Psychometric Properties of Tools Used for Children and Adolescents With Visual Impairments: A systematic Review Study

Objectives: The use of standard tools can show the exact effects of interventions in children and adolescents with visual impairment (CYP-VI). However, to date, no comprehensive review study has evaluated the general characteristics and psychometrics of the instruments used in CYP-VI. Therefore, the present study investigated the psychometric properties of the tools used for CYP-VI.  Methods: Databases of Cochrane, Scopus, PubMed, Web of Science, Iran Medex, Magiran, National Library of Iran (INL) and Google Scholar were searched using Persian and English keywords until 2021. The studies and tools used in CYP-VI were reviewed by two people in terms of inclusion criteria. Relevant information and quality assessment of the tools were checked with the adapted Casmin checklist (COSMIN) and Critical Review Form – Quantitative Studies. Psychometric properties of the studied instruments in the narrative categories were analyzed with face, content, criterion-dependent and reliability with internal and external reliability subgroups. Results: Out of 1738 articles found, 39 studies were analyzed. Out of 39 articles, 26 were of high quality and others were of medium level. Study design included tool development / cultural adaptation, experimental, longitudinal or cross-sectional studies. Assessments were categorized into developmental (general skills, cognitive and social skills), Activities of Daily Living (ADL), Quality of Life (QoL) and Functional Vision (FV). Among the developmental tools; Only Decker intelligence test, vision related quality of life, Cardiff visual acuity questionnaire for children, first and second versions of LV Prasad functional vision questionnaire and functional vision questionnaire for children and young people with desirable psychometric properties have been reported. In relation to adaptive instruments, the changes made included the use of auditory, tactile, olfactory and motor aids, vocabulary changes, instrumental methods and the use of assistive devices, only a few of which reported psychometric properties.  Conclusion: This review study shows that limited tools have been designed for CYP-VI whose validity and reliability have not been fully evaluated and reported. However, to improve the quality of studies and control systematic errors, we need standard tools.