The spectrum of cerebral visual impairment as a sequel to premature birth: an overview

Visuospatial processing in early brain-based visual impairment is associated with differential recruitment of dorsal and ventral visual streams

Visuospatial processing impairments are prevalent in individuals with cerebral visual impairment (CVI) and are typically ascribed to "dorsal stream dysfunction" (DSD). However, the contribution of other cortical regions, including early visual cortex (EVC), frontal cortex, or the ventral visual stream, to such impairments remains unknown. Thus, here, we examined fMRI activity in these regions, while individuals with CVI (and neurotypicals) performed a visual search task within a dynamic naturalistic scene. First, behavioral performance was measured with eye tracking. Participants were instructed to search and follow a walking human target. CVI participants took significantly longer to find the target, and their eye gaze patterns were less accurate and less precise. Second, we used the same task in the MRI scanner. Along the dorsal stream, activation was reduced in CVI participants, consistent with the proposed DSD in CVI. Intriguingly, however, visual areas along the ventral stream showed the complete opposite pattern, with greater activation in CVI participants. In contrast, we found no differences in either EVC or frontal cortex between groups. These results suggest that the impaired visuospatial processing abilities in CVI are associated with differential recruitment of the dorsal and ventral visual streams, likely resulting from impaired selective attention.

Optic atrophy in prematurity: pathophysiology and clinical features

Optic atrophy is an important cause of visual impairment in children, and the aetiological profile has changed over time. Technological advancements led by neuroimaging of the visual pathway and imaging of the optic nerve with optical coherence tomography have accelerated the understanding of this condition. In the new millennium, an increasing prevalence of prematurity as a cause of optic atrophy in children has been highlighted. This new shift has been linked with increasing rates of premature births and improved neonatal survival of preterm infants. The available literature is limited to hospital and registry-based cohorts with modest sample sizes, methodological heterogeneity and selection bias limitations. Larger studies that are better designed are required to better understand the contribution of prematurity to the disease burden. In addition to considering other life-threatening aetiologies, screening for premature birth should be covered as part of a comprehensive history when evaluating a child with paediatric optic atrophy.

Visual search patterns during exploration of naturalistic scenes are driven by saliency cues in individuals with cerebral visual impairment

We investigated the relative influence of image salience and image semantics during the visual search of naturalistic scenes, comparing performance in individuals with cerebral visual impairment (CVI) and controls with neurotypical development. Participants searched for a prompted target presented as either an image or text cue. Success rate and reaction time were collected, and gaze behavior was recorded with an eye tracker. A receiver operating characteristic (ROC) analysis compared the distribution of individual gaze landings based on predictions of image salience (using Graph-Based Visual Saliency) and image semantics (using Global Vectors for Word Representations combined with Linguistic Analysis of Semantic Salience) models. CVI participants were less likely and were slower in finding the target. Their visual search behavior was also associated with a larger visual search area and greater number of fixations. ROC scores were also lower in CVI compared to controls for both model predictions. Furthermore, search strategies in the CVI group were not affected by cue type, although search times and accuracy showed a significant correlation with verbal IQ scores for text-cued searches. These results suggest that visual search patterns in CVI are driven mainly by image salience and provide further characterization of higher-order processing deficits observed in this population.

Australian children with cerebral visual impairment: using what we know now to improve future approaches

PURPOSE

Little has been reported on Australian children with Cerebral Vision Impairment (CVI). This paper aims to present the outcome of an audit focussed on children with the primary diagnosis of CVI, using findings from the Australian Childhood Vision Impairment Register (ACVIR).

METHODS

Records on 132 children (49% girls, 51% boys) from ACVIR data gathered from both the child's parent/guardian and their eye health professional were reviewed. The child's demographics, level of vision impairment, birth history, diagnostic journey, secondary ocular diagnoses, comorbidities and low vision support were analyzed. Several correlations were investigated using a Kendall's tau-b analysis including the relationship between vision and age of diagnosis; level of vision and developmental delay; and age of suspicion of visual impairment and age of diagnosis.

RESULTS

The most common level of visual impairment was blindness (39%), and most children were suspected and diagnosed of visual impairment in the first 6 months of life. The majority of children were born full term (72%), weighing >2000gms (84%). Nearly half of the cohort of children (48%) had a secondary ocular diagnosis with 44% having nystagmus. The majority of children (80%) had additional health problems, and 85% of children had additional disabilities, with 79% having developmental delay.

CONCLUSION

While the findings of this audit cannot be generalized to a wider population of Australian children with CVI, the outcome encourages continued discussion on CVI, to explore comprehensive assessment approaches which facilitate timely and accurate diagnosis.

Validation of the Austin Assessment: A screening tool for cerebral visual impairment related visual issues

Cerebral visual impairment is the most common cause of vision impairment affecting children in the economically developed world with a prevalence rate of approximately 3.4%. Currently there are limited options for screening for cerebral visual impairment, resulting in many children going undiagnosed, especially those that have normal visual acuity. The aim of this research was to validate an iPad App called the Austin Assessment, which was developed as a potential screening tool for cerebral visual impairment related visual issues. The research involved three separate phases: (1) creating a database of normative ranges for children aged 5-18 across the different variables of the Austin Assessment, (2) using the Austin Assessment to screen children aged 5-13 to assess the effectiveness of the Austin Assessment as a screening tool for CVI related visual issues, and (3) conducting specific validation research assessing children using the Austin Assessment and an already validated visual search tool. Each phase used different quantitative research methodologies to help show the effectiveness of the Austin Assessment as a screening tool for cerebral visual impairment related visual issues. From phase one of the research, thresholds were established for three variables of the Austin Assessment for the age groupings of 5-8, 9-12 and 13-18. If a child meets one of these thresholds this indicates further assessment is required to determine if they do in fact have cerebral visual impairment related visual issues. Phase two identified 17 children out of 270 who had clinical findings indicating visual issues; potentially indicative of CVI; investigation into the nature of these visual issues is ongoing. Phase three found that the Austin Assessment has moderate diagnostic value for each age group, with good sensitivity and specificity, making it effective at distinguishing those children who have visual issues from those who have typical vision. Further investigation is needed to confirm this initial validation.

Childhood cerebral visual impairment subtype classification based on an extensive versus a limited test battery

Purpose

To classify CVI subtypes and compare the added value of an extensive test battery over a limited test battery in subtype classification of cerebral visual impairment (CVI) in children.

Methods

Seventy-five children with a clinical diagnosis of CVI (median [IQR] age: 9 [7-12] years) were identified from the medical records. The extensive test battery included visual acuity, contrast sensitivity, ocular alignment, eye movement analysis, visual field analysis, optic nerve head evaluation, and evaluation of visual perception. The limited test battery included visual acuity, contrast sensitivity, ocular alignment, and evaluation of visual perception. Principal component analysis (PCA) followed by cluster analysis was done, for both test batteries separately, to determine the optimum subtype classification for CVI.

Results

Fifty-one participants with an extensive test battery with mild to moderate visual impairment were included in the main analysis. This resulted in four CVI subtypes for the extensive test battery (subtle characteristics, higher-level visual function deficits, lower-level visual function deficits, and higher- and lower- level visual function deficits) and three CVI subtypes for the limited test battery (subtle characteristics, higher-level visual function deficits, and higher- and lower- level visual function deficits). There were significant differences between the subtypes for 9 out of 10 measures of the extensive and all 4 measures of the limited test battery (p < 0.05). The subtle characteristics subtype (extensive n = 19, limited n = 15) showed near normal lower and higher-level visual functions in both test batteries. The higher-level visual function deficits subtype (extensive n = 18, limited n = 24) showed near normal visual acuity combined with significant visual perceptual deficits in both test batteries; accompanied by visual pathways defects and abnormal eye movement behavior in the extensive test battery. The higher- and lower- level visual function deficits subtype (extensive n = 4, limited n = 12) showed both higher and lower-level visual function deficits in both test batteries, but application of the extensive test battery revealed additional visual pathways defects and abnormal eye movement behavior. The lower-level visual function deficits CVI subtype (extensive n = 10) was a new subtype identified by the extensive test battery. This subtype showed lower-level visual function deficits together with abnormal eye movement measures.

Conclusion

This data-driven study has provided meaningful CVI subtype classifications based on the outcomes of various key functional and structural measures in CVI diagnosis. Comparison of the extensive test battery to the limited test battery revealed the added value of an extensive test battery in classifying CVI. The outcomes of this study, therefore, have provided a new direction in the area of CVI classification.

An Evidence-Based Approach to Augmentative and Alternative Communication Design for Individuals With Cortical Visual Impairment

PURPOSE

This article highlights the contributions of three pillars of an evidence-based practice approach (service providers, researchers, and families/clients) in the development of a framework to offer a way forward for professionals, families, and technology companies to support optimal visual and communication outcomes of individuals with cortical visual impairment (CVI) who use augmentative and alternative communication (AAC). By providing available research findings as well as practical information and lived experiences, the article offers clinical considerations and design features that can lead to addressing the unique needs of these individuals.

METHOD

This article reviews literature concerning what is known about CVI and describes in detail and from multiple viewpoints important features required in AAC systems to support individuals with CVI and enable them to communicate effectively.

RESULTS

Components necessary for teams, communication partners, and AAC designers to optimize AAC system design in CVI are presented using external research evidence as internal evidence from lived experience to support their importance.

CONCLUSIONS

An AAC system design that is tailored to the unique visual processing characteristics in CVI is likely to promote positive communication outcomes. The presentation of the lived experience of an individual who has CVI themselves illustrates the need for individualized assessments and interventions that incorporate and reflect the research presented here.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23902239.

Visual outcome at 2.5 years of age in ω-3 and ω-6 long-chain polyunsaturated fatty acid supplemented preterm infants: a follow-up of a randomized controlled trial

Background

We investigated ophthalmological outcomes at 2.5 years of corrected age in children born extremely preterm (EPT) to evaluate the effects of postnatal enteral supplementation with ω-3 and ω-6 long-chain polyunsaturated fatty acids.

Methods

In the Mega Donna Mega clinical trial, EPT infants born at less than 28 weeks of gestation were randomized to receive an enteral supplementation of docosahexaenoic acid (DHA) and arachidonic acid (AA) from birth to 40 weeks postmenstrual age. In this exploratory follow-up at 2.5 years of corrected age, we assessed visual acuity (VA), refraction, manifest strabismus, and nystagmus. Satisfactory VA was defined as ≥20/63. Multiple imputation (MI) was used to address the issue of missing data.

Findings

Of 178 children in the trial, 115 (with median gestational age (GA) of 25 + 4/7 weeks and median birth weights of 790 g) were ophthalmologically assessed at a median corrected age of 2.7 years (range 2.0-3.9 years). VA assessment was missing in 42.1% (75/178), in 41.7% (35/84) of the AA/DHA supplemented infants, and in 42.6% (40/94) of the control infants. After MI and adjustments for GA, study center, plurality, and corrected age at VA exam, no significant effect of AA/DHA supplementation was detected in VA outcome (≥20/63) (odds ratio 2.16, confidence interval 95% 0.99-4.69, p = 0.053).

Interpretation

In this randomized controlled trial follow-up, postnatal supplementation with enteral AA/DHA to EPT children did not significantly alter VA at 2.5 years of corrected age. Due to the high loss to follow-up rate and the limited statistical power, additional studies are needed.

Funding

The Swedish Medical Research Council #2020-01092, The Gothenburg Medical Society, Government grants under the ALF agreement ALFGBG-717971 and ALFGBG-971188, De Blindas Vänner, Knut and Alice Wallenberg Foundation - Wallenberg Clinical Scholars, NIHEY017017, EY030904BCHIDDRC (1U54HD090255 Massachusetts Lions Eye Foundation) supported the study.

Visual Behaviours (ViBes) in Cerebral Visual Impairment: Validating a Descriptive Tool to Support Diagnosis and Monitoring

Introduction

Cerebral visual impairment (CVI) is the most common cause of visual impairment in children in the UK. Diagnosis is based on identification of visual behaviours (ViBes) relating to visual dysfunction. Examination techniques and inventories have been developed to elicit these in children with a developmental age of two years or more. The absence of a structured approach to recording visual behaviours in children with complex needs is a barrier to diagnosis. The aim of the study was to develop a matrix of visual behaviours seen in pre-verbal and pre-motor children with visual impairment and establish its content validity and inter-rater reliability.

Methods

ViBe content validation:: Visual behaviour descriptors relating to visual function were collated and categorised by expert consensus of vision professionals into a matrix composed of three functions (attention, field/fixation, motor response) and five levels (0 = no awareness; 1 = visual awareness; 2 = visual attention; 3 = visual detection; 4 = visual understanding).ViBe inter-rater reliability:: The participants (two orthoptists, an optometrist, an ophthalmologist and two qualified teachers of the visually impaired) used the ViBe matrix to independently score each of 17 short video clips of children demonstrating visual behaviours seen in CVI.

Results

The ViBe matrix will be presented. Cohen's kappa for the matrix was 0.67, demonstrating moderate-to-strong inter-rater reliability.

Conclusion

The development of standardised descriptors can support clinicians and teachers in identifying areas of concern for children with complex needs. In addition, the ViBe matrix could be utilised in research, clinical and diagnostic reports to clearly communicate the areas of visual dysfunction and track progress resulting from interventions.

Key Points

The absence of a structured approach to recording visual behaviours in children with complex needs is a barrier to diagnosis.The ViBe matrix offers descriptors relating to visual behaviours and has demonstrated acceptable inter-rater reliability.The tool may support the identification and diagnosis of cerebral visual impairment in a population of children who cannot access standard testing.

Interventions for children with cerebral visual impairment: A scoping review

AIM

To examine the nature and scope of the literature on interventions implemented for children with cerebral visual impairment (CVI).

METHOD

Using a scoping review methodology, a systematic search of the literature was conducted using four databases including PubMed, Web of Science, Scopus, and Embase. Titles and abstracts were screened and data were extracted and synthesized from full-text, eligible studies. Twenty-three articles were identified and evaluated using quality criteria.

RESULTS

Twenty-three of the 895 studies were included with children aged between 1 month and 17 years 6 months. Interventions were grouped into six categories including visual stimulation, task/environmental adaptations, vision training, acupuncture, stem cell transplantation, and transcranial electric stimulation. Outcome measures examined changes in visual function, functional vision, and visual processing.

INTERPRETATION

Intervention research for children with CVI is in its infancy. Interventions for children with CVI may be beneficial; however, comparing results is difficult due to inconsistency in outcome measures. Most of the intervention studies had lower-level evidence and included small sample sizes. High-quality studies with larger samples and comparison groups are needed to fully understand which evidence-based interventions are most effective for children with CVI. With the incidence of CVI increasing, further development and validation of intervention methods is imperative.

WHAT THIS PAPER ADDS

Intervention studies for children with cerebral visual impairment (CVI) are sparse. Most intervention studies for children with CVI have low-level evidence with low critical appraisal scores. High-quality, controlled intervention studies are needed to guide families and clinicians toward evidence-based practice.

"Even though a lot of kids have it, not a lot of people have knowledge of it": A qualitative study exploring the perspectives of parents of children with cerebral/cortical visual impairment

BACKGROUND

Cerebral/Cortical Visual Impairment (CVI) is the leading cause of visual impairment in children and can negatively impact participation in daily activities.

METHODS AND PROCEDURE

This qualitative study used virtual focus groups and an online questionnaire to understand the perspectives of families with children who have CVI. Constant comparison analysis was used to analyze focus group transcripts and extract themes. The PEDI-CAT and an online questionnaire were administered to characterize the study population.

OUTCOMES AND RESULTS

Four themes were identified: (1) Awareness of CVI and its effect on the child and family, (2) Parent experiences, (3) Child factors and functional implications, and (4) Supports that enhance child development/vision.

CONCLUSIONS AND IMPLICATIONS

Findings from this study highlight the substantial impact that lack of CVI awareness had on parent experiences. Lack of awareness led to late diagnosis, missed intervention opportunities, and caregiver burden. Due to insufficient resources, parents had to educate themselves and service providers about CVI and advocate for their child's needs. Healthcare and educational providers who work with pediatric neurodevelopmental populations must be knowledgeable about clinical features of CVI, task and environmental adaptations to support vision and implementation of family-centered care.

Vision function in children 10 years after grade 3 or 4 intraventricular haemorrhage with ventricular dilation: A masked prospective study

AIM

We examined children 10 to 11 years after grade 3 or 4 intraventricular haemorrhage and ventricular dilation (IVHVD) and investigated whether the grade of IVHVD affected their visual outcome. We explored associations between visual outcomes with cognitive outcomes and extra support at school.

METHOD

The visual examinations were part of a 10-year follow-up study for children in a randomized trial. Testers followed a protocol and were masked to whether the child had experienced grade 3 or grade 4 IVHVD and all other data.

RESULTS

Thirty-two children were tested: 24 were male and mean (standard deviation) age was 10 years 5 months (1 year 2 months); range 8 years 9 months to 12 years 9 months. All had at least one visual impairment. The median (interquartile range) number of impairments per child was six (six to nine) for children who experienced a grade 4 IVHVD compared with three (two to four) for children who experienced a grade 3 IVHVD (p = 0.003). Each extra vision impairment per child was associated with increased educational support at school, after adjustment for developmental age equivalence (odds ratio = 1.7 [95% confidence interval 1.1-2.6], p = 0.015).

INTERPRETATION

Children who experience grade 3 or 4 IVHVD have a high level of visual morbidity at age 10 to 11 years. These children may have unmet visual needs and their outcomes might improve if these needs could be addressed.

WHAT THIS PAPER ADDS

Parent-reported questionnaire responses underestimated directly assessed visual morbidity. Grade 4 intraventricular haemorrhage and ventricular dilatation (IVHVD) was followed by more vision impairments than grade 3 IVHVD. Simple tests of visual perceptual skills correlated with the neuropsychology tests. Children with supranuclear eye movement disorders were more likely to be receiving extra help at school. Each additional visual impairment increased the likelihood of extra educational support.

Including visual orienting functions into cerebral visual impairment screening: Reliability, variability, and ecological validity

BACKGROUND

Cerebral visual impairment (CVI) is a heterogeneous brain-based visual processing disorder in which basic visual orienting functions (VOF) and higher-order perception can be impaired.

AIMS

To evaluate (1) the test-retest reliability and variability of an eye tracking-based VOF paradigm, and related clinical characteristics, and (2) the relations between VOF (variability) and daily visual functioning and visuoperceptual dimensions.

METHODS AND PROCEDURES

Thirty-three children with CVI (Males=14; mean age=9 years 10 months) underwent eye tracking thrice, completed a visuoperceptual battery, and parents completed the Flemish CVI questionnaire. VOF reliability and variability of reaction time (RTF), fixation duration and accuracy were assessed with intraclass correlation coefficient (ICC), Bland-Altman plots, and coefficient of variation. Relations were analysed with linear mixed models.

OUTCOMES AND RESULTS

Highly salient visual stimuli had good RTF reliability (ICCs=0.75) and triggered less variable VOF. Intermediate and low salience stimuli had poor-to-moderate reliability and triggered more variable VOF. Younger performance age related to more VOF variability. Greater visual (dis)interest, clutter and distance viewing impairments, and a weaker visuoperceptual profile related to slower RTF.

CONCLUSIONS AND IMPLICATIONS

Highly salient stimuli reveal a child's 'optimal' visual performance, whereas intermediate and low salience stimuli uncover VOF variability, which is a key CVI hallmark to detect.

Assessing visuospatial processing in cerebral visual impairment using a novel and naturalistic static visual search task

BACKGROUND

Cerebral visual impairment (CVI) is a brain based visual disorder associated with the maldevelopment of central visual pathways. Individuals with CVI often report difficulties finding a target of interest in cluttered and crowded visual scenes. However, it remains unknown how manipulating task demands and other environmental factors influence visual search performance in this population.

AIM

We developed a novel and naturalistic virtual reality (VR) based static visual search task combined with eye tracking called the "virtual toy box" to objectively assess visual search performance in CVI.

METHODS AND PROCEDURES

A total of 38 individuals with CVI (mean age 13.18 years ± 3.58 SD) and 53 controls with neurotypical development (mean age 15.25 years ± 5.72 SD) participated in the study. In a first experiment, study subjects were instructed to search for a preselected toy presented among a varying number of surrounding distractor toys (set size ranging from 1 to 36 items). In a second experiment, we assessed the effects of manipulating item spacing and the size of the visual area explored (field of view; FOV).

OUTCOMES AND RESULTS

Behavioral outcomes collected were success rate, reaction time, gaze error, visual search area, and off-screen percent (an index of task compliance). Compared to age-matched controls, participants with CVI showed an overall impairment with respect to all the visual search outcomes of interest. Specifically, individuals with CVI were less likely and took longer to find the target, and search patterns were less accurate and precise compared to controls. Visual search response profiles were also comparatively less efficient and were associated with a slower initial pre-search (visual orienting) response as indexed by higher slope and intercept values derived from the analysis of reaction time × set size functions. Search performance was also more negatively affected in CVI at the smallest as well as largest spacing conditions tested, while increasing FOV was associated with greater decreased gaze accuracy and precision CONCLUSIONS AND IMPLICATIONS: These results are consistent with a general profile of impaired visual search abilities in CVI as well as worsening performance with increased visual task demands and an overall sensitivity to visual clutter and crowding. The observed profile of impaired visual search performance may be associated with dysfunctions related to how visual selective attention is deployed in individuals with CVI.

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.

Retrospective evaluation of ophthalmological and neurological outcomes for infants born before 24 weeks gestational age in a Swedish cohort

OBJECTIVES

To retrospectively evaluate ophthalmological and neurological outcomes in a Swedish cohort of infants born before 24 weeks gestational age (GA) and explore risk factors for visual impairment.

SETTING

Eye and paediatric clinics in Sweden.

PARTICIPANTS

Infants screened for retinopathy of prematurity (ROP) (n=399), born before 24 weeks GA, 2007-2018. Cases were excluded if ophthalmological follow-up records could not be traced.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcomes were ophthalmological, including visual acuity (VA), refractive error, strabismus, nystagmus and cerebral visual impairment (CVI). Secondary outcomes comprised neonatal and neurological morbidities. Data were retrospectively retrieved from medical records.

RESULTS

The 355 assessed children had a median GA of 23 weeks and 2 days and a median birth weight of 565 g. At the last available ophthalmological examination, the median age was 4.8 years (range 0.5-13.2 years). Nystagmus was recorded in 21.1%, strabismus in 34.8%, and 51.0% wore spectacles. Seventy-three of 333 (21.9%) were visually impaired, defined as being referred to a low vision clinic and/or having a VA less than 20/60 at 3.5 years of age or older. ROP treatment was a significant risk factor for visual impairment (OR 2.244, p=0.003). Visually impaired children, compared with children without visual impairment, more often had neurological deficits such as intellectual disability 63.8% versus 33.3% (p<0.001), epilepsy 21.1% versus 7.5% (p=0.001) and autism spectrum disorders 32.8% versus 20.9% (p=0.043). Nine of the 355 children had been diagnosed with CVI.

CONCLUSIONS

Children born before 24 weeks GA frequently had visual impairment in association with neurological deficits. CVI was rarely diagnosed. A multidisciplinary approach for the evaluation and habilitation of these vulnerable infants is warranted. National follow-up guidelines need to be developed and implemented.

Assessing Higher-Order Visual Processing in Cerebral Visual Impairment Using Naturalistic Virtual-Reality-Based Visual Search Tasks

Cerebral visual impairment (CVI) is a brain-based disorder associated with the maldevelopment of central visual pathways. Individuals with CVI often report difficulties with daily visual search tasks such as finding a favorite toy or familiar person in cluttered and crowded scenes. We developed two novel virtual reality (VR)-based visual search tasks combined with eye tracking to objectively assess higher order processing abilities in CVI. The first (virtual toybox) simulates a static object search, while the second (virtual hallway) represents a dynamic human search task. Participants were instructed to search for a preselected target while task demand was manipulated with respect to the presence of surrounding distractors. We found that CVI participants (when compared to age-matched controls) showed an overall impairment with visual search on both tasks and with respect to all gaze metrics. Furthermore, CVI participants showed a trend of worsening performance with increasing task demand. Finally, search performance was also impaired in CVI participants with normal/near normal visual acuity, suggesting that reduced stimulus visibility alone does not account for these observations. This novel approach may have important clinical utility in helping to assess environmental factors related to functional visual processing difficulties observed in CVI.

Neural correlates associated with impaired global motion perception in cerebral visual impairment (CVI)

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Cerebral visual impairment (CVI) is associated with impaired global motion processing.

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Mean motion coherence thresholds was higher in individuals with CVI.

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fMRI responses in area hMT+ showed an aberrant response profile in CVI.

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White matter tract reconstruction revealed cortico-cortical dysmyelination in CVI.

Cerebral visual impairment (CVI) is associated with a wide range of visual perceptual deficits including global motion processing. However, the underlying neurophysiological basis for these impairments remain poorly understood. We investigated global motion processing abilities in individuals with CVI compared to neurotypical controls using a combined behavioral and multi-modal neuroimaging approach. We found that CVI participants had a significantly higher mean motion coherence threshold (determined using a random dot kinematogram pattern simulating optic flow motion) compared to controls. Using functional magnetic resonance imaging (fMRI), we investigated activation response profiles in functionally defined early (i.e. primary visual cortex; area V1) and higher order (i.e. middle temporal cortex; area hMT+) stages of motion processing. In area V1, responses to increasing motion coherence were similar in both groups. However, in the CVI group, activation in area hMT+ was significantly reduced compared to controls, and consistent with a surround facilitation (rather than suppression) response profile. White matter tract reconstruction obtained from high angular resolution diffusion imaging (HARDI) revealed evidence of increased mean, axial, and radial diffusivities within cortico-cortical (i.e. V1-hMT+), but not thalamo-hMT+ connections. Overall, our results suggest that global motion processing deficits in CVI may be associated with impaired signal integration and segregation mechanisms, as well as white matter integrity at the level of area hMT+.

Factors for changes in self-care and mobility capabilities in young children with cerebral palsy involved in regular outpatient rehabilitation care

Background

Assessing prognosis of self-care and mobility capabilities in children with cerebral palsy (CP) is important for goal setting, treatment guidance and meaningful professional-caregiver conversations.

Aims

Identifying factors associated with changes in self-care and mobility capabilities in regular outpatient multidisciplinary paediatric CP rehabilitation care.

Methods and procedures

Routinely monitored longitudinal data, assessed with the Paediatric Evaluation of Disability Inventory (PEDI-Functional-Skills-Scale, FSS 0–100) was retrospectively analysed. We determined contributions of age, gross-motor function, bimanual-arm function, intellectual function, education type, epilepsy, visual function, and psychiatric comorbidity to self-care and mobility capability changes (linear-mixed-models).

Outcomes and results

For 90 children (53 boys), in all Gross-Motor-Function-Classification-System (GMFCS) levels, 272 PEDI's were completed. Mean PEDI–FSS–scores at first measurement (median age: 3,2 years) for self-care and mobility were 46.3 and 42.4, and mean final FSS-scores respectively were 55.1 and 53.1 (median age: 6,5 years). Self-care capability change was significantly associated with age (2.81, p < 0.001), GMFCS levels III-V (-9.12 to -46.66, p < 0.01), and intellectual impairment (-6.39, p < 0.01). Mobility capability change was significantly associated with age (3.25, p < 0.001) and GMFCS levels II-V (-6.58 to -47.12, p < 0.01).

Conclusions and implications

Most important prognostic factor for self-care and mobility capabilities is GMFCS level, plus intellectual impairment for self-care. Maximum capability levels are reached at different ages, which is important for individual goal setting and managing expectations.

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Capabilities of children with CP improve modestly over time in outpatient rehabilitation.

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Children with more severe CP reach maximum mobility and self-care levels at an earlier age.

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After this maintaining capabilities is more realistic than improvement.

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Important prognostic factors are GMFCS level and intellectual impairment.

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Routine monitoring can aid goal setting and expectation management in communication with families.

The relation between visual orienting functions, daily visual behaviour and visuoperceptual performance in children with (suspected) cerebral visual impairment

BACKGROUND

Children with cerebral visual impairment (CVI) present heterogeneous visual orienting functions (VOF) and higher-order perception. Multiple assessment methods evaluate CVI, but the relations between them remain unclear.

AIM

To investigate the relations between VOF and (1) daily life behaviour and (2) visuoperceptual tests in children with (suspected) CVI.

METHODS AND PROCEDURES

VOF were tested with a validated eye tracking-based paradigm. Visual perception was assessed using the children's visual impairment test for 3- to 6-year olds (CVIT 3-6) and (retrospective) visuoperceptual dimension results. Caregivers completed the Flemish cerebral visual impairment questionnaire (FCVIQ) and an expert panel scored relations between VOF and the other methods. We compared experts' survey responses with data-based results (linear mixed models and correlations).

OUTCOMES AND RESULTS

Fourty-four children (23 boys, 21 girls; median age = 7y11mo, SD = 2y7mo) participated. Twenty-one experts completed the survey. Slower VOF was significantly associated with (1) object and face processing impairments, (2) visual (dis)interest, (3) worse visual spatial perception (to local motion and form stimuli), and (4) worse CVIT 3-6 object and scene recognition (to cartoon stimuli).

CONCLUSIONS AND IMPLICATIONS

Integration of VOF with existing visual assessments provides a better clinical picture of CVI and can prevent misdiagnosing children as inattentive, incapable, or unmotivated.

Early Screening of Visual Processing Dysfunctions in Children Born Very or Extremely Preterm

Introduction: Children with early brain damage or dysfunction are at risk of developing cerebral visual impairment (CVI), including visual processing dysfunctions (VPD), which currently remain largely undetected until school age. Our aim was to systematically screen for possible VPD in children born very or extremely preterm from 1 to 2 years corrected age (CA) and to evaluate the effectiveness of early referral. Method: We included N = 48 children born < 30 weeks from 1 year CA. They underwent a two-step VPD screening based on (1) neurological signs indicative of visual brain damage evaluated by neonatologists and/or pediatric neurologist and (2) a functional assessment of visual orienting functions (VOF) with an eye tracking-based test. If at least one of these assessments was abnormal for their age, the children were classified as a risk of VPD and referred to undergo conventional visual diagnostics: ophthalmic exam and visual function assessment (VFA). At 2 years CA, VOF screening was repeated and neurodevelopment was assessed. Results: 18 children (38%) were classified as at risk of VPD at 1 year CA. 7 children had abnormal neurological signs, 5 children had abnormal VOF, and 6 children had both. Subsequent ophthalmic exams (N = 14) showed severe hypermetropia in 21% and strabismus in 14%. VFA (N = 10) showed abnormal visual function and behavior in only 1 child. At 2 years CA, the total group showed an increase in abnormal VOF. Whereas the children at risk showed some normalization, the group without VPD risk at 1 year CA showed deterioration of VOF. Neurodevelopmental outcome did not clearly differ between risk groups. Conclusion: Our findings show a substantial risk of VPD during visual screening (in 38%) at 1 year CA, but relatively few deficits on subsequent conventional ophthalmic exams and VFA. The data suggest that most conventional visual diagnostic methods at this young age are not related to the established VPD risks. VOF assessment should be used complimentary to these methods. The fact that at 2 years CA the number of children with a VPD risk based on abnormal VOF increased argues for more extensive and continuous screening in risk groups, at least until school age.

Motion Processing Deficits in Children With Cerebral Visual Impairment and Good Visual Acuity

Purpose

We sought to characterize neural motion processing deficits in children with cerebral visual impairment (CVI) who have good visual acuity using an objective, quantifiable method (steady-state visual evoked potentials [SSVEPs]).

Methods

We recorded SSVEPs in response to three types of visual motion – absolute motion and more complex relative and rotary motion, comparing them to form-related vernier and contour responses. We studied a group of 31 children with CVI diagnosed via detailed clinical examinations and 28 age-matched healthy controls.

Results

Using measurements made at the appropriate response harmonics of the stimulation frequency, we found significant deficits in cerebral processing of relative and rotary motion but not of absolute motion in children with CVI compared with healthy controls. Vernier acuity, in keeping with good recognition acuity in both groups, was not different, nor were contour-related form responses.

Conclusions

Deficits for complex motion but relative sparing of elementary motion and form-related signals suggests preferential damage to extra-striate visual motion areas in children with CVI. The fact that these preferential losses occur in the absence of significant acuity loss indicates that they are not secondary to reduced visual acuity, but rather are an independent vulnerability in CVI. These results corroborate parental and caregivers’ reports of difficulties with tasks that involve motion perception in children with CVI.

Visual search performance in cerebral visual impairment is associated with altered alpha band oscillations

Individuals with cerebral visual impairment (CVI) often present with deficits related to visuospatial processing. However, the neurophysiological basis underlying these higher order perceptual dysfunctions have not been clearly identified. We assessed visual search performance using a novel virtual reality based task paired with eye tracking to simulate the exploration of a naturalistic scene (a virtual toy box). This was combined with electroencephalography (EEG) recordings and an analysis pipeline focusing on time frequency decomposition of alpha oscillatory activity. We found that individuals with CVI showed an overall impairment in visual search performance (as indexed by decreased success rate, as well as increased reaction time, visual search area, and gaze error) compared to controls with neurotypical development. Analysis of captured EEG activity following stimulus onset revealed that in the CVI group, there was a distinct lack of strong and well defined posterior alpha desynchronization; an important signal involved in the coordination of neural activity related to visual processing. Finally, an exploratory analysis revealed that in CVI, the magnitude of alpha desynchronization was associated with impaired visual search performance as well as decreased volume of specific thalamic nuclei implicated in visual processing. These results suggest that impairments in visuospatial processing related to visual search in CVI are associated with alterations in alpha band oscillations as well as early neurological injury at the level of visual thalamic nuclei.

Early visuospatial attention and processing and related neurodevelopmental outcome at 2 years in children born very preterm

BACKGROUND

The ability to perceive and process visuospatial information is a condition for broader neurodevelopment. We examined the association of early visuospatial attention and processing with later neurodevelopmental outcome in very preterm infants.

METHODS

Visuospatial attention and processing was assessed in 209 children (<30 weeks gestation) using an easy applicable eye tracking-based paradigm at 1 and 2 years. Average reaction times to fixation (RTF) on specific visual stimuli were calculated, representing time needed for overall attention (Cartoon stimuli) and processing (Motion and Form stimuli). Associations between RTFs and various measures of development at 2 years including cognitive and motor development (Bayley Scales of Infant and Toddler Development-Third edition; Bayley-III), language (Lexi test) and behavior (Child Behavior Checklist) were examined.

RESULTS

At 1 year, 100 ms slower Cartoon and Motion RTFs were associated with lower cognitive Bayley-III scores (-4.4 points, 95%CI: -7.4; -1.5 and -1.0 points, -1.8; -0.2, respectively). A 100 ms slower Cartoon RTF was associated with a 3.5 (-6.6; -0.5) point decrease in motor Bayley-III score.

CONCLUSIONS

Visuospatial attention and motion processing at 1 year is predictive of overall cognitive and motor development 1 year later. The nonverbal eye tracking-based test can assist in early detection of preterm children at risk of adverse neurodevelopment.

IMPACT

Visuospatial attention and processing at 1 year corrected age is predictive for overall cognitive and motor development 1 year later in preterm infants. First study to relate early visuospatial attention and processing with later neurodevelopmental outcome in preterm children. Early detection of preterm children at risk of adverse neurodevelopment, which allows for more timely interventions.

Visual perception supported by verbal mediation in an individual with cerebral visual impairment (CVI)

Cerebral visual impairment (CVI) often presents with deficits associated with higher order visual processing. We report a case of an individual with CVI who uses a verbal mediation strategy to perceive and interact with his visual surroundings. Visual perceptual performance was assessed using a virtual reality based visual search task combined with eye tracking. Functional magnetic resonance imaging (fMRI) was employed to identify the neural correlates associated with this strategy. We found that when using verbal mediation, the individual could readily detect and track the target within the visual scene which was associated with robust activation within a network of occipito-parieto-temporal visual cortical areas. In contrast, when not using verbal mediation, the individual was completely unable to perform the task, and this was associated with dramatically reduced visual cortical activation. This unique compensatory strategy may be related to the individual's use of verbal working memory for the purposes of understanding complex visual information.

Cerebral visual impairment-related vision problems in primary school children: a cross-sectional survey

AIM

To estimate how many children in mainstream primary schools have cerebral visual impairment (CVI)-related vision problems and to investigate whether some indicators might be useful as red flags, if they were associated with increased risk for these problems.

METHOD

We conducted a survey of primary school children aged 5 to 11 years, using whether they were getting extra educational help and/or teacher- and parent-reported behaviour questionnaires to identify children at risk for CVI. These and a random 5% sample were assessed for CVI-related vision problems. We compared the usefulness of potential red flags using likelihood ratios.

RESULTS

We received questionnaires on 2298 mainstream-educated children and examined 248 children (152 [61%] males, 96 females [39%]; mean age 8y 1mo, SD 20mo, range 5y 6mo-11y 8mo). We identified 78 out of 248 children (31.5% of those examined, 3.4% of the total sample), who had at least one CVI-related vision problem. The majority (88%) were identified by one or more red flag but none were strongly predictive. Fewer than one in five children with any CVI-related vision problem had reduced visual acuity.

INTERPRETATION

Children with CVI-related vision problems were more prevalent than has been appreciated. Assessment of at-risk children may be useful so that opportunities to improve outcomes for children with CVI-related vision problems are not missed.

Visual Neuropsychology in Development: Anatomo-Functional Brain Mechanisms of Action/Perception Binding in Health and Disease

Vision is the main entrance for environmental input to the human brain. Even if vision is our most used sensory modality, its importance is not limited to environmental exploration. Rather it has strong links to motor competences, further extending to cognitive and social aspects of human life. These multifaceted relationships are particularly important in developmental age and become dramatically evident in presence of complex deficits originating from visual aberrancies. The present review summarizes the available neuropsychological evidence on the development of visual competences, with a particular focus on the associated visuo-motor integration skills in health and disease. With the aim of supporting future research and interventional settings, the goal of the present review is to constitute a solid base to help the translation of neuropsychological hypotheses into straightforward empirical investigations and rehabilitation/training protocols. This approach will further increase the impact, ameliorate the acceptance, and ease the use and implementation of lab-derived intervention protocols in real-life situations.

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.

Evidence for Attentional Phenotypes in Infancy and Their Role in Visual Cognitive Performance

Infant visual attention rapidly develops during the first year of life, playing a pivotal role in the way infants process, learn, and respond to their visual world. It is possible that individual differences in eye movement patterns shape early experience and thus subsequent cognitive development. If this is the case, then it may be possible to identify sub-optimal attentional behaviors in infancy, before the emergence of cognitive deficit. In Experiment 1, a latent profile analysis was conducted on scores derived from the Infant Orienting with Attention (IOWA) task, a cued-attention task that measures individual differences in spatial attention and orienting proficiency. This analysis identified three profiles that varied substantially in terms of attentional efficiency. The largest of these profiles (“high flexible”, 55%) demonstrated functionally optimal patterns of attentional functioning with relatively rapid, selective, and adaptive orienting responses. The next largest group (“low reactive”, 39.6%) demonstrated low attentional sensitivity with slow, insensitive orienting responses. The smallest group (“high reactive”, 5.4%) demonstrated attentional over-sensitivity, with rapid, unselective and inaccurate orienting responses. A linear mixed effect model and growth curve analysis conducted on 5- to 11-month-old eye tracking data revealed significant stable differences in growth trajectory for each phenotype group. Results from Experiment 2 demonstrated the ability of attentional phenotypes to explain individual differences in general cognitive functioning, revealing significant between-phenotype group differences in performance on a visual short-term memory task. Taken together, results presented here demonstrate that attentional phenotypes are present early in life and predict unique patterns of growth from 5 to 11 months, and may be useful in understanding the origin of individual differences in general visuo-cognitive functioning.

Brain Damage and Visuospatial Impairments: Exploring Early Structure-Function Associations in Children Born Very Preterm

BACKGROUND

To provide insight into early neurosensory development in children born very preterm, we assessed the association between early structural brain damage and functional visuospatial attention and motion processing from one to two years corrected age.

METHODS

In 112 children born at less than 32 weeks gestational age, we assessed brain damage and growth with a standardized scoring system on magnetic resonance imaging (MRI; 1.5 Tesla) scans performed at 29 to 35 weeks gestational age. Of the children with an MRI scan, 82 participated in an eye tracking-based assessment of visuospatial attention and motion processing (Tobii T60XL) at one year corrected age and 59 at two years corrected age.

RESULTS

MRI scoring showed good intra- and inter-rater reproducibility. At one year, 10% children had delayed attentional reaction times and 23% had delayed motion reaction times. Moderate to severe brain damage significantly correlated with slower visuospatial reaction times. At two years, despite attention and motion reaction times becoming significantly faster, 20% had delayed attentional reaction times and 35% had delayed motion reaction times, but no correlations with MRI scores were found. The presence of structural brain damage was associated with abnormal functional performance over age.

CONCLUSIONS

The present study indicates an association between moderate to severe brain damage and visuospatial attention and motion processing dysfunction at one year corrected age. This provides a new perspective on comprehensive MRI scoring and quantitative functional visuospatial assessments and their applicability in children born very preterm in their first years of life.

As-indicated versus routine vision screening of preterm children: a 17-year retrospective regional study

PURPOSE

To investigate outcomes of routine vision screening compared to as-indicated ophthalmological investigation of all children born preterm in a Danish region from 1997 to 2014.

METHODS

All children born preterm (gestation age < 32 weeks or birthweight < 1500 g) screened for retinopathy of prematurity (ROP) were divided into two groups. From 1997 to 2009, only children treated for ROP or referred for visual problems received ophthalmological investigation (as-indicated group). From 2010 to 2014, all ROP-screened infants were offered ophthalmological investigation at 6 months and 3 years of age (screening group).

RESULTS

A total of 560 children were included in the as-indicated period, 41 and 87 were referred for ophthalmological investigation at 6 months and 3 years, respectively. In the screening period, 295 children were included, 251 and 150 of whom underwent vision evaluation at 6 months and 3 years, respectively. Mean visual acuity was 4.1 cycles per degree with Teller acuity cards at 6 months and 0.78 decimal at 3 years. At 3 years, 2.7%(n = 11) in the as-indicated versus 3.5%(n = 10) screening group had visual acuity < 6/18 (p = 0.24). Cerebral palsy (n = 28) and epilepsy (n = 5) were significantly related to vision impairment (p = 0.001/0.006), while treated ROP was not (n = 13). Refractive error was common at 3 years (61%), especially astigmatism (50%). Gestational age, birthweight and ROP were not associated with vision impairment or refractive error.

CONCLUSION

Screening preterm children at 6 months and 3 years did not reveal more visually impaired children compared to examination when indicated.

Early intervention for children at risk of visual processing dysfunctions from 1 year of age: a randomized controlled trial protocol

Background

An increasing number of children are suffering from brain damage-related visual processing dysfunctions (VPD). There is currently a lack of evidence-based intervention methods that can be used early in development. We developed a visual intervention protocol suitable from 1 year of age. The protocol is structured, comprehensive and individually adaptive, and is paired with quantitative outcome assessments. Our aim is to investigate the effectiveness of this first visual intervention program for young children with (a risk of) VPD.

Methods

This is a single-blind, placebo-controlled trial that is embedded within standard clinical care. The study population consists of 100 children born very or extremely preterm (< 30 weeks) at 1 year of corrected age (CA), of whom 50% are expected to have VPD. First, children undergo a visual screening at 1 year CA. If they are classified as being at risk of VPD, they are referred to standard care, which involves an ophthalmic and visual function assessment and a (newly developed) visual intervention program. This program consists of a general protocol (standardized and similar for all children) and a supplement protocol (adapted to the specific needs of the child). Children are randomly allocated to an intervention group (starting upon inclusion at 1 year CA) or a control group (postponed: starting at 2 years CA). The control group will receive a placebo treatment. The effectiveness of early visual intervention will be examined with follow-up visual and neurocognitive assessments after 1 year (upon completion of the direct intervention) and after 2 years (upon completion of the postponed intervention).

Discussion

Through this randomized controlled trial we will establish the effectiveness of a new and early visual intervention program. Combining a general and supplement protocol enables both structured comparisons between participants and groups, and custom habilitation that is tailored to a child’s specific needs. The design ensures that all included children will benefit from participation by advancing the age at which they start receiving an intervention. We expect results to be applicable to the overall population of children with (a risk of) VPD early in life.

Trial registration

Netherlands Trial Register: NTR6952. Registered 19 January 2018.

Perinatal risk factors for visuospatial attention and processing dysfunctions at 1 year of age in children born between 26 and 32 weeks

BACKGROUND

Children born preterm are at risk of visuospatial attention orienting and processing dysfunctions, which can be quantified early in life using visually-guided eye movement responses.

AIMS

To identify the prevalence and perinatal risk factors for visuospatial attention orienting and processing dysfunctions in children born preterm of 1 year of corrected age (CA).

STUDY DESIGN

123 children born between 26 and 33 weeks of gestation underwent a nonverbal visuospatial test at 1y CA, using an eye tracking-based paradigm. For the detected high-salient (cartoon and contrast), intermediate-salient (form and motion) and low-salient (color) stimuli, we quantified the reaction time to fixation (RTF). RTFs were compared to normative references from an age-matched control group (N = 38). The prevalence of perinatal risk factors (gestational age and weight, indices of neurological damage, overal sickness, respiratory failure, and retinopathy) was compared between the groups with normal and delayed RTFs.

RESULTS

At 1y CA, the preterm group had 7-20% less detected stimuli than the control group, particularly for intermediate and low-salient stimuli. Compared to normative RTFs, modest delays were found for high-salient cartoon (in 19% of preterm children) and contrast (8%), intermediate-salient motion (23%) and form (21%), and low-salient color stimuli (8%). These children had a significantly higher prevalence of perinatal risk factors for respiratory failure and intraventricular hemorrhages.

CONCLUSIONS

Children born between 26 and 32 weeks have a modest risk (8-23%) of visuospatial attention and processing dysfunction. This warrants early monitoring and support of general visual development in preterm children at risk of respiratory distress and disrupted cerebral blood flow.

Refractive error and ocular findings among infants and young children with severe problem behavior and developmental disabilities

The prevalence of refractive error and ocular disorders among infants and young children with severe behavioral problems and developmental disorders is not well defined, particularly in developing countries. We performed a retrospective review of ophthalmic examinations performed during a National Institutes of Health-funded cohort study of very young children in Peru with behavioral problems and at risk for developmental disorders. 222 children between the ages of 0 and 4 years (mean 2.2 ± 0.9 years) were examined and 100 (45.0%) had an abnormal ocular exam. Overall, the prevalence of refractive error was 33.3%, nystagmus was 12.2%, and strabismus was 10.9%. Among children with Down syndrome, refractive error ranged from 46.2% at age 2 to 85.7% at age 4. Refractive error and ocular disorders are highly prevalent even at a young age in children with behavioral problems and developmental disorders. Much of the visual impairment in this population is treatable; early identification and intervention can have a lifelong positive impact on neurodevelopment.

Vision in children with autism spectrum disorder: a critical review

Autism spectrum disorder (ASD) is a common neurodevelopmental condition with approximately 1-2 per cent prevalence in the population. The condition has lifelong effects for the individual and family, and early intervention and management helps maximise quality of life and outcomes. Many studies of vision in ASD have attempted to link the behavioural and sensory deficits in ASD with underlying visual processing. From this work, it is clear that individuals with ASD 'see' and process the world differently, but there remain gaps in our understanding. This review will summarise our current knowledge of key aspects of visual functions and the optometric profile of ASD. This includes findings regarding visual acuity and contrast sensitivity, refractive error, eye movements, binocular vision, near visual functions and retinal structure in ASD. From this, a pattern of knowledge emerges for children with ASD: we should expect normal visual acuity; there will likely be atypical eye movements and susceptibility for subtle visuo-motor deficits, there is an increased prevalence of strabismus; an increased likelihood of astigmatism and possibly other refractive errors; attention, crowding and task complexity will likely be problematic; and retinal structure and function may be compromised. Bringing this together, these findings highlight that further work is necessary, not only to understand how higher-level functions link to behaviours, but also to ensure there is a sound understanding of the building-blocks of vision to fully grasp the profile of visual processing as a whole in ASD. This review will give a translational viewpoint for clinicians, and underline the benefits of comprehensive vision care in ASD.

Pathophysiology, screening and treatment of ROP: A multi-disciplinary perspective

The population of infants at risk for retinopathy of prematurity (ROP) varies by world region; in countries with well developed neonatal intensive care services, the highest risk infants are those born at less than 28 weeks gestational age (GA) and less than 1 kg at birth, while, in regions where many aspects of neonatal intensive and ophthalmological care are not routinely available, more mature infants up to 2000 g at birth and 37 weeks GA are also at risk for severe ROP. Treatment options for both groups of patients include standard retinal laser photocoagulation or, more recently, intravitreal anti-VEGF drugs. In addition to detection and treatment of ROP, this review highlights new opportunities created by telemedicine, where screening and diagnosis of ROP in remote locations can be undertaken by non-ophthalmologists using digital fundus cameras. The ophthalmological care of the ROP infant is undertaken in the wider context of neonatal care and general wellbeing of the infant. Because of this context, this review takes a multi-disciplinary perspective with contributions from retinal vascular biologists, pediatric ophthalmologists, an epidemiologist and a neonatologist. This review highlights the latest insights regarding cellular and molecular mechanisms in the formation of the retinal vasculature in the human infant, pathogenesis of ROP, detection and treatment of severe ROP, the risks and benefits of anti-VEGF therapy, the identification of new therapies over the horizon, and the optimal neonatal care regimen for best ROP outcomes, and the benefits and pitfalls of telemedicine in the remote screening and diagnosis of ROP, all of which have the potential to improve ROP outcomes.

Development and face validity of a cerebral visual impairment motor questionnaire for children with cerebral palsy

AIM

The objectives of this study were (i) to develop two cerebral visual impairment motor questionnaires (CVI-MQ's) for children with cerebral palsy (CP): one for children with Gross Motor Function Classification System (GMFCS) levels I, II and III and one for children with GMFCS levels IV and V; (ii) to describe their face validity and usability; and (iii) to determine their sensitivity and specificity.

BACKGROUNDS

The initial versions of the two CVI-MQ's were developed based on literature. Subsequently, the Delphi method was used in two groups of experts, one familiar with CVI and one not familiar with CVI, in order to gain consensus about face validity and usability. The sensitivity and specificity of the CVI-MQ's were subsequently assessed in 82 children with CP with (n = 39) and without CVI (n = 43). With the receiver operating curve the cut-off scores were determined to detect possible presence or absence of CVI in children with CP.

RESULTS

Both questionnaires showed very good face validity (percentage agreement above 96%) and good usability (percentage agreement 95%) for practical use. The CVI-MQ version for GMFCS levels I, II and III had a sensitivity of 1.00 and specificity of 0.96, with a cut-off score of 12 points or higher, and the version for GMFCS levels IV and V had a sensitivity of 0.97 and a specificity of 0.98, with a cut-off score of eight points or higher.

CONCLUSION

The CVI-MQ is able to identify at-risk children with CP for the probability of having CVI.

Gross motor function in children with spastic Cerebral Palsy and Cerebral Visual Impairment: A comparison between outcomes of the original and the Cerebral Visual Impairment adapted Gross Motor Function Measure-88 (GMFM-88-CVI)

PURPOSE

To investigate whether the adapted version of the Gross Motor Function Measure-88 (GMFM-88) for children with Cerebral Palsy (CP) and Cerebral Visual Impairment (CVI) results in higher scores. This is most likely to be a reflection of their gross motor function, however it may be the result of a better comprehension of the instruction of the adapted version.

METHOD

The scores of the original and adapted GMFM-88 were compared in the same group of children (n=21 boys and n=16 girls), mean (SD) age 113 (30) months with CP and CVI, within a time span of two weeks. A paediatric physical therapist familiar with the child assessed both tests in random order. The GMFCS level, mental development and age at testing were also collected. The Wilcoxon signed-rank test was used to compare two different measurements (the original and adapted GMFM-88) on a single sample, (the same child with CP and CVI; p<0.05).

RESULTS

The comparison between scores on the original and adapted GMFM-88 in all children with CP and CVI showed a positive difference in percentage score on at least one of the five dimensions and positive percentage scores for the two versions differed on all five dimensions for fourteen children. For six children a difference was seen in four dimensions and in 10 children difference was present in three dimensions (GMFM dimension A, B& C or C, D & E) (p<0.001).

CONCLUSION

The adapted GMFM-88 provides a better estimate of gross motor function per se in children with CP and CVI that is not adversely impacted bytheir visual problems. On the basis of these findings, we recommend using the adapted GMFM-88 to measure gross motor functioning in children with CP and CVI.

Impact of Cerebral Visual Impairments on Motor Skills: Implications for Developmental Coordination Disorders

Cerebral visual impairment (CVI) has become the primary cause of visual impairment and blindness in children in industrialized countries. Its prevalence has increased sharply, due to increased survival rates of children who sustain severe neurological conditions during the perinatal period. Improved diagnosis has probably contributed to this increase. As in adults, the nature and severity of CVI in children relate to the cause, location and extent of damage to the brain. In the present paper, we define CVI and how this impacts on visual function. We then define developmental coordination disorder (DCD) and discuss the link between CVI and DCD. The neuroanatomical correlates and aetiologies of DCD are also presented in relationship with CVI as well as the consequences of perinatal asphyxia (PA) and preterm birth on the occurrence and nature of DCD and CVI. This paper underlines why there are both clinical and theoretical reasons to disentangle CVI and DCD, and to categorize the features with more precision. In order to offer the most appropriate rehabilitation, we propose a systematic and rapid evaluation of visual function in at-risk children who have survived preterm birth or PA whether or not they have been diagnosed with cerebral palsy or DCD.

Visuo-manual coordination in preterm infants without neurological impairments

The extent of and reasons for visuo-manual coordination deficits in moderate and late preterm born infants without neurological impairments are not well known. This paper presents a longitudinal study on the visuo-manual development of twelve preterm infants, born after 33-36 weeks of gestation without neurological complications, between the ages of 6 and 12 months. Visuo-manual integration and grasping were assessed using the Peabody Developmental Motor Scales, along with bimanual coordination and handedness tests. Visual function was examined once prior to the beginning of the study. Gross motor development was also evaluated every month. Preterm infants were compared to a control group of ten full-term infants according to corrected age. Compared to full-terms, the visual perception of preterm infants was close to normal, with only a measure of visual fixation lower than in full-terms. In contrast, preterm infants had delayed development of visuo-manual integration, grasping, bimanual coordination, and handedness even when compared using corrected age. Tonicity and gestational age at birth were the main variables associated to the delays. These results are discussed in terms of the possible factors underlying such delays. They need to be confirmed on a larger sample of preterm born children, and to be correlated with later development. This would allow developing markers of future neuropsychological impairments during childhood.

Convergence and Accommodation Development Is Preprogrammed in Premature Infants

PURPOSE

This study investigated whether vergence and accommodation development in preterm infants is preprogrammed or is driven by experience.

METHODS

Thirty-two healthy infants, born at mean 34 weeks gestation (range, 31.2-36 weeks), were compared with 45 healthy full-term infants (mean 40.0 weeks) over a 6-month period, starting at 4 to 6 weeks postnatally. Simultaneous accommodation and convergence to a detailed target were measured using a Plusoptix PowerRefII infrared photorefractor as a target moved between 0.33 and 2 m. Stimulus/response gains and responses at 0.33 and 2 m were compared by both corrected (gestational) age and chronological (postnatal) age.

RESULTS

When compared by their corrected age, preterm and full-term infants showed few significant differences in vergence and accommodation responses after 6 to 7 weeks of age. However, when compared by chronological age, preterm infants' responses were more variable, with significantly reduced vergence gains, reduced vergence response at 0.33 m, reduced accommodation gain, and increased accommodation at 2 m compared to full-term infants between 8 and 13 weeks after birth.

CONCLUSIONS

When matched by corrected age, vergence and accommodation in preterm infants show few differences from full-term infants' responses. Maturation appears preprogrammed and is not advanced by visual experience. Longer periods of immature visual responses might leave preterm infants more at risk of development of oculomotor deficits such as strabismus.

Reliability of the modified Paediatric Evaluation of Disability Inventory, Dutch version (PEDI-NL) for children with cerebral palsy and cerebral visual impairment

PURPOSE

The aims of this study were to adapt the Paediatric Evaluation of Disability Inventory, Dutch version (PEDI-NL) for children with cerebral visual impairment (CVI) and cerebral palsy (CP) and determine test-retest and inter-respondent reliability.

METHOD

The Delphi method was used to gain consensus among twenty-one health experts familiar with CVI. Test-retest and inter-respondent reliability were assessed for parents and caregivers of 75 children (aged 50-144 months) with CP and CVI. The percentage identical scores of item scores were computed, as well as the interclass coefficients (ICC) and Cronbach's alphas of scale scores over the domains self-care, mobility, and social function.

RESULTS

All experts agreed on the adaptation of the PEDI-NL for children with CVI. On item score, for the Functional Skills scale, mean percentage identical scores variations for test-retest reliability were 73-79 with Caregiver Assistance scale 73-81, and for inter-respondent reliability 21-76 with Caregiver Assistance scale 40-43. For all scales over all domains ICCs exceeded 0.87. For the domains self-care, mobility, and social function, the Functional Skills scale and the Caregiver Assistance scale have Cronbach's alpha above 0.88.

CONCLUSION

The adapted PEDI-NL for children with CP and CVI is reliable and comparable to the original PEDI-NL.

Antecedents and correlates of visual field deficits in children born extremely preterm

AIM

We sought to identify the antecedents and correlates of visual field deficits (VFDs) at age 2 years among infants born before the 28th week of gestation.

METHODS

The visual fields of 1023 infants were assessed by confrontation at age 2 years. We compared the ante-and postnatal characteristics and exposures of the 65 infants with a VFD to their peers who did not have a VFD. We used time-oriented logistic regression risk models to assess the associations of potential antecedents and correlates with a VFD.

RESULTS

In the final regression model, VFD was associated with maternal consumption of aspirin during the current pregnancy, recurring/persistent acidemia during the first 3 postnatal days, cerebral ventriculomegaly seen on neonatal ultrasound, prethreshold retinopathy of prematurity (ROP), and supplemental oxygen and ventilator dependence at 36 weeks post-menstrual age. Birth before the 27th week was also associated with increased risk, but its significance was diminished by the addition of postnatal variables.

CONCLUSION

In this sample of extremely preterm born infants, antenatal as well as early and late postnatal characteristics and exposures are associated with an increased risk of having a VFD. Our study adds to our knowledge about the complex etiology of visual deficits of prematurity, and supports a multifactorial cause of these deficits.

Viewing behavior and related clinical characteristics in a population of children with visual impairments in the Netherlands

Children with visual impairments are very heterogeneous in terms of the extent of visual and developmental etiology. The aim of the present study was to investigate a possible correlation between prevalence of clinical risk factors of visual processing impairments and characteristics of viewing behavior. We tested 149 children with visual information processing impairments (90 boys, 59 girls; mean age (SD)=7.3 (3.3)) and 127 children without visual impairments (63 boys and 64 girls, mean age (SD)=7.9 (2.8)). Visual processing impairments were classified based on the time it took to complete orienting responses to various visual stimuli (form, contrast, motion detection, motion coherence, color and a cartoon). Within the risk group, children were divided into a fast, medium or slow group based on the response times to a highly salient stimulus. The relationship between group specific response times and clinical risk factors was assessed. The fast responding children in the risk group were significantly slower than children in the control group. Within the risk group, the prevalence of cerebral visual impairment, brain damage and intellectual disabilities was significantly higher in slow responding children compared to faster responding children. The presence of nystagmus, perceptual dysfunctions, mean visual acuity and mean age did not significantly differ between the subgroups. Orienting responses are related to risk factors for visual processing impairments known to be prevalent in visual rehabilitation practice. The proposed method may contribute to assessing the effectiveness of visual information processing in children.

Long-term growth and general health for the tiniest or most immature infants

Given the improving survival rates of extremely preterm (EP, gestational age <28 weeks) infants, there is a need to understand their general growth and health outcomes not only in childhood, but also into adulthood. EP children are shorter and lighter compared with term children at term-equivalent age; with time, the weight disadvantage diminishes but the height disadvantage remains relatively unchanged. EP children and young adults also have higher rates of reported health concerns, medical conditions and visual impairment. Hospital readmissions are higher in early childhood, mostly attributed to respiratory illness. Individuals born EP have reduced bone health and are at increased risk for metabolic disorders. Increased rates of conditions such as diabetes or pathological fractures are not reported in the literature, although follow-up studies so far have only tracked EP individuals into young adulthood. Consequently, health care utilization and costs are increased in EP children and young adults. A thorough knowledge of the health risks related to EP birth is essential in planning surveillance and intervention strategies to optimize their health and wellbeing. Despite the increased risk of health problems, EP young adults generally report their quality of life to be similar to that reported in their term counterparts.