Cortical blindness in children: a study of etiology and prognosis

Longitudinal neurological analysis of moderate and severe pediatric cerebral visual impairment

Introduction

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

Method

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

Results

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

Conclusion

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

The Multidisciplinary Guidelines for Diagnosis and Referral in Cerebral Visual Impairment

Introduction

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

Patients and Methods

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

Results

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

Conclusion

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

Evidence-Based Clinical Practice Guideline: Comprehensive Pediatric Eye and Vision Examination

Republished with written permission granted from the American Optometric Association, October 2, 2020.

LMDS-1, a potential TrkB receptor agonist provides a safe and neurotrophic effect for early-phase Alzheimer's disease

RATIONALE

The signaling pathways of tropomyosin-related kinase B (TrkB) receptor play a pivotal role in axonal sprouting, proliferation of dendritic arbor, synaptic plasticity, and neuronal differentiation. The levels of BDNF and TrkB receptor were reduced in patients with Alzheimer's disease (AD).

OBJECTIVES

The activation of TrkB signaling pathways is a potential strategy for AD therapies. We intended to identify potential TrkB agonists to activate the neuroprotective signaling to alleviate the pathological features of AD mice.

RESULTS

Both of the Aβ-deteriorated hippocampal primary neurons and mouse models were generated and showed AD characteristics. We first investigated 12 potential TrkB agonists with primary hippocampal neurons of mice. Both 7,8-DHF and LMDS-1 were identified to have better effect than the other compounds on dendritic arborization of the neurons and were further applied to the Aβ-injected mouse model. The short-term cognitive behavior and pathology in the mice were improved by LMDS-1. Further investigation indicated that LMDS-1 activated the TrkB through phosphorylation at Y516 rather than Y816. In addition, the ERK but not CaMKII or Akt was activated in the mouse hippocampus with LMDS-1 administration. LMDS-1 treatment also upregulated CREB and BDNF while downregulated the GSK3β active form and tau phosphorylation.

CONCLUSIONS

This study suggests that LMDS-1 upregulates the expression of BDNF and ameliorates the early-phase phenotypes of the AD-like mice through the pTrkB (Y516)-ERK-CREB pathway. In addition, LMDS-1 has better effect than 7,8-DHF in ameliorating the behavioral and pathological features of AD-like mice.

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

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

Transient cortical blindness following intracardiac repair of congenital heart disease in an 11-year-old boy

Postoperative blindness (PB) primarily involves reception and conductance parts of the visual pathway due to ischemia following cessation of blood supply, for example, retinal vascular occlusion. Although a rare cause of PB, cortical blindness (CB), which results from ischemia/infarction of visual cortex, has a poor outcome due to its mostly nonreversible nature. Ischemic optic neuropathy is the most common cause of PB following cardiac surgeries. CB following cardiac surgeries involving cardiopulmonary bypass has been rarely reported. Only a few of those articles reported partial or complete reversal of CB. We report an incidence of transient CB in an 11-year-old child who was operated for double chambered right ventricle with ventricular septal defect.

Cardiac arrest and post resuscitation of the brain

Primary out-of-hospital cardiac arrest in childhood is rare but survival is a little better for children than for adults, although the prognosis for infants is very poor. Hypoxic-ischaemic encephalopathy after in-hospital cardiac arrest in children undergoing complicated treatment for previously untreatable conditions is now a common problem and is probably increasing. An additional ischaemic insult worsens the prognosis for other encephalopathies, such as that occurring after accidental or non-accidental head injury. For near-drowning, the prognosis is often good, provided that cardiopulmonary resuscitation (CPR) is commenced immediately, and the child gasps within 40 minutes of rescue and regains consciousness soon afterwards. The prognosis is much worse for the nearly drowned child admitted to casualty or the emergency room deeply unconscious with fixed dilated pupils, requiring continuing CPR and with an arterial pH <7, especially if there is little recovery by the time of admission to the intensive care unit. The use of adrenaline, sodium bicarbonate and calcium appears to worsen prognosis. Neurophysiology, specifically serial electroencephalography and evoked potentials, is the most useful tool prognostically, although neuroimaging and biomarkers may play a role. In a series of 89 patients studied after cardiac arrest in three London centres between 1982 and 1985, 39% recovered consciousness within one month. Twenty seven percent died a cardiac death whilst in coma, and the outcome in the remainder was either brain death or vegetative state. EEG and initial pH were the best predictors of outcome in this study. Seizures affected one third and were associated with deterioration and worse outcome. The advent of extracorporeal membrane oxygenation (ECMO) and the positive results of hypothermia trials in neonates and adults have rekindled interest in timely management of this important group of patients.

[Cerebral visual impairment in brain-damaged children - four case studies]

Cerebral visual impairment is one of the main causes of childhood visual impairment in developed countries. These disorders are often linked with pre- or perinatal hypoxic brain injuries. The patterns of brain injuries depend on the severity and duration of hypoxia and the child's age. In premature children, periventricular leukomalacia affects the optic radiations and the subcortical visual brain. In full-term newborn babies, chronic hypoxia leads to the damage of the visual cortex and acute hypoxia damages the basal ganglia. They recover from cortical blindness in variable ways. Visual dysfunction is characterized by fixation troubles, subnormal acuity (crowding), difficulty with perceiving visual fields, movements, depth, cognitive defects (agnosia of images, objects or faces, visuospatial disorders), ocular motility disorders (tonic gaze deviation, strabismus, nystagmus). Accompanying these cerebral injuries, there are accommodation defects and optic disk abnormalities that vary according to the gestational age at the time of hypoxia.

Restitution of visual functions in cerebrally blind children

In adult patients who suffer from a visual field defect due to cerebral lesions, visual functions can be restored by systematic visual field training. Such visual field training is not feasible in young, brain-damaged children, who are unable to cooperate like adults. We have already shown earlier [Werth, R., and Moehrenschlager, M. (1999). The development of visual functions in cerebrally blind children during a systematic visual field training. Restorative Neurology and Neuroscience, 15, 229-241.] that systematic visual field training, which requires no ability to understand instructions or to cooperate, is successful in brain-damaged children and may lead to complete recovery of the visual field within 3 months. The present study provides more behavioral evidence and a control of intraocular light scatter. In addition to the earlier study, the luminance difference thresholds in the recovered visual field were compared with those of a normal control group. Seventeen children aged 1-4 years who had been blind for more than 1 year after perinatal asphyxia and two children suffering from homonymous hemianopia due to asphyxic-ischemic lesions participated in systematic visual field training. The functional visual field was assessed with a specially designed arc perimeter. Visual functions developed within a training period of 3 months in 11 children who received visual field training, whereas there was no recovery in the control group (N=37). The findings support the assumption that systematic visual field training facilitates the development of vision in cerebrally blind children. In two children who recovered from blindness, it was shown in functional magnetic resonance imaging (fMRI) that brain tissue in the area of the visual cortex contralateral to the blind visual hemifield was activated by light. In two children suffering from asphyxic-ischemic lesions who did not recover only brain tissue in the area of the visual cortex contralateral to the good visual hemifield could be activated by light. These results support the assumption that activity in spared tissue of the striate and extrastriate visual cortex are a necessary condition for recovery of the visual field in children suffering from cerebral blindness.

Visual function in the brain-damaged child

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

Neurotrophin-3 is required for appropriate establishment of thalamocortical connections

In the vertebrate brain, the thalamus serves as a relay and integration station for diverse neuronal information en route from the periphery to the cortex. Formation of the thalamocortical tract occurs during pre- and postnatal development, with distinct thalamic nuclei projecting to specific cortical regions. The molecular forces that underlie the invasion by axons into specific cortical layers followed by activity-dependent maturation of synapses are poorly understood. We show that genetic ablation of neurotrophin-3 (NT-3) in the mouse neocortex results in reduction of a set of anatomically distinct axonal bundles projecting from thalamus through cortical white matter. These bundles include thalamocortical axons that normally establish connections with retrosplenial and visual cortex, sites of early postnatal NT-3 expression. These results implicate neurotrophins in the critical stage of precise thalamocortical connections.

Damage to intracranial optic pathways in fatal closed head injury in man

Head injury is a leading cause of visual impairment. This is partly due to direct trauma to the eye and optic nerve but much of the damage involves the intracranial optic pathways. We have studied the frequency, distribution and nature of the intracranial lesions of the optic pathways at autopsy in 45 cases of severe closed head injury, and examined the correlation between these post-mortem lesions and the ante-mortem clinical findings. Twenty-four of the patients had been involved in road traffic accidents. The ages ranged from 9 to 88 years (mean 46.4), the Glasgow Coma Score (GCS) on admission ranged from 3 to 15 (mean 5), and the survival time after injury from 2.5 h to15 days (mean 3.3 days). Skull fractures were present in 75.6% of the cases. Histological assessment included the use of immunohistochemistry for beta-amyloid precursor protein (beta-APP) and the microglial marker CD68. Axonal injury of varying severity was demonstrable in all cases, and in 39 (87%) the optic chiasm, tracts or radiations were involved, usually in more than one region. The severity of axonal injury was mild in 11 (24%), moderate in 9 (20%) and severe in 19 (42%) cases. The optic radiation at the level of the trigone of the lateral ventricle was particularly frequently and severely affected. The least affected parts of the intracranial optic pathways were the optic chiasm and the posterior segment of the optic nerve. The severity of injury to the optic pathways did not always reflect severity of axonal injury elsewhere in the brain and correlated poorly with the type of trauma (high- or low-velocity), presence of skull fractures or evidence of raised intracranial pressure (ICP). Of the 39 patients who survived more than 6 h, histological evidence of ischaemic injury to the primary optic cortex was present in 26 (67%) and was severe in 12. We conclude that the visual pathways are affected in a high proportion of patients with fatal closed head injury, nerve fibres in the optic radiations being particularly vulnerable. The findings suggest that damage to the posterior parts of the optic pathways may be under-diagnosed among patients with head injury.

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

BACKGROUND/AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Visual behaviours of neurologically impaired children with cerebral visual impairment: an ethological study

BACKGROUND/AIMS

Visual functions of neurologically impaired children with permanent cerebral visual impairment (CVI) can be difficult to determine. This study investigated the behavioural profile of CVI children by means of ethological observations in order to gain a better understanding of their visual functions.

METHODS

Video registrations of nine subjects who were unable to undergo more orthodox methods of visual function testing were observed and analysed by an ethologist.

RESULTS

A series of behaviours (direct signs) and supportive or confirming behavioural elements (indirect signs) indicating some visual perception in the children were found.

CONCLUSION

Detailed ethological observations of visual behaviour were shown to be useful for analysing visual functions of children with permanent CVI.

The prognostic value of flash visual evoked potentials in the assessment of non-ocular visual impairment in infancy

The results of flash visual evoked potentials (VEPs) in 44 infants blind or severely visually impaired from non-ocular causes are presented, and related to the subsequent visual outcome. Ocular causes of visual impairment were excluded by clinical examination and electroretinography. Using a 2 x 2 contingency table, a significant association between VEP and outcome was demonstrated (chi 2 = 3.51, 1 d.f., p = 0.05). Of 13 infants with normal VEPs, 11 demonstrated substantial visual improvement (negative predictive value = 84.6%). However, of the 31 with abnormal VEPs, only 14 remained severely impaired/blind; the other 17 demonstrating visual improvement (positive predictive value = 45.1%). The sensitivity of the method was high in that 14 of 16 (87.5%) infants who remained impaired/blind had abnormal VEPs, but specificity was low as only 11 of 28 (39.3%) who showed visual improvement had normal VEPs. The accuracy of the technique was therefore low, 25 of 44 (56.8%) being true positive/ negative. With regard to visual outcome when faced with an apparently blind infant, it is important not to be too pessimistic for, as is shown in this study, 28 of 44 demonstrated substantial improvement. There are no absolute indicators of prognosis, but the presence of structural cerebral lesions and a history of either neonatal meningitis or encephalopathy are relatively bad prognostic signs. The flash VEP, despite its limitations, is a useful prognostic tool, particularly in those apparently blind infants whose normal ocular examination/electroretinogram is accompanied by normal VEPs. Those with abnormal VEPs, however, do not necessarily have a poor prognosis, but should be followed-up as maturational changes and/or improvements in function of the sensory pathway will be reflected in the evoked potentials.

Prognostic value of visual evoked potentials (VEP) in infants with visual inattentiveness

Visual evoked potentials elicited by strobe flash (fVEPs) were recorded in 56 infants (3 months to 15 months of age) with visual inattentiveness but without prechiasmal problems. Their visual status was reexamined one or more years later when 41 children were found to be visually competent (Group NB) and 15 were blind (Group B). We also evaluated a group of 32 age-matched children who had no visual symptoms (Group C). It was found that well organized VEP waveforms over one or both hemispheres (Types U and S), or those with a characteristic negative shift (Type N) suggest favorable prognosis. Integrated voltage of the VEP correlated well with long-term prognosis for visual recovery. The vertex VEP also (had) provided some predictions for visual prognosis. Overall results indicate good prognosis if related to sufficient voltage and complexity of the VEP components.

Transient cortical blindness in an infant exposed to methamphetamine

An 11-month-old boy was brought to the pediatric emergency department for evaluation of acute onset of irritability and involuntary side-to-side turning of the head. Neurologic examination revealed cortical blindness. Toxicologic studies of blood and urine were positive for methamphetamine. The infant's vision and activity returned to normal within 12 hours. The possible mechanisms of this unusual form of amphetamine toxicity are discussed.

Cortical visual impairment in children

Cortical visual impairment (CVI) in children is most commonly caused by peri- or post-natal hypoxia-ischemia, but may also occur following other insults, e.g., trauma, epilepsy, infections, drugs or poisons, and certain neurologic diseases. The disorder differs considerably in etiology, physical findings, and, perhaps, prognosis, from the cortical blindness seen in adults. The same event that causes CVI by damaging the geniculate and/or extrageniculate visual pathways may also damage other areas of the brain, or the retina, optic nerves, or chiasm. Thus, children with CVI often have other neurological problems. Diagnosis may require the participation of a multidisciplinary team and the use of special visual testing techniques. Due to the uncertainty concerning the prognosis in CVI, clinicians should remain optimistic about the child's potential for some vision recovery.

The visual-evoked response in infants with central visual impairment

We studied ten children with central visual impairment with a known neurologic defect and an abnormal visual-evoked response who had results of repeat electrophysiologic testing evaluated at the Children's Hospital of Philadelphia from December 1989 through July 1991. Central visual impairment is defined as poor visual function with a normal anterior visual pathway. Age at first examination ranged from 5 to 48 months with a followup of two to 31 months. Repeat visual-evoked response testing showed improvement in seven patients and no change in three. Grating acuity as measured by the Teller acuity card procedure, performed in nine of ten patients, improved in seven, showed no change in one, and declined in one. We found a potentially favorable prognosis for those infants with central visual impairment, despite an initially abnormal visual-evoked response. We used a clinical approach to this disorder to improve diagnostic categorization and prognostic capabilities in central visual impairment.

Cortical visual impairment following bacterial meningitis: magnetic resonance imaging and visual evoked potentials findings in two cases

Cortical visual impairment (CVI) following bacterial meningitis is a very uncommon complication. Two children with CVI following bacterial meningitis are reported. Bacterial agents were Haemophilus influenzae type B in one and meningococci in the other child. Both children showed only insufficient recovery from CVI, mental retardation and residual neurological symptoms. Flash visual evoked potentials (VEP) showed preserved cortical response at onset of CVI. Re-evaluations several months later showed significantly reduced amplitudes, but normal latencies for P100. Thus, flash VEP does not allow prediction of visual outcome. MRI results have not been reported before. MRI at onset of diagnosis showed occipital parenchymal irregularities with enlarged sulci and subarachnoid spaces. Follow up MRI 15 months after onset of CVI in one patient showed marked atrophy of the occipital cortex, hyperintensities of the cortical white matter and no visible optic radiation. The MRI findings indicate hypoxic-ischaemic lesions in the border zone between the distribution of the great cerebral arteries.

The prevalence of cerebral visual disturbance in children with cerebral palsy

Assessment of visual acuity using the visual acuity card procedure in 164 children with cerebral palsy revealed low visual acuity in 71 per cent. Results of ophthalmological examination were available for 74 of these patients, but could not explain adequately the low visual acuity of 36 of the 43 patients (84 per cent) assessed by both the acuity card procedure and other techniques. There is a high probability that cerebral visual disturbance is present in these patients. Awareness of visual disability when compiling a programme of visual and neurodevelopmental stimulation for children with cerebral palsy is essential.