Development and validation of a Children’s Visual Function Quality of Life (CVF-QoL) instrument for rural school-going children with visual impairment within a South African context.

Abstract

Background: Vision problems that arise early in life can significantly impact children's performance in school, sports and recreation, and social interactions. Evaluating visual function and quality of life in children with visual impairments is crucial for understanding the effects on their lives and assessing interventions' effectiveness. Although several tools exist to measure these aspects in children, they have been compiled largely within developed countries, resulting in a lack of similar instruments specifically designed for rural school-going children, particularly in middle- to low-income countries. Purpose: This study aimed to develop and validate an instrument measuring Children's Visual Function Quality of Life (CVF-QoL) for rural school-going children aged 6 to 17 in South Africa with uncorrected refractive errors, visual impairments and blindness. Methods: The development of the CVF-QoL instrument involved several steps. First, items were generated through a literature review. Next, focus group discussions were conducted to explore the role of vision in children's lives, involving experts and the children themselves. The readability of the instrument was assessed, leading to the creation of two versions of the CVF-QoL instrument, one for 6-9-year-olds and the other for 10-17-year-olds. The content of both versions underwent validation by experts, and pretesting with children was carried out for each version. Each version was administered to 40 learners, after which internal consistency was evaluated using the Cronbach alpha test. Additional questionnaires were taken home for completion 10 days later, and the results were compared to assess the stability of the versions. The validated English versions of the CVF-QoL instruments were then translated into Sepedi using a forward-backwards translation method. Further validation was achieved by comparing the original English versions with the Sepedi versions of the CVF-QoL instrument. Results: 769 items were identified from the literature review, while 477 statements were generated from the focus group discussions and converted into items. After merging similar items and eliminating duplicates, 91 items were retained and classified into eight domains based on the literature. These items were divided into two versions of the CVF-QoL: Version 1.1 for ages 10-17 years and Version 2.1 for ages 6-9 years. Both versions demonstrated clarity, coherence, and relevance, with item content validity indices (I-CVI) of 0.85 for Version 1.1 and 0.86 for Version 2.1. Following pretesting, the version for ages 10-17 years contained 89 items, while the version for ages 6-9 years included 63 items. After administering the two versions, the overall Cronbach score was 0.946 for Version 1.1 and 0.777 for Version 2.1. Test-retest results indicated stability for both versions, with Cronbach alpha scores of 0.940 for Version 1.1 and 0.800 for Version 2.1. The Sepedi versions of the CVF-QoL were also found to be valid, with internal consistency scores of 0.930 for Sepedi Version 1.1 and 0.762 for Sepedi Version 2.1. The English versions of the CVF-QoL were compatible with the translated Sepedi versions. Conclusion: The CVF-QoL instruments are valid for assessing the quality of life-related to visual function in rural school-going children with visual impairments within the South African context.