There is much discussion about these two terms. Some believe that the term cortical refers to a historic affiliation with a condition described by Dr. James Jan & his associates. That is true. Some believe that the term cortical visual impairment has been replaced by a term called cerebral visual impairment and that the diagnoses are essentially interchangeable. That is not true.
According to Dutton and others, cerebral and cortical visual impairment are terms used to describe different constructs but share an important element. Both cerebral and cortical visual impairment are used to describe brain-based visual processing disorders. But, simply put, cerebral visual impairment is a term used to describe all forms of visual processing disorders including what once was called, visual perceptual disorders. These disorders can include dyslexia, prosopagnosia/facial blindness, and visual figure-ground disorders. It is a broad definition and the children with cerebral visual impairment may have needs that are best supported by a special educator who has expertise in reading, learning support, or general special education. Some with cerebral visual impairment may be referred to a teacher of the visually impaired and possibly an O&M Specialist, others will not. Commonly, children with cerebral visual impairment are first identified as having visual difficulties in early education or reading activities. It presents as a subtle disorder that may escape the notice of parents and providers until as late as school-age.
By contrast, the term, cortical visual impairment is designated for individuals who adhere to a specific profile of visual and behavioral characteristics, the 10 CVI characteristics. They share some important things in common with their “cerebral cousins” but these children are fundamentally visually impaired and are identified early on by their parents as “not seeing well”. Parents of children with cortical visual impairment frequently describe their concerns about vision to their child’s pediatrician in the first months of the child’s life. In all cases, children with cortical visual impairment require the services of vision educators and O&M Specialists.
And, why does this matter? In the end, it is critical that students receive the proper services that match their needs. Teachers of the visually impaired are not trained to evaluate or diagnose reading problems. They are not trained to evaluate or diagnose visual perceptual disorders. Conversely, reading specialists are not skilled in methodology associated with visual impairment or O&M instruction. Ideally, it would be lovely if all educators could do it all. But, clearly, even those in the field of visual impairment are still working hard to learn about the complex and specialized needs of students with CVI. The concept that one educator can be competent in all areas of instruction is simply ludicrous.
So, here’s where we are. If your child receives services from an educator who describes cerebral visual impairment, you may need to ask some follow up questions. I recommend you ask whether that professional will be using The CVI Range to evaluate functional vision. You may want to ask the professional whether they consider your child visually impaired and thus in need of a program that centers on providing access and consistent specialized direct instruction to remediate the developmental and learning risks posed by CVI. You may need to be aware that regardless of the number of additional complexities, your child qualifies for more than vision consultation and should be carefully evaluated for O&M services.
Dr. Sharon Lehman has suggested a solution. She wisely sees the differences in the cortical/cerebral terminology. Dr. Lehman recognizes the risks inherent to conflating these two categories together while also knowing that both groups have a right to appropriate services. Her solution is to create an overarching descriptor called Brain-Based visual impairment with subcategories of cerebral and cortical. In doing so, both conditions can be fully recognized and defined appropriately. In taking Dr. Lehman’s approach, both cerebral and cortical visual impairments can co-exist and be defined without compromise to the educational needs of the student. I sincerely hope Dr. Lehman’s approach will come to fruition. In the meantime, I will continue to fight the good fight to ensure that the cortical continues to be used with distinction.