Cortical Visual Impairment (CVI)
What is CVI? *
Cortical visual impairment (CVI) is a neurological form of visual impairment caused by “damage or atypical structures in the visual pathways and/or visual processing centers of the brain” (Roman Lantzy, 2018).
CVI is the leading cause of visual impairment in children in countries or regions with access to quality neonatal health care.
How is it different from other visual impairments?
Individuals with CVI often have healthy eyes and obtain normal results on an eye exam, because it is the processing of vision in the brain that is atypical. CVI does not have an impact on visual acuity, contrast sensitivity, or many of the other symptoms of ocular visual impairments. CVI cannot be corrected with glasses.
Children and youth with CVI can be expected to make progress in their visual functioning over time if provided with appropriate assessment and intervention. CVI requires a very different approach to instructional supports and environmental/material adaptations as compared with ocular visual impairments.
How is CVI diagnosed?
There are 3 criteria for diagnosing cortical visual impairment:
- History of neurological impact, abnormal development, damage or trauma (the most common causes are anoxic brain injury associated with premature birth or other TBI [hypoxic ischemic encephalopathy, periventricular leukomalacia, stroke or seizure]). CVI can also be associated with genetic syndromes such as AGS, CDKL5, )
- Abnormal visual behaviors that cannot be explained by the clinical eye exam
- The presence of unique visual characteristics associated with There are 10 characteristics associated with CVI, and each will look different depending on where the individual’s visual processing falls on a range of visual functioning.
10 Characteristics of CVI**
- Color preferences (often red, yellow, saturated). Does your child choose objects/toys of his favorite color consistently over toys of other colors?
- Need for movement (to elicit/sustain attention). Do you have to shake/move a toy/object before your child will look at it?
- Visual latency (processing time). Does it take longer for your child to “find” something you show him than you would expect?
- Visual field preferences. Does your child only look at toys/objects when they are in the same position/orientation, i.e., left, right, up, down?
- Difficulty with visual complexity (array, target/object, multisensory, faces). Does your child “tune out” during large gatherings or trips to busy places like the grocery store or the mall?
- Need for/attraction to light. Does your child have a tendency to stare at lights?
- Difficulty with distance viewing. Does your child look at toys close to him more than toys far away?
- Atypical visual reflexes (blink to touch, blink to threat). When you move your hand towards the bridge of your child’s nose, does he not blink?
- Difficulty with visual novelty (easier with familiar objects, people, settings). Does your child use his vision more frequently at home (familiar) than almost every other place (unfamiliar)?
- Difficulty with visually guided reach (looking and reaching/touching at the same time. Will your child look, turn away, then reach for a toy?
Measuring Function in CVI
Visual functioning in CVI is measured across the CVI Range (0-10), with three major phases describing level of impact of the CVI Characteristics on the individual’s ability to use her vision functionally:
- 0-3 Phase I Most severe impact on visual functioning
- 3-7 Phase II Moderate impact on visual functioning
- 7-10 Phase III Closest to typical visual functioning
It is important to identify a child’s specific visual functioning on the CVI Range with regard to each characteristic, as the intervention approaches needed to support progress in visual functioning are unique to each Phase.
Frequently Asked Questions about CVI
Who can diagnose CVI?
An ophthalmologist, neuro-ophthalmologist, optometrist, neurologist, or other clinical specialist.
The eye exam said “normal” or “unable to test” but I know that my child/student has atypical visual behaviors. What should I do?
Make sure that the clinical specialist has knowledge of and ability to diagnose CVI before making the appointment. Clinical vision specialists who have expertise in the structure of the eyes may not necessarily be familiar with or able to diagnose CVI.
The functional vision assessment (FVA) did not address the unique characteristics of CVI. What should I do?
You are entitled to educational assessment that is relevant to your child’s specific visual condition(s). You can ask for an assessment that addresses the unique visual implications of CVI, which is very different from other ocular forms of visual impairment.
I have heard other terms for CVI that are confusing, such as “cerebral visual impairment” or “cortical blindness.” Is there a difference?
“Cerebral visual impairment” is not the same as cortical visual impairment. Cerebral visual impairment refers to a larger “umbrella” category of neurological visual conditions, including dyslexia and synesthesia. “Cortical blindness” is an incorrect term, because individuals with CVI are never totally blind, in the absence of an additional ocular visual impairment. They always have some vision.
Resources on CVI
Perkins School for the Blind’s E-Learning has online learning resources for professionals and families
Pediatric Cortical Visual Impairment Society (PCVIS)
A family advocacy group with extensive resources on CVI
Little Bear Sees is a website for families that provides resources
Kaleidescope: The Cortical Visual Impairment Podcast are unique perspectives from families and professionals
Texas School for the Blind & Visually Impaired has training resources and videos
Paths to Literacy has resources and intervention ideas on CVI
Salient Features Collaborative is a website collaboration by professionals to support children with CVI
Lighthouse Guild’s National Tele-Support Group for families of children/youth with CVI.
Professional Development Opportunities
- Perkins E-Learning online classes on a variety of topics related to CVI
- For experienced professionals, an Endorsement in CVI assessment and intervention is offered by Perkins
*Created by Christopher Russell, MS, Ed, TVI, CVI Range Endorsed; Project Coordinator, New York Deaf-Blind Collaborative. firstname.lastname@example.org;
**Roman-Lantzy, C. (2018). Cortical Visual Impairment: An Approach to Assessment and Intervention. New York: AFB Press