(n = 8). Infants < 34 weeks' gestation were included in group 2(n = 11). All 19 children underwent MRI.

RESULTS

Normal MRI always correlated with better visual outcome, regardless of the gestational age at which the insult occurred. Among infants born at or later than 34 weeks' gestation, a favorable visual recovery occurred in two with normal MRI findings. The presence of infarcts or periventricular leukomalacia indicated that full visual recovery would not occur. Among infants born before 34 weeks' gestation, the MRI findings were normal in two who had a favorable visual outcome. A normal visual cortex and the absence of periventricular leukomalacia were helpful in prognosticating the visual outcome. A general delay in the myelination-particularly in the myelination of the optic radiation-was a common finding and until now has not been described in children with CVI routinely.

CONCLUSION

MRI's ability to follow the process of myelination may be of predictive value. MRI, therefore, should be obtained in a child with CVI following perinatal hypoxia.