Terminology and Current Concepts
The condition currently referred to as cerebral visual impairment (CVI) was previously described as cortical visual impairment. The term cortical originated from early reports that attributed childhood visual loss primarily to damage of the primary visual cortex [1]. Subsequent studies demonstrated that visual dysfunction in these children frequently involves distributed visual processing networks extending beyond the primary visual cortex, including the dorsal and ventral streams within the parietal and temporal lobes [2]. This evidence prompted a shift in terminology from ‘cortical’ to ‘cerebral’ visual impairment, reflecting recognition that damage to multiple components of the cerebral visual network, rather than cortical injury alone, can result in visual dysfunction [3]. Contemporary definitions therefore characterize CVI as encompassing both lower-order visual deficits, such as reduced visual acuity and visual field impairment, and higher-order perceptual deficits arising from dysfunction of central visual pathways [4].
Concurrently, the term ‘cerebral visual disorders’ (CVD) has been proposed as a broader conceptual framework. This proposal is based on the view that CVI represents a spectrum of brain-based visual dysfunction and that some affected individuals do not meet conventional criteria for visual impairment, despite preserved visual acuity and clinically meaningful perceptual difficulties [4]. Within this framework, CVD refers to a broad range of visual processing disorders attributable to cerebral dysfunction, whereas CVI refers more specifically to visual deficits that are both clinically significant and functionally impairing. Ongoing debate reflects attempts to balance conceptual inclusivity with diagnostic specificity. There is concern that indiscriminate application of the term CVI to subtle visuoperceptual difficulties secondary to cerebral dysfunction may diminish its clinical specificity [5]. The rationale for adopting the term visual disorders is to acknowledge neurologically based visual difficulties that may not fulfill traditional definitions of visual impairment but nonetheless warrant clinical recognition and intervention. Hyvarinen [6] has emphasized the limitations of existing definitions of CVI and the need for broader conceptual frameworks.
At present, however, CVI remains the most widely accepted and clinically used term for childhood brain-based visual dysfunction in both clinical practice and research. Broader conceptual terms such as CVD are therefore best understood as complementary frameworks rather than as established diagnostic labels.
Historically, a lack of consensus regarding definitions has resulted in inconsistent terminology. In a systematic review, Sakki et al. [7] analyzed existing definitions and proposed a consensus definition of CVI as a verifiable visual dysfunction not attributable to disorders of the anterior visual pathways or to coexisting ocular impairment. This widely cited definition emphasizes that CVI is diagnosed through exclusion of ocular and optic nerve pathology as the primary cause of visual dysfunction, thereby directing attention toward functional visual impairment associated with perinatal brain injury or abnormal brain development. However, this definition has been regarded as an initial framework rather than a comprehensive description. More recent expert workshops, including those convened by the National Institutes of Health (NIH) CVI Working Group, have further refined this concept by emphasizing that CVI encompasses a spectrum of severity and phenotypes, frequently co-occurs with other neurodevelopmental disorders, and is distinct from adult-onset cortical blindness [8]. In current clinical practice, CVI is widely used as the standard term for childhood brain-based visual dysfunction, with the understanding that it includes a heterogeneous range of visual deficits extending beyond focal cortical lesions. Overall, terminology has evolved from a narrow concept of cortical blindness to CVI as the established diagnostic framework, while broader conceptual terms such as CVD continue to be discussed in ongoing efforts to refine nomenclature and diagnostic criteria internationally [9].
Epidemiology and Etiology
CVI is now recognized as a leading cause of visual impairment in children across many high-income countries. Recent estimates indicate that in developed regions, approximately 30%-50% of children with registered visual impairment have CVI as a primary or contributory cause [1]. In the United Kingdom, for example, CVI has been identified in approximately 40%-48% of children with visual impairment [10]. This epidemiological shift is widely attributed to improved survival of high-risk infants over recent decades, particularly those born preterm or affected by neonatal brain injury, who now survive with neurodevelopmental sequelae that include visual dysfunction.
Importantly, CVI is not confined to children receiving care within ophthalmic services. Population-based studies indicate that a substantial proportion of children in mainstream educational settings have CVI-related visual difficulties that remain unrecognized. In a cross-sectional survey of mainstream primary schools in the United Kingdom, approximately 3.4% of children demonstrated at least one measurable visual deficit attributable to cerebral dysfunction. This finding suggests that milder phenotypes of CVI are common and frequently underdiagnosed within the general population, particularly when visual acuity appears relatively preserved [11].
In contrast, epidemiological data on CVI in Asian countries, including Korea, remain limited. To date, no large-scale population-based studies have systematically estimated the prevalence of CVI among Korean children. Given comparable advances in neonatal intensive care and survival of high-risk infants in Korea, it is plausible that the burden of CVI is similar to that reported in other high-income settings. The absence of population-level data therefore represents an important knowledge gap and underscores the need for improved clinical recognition and well-designed epidemiological studies spanning both pediatric healthcare and educational systems.
CVI is fundamentally a neurodevelopmental disorder that most commonly arises from perinatal brain injury or abnormal brain development [12]. Prematurity and low birth weight represent the most important risk factors, reflecting the vulnerability of immature cerebral white matter during critical periods of visual pathway development [7,12]. Survivors of extreme prematurity account for a substantial proportion of children diagnosed with CVI, with periventricular leukomalacia and hypoxic-ischemic encephalopathy recognized as well-established antecedents [7]. Consistent with this pathophysiology, CVI is particularly prevalent among children with cerebral palsy, periventricular white matter injury, or hydrocephalus [13].
Additional etiologies include perinatal asphyxia, neonatal seizures, intracranial hemorrhage, and stroke, all of which can disrupt retrochiasmatic visual pathways extending from the optic tract to associative visual cortices [12,13]. In both population-based and clinical studies, an abnormal neonatal or perinatal history consistently emerges as the strongest predictor that a child’s visual dysfunction is cerebral rather than ocular in origin [7,14].
Genetic and developmental disorders are also increasingly recognized contributors to CVI. Brain malformations and neurogenetic conditions may present with CVI as part of a broader neurodevelopmental phenotype and are frequently accompanied by additional cognitive, motor, or behavioral impairments [14]. Despite the heterogeneity of underlying etiologies, these conditions converge on bilateral cerebral dysfunction affecting visual processing networks, most commonly in the context of early brain injury or abnormal neurodevelopment [12].
Clinical Features and Diagnostic Pathways
Children with CVI often present with visual behaviors that are disproportionate to findings on routine ophthalmological examination. Unlike ocular visual impairment, in which abnormalities of the eye or anterior visual pathways are typically evident, children with CVI frequently have normal ocular structures and intact pupillary responses yet demonstrate inefficient or atypical use of vision in everyday situations [3]. A key clinical feature is marked variability in visual performance, which fluctuates according to context, environmental complexity, fatigue, and attentional load.
Common clinical features include inconsistent visual attention, impaired visual orienting, and difficulty sustaining gaze. Many children perform relatively well when a single object is presented in isolation, particularly if it is large, high-contrast, or familiar, yet show marked difficulty locating or identifying objects in visually complex environments. This difficulty with visual crowding is a frequent source of parental concern and commonly interferes with daily activities such as object finding or navigation in busy spaces. Delayed responses to visual stimuli, referred to as visual latency, are also characteristic, with affected children requiring additional time to fixate or initiate visually guided actions. Selective visual preferences, including attraction to lights, shiny objects, or specific colors, are often reported and may further complicate interpretation of visual function.
CVI encompasses a wide range of visual deficits. Lower-order impairments may involve visual acuity, visual fields, or oculomotor function, whereas higher-order deficits affect visual perception, visuospatial processing, motion perception, and visuomotor integration. These impairments may occur in isolation or in combination within the same child. Importantly, preserved or near-normal visual acuity does not exclude CVI and may delay recognition, as visual difficulties are frequently misattributed to behavioral, attentional, or cognitive problems. CVI also commonly co-occurs with other neurodevelopmental disorders, further obscuring the clinical picture and reinforcing the need to prioritize functional vision assessment over isolated visual measures [15].
The diagnosis of CVI is clinical and multidisciplinary. Evaluation begins with careful review of developmental and perinatal history alongside systematic observation of visual behavior. Relevant historical features often include prematurity, neonatal brain injury, seizures, or prolonged neonatal intensive care, in combination with caregiver reports of context-dependent visual difficulties. Functional vision assessment is central to diagnosis and emphasizes real-world visual use rather than performance on isolated tests. A comprehensive ophthalmological examination is required to exclude ocular or anterior visual pathway pathology that could account for the findings, while recognizing that ocular and cerebral contributions to visual dysfunction may coexist [3].
Current practice emphasizes structured assessment of visual processing using developmentally appropriate observational tools and parent-reported questionnaires rather than reliance on acuity testing alone. When feasible, evaluation of visual fields, contrast sensitivity, and visuomotor function may provide additional clinically relevant information. Vision-focused neuropsychological or occupational therapy assessments can further delineate deficits in visual perception, figure-ground discrimination, spatial awareness, and visuomotor integration, enabling more precise characterization of the child’s individual visual profile.
Neuroimaging is useful for an etiological evaluation, but is not required for diagnosis. Brain magnetic resonance imaging (MRI) may demonstrate abnormalities commonly associated with CVI, including periventricular white matter injury, hypoxic-ischemic lesions, cortical malformations, or diffuse cerebral injury. Involvement of the retrochiasmatic visual pathways, particularly the optic radiations and associative visual cortices, may correspond to observed visual deficits. However, normal MRI findings do not exclude CVI, especially in milder phenotypes or cases dominated by functional network disruption. Imaging findings should therefore be interpreted in conjunction with clinical and functional assessments rather than as standalone diagnostic criteria.
In Korea, a parent-reported screening questionnaire has been developed to support early identification of CVI-related visual behaviors in young children. This tool facilitates recognition within routine clinical practice and promotes earlier referral for comprehensive evaluation [16], which is particularly valuable during early childhood when formal vision testing options are limited.
Overall, CVI presents with heterogeneous and often subtle clinical features. Accurate diagnosis requires integration of developmental history, observed visual behavior, functional vision assessment, and multidisciplinary expertise. Recognition of characteristic visual patterns, particularly in children with established neurodevelopmental risk factors, is essential for timely diagnosis and initiation of appropriate intervention.
Screening Tools for Early Identification
Early identification of CVI is critical, as timely intervention has been associated with improved functional visual and developmental outcomes [3]. Nonetheless, early detection of CVI remains challenging, particularly during infancy and early childhood. Standard ophthalmological examinations may be normal, and conventional vision tests are often insensitive to higher-order visual processing deficits or difficult to interpret reliably at young ages [17]. Therefore, children with CVI may remain unrecognized until visual demands increase later in childhood. To address this diagnostic gap, screening strategies have increasingly emphasized assessment methods that capture functional visual behaviors as they occur in everyday environments.
Traditionally, visuospatial and visual perceptual abilities in children have been evaluated using standardized performance-based instruments such as the Developmental Test of Visual Perception, the Beery-Buktenica Developmental Test of Visual-Motor Integration, and the Motor-Free Visual Perception Test [18]. Although these tools are widely used in both clinical and research settings, they have recognized limitations in the context of CVI screening. Most require intact motor performance and sustained cooperation, and their application is generally restricted to children older than 4 years. In addition, test performance may be influenced by global cognitive ability, attention, and motor function, making it difficult to isolate visual perceptual impairment, particularly in younger children or those with neurodevelopmental comorbidities.
For infants and preschool-aged children, only a limited number of tools have been developed to assess functional vision more directly. Instruments such as the a test battery of child development for examining functional vision (ABCDEFV), designed for children up to 36 months of age, and computerized assessments of visual perception in preschool children have been used in selected clinical and research contexts. However, these tools are not specific to CVI screening and are often difficult to implement within routine clinical practice due to time, equipment, or training requirements.
Internationally, early screening efforts relied largely on brief questionnaires derived from longer CVI inventories, most notably simplified question sets designed to probe dorsal stream-related visual behaviors. These tools typically assessed difficulties with visually guided reaching, object localization in cluttered environments, navigation in familiar settings, and other visuospatial functions. Their principal advantage was feasibility, allowing rapid administration in clinical or educational contexts. While these instruments contributed to increased awareness of CVI and facilitated referral in some cases, subsequent validation studies identified important limitations. In particular, low specificity and high false-positive rates were observed, especially among children with other neurodevelopmental conditions such as intellectual disability or autism spectrum disorder [1]. These findings highlighted that many behaviors queried in brief screening tools are not specific to CVI and underscored the need for developmentally appropriate instruments with stronger psychometric foundations, particularly for use in infants and preschool-aged children.
Several parent-reported questionnaires have been developed to address visual perceptual difficulties in specific pediatric populations. Houliston et al. [19] a 22-item parental questionnaire targeting cognitive visual problems in children with hydrocephalus, primarily applicable to children 5 years of age and older. This questionnaire included items reflecting parental concerns regarding visual perception, visual field loss, and visual attention difficulties. Other instruments, such as the questionnaire developed by Pueyo et al. [20] for infants younger than 24 months, were designed to support ophthalmological evaluation of visual behavior but were not intended as screening tools for CVI. Overall, most existing questionnaires were developed for older children, and normative data for younger age groups have remained limited.
In response to these limitations, a major advance was achieved with the development of the parental questionnaire for CVI in Korea. This instrument was developed for children younger than 72 months, thereby addressing a critical gap in early childhood screening [16]. Unlike earlier tools adapted from questionnaires designed for older children, this instrument was constructed specifically to reflect age-appropriate visual behaviors observed during infancy and the preschool period. The questionnaire assesses domains including visual attention to people and objects, responses to visual novelty, visual preferences, and integration of vision with movement during daily activities. These items were selected to capture early manifestations of both dorsal and ventral stream dysfunction in a manner aligned with early developmental stages (Table 1).
Validation studies demonstrated excellent internal consistency and provided age-referenced normative data based on a large cohort of typically developing children. One notable finding was that questionnaire scores increased rapidly during the first 3 years of life, with most children approaching near-maximal scores by approximately 3 years of age. Thereafter, gains were more gradual. This developmental trajectory is consistent with current understanding of maturation of visual processing networks in early childhood and supports the clinical premise that delayed acquisition of early visual integrative behaviors may signal underlying cerebral visual dysfunction. The availability of age-specific normative data allows clinicians to interpret questionnaire results within a developmental framework rather than relying on arbitrary cut-off values.
The strengths of the Korean parental questionnaire are particularly relevant to early clinical practice. The instrument is easy to administer, relies on caregiver observations in naturalistic settings, and captures subtle visual behaviors that may not be evident during brief clinic visits. By formalizing parental observations, it facilitates earlier recognition of atypical visual behaviors and supports timely referral for further evaluation. Importantly, it represents one of the few systematically developed and validated CVI screening tools originating from an Asian population, enhancing its applicability within local clinical and cultural contexts. As with other parent-reported instruments, responses may be influenced by caregiver interpretation and contextual factors. The questionnaire is intended as a screening tool rather than a diagnostic measure, and positive findings should prompt comprehensive ophthalmological and neurodevelopmental evaluation.
Overall, parental questionnaires play a central role in identifying CVI promptly by capturing functional visual behaviors that may not be detected through standard clinical testing [15]. Evidence indicates that earlier recognition facilitates targeted interventions and improved functional outcomes; thus, structured screening is increasingly advocated, particularly in high-risk populations such as preterm infants and children with neurodevelopmental disorders [3].
Management and Prognosis
Management of CVI focuses on maximizing functional vision through habilitation rather than cure, as no medical or surgical treatment can reverse the underlying cerebral injury. Owing to neuroplasticity, particularly during early childhood, many children demonstrate meaningful improvement in visual function over time, especially when intervention is initiated early [3,4]. Accordingly, early engagement of vision-specific intervention services is recommended once CVI is suspected or diagnosed.
A central management principle is environmental adaptation to reduce visual demand and support effective visual access. Consensus-based guidance emphasizes simplifying visual scenes, enhancing contrast, allowing additional response time, and presenting visual information in a controlled and predictable manner [3,15]. Practical strategies include reducing background clutter, using large and high-contrast materials, minimizing unnecessary movement, and presenting one object at a time. Collectively, these adaptations can substantially improve visual performance and engagement in daily activities and educational settings.
Targeted visual habilitation programs, typically delivered by vision specialists or occupational therapists, aim to improve visual attention, visual processing, and visuomotor integration. These interventions are individualized according to the child’s visual profile, for example by emphasizing motion perception and spatial localization in dorsal stream dysfunction or object recognition in ventral stream impairment. Although high-quality randomized trials remain limited, clinical studies and expert consensus suggest that structured, task-oriented visual practice can improve functional outcomes in selected children [4]. Assistive technologies and compensatory strategies that leverage other sensory modalities may further promote participation and independence.
Because CVI frequently coexists with motor, cognitive, and communication difficulties, management is most effective when delivered through an interdisciplinary approach. Collaboration among pediatric neurologists, ophthalmologists, therapists, educators, and families is essential to ensure coordinated assessment and intervention. Family education is a key component of management, as caregivers play a central role in implementing strategies consistently across home, school, and community environments [15].
Prognosis in CVI is highly variable and depends on the severity, extent, and timing of the underlying brain injury, as well as the presence of comorbid neurodevelopmental conditions. Many children, particularly those with milder or predominantly higher-order visual deficits, show gradual improvement in visual attention and functional vision over time, whereas others with extensive bilateral cerebral injury may experience persistent visual impairment [3,4]. Importantly, CVI is typically non-progressive, and deterioration in visual function is uncommon in the absence of new neurological insults.
Longitudinal studies and expert consensus indicate that earlier identification and intervention are associated with better functional and developmental outcomes. Nevertheless, residual visual processing difficulties often persist, even in children whose visual acuity improves. Educational outcomes therefore vary widely, ranging from successful participation in mainstream schooling with appropriate educational supports, when available, to the need for specialized educational services in more severe cases. Accurate counseling should strike a balance between optimism regarding potential improvement and realistic expectations tailored to the individual child’s neurological and developmental profile.
Conclusion
CVI, historically referred to as cortical visual impairment and sometimes conceptualized as a broader form of cerebral visual dysfunction, has emerged as a leading cause of permanent visual disability in children, particularly in high-income countries. It is fundamentally a brain-based visual disorder, characterized by deficits in cerebral visual processing pathways that cannot be explained by ocular pathology. This neurological etiology is reflected in its epidemiology, as children with perinatal brain injury risk factors such as prematurity and hypoxic-ischemic events are particularly susceptible, underscoring the importance of early recognition. Parents and caregivers often serve as the first observers of atypical visual behaviors, and parent-reported screening tools can support early identification, although they must be interpreted cautiously given the potential for false-positive findings.
Optimal management of CVI requires an interdisciplinary approach combined with early, individualized interventions. Pediatric neurologists, ophthalmologists, orthoptists or optometrists, and neuropsychologists should collaborate from diagnosis through rehabilitation to ensure comprehensive assessment and coordinated support. Early referral to specialized vision rehabilitation and educational support services is recommended to maximize functional vision development. Many children with CVI demonstrate meaningful improvements over time, whereas others experience enduring visual processing challenges, highlighting the need for ongoing support and accommodations. Continued research and international consensus efforts remain imperative to refine diagnostic criteria, develop evidence-based therapies, and inform prognosis. By prioritizing early recognition, interdisciplinary care, and systematic knowledge sharing, the pediatric neurology community can substantially improve outcomes for children with CVI.
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