A child passes every eye examination with flying colours, yet struggles to recognise their own parents' faces or navigate a crowded classroom. The physical organs function perfectly, but somewhere between the eyes and the brain, a critical disconnect occurs. This scenario plays out repeatedly across Malaysia, where cerebral or cortical visual impairment (CVI) silently affects thousands of children, often going undiagnosed for years while parents and teachers mistake the symptoms for behavioural problems or developmental disorders.
The scale of the issue became clearer following a 2024 Technology Review by the Health Ministry's Malaysian Health Technology Assessment Section (Mahtas), which revealed that CVI accounts for 24.2% of childhood vision loss cases in the country. This figure surpasses other known causes including congenital cataract at 16.6% and retinoblastoma at 6.2%, making CVI the leading cause of visual impairment among Malaysian children. Despite this sobering statistic, the condition remains widely overlooked and misunderstood, with symptoms routinely misattributed to learning disabilities, attention-deficit disorder (ADD), autism or simple behavioural stubbornness.
The fundamental challenge in identifying CVI lies in its invisible nature. When a child undergoes standard eye examinations, everything appears normal. The eye's optical system focuses light correctly onto the retina, the visual pathway transmits signals properly, and the physical anatomy shows no obvious defects. Parents leave the optician or ophthalmologist's office reassured that their child's eyes are fine, yet the underlying problem persists. This paradox occurs because CVI is not an ocular condition at all—it is a neurological one. The brain's visual processing pathways have been damaged or fail to develop properly, rendering the child unable to interpret the visual information their eyes collect.
Consultant paediatric ophthalmologist and strabismus surgeon Dr Norazah Abdul Rahman uses a striking analogy to explain the mechanics of CVI: "The eye is like a printer. It prints whatever we see and the printed copy goes to the brain to be processed. When you have CVI, the brain's visual-processing pathways fail to interpret what the eyes see." The brain's normal function involves a three-step cycle of encoding, storage and retrieval. Information travels from the eyes to the visual cortex, becomes organised in the hippocampus, and is permanently stored across interconnected neural networks. With CVI, children see a constantly shifting kaleidoscope of images, but they lack the neurological infrastructure to assign meaning to what they observe.
The behavioural manifestations of CVI create profound frustration for both child and caregiver. Affected children typically exhibit delayed or slow visual responses, struggle to identify visual complexity in objects, environments or human faces, and have particular difficulty with distance viewing. Many are drawn to primary light sources, which paradoxically helps them focus on target objects. In some cases, children with CVI cannot recognise their parents' faces despite seeing them daily, a disconnect that understandably distresses families and sometimes prompts unfounded suspicions of emotional neglect or psychological disorder. The confusion deepens when parents observe that their child can fixate on a bright screen or follow a flashlight beam, only to seemingly ignore the parent's face in ordinary lighting.
The causes of CVI typically involve events that compromise the brain's oxygen supply, disrupt structural development, or damage the brain's physical integrity. In infants and young children, these may include perinatal asphyxia, premature birth with intraventricular haemorrhage, hydrocephalus, traumatic brain injury, infections such as meningitis or encephalitis, hypoglycaemia, seizure disorders, or genetic and metabolic conditions. Many CVI cases trace back to complications during pregnancy or birth, making prevention and early screening particularly relevant to Malaysia's public health agenda. However, the condition's lack of visibility in medical training and public awareness means that even when children are referred to specialists, the diagnosis may be delayed or missed entirely.
Dr Norazah emphasises that CVI remains novel territory for Malaysia's medical community, or at least unrecognised territory. She notes that referrals sometimes come from paediatric neurologists who suspect the condition, but the pathway to diagnosis remains inconsistent. Part of the problem is that CVI screening and diagnosis is both time-intensive and requires multidisciplinary expertise. A comprehensive ophthalmological assessment for suspected CVI can take two hours or more, and the process demands input from the child's primary caregiver—whether parent, babysitter or grandparent—since observing the child's visual behaviour in everyday settings is crucial for accurate diagnosis. Once refractive errors are ruled out and the child's visual acuity is confirmed as normal, the focus shifts to rehabilitation and retraining.
Rehabilitation for CVI involves systematically retraining the brain to process and retain visual information. Dr Norazah describes the process: therapists slowly introduce children to colours, shapes and sizes, helping them understand what they see and consolidate visual memories. Children gradually learn to recognise, remember and store visual information, building the neural pathways that should have developed naturally. This rehabilitation is not a quick fix—it requires patience, consistency and sustained engagement from parents and caregivers. The severity of each child's condition determines the rehabilitation approach, with some children making dramatic progress while others require lifelong support. Early identification is crucial, as intervention during childhood offers the best opportunity to optimise visual potential.
For Malaysian parents and educators, the implications are significant. Children misdiagnosed as having autism, ADD or behavioural problems may be subjected to inappropriate interventions while the actual neurological issue goes unaddressed. Teachers who misinterpret visual processing difficulties as wilful inattention or defiance may unnecessarily frustrate and stigmatise affected children. The lack of public awareness means that many families struggle in isolation, unaware that their child's struggles have a name, a diagnosis, and evidence-based treatments. Healthcare providers require better training to recognise CVI's subtle presentations and implement appropriate referral pathways.
The path forward requires systemic change across multiple levels. Medical schools and continuing education programmes must include CVI in curricula so that paediatricians, general practitioners and eye care professionals can recognise and appropriately refer suspected cases. Public health campaigns should educate parents about the distinction between eye problems and visual processing disorders, particularly those at higher risk due to birth complications or early childhood illness. Rehabilitation services must be expanded and made accessible across the country, particularly in rural areas where specialist expertise is scarce. For Malaysian families currently navigating this journey in confusion and frustration, greater awareness and earlier diagnosis could transform outcomes, allowing children with CVI to unlock their visual potential and participate fully in family and school life.
