Recognizing Cortical Visual Impairment in Children

Cerebral/cortical visual impairment (CVI) is a leading cause of childhood visual impairment in the US and other developed countries. Yet it can go unrecognized when a child’s eyes appear healthy and other disabilities take center stage.CVI can be defined as a spectrum of visual impairments caused by an underlying brain abnormality that affects the development of visual processing pathways and is characterized by deficits in the function of the eye and how a person uses vision in everyday activities.A UK study found that at least 3% of mainstream primary school children had one or more CVI-related vision problems. The difficulties may become more apparent as visual demands increase over time at home and school.For physicians, the challenge is to recognize when a reassuring eye exam does not explain how a child uses vision and to connect that child with further assessment and support.Why CVI Goes Unrecognized“CVI is grossly underdiagnosed,” Christine Roman-Lantzy, PhD, director of Pediatric VIEW at the Children’s Home of Pittsburgh, Pittsburgh, told Medscape Medical News.“One of the most common reasons is that these children often have a normal or near-normal eye exam, so pediatricians or pediatric ophthalmologists don’t necessarily look more deeply,” she said. Parents, however, usually have a sense that something’s not right with the child’s vision.Many of these children also have other disabilities and “front-burner issues” — difficulty walking, eating, or speaking — so the visual problem may not be attended to. “But the visual impairment may actually be impacting the development of these other areas as well.”The behaviors of children with CVI can lead physicians to misdiagnose them. Children captivated by movement may be seen as having attention-deficit issues. Those who seek sameness and familiarity or cannot consistently make eye contact may be misdiagnosed with autism, Roman-Lantzy said. Difficulty recognizing people and interpreting overwhelming stimuli can contribute to anxiety.Edward Kuwera, MD, assistant professor of ophthalmology and fellowship program director in Pediatric Ophthalmology and Adult Strabismus at Johns Hopkins Medicine, Baltimore, likewise sees children whose visual difficulties have been attributed to developmental delays, attention-deficit/hyperactivity disorder, autism, or other neurologic problems. These diagnoses can coexist with CVI, but the question is whether visual processing difficulties are also contributing to the child’s presentation.Why CVI Is IncreasingAdvances that allow children with neurologic disorders or brain injuries to survive longer than they would have done in the past have contributed to CVI’s growing prominence as a cause of childhood visual impairment.Advances in neonatal care also play a role. “When I first started practicing medicine, we referred to a baby born at 32 weeks as ‘extremely premature.’ Now, babies are being saved on a regular basis as early as 23 weeks. They’re surviving, but many have complex needs going forward,” Roman-Lantzy said.In CVI, the visual processing centers of the brain are injured or affected, she said. “The word ‘injury’ may not be a perfect description because sometimes the structure is fine, but the function isn’t fine.”CVI can be associated with hypoxic-ischemic encephalopathy, white matter damage, genetic disorders, or large brain bleeds, all of which can affect the visual pathways. “That’s another challenge — there isn’t necessarily a one-to-one correspondence between the injury and its impact on the visual pathways,” Roman-Lantzy said.Recognition and ReferralPediatricians, primary care physicians, ophthalmologists, and parents each have a role in recognizing possible CVI.Kuwera said CVI should be on a pediatric ophthalmologist’s radar when there is a “mismatch” between the eye exam and how a child presents and uses vision. The role of a pediatric ophthalmologist is to identify whether there is a concern for CVI and, if so, determine how we can help to optimize vision for this person, he said.For pediatricians and primary care physicians, a useful starting point is to ask parents how the child finds toys, recognizes people, reaches for objects, and manages busy environments. Then review neurologic and birth history alongside those observations, rather than relying on acuity screening alone. Children with concerning histories or unusual visual behaviors warrant pediatric ophthalmologic evaluation.Beyond the Eye ChartRoman-Lantzy believes that all children who have had a neurologic event should be screened for potential CVI. Specifically, she recommends a functional vision assessment. “This probes the possible presence of the specialized ways that children with CVI interact with the world,” she said.She developed the CVI Range to examine how CVI affects a child’s use of vision in everyday activities. It assesses 10 “broad characteristics” and has been found to be a reliable and valid measure of functional vision in children with CVI.Roman-Lantzy pointed to clues that might suggest the presence of CVI, and which are included in the CVI Range. These include delayed visual responses; a preference for colors and moving targets or particular areas of the visual field; difficulty with clutter, unfamiliar objects, or distance viewing; light-gazing; atypical visual reflexes; and difficulty looking and reaching at the same time.Color preference, for example, is not simply an obsession, Roman-Lantzy said. Color helps the child notice something because they can see something better when it has a vibrant color.The need for a target to move in order to be noticed is another clue. “They notice movement particularly well, so much so that things that are moving will capture their attention, but something or someone sitting still in front of them may be disregarded,” she said.Visual latency — how long it takes for a visual response to occur — is equally important. “This delayed response is a clue,” Roman-Lantzy said. “Because of the additional time it takes to process something in the visual parts of the brain, an event may be happening in the ‘now,’ but these children don’t process it for a few moments.”The Impact of CVI on Everyday Life“The condition affects every waking moment, how they walk, socialize, learn, and interact with their environment,” Roman-Lantzy said.Visual field difficulties can make steps or drop-offs hard to detect. Visual latency can also pose serious safety risks — for example, in crossing a street. The child might notice a car approaching, but “it’s not visually happening in real time. The car might be about to hit them, but to them, it looks as though the car is still down the block,” Roman-Lantzy said.“The world looks like a kaleidoscope — fragmented and shattered,” she continued. “These children are often more fearful in new places because they can’t figure out where they are or what’s around them. A picture book they’ve never seen before might look like a lot of visual nonsense.” Familiarity may help explain why a child can engage with one book or activity but struggle when a new one is introduced.Noise can make visual tasks more difficult for some children. In a noisy classroom, a child may put their head down or appear inattentive rather than reveal the effort required to interpret what is happening.The cognitive ability of children with CVI ranges along a continuum, Roman-Lantzy said. “Some are gifted, some may go on to college with appropriate adaptations, while others have cognitive impairments.”She noted that IQ tests don’t accurately gauge the child’s intellectual ability because visually demanding tasks may obscure what a child knows. For example, a child asked to select a shape may have trouble interpreting the image, rather than understanding the question. That distinction matters when assessing learning needs and making educational placements.Supports and AdaptationsManagement of the condition involves supporting the child and tailoring the environment to their functional vision. Kuwera refers patients to teachers who are trained to work with individuals with low vision.Once functional vision has been assessed, “the supports we put in place become the ‘corrective lenses,’ so to say, for the condition,” Roman-Lantzy said. For example, a child may need words presented in a vibrant color or on a backlit screen, movement to help notice a target, or verbal descriptions, she suggested. “Vision, language, and learning all come together to help this child learn to ‘see,’ and each child will need an individualized combination of approaches, based on their particular needs.”Kuwera, who is the associate residency program director at the Wilmer Eye Institute, advises parents and teachers to reduce clutter. For example, laying out several fruits while teaching their names may present an overwhelming amount of visual information. “The child can more easily learn ‘apple’ if that’s the only object in the field. Then you can start to introduce more complexity.”Early intervention and school-based vision services can help families translate assessment findings into everyday accommodations. The goal is access to learning, communication, and daily activities; improvement varies and evidence for specific CVI interventions remains limited.“The expectation is that children actually can improve their functional vision in the home and at school if they get the correct adaptations,” Roman-Lantzy said.Further information, resources, and education can be obtained through the Pediatric VIEW website.Roman-Lantzy and Kuwera reported no relevant financial relationships. Batya Swift Yasgur, MA, LSW, is a freelance writer with a counseling practice in Teaneck, New Jersey. She is a regular contributor to numerous medical publications, including Medscape and WebMD.