CVI Range Assessment Validated as Reliable Measure of Functional Vision in Children

Brain-based vision loss ranks as the leading cause of visual impairment among children in the US and other developed countries, yet the most widely used tool for gauging how children with the condition use their sight in daily life had long lacked rigorous clinical validation. New evidence has begun to close that gap, with investigators reporting that a standardized functional vision assessment was a valid and reliable measure of how children with cerebral/cortical visual impairment (CVI) use their vision, according to findings published in Ophthalmology Science.¹

CVI is a brain-based disorder that affects the visual processing pathways rather than the eyes themselves. Because standard eye examinations measure visual function such as acuity and contrast sensitivity, they frequently underestimate or miss the everyday visual difficulties children with CVI experience. Clinicians have described a disconnect in which a child's ability to use vision during daily activities is worse than eye clinic findings would predict, a mismatch tied to higher-order visual processing deficits that can substantially affect quality of life.

Addressing a Gap in Functional Vision Measurement

The CVI Range for Clinical Research (CVI Range-CR) is a standardized version of the CVI Range, an assessment developed decades ago that became the most widely used functional vision measure for children with CVI. The original tool has guided individualized interventions delivered by teachers of students with visual impairments, occupational therapists, and other low vision specialists, but it was often administered in a nonstandardized manner to support personalized recommendations. That flexibility made it poorly suited to serve as an outcome measure in clinical trials, prompting the authors to build a standardized version for research.

The need for such a tool reflects a broader gap in the field.² A scoping review of pediatric CVI interventions found that although functional gains were achievable, no evidence-based intervention protocol existed to guide rehabilitation therapists, and its authors underscored the need for standardized, objective measures of function for this population. A validated assessment that can quantify functional vision and detect change over time offers a foundation for testing whether emerging treatments meaningfully affect how children use their vision.¹

The prospective, longitudinal cohort study enrolled 40 children with CVI who were assessed at baseline and again 1 year later. Participants had a mean age of 4.3 years, and 65% were boys. The cohort was racially and ethnically diverse, including children who were White (40%), Hispanic or Latino (30%), Asian or Pacific Islander (13%), and Black or African American (5%). All participants had developmental delay, 90% had seizures, and 53% had cerebral palsy, with common ophthalmic comorbidities including strabismus (78%), optic atrophy (43%), significant refractive error (43%), and nystagmus (30%). One-year follow-up assessments were completed for 34 children (85%).

Reliability, Validity, and Internal Consistency Findings

The CVI Range-CR performed well across the measures tested. The assessment demonstrated high internal consistency (McDonald's ω = 0.96) and excellent intrarater reliability, with intraclass correlation coefficients (ICCs) ranging from 0.88 to 0.98 when the same grader scored recordings at 2 time points. Interrater reliability among 1 in-person and 2 remote graders was good to excellent (ICC, 0.74-0.88).

Scores also correlated strongly with a pediatric neuro-ophthalmologist's clinical assessment of visual behavior, measured on a 6-level visual behavior scale (Spearman correlation coefficient, 0.76-0.86; P < .0001), supporting the assessment's validity.

Detecting Change in Functional Vision Over Time

The CVI Range-CR was also sensitive to change. Over 1 year, scores improved modestly but significantly on both scoring methods (Across-CVI Characteristics average, +0.35 [P = .002]; Within-CVI Characteristics average, +0.31 [P = .001]), and visual behavior scale scores rose in tandem. Because the average difference between graders exceeded the average change over one year, the authors recommended that longitudinal studies use consistent graders, potentially through remote grading of recorded assessments at a centralized reading center. They concluded that the assessment "is a reliable and valid measure of functional vision in children with CVI."

However, the findings should be interpreted with several limitations in mind. The cohort skewed toward children with lower levels of functional vision, and only 6 participants (15%) reached the most advanced phase during the study, reflecting the more severe disease typical of a tertiary referral clinic. Enrollment was also limited to children aged 12 months to 10 years, so the results may not apply to older children. Although 6 participants (15%) were lost to follow-up, they did not differ significantly from those retained on baseline demographics or scores.

The authors acknowledged that the time required to train examiners, administer the assessment, and score it remains a barrier to wider use in multicenter research. They said planned work would use artificial intelligence to develop a shorter version with automated scoring so future CVI trials could judge treatments not only by what clinicians measure in the eye clinic but also by how children use their vision at home and school.

References

1. Chang MY, Reid MW, Roman-Lantzy C, et al. Validity and reliability of the CVI Range for Clinical Research: baseline and one-year results. Ophthalmol Sci. 2026;6(7):101233. doi:10.1016/j.xops.2026.101233
2. Weden K, DeCarlo DK, Barstow E. A scoping review of intervention for pediatric cerebral visual impairment: calling all pediatric occupational therapists. Occup Ther Health Care. 2023;37(3):326-356. doi:10.1080/07380577.2023.2172761