Development and validation of the Visual Function Battery for Children with Special Needs.

Abstract

To develop and validate the Visual Function Battery for Children with Special Needs (VFB-CSN). This was a scale development and validation study with (1) construct and item generation and (2) evaluations of interrater reliability, acceptability, and content, ecological, and convergent validities. Children with special needs were recruited for the reliability (n=32) and validity (n=95) investigations. The construct and items were generated based on literature review and an expert panel. We constructed eight categories, namely visual reflex, ocular muscle balance, visual acuity, oculomotor, visual field, contrast sensitivity, colour/form vision, and visual attention. Both functional assessment and standardized tests were adopted. The reliabilities were high for the whole VFB-CSN (intraclass correlation coefficient [ICC]=0.90, 95% confidence interval [CI]=0.80-0.90) and good for the oculomotor, contrast sensitivity, and colour/form vision (ICC=0.80-0.86, 95% CI=0.50-0.93). Correlations between the VFB-CSN and the Functional Vision Questionnaire were strong and acceptable for the contrast sensitivity, acuity, and colour/form vision (r=0.79, r=0.69, r=0.69, r=0.70 respectively). The correlation between the VFB-CSN and standardized visual acuity test was acceptable (r=-0.72). The VFB-CSN is a reliable and valid multifaceted battery for children with special needs. Acceptable psychometric properties were also found for the acuity and contrast sensitivity. The Visual Function Battery for Children with Special Needs (VFB-CSN) can measure several types of visual function. The VFB-CSN also measures varying degrees of visual impairment in children with special needs. The VFB-CSN provides functional assessment and quantitative measurement for children with disability and difficulty in cooperating on standardized tests.