Development of an instrument to assess vision-related quality of life in young children.

Quality of life (QOL) instruments are increasingly utilized in ophthalmological research. Measuring vision-related QOL in young children is complicated by constantly evolving abilities related to normal growth and development. Our aim was to develop vision-related QOL instruments for children in different age ranges <==7 years, and to provide initial validation of these instruments. Cross-sectional study. Multicenter. 773 pediatric patients (age <==7 years) with a wide range of ophthalmological diagnoses. Questionnaire. A 61-item prototype instrument with a wide variety of items was applied to 403 consecutive patients. The usefulness of items was evaluated as a function of age in order to derive two age-group specific instruments and to find the age limit dividing the age groups. Thus, age-specific versions of a Children's Visual Function Questionnaire (CVFQ) were defined for ages <3 years and >/=3 years, and applied to a convenience sample of patients. Subscale scores. Factor analysis helped identify underlying dimensions of the data, and corresponding subscales were defined. Validation was provided by examining the internal consistency reliability and by exploring the associations between scores and clinical characteristics. Subscales for General health, General vision, Competence, Personality, Family impact, and Treatment were defined, with internal consistency reliabilities ranging from 0.60 to 0.86. The association between subscales scores and age was weak, whereas strong correlations were found with the level of visual impairment and type of visual diagnosis. The CVFQ assesses the impact of visual impairment on children and their families, and is expected to become a useful tool for the pediatric vision research community.