The second version of the L. V. Prasad-functional vision questionnaire

Area of Science:

• Ophthalmology
• Public Health
• Psychometrics

Background:

• The original L. V. Prasad-Functional Vision Questionnaire (LVP-FVQ) assessed daily task difficulties in visually impaired (VI) Indian school children.
• The LVP-FVQ had limitations including inadequate measurement precision and lack of dimensionality assessment.
• The original questionnaire also lacked items on technology use.

Purpose of the Study:

• To develop and validate the second version of the L. V. Prasad-Functional Vision Questionnaire (LVP-FVQ II).
• To address the psychometric limitations of the original LVP-FVQ.
• To enhance the assessment of functional vision in visually impaired children, including technology use.

Main Methods:

• Item extraction from existing questionnaires and focus group discussions with VI children and parents.
• Pilot testing of a 32-item questionnaire, retaining six items from the original LVP-FVQ.
• Validation of the 27-item LVP-FVQ II using Rasch analysis in 150 children with VI.

Main Results:

• Four mobility items were deleted due to secondary dimensionality, resulting in a 23-item unidimensional LVP-FVQ II.
• The LVP-FVQ II demonstrated good measurement precision, effective targeting, and no significant differential item functioning.
• The questionnaire showed high reliability and validity across various demographic factors.

Conclusions:

• The LVP-FVQ II exhibits superior measurement properties and interval-level scores compared to the LVP-FVQ.
• It is a reliable and valid tool for assessing daily task difficulties in VI school children in India.
• The LVP-FVQ II can be adapted for use in other developing countries.