From vision to cognition: potential contributions of cerebral visual impairment to neurodevelopmental disorders.

Vision has a crucial role to play in human development and functioning. It is, therefore, not surprising that vision plays a fundamental role in the development of the child. As a consequence, an alteration in visual function is, therefore, likely to hinder the child's development. Although ocular disorders are well known, diagnosed and taken into account, cerebral visual impairments (CVI) resulting from post-chiasmatic damage are largely underdiagnosed. However, among the disorders resulting from an episode of perinatal asphyxia and/or associated with prematurity, or neonatal hypoglycaemia, CVIs are prominent. In this article, we focus on the role of the possible effects of CVI on a child's learning abilities, leading to major difficulty in disentangling the consequences of CVI from other neurodevelopmental disorders (NDD) such as dyslexia, dyscalculia, dysgraphia, attention-deficit/hyperactivity disorder (ADHD), developmental coordination disorder (DCD) and autism spectrum disorders (ASD). Although we focus here on the possible overlap between children with CVI and children with other NDD, De Witt et al. (Wit et al. Ear Hear 39:1-19, 2018) have raised exactly the same question regarding children with auditory processing disorders (the equivalent of CVI in the auditory modality). We underline how motor, social and cognitive development as well as academic success can be impaired by CVI and raise the question of the need for systematic evaluation for disorders of vision, visual perception and cognition in all children presenting with a NDD and/or previously born under adverse neurological conditions.

Clinical use of the Insight Inventory in cerebral visual impairment and the effectiveness of tailored habilitational strategies.

AIM: To investigate the utility of the Insight Inventory (a structured clinical inventory completed by caregivers) for assessment of children with cerebral visual impairment; and to investigate effectiveness of tailored habilitational strategies derived from the responses to the Insight Inventory. METHOD: Fifty-one eligible children (26 males, 25 females; mean age 9y 5mo, SD 3y, range 5-16y) were recruited from Great Ormond Street Hospital, London. They underwent baseline assessment including neuro-ophthalmological and neuropsychological evaluations, and parent- and child-reported ratings on a questionnaire-based measure of quality of life. Parents also completed the Insight Inventory. On the basis of responses to the Inventory, families received individualized habilitational strategies. Follow-up assessments 6 months later included repeating the Insight Inventory and quality of life questionnaires. RESULTS: Correlations were found between the Insight Inventory and the Wechsler Intelligence Scale for Children, Fourth Edition, the Beery-Buktenica Test of Visual-Motor Integration, and the Benton Facial Recognition Test, suggesting that the Insight Inventory is an effective tool to estimate visual-perceptual difficulties. At 6 months follow-up, caregiver reports indicated significant improvements in the quality of life of children below the age of 12 years. INTERPRETATION: The Insight Inventory is a simple questionnaire which covers practical aspects of cognitive visual function in everyday life. It provides in-depth information about the aspects that children struggle with. It can also guide programmes of individualized habilitation strategies, which may enhance the quality of life of younger children. WHAT THIS PAPER ADDS: Questionnaire scores demonstrate biologically plausible correlations with formal neuropsychological tests of visual function. After administration of matched practical habilitational strategies, younger children showed improvement in quality of life and functional vision scores.

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

PURPOSE: In children born prematurely, impairment of vision due to damage to the brain is more common than due to retinopathy of prematurity. Yet, the diagnosis of cerebral visual impairment may be missed. The subject of cerebral visual impairment in children is reviewed in order to explain and draw attention to the types of visual deficits and behaviours that may result as a sequel to premature birth. METHODS: A wide range of sources of data has been employed to assemble this overview. The principal reference source is PubMed. RESULTS: The material presented highlights the origin and range of visual deficits that result from damage to the brain, related to premature birth. Deficits of primary visual functions, perceptual dysfunction, simultanagnostic visual disorders and impaired visual guidance of movement (optic ataxia), as well as disorders of visual attention and memory, can occur in a variety of combinations and degrees. The resulting behavioural outcomes are described. CONCLUSION: Identification and characterisation of impaired vision, due to prematurity associated damage to the brain, are essential. This is required so as to ensure that affected children are not inappropriately disadvantaged on account of the diagnosis being missed or inadequately acted upon, but instead, they are managed optimally, both at home and at school, so that their development is enhanced to the greatest advantage.

Sensitivity and specificity of the step VEP in suspected functional visual acuity loss.

BACKGROUND/AIM: Early and accurate diagnosis of functional visual loss (FVL) allows optimum management. Visual evoked potentials (VEPs) offer a means of objectively estimating acuity and therefore could assist with early and accurate diagnosis. The aim of this study was to assess the sensitivity and specificity of the step VEP in diagnosing FVL. METHODS: A retrospective audit was conducted in 36 school-aged children presenting with reduced visual acuity and clinical suspicion of FVL. All had undergone step VEP testing as part of their investigation. Medical notes were reviewed, and where necessary, referring centres, general practitioners or electronic clinical portals were consulted to obtain longer-term outcome data. RESULTS: Twenty-seven of the 36 patients (75%) were classified as having had FVL: all had a normal step VEP spatial threshold. Nine patients (25 %) had an organic cause for their acuity loss, of whom seven had abnormal step VEP spatial thresholds: the other two patients had some functional overlay to their organic disease. The step VEP sensitivity was 78% (95% confidence interval 40-96%), and specificity was 100% (95% confidence interval 84-100%). CONCLUSION: The high specificity of the step VEP for FVL warrants increased suspicion of an organic cause should the step VEP spatial threshold be abnormal.

Cerebral visual dysfunction in prematurely born children attending mainstream school.

PURPOSE: Although premature birth is recognised as a cause of cerebral visual impairment (CVI), which can include cerebral visual dysfunction (CVD), the incidence and nature of CVD in prematurely born children is not known. METHODS: A prospective, controlled investigation was undertaken of forty-six, mainstream primary school children, prematurely born with gestations of 24.0-34.6 weeks, and of 130 control (term-born) children. Assessments were made of IQ, ophthalmic functions, visual perception and visual attention. Structured history-taking seeking evidence of behavioural features of CVI used a question inventory. Obstetric, neonatal and paediatric medical histories were documented from case records. RESULTS: Fifteen out of forty-six (33 %) of the prematurely born children-"cluster A"-revealed behaviours corresponding with CVD on cluster analysis of the CVI inventory. The whole prematurely born group performed worse than controls on all visual perception tests and all four visual attention tests. Children in cluster A were responsible for this effect, performing worse than controls on all visual perception and visual attention tests except visual closure, while cluster B prematurely born children performed no differently to controls. CONCLUSIONS: The prevalence of CVD in these prematurely born children is between 21-47 % (95 % CI), with a pattern similar to "dorsal stream dysfunction". Currently available perceptual tests appear to be unable to identify the specific pattern of problems noted in this group. Many studies have provided evidence of cognitive and intellectual dysfunction in prematurely born children, and it is possible that CVD is a contributor. The CVI inventory is a potential means of identifying and characterising the condition, which can be ameliorated with simple strategies.

Commentary: Profiling Children With Cerebral Visual Impairment (CVI) Using Multiple Methods of Assessment to Aid in Differential Diagnosis.

PROFILING CHILDREN WITH CEREBRAL VISUAL IMPAIRMENT USING MULTIPLE METHODS OF ASSESSMENT TO AID IN DIFFERENTIAL DIAGNOSIS: Amanda H. Lueck , Gordon N. Dutton , Sylvie Chokron Seminars in Pediatric Neurology Volume 31, October 2019, Pages 5-14 Cerebral (cortical) visual impairment (CVI), the primary cause of visual impairment in chil dren in high-income countries, is increasing globally due to improved life-saving measures for premature and full-term infants. Yet the consequences of this condition are only begin ning to be understood and addressed. According to the topography, site, and the extent of the pathology, the deficit may variably concern central visual functions, visual field, percep tion of movement, visual analysis, visual exploration, attention, or visual memory, as well as visual guidance of movement. Each affected child has a unique clinical picture, which needs to be identified and individually profiled. This is probably the underlying reason that CVI is commonly underdiagnosed or misdiagnosed, especially in children, and, as a consequence, the full range of potential behavioral outcomes are not identified and adequately addressed. The present paper shows how the use of multiple methods of assessment can improve understanding of children with CVI.

A new look at the safety and tolerability of prostaglandin analogue eyedrops in glaucoma and ocular hypertension.

INTRODUCTION: In the last 25 years, topical prostaglandin analogues (PGAs) have emerged to become first line and first choice therapeutic options in the management of glaucoma and ocular hypertension (OHT). Although the short-term efficacy and safety of PGAs has been extensively investigated, less is known about their long term safety and tolerability. This gap in current knowledge is clinically relevant, because treatment-related adverse events and long-term tolerability issues are key determinants of the overall success of long-term therapy and the final outcome of a lifelong, symptomless disease like glaucoma. AREAS COVERED: We include selected evidence pertaining to the safety and tolerability of available and emerging PGA formulations. We also outline PGA formulations with different concentrations of the active ingredient, different preservatives, and preservative-free (PF) options. EXPERT OPINION: Undoubtedly PGAs will continue to play a major role in the medical therapy of glaucoma and OHT. Despite extensive literature and prolonged clinical experience with these agents worldwide, a number of areas that warrant further research have been identified in the present review. Recently launched novel PGAs, or those still in development offer new opportunities and future challenges.

The Pulfrich effect in the clinic.

First described in 1922 by Carl Pulfrich, the Pulfrich effect is a stereo-illusion thought to be caused by an inter-ocular signal latency difference stimulating neurons jointly tuned to disparity and motion. Clinically, this can be a spontaneous manifestation due to various ocular and central visual pathway pathologies, and cause symptoms independent of a range of routine visual parameters which may seem bizarre to both the patient and the clinician. Eliciting such symptoms of difficulties with motion and depth perception in a clinical history should direct the clinician to the possibility of the presence of the spontaneous Pulfrich effect, and to proceed to test for it. A spontaneous Pulfrich effect may be the first presentation of a previously undiagnosed condition, and warrants further investigation to identify the underlying cause. Alternatively, a spontaneous Pulfrich effect may be the unrecognized complication of a previously diagnosed condition. The symptoms associated with a spontaneous Pulfrich effect can be managed by treating the underlying cause in reversible conditions, or by prescribing appropriate monocular tinted lenses in front of the unaffected or less affected eye in persistent conditions.

The effects of visual degradation on face discrimination.

PURPOSE: People with reduced visual acuity (VA) and/or contrast sensitivity have difficulty recognizing faces and facial expressions. We have quantified these difficulties, using a synthetic face discrimination task employing both normal and artificially degraded vision. METHODS: VA and contrast thresholds were measured using an optimised staircase procedure [Freiburg acuity Test (FrACT)] in 25 young adults (aged 18-24 years) with corrected visual acuity of 0.0 logMAR or better and with four levels of vision degraded with Bangerter occlusion foils. For face discrimination, male face images were synthesised from 37 cardinal points (position of eyes, width of nose, head shape etc) derived from frontal face photographs and manipulated by altering the points as a fraction of the mean head radius. Face discrimination thresholds (% difference) were measured from a simultaneous four-alternative forced choice of 'odd one out' from three identical faces and one that differed. Psychometric functions were measured for four participants with normal and degraded vision. Subsequently, the difference between faces was fixed at twice the discrimination thresholds and the size of the faces manipulated using the FrACT threshold procedure in 25 participants. Data were converted to equivalent face discrimination distances for realistic face dimensions. RESULTS: With normal vision, face discrimination thresholds ranged from 2.7% to 5.6%; these increased systematically and were more variable with visual degradation. When manipulating face size, face discrimination distance was highly correlated with both acuity and contrast sensitivity (r(2) = 0.77 and 0.80 respectively, p < 0.01). The mean distance with normal vision was 15.3 m (14.5-16.2 ± S.E.M.). With vision degraded to 0.6 logMAR (6/24 Snellen, contrast threshold 15%) the mean face discrimination distance was reduced to 3.9 m (3.7-4.1, ±S.E.M.). CONCLUSIONS: Poor face discrimination has a profound impact on real-life social communication. Here we report that artificial visual degradation also adversely impacts a synthetic face recognition task. As a rule of thumb, reduction in VA of 0.3 logMAR (halving the decimal VA) reduces the face recognition distance by a factor of 0.6 times. The FrACT-based face discrimination task provides an efficient new tool to quantify and monitor face discrimination ability.

Cortical Visual Impairments and Learning Disabilities.

Medical advances in neonatology have improved the survival rate of premature infants, as well as children who are born under difficult neurological conditions. As a result, the prevalence of cerebral dysfunctions, whether minimal or more severe, is increasing in all industrialized countries and in some developing nations. Whereas in the past, ophthalmological diseases were considered principally responsible for severe visual impairment, today, all recent epidemiological studies show that the primary cause of blindness and severe visual impairment in children in industrialized countries is now neurological, with lesions acquired around the time of birth currently comprising the commonest contributor. The resulting cortical or cerebral visual impairments (CVIs) have long been ignored, or have been confused either with other ophthalmological disorders causing low vision, or with a range of learning disabilities. We present here the deleterious consequences that CVI can have upon learning and social interaction, and how these can be given behavioral labels without the underlying visual causes being considered. We discuss the need to train and inform clinicians in the identification and diagnosis of CVI, and how to distinguish the diagnosis of CVI from amongst other visual disorders, including the specific learning disorders. This is important because the range of approaches needed to enhance the development of children with CVI is specific to each child's unique visual needs, making incorrect labeling or diagnosis potentially detrimental to affected children because these needs are not met.

Perceptual visual dysfunction in children - An Indian perspective.

Perceptual visual dysfunction (PVD) comprises a group of vision disorders resulting from dysfunction of the posterior parietal and/or temporal lobes. Often, affected children have normal/near normal visual acuities and/or visual fields, but have difficulties in activities of daily living involving the use of vision. PVDs are known to be common among children with risk factors such as a history of prematurity and/or neurodevelopmental disorders. The inferior temporal lobes and ventral stream transform visual signals into perception, while the posterior parietal lobes and dorsal stream transform visual signals to non-consciously map the scene to guide action and facilitate attention. Dysfunction of these can lead to specific visual impairments that need to be identified during history taking, triggering ascertainment of further details by a structured inventory approach. Clinical tests to elicit dorsal and ventral stream visual dysfunctions have good specificity but low sensitivity. Neuropsychologists are rarely available in the developing world to perform detailed assessments, but there are a few tests that can be used by eye care professionals with some training. Optical coherence tomography (OCT) showing thinning of the ganglion cell layer and retinal nerve fiber layer is being explored as a potential tool for rapid assessment in the clinic. The behavioral outcomes of PVD can mimic psychological conditions including autism spectrum disorder, attention deficit hyperactivity disorder, specific learning disability, and intellectual impairment, and one needs to be aware of overlap among these differential diagnoses. A practical functional approach providing working solutions for each child's set of difficulties in day-to-day activities is needed.

The treatment of glaucoma using topical preservative-free agents: an evaluation of safety and tolerability.

Introduction: Preservative-free (PF) medications represent a valuable treatment strategy in the lifelong management of glaucoma. By removing preservative toxicity, PF formulations provide tangible clinical benefits to glaucoma patients worldwide. They improve tolerability and adherence, leading to a positive impact in long-term intraocular pressure (IOP) control.Areas covered: A critical review of the subject is provided, including selected evidence on the safety and tolerability of currently available topical PF formulations. Cumulative evidence confirms that topical PF medications are at least equally efficacious to their preserved equivalents. There is convincing short-term evidence for superior tolerability and safety of PF formulations compared to preserved medications. The long-term benefits and success of PF therapy requires further elucidation.Expert opinion: Successful stepwise administration of medical therapy for glaucoma remains elusive. There is a greater risk for ocular toxicity and therapy failure with preserved topical glaucoma therapy. Currently available and emerging PF therapy options potentially optimize lifelong stepwise glaucoma therapy and may enhance outcome. To avert complications from preservatives leading to poor adherence, ideally, future antiglaucoma therapy should become 100% PF. There are still key aspects of PF therapy that warrant further investigation.

An 8-month-old Baby Girl with Slight Drooping of Left Upper Eyelid.

An 8-month-old baby girl, who accompanied her sister with an eye problem, was incidentally noticed to have smaller left eye compared to the right. The mother said that it had been present for 2 months. The child showed no detectable focal neurological deficits. Her vision was age appropriate in both eyes. A slight left-sided ptosis was present. Her eye movements were full in both eyes and there was no evidence of strabismus. Bilateral fundus examination was normal. The child had anisocoria (left pupil being smaller than the right one) and left hemifacial anhidrosis, which prompted the diagnosis of Horner's syndrome. Magnetic resonance imaging of her chest showed a mass lesion in the apical region of the left lung which was later excised and found to be a neuroblastoma. This emphasizes the importance of having an eye on the siblings of children who come to the hospital.

Une petite fille de 8 mois, qui accompagnait sa soeur souffrant d'un problème oculaire, a par hasard été remarquée pour avoir un oeil gauche plus petit que le droit. La mère a dit qu'il était présent depuis 2 mois. L'enfant n'a montré aucun déficit neurologique focal détectable. Sa vision était adaptée à l'âge pour les deux yeux. Un léger ptosis gauche était présent. Ses mouvements oculaires étaient normaux pour les deux yeux et il n'y avait aucun signe de strabisme. L'examen bilatéral du fond d'oeil était normal. L'enfant avait une anisocorie (la pupille gauche étant plus petite que la droite) et une anhidrose hémifaciale gauche, ce qui a conduit au diagnostic de syndrome de Horner. Une IRM thoracique réalisée a montré une masse tissulaire de la région apicale du poumon gauche qui a ensuite été réséquée.L'examen anatomopathologique a révélé qu'ils agissait d'un neuroblastome. Cela souligne l'importance de garder un oeil sur la fratrie des enfants qui viennent consulter à l'hôpital.

Simultanagnosia as a cause of visual disturbance following Posterior Reversible Encephalopathy Syndrome (PRES): A case report.

Simultanagnosia resulting from dorsal stream dysfunction is an under recognized condition. In this case report we describe the case of a young woman who developed posterior reversible encephalopathy syndrome (PRES), and who recovered visual acuities of 20/20 in each eye, along with normal visual fields and contrast sensitivities, yet experienced persistent symptoms of perceptual dysfunction. Detailed and systematic history taking revealed consistent visual difficulties typical of dorsal stream dysfunction. After a detailed explanation of her symptomatology and training in a range of strategies to cope, the patient experienced a great improvement in her day-to-day functioning.

Binasal visual field defects are not specific to vigabatrin.

This study investigated the visual defects associated with the antiepileptic drug vigabatrin (VGB). Two hundred four people with epilepsy were grouped on the basis of antiepileptic drug therapy (current, previous, or no exposure to VGB). Groups were matched with respect to age, gender, and seizure frequency. All patients underwent objective assessment of electrophysiological function (wide-field multifocal electroretinography) and conventional visual field testing (static perimetry). Bilateral visual field constriction was observed in 59% of patients currently taking VGB, 43% of patients who previously took VGB, and 24% of patients with no exposure to VGB. Assessment of retinal function revealed abnormal responses in 48% of current VGB users and 22% of prior VGB users, but in none of the patients without previous exposure to VGB. Bilateral visual field abnormalities are common in the treated epilepsy population, irrespective of drug history. Assessment by conventional static perimetry may neither be sufficiently sensitive nor specific to reliably identify retinal toxicity associated with VGB.

The useful field of view test, normative data in children of school age.

PURPOSE: The incidence of early brain injury in children is rising, mainly because of changing reproductive demographics and better perinatal care. Early brain injury may be associated with altered visual perception and visuospatial attention. The useful field of view test (UFOV) has been developed to assess visual attention and processing speed in the elderly. The UFOV may have utility in the evaluation of children with early brain injury. The aim of this study was to collect age-specific normative data for the UFOV test. METHODS: Subjects were recruited from visitors at Glasgow Science Centre. One hundred thirty-five healthy children and young adults were tested (range: 5-22 years). After a comprehensive visual screening to establish normal visual function, all three subtests of the UFOV (1: Processing Speed; 2: Divided Attention; 3: Selective Attention) were performed. RESULTS.: All the children were able to understand and complete all subtests. UFOV scores improved monotonically with age, for all subtests, throughout the primary school years, with subtest 3 showing the greatest improvement. By age 14, UFOV scores had reached adult levels. DISCUSSION: UFOV performance shows measurable improvement during middle to late childhood, as has been previously found for abilities such as visual acuity. This is a simple test, which was easily understood and performed by all children in the study. Thus, we believe that our results are suggestive of continuing development in visual attention and processing during this period. CONCLUSIONS: The UFOV is an objective, standardized computer-based test of visual attention. This study indicates suitability for use with children. It remains to be determined how successful this test proves to be in discriminating between normal children and those with early brain injury.

Hemianopia and Features of Bálint Syndrome following Occipital Lobe Hemorrhage: Identification and Patient Understanding Have Aided Functional Improvement Years after Onset.

Introduction. Cerebral visual impairment (CVI) can present around birth or any time thereafter. Homonymous hemianopia is a common feature. The concept that functional improvement is unattainable augurs against active management. Dorsal stream dysfunction (or Bálint syndrome when severe) results from bilateral posterior parietal dysfunction but may go undetected, especially in children. Case Presentation. At 16 the patient suffered spontaneous left occipital lobe brain hemorrhage from a ruptured arteriovenous malformation. This was surgically excised. Short lived right upper limb intermittent jerking, with additional left sided weakness, ensued. Anomalous EEG recordings, with right-sided bias, arose from the posterior temporoparietal area. A right homonymous hemianopia was evident. During the ensuing 17 years she experienced multiple complex difficulties, until, at a lecture describing how to identify and support children with CVI, she realized she herself had many of the difficulties described. Visual assessment identified hemianopia and dorsal stream dysfunction. Discussion. Following identification, characterization, and explanation of the impact of her visual difficulties, she both gained greater awareness of her visual difficulties and their impact and developed a range of strategies leading to functional improvement of her visual field loss and amelioration of her dorsal stream dysfunction, with great improvement in quality of life.