Development and Psychometric Evaluation of the Functional Vision Scale for Adults

Area of Science:

• Occupational therapy and rehabilitation science.
• Ophthalmology and vision science.
• Psychometrics and measurement science.

Background:

• Assessing functional vision is crucial for daily living and occupational performance.
• Existing measures may not fully capture the occupation-centred aspects of functional vision.
• A validated patient-reported outcome measure is needed for adults.

Purpose of the Study:

• To develop and psychometrically evaluate the Functional Vision Scale for Adults (FVSA).
• To create an occupation-centred, patient-reported outcome measure for daily functioning.
• To assess functional vision across key occupational performance domains.

Main Methods:

• Scale development involved literature review, expert consultation (n=10), and pilot testing (n=55).
• The final 33-item FVSA was administered to 526 adults (154 with visual problems).
• Psychometric properties evaluated included construct validity (EFA/CFA), known-group validity, internal consistency (Cronbach's α, McDonald's ω), and test-retest reliability (ICC).

Main Results:

• Factor analysis supported a four-factor structure: education, activities of daily living (ADLs), social participation, and instrumental ADLs (IADLs).
• The FVSA demonstrated known-group validity, with significant differences between adults with and without visual problems (p < 0.05).
• The scale showed excellent reliability (ICC = 0.835) and high internal consistency (ω = 0.946, α = 0.933).

Conclusions:

• The Functional Vision Scale for Adults (FVSA) is a psychometrically sound instrument.
• FVSA provides a reliable and valid occupation-centred assessment of functional vision in adults.
• This scale can inform occupational therapy interventions and vision rehabilitation strategies.