Methods for conceptualising 'visual ability' as a measurable construct in children with cerebral palsy

Area of Science:

• Pediatric ophthalmology
• Rehabilitation science
• Child development

Background:

• Vision impairment significantly impacts functioning and disability in children with cerebral palsy.
• Assessing vision abilities requires psychometrically sound tools for clinical practice and research.
• A clear construct definition for 'visual ability' is needed to ensure the validity and reliability of existing measures.

Purpose of the Study:

• To develop a conceptual framework for 'visual ability' as a measurable construct in children.
• To identify and categorize observable visual behaviors reflecting how children use vision.

Main Methods:

• A two-phase process involving deductive content analysis and inductive thematic analysis of items from 19 vision assessment tools.
• Linking assessment items to the International Classification of Functioning, Disability and Health - Child and Youth version (ICF-CY).

Main Results:

• Existing tools measure vision across ICF-CY domains: Body Functions, Activities and Participation, and Environmental/Personal Factors.
• Vision at the Activity level was conceptualized as 'how vision is used', forming a single measurable construct.
• Identified 13 themes of observable visual behaviors, including 7 abilities (e.g., searching, following) and 4 interactions (e.g., interacting with faces, objects).

Conclusions:

• 'Visual ability' can be clearly defined as a measurable construct at the ICF-CY Activity level, focusing on 'how vision is used'.
• This study provides a foundation for developing new assessment items based on identified observable visual behaviors.
• The findings support the advancement of vision assessment tools for children with cerebral palsy.