The reliability and validity of the daily activities dependence on vision (DADV) scale to evaluate vision related functional limitations

The purpose was to determine the reliability and validity of the DADV scale to evaluate vision-related functional limitations in persons over 65 years. Cross sectional study was performed to determine the reliability and validity of a questionnaire (9 items). A total of 1387 subjects were selected by random sampling. An analysis of the intra/inter-observer reliability was performed and the convergent validity with the Visual Function Index, 14 items (VF-14) was determined. The number of patients who had some difficulty in performing any of the activities was 223 (19.2%; 95%CI = 16.9–21.5). The intraclass correlation coefficient (ICC) of the intra/inter-observer reliability analysis was 0.883 and 0.900, respectively. Factorial analysis demonstrated that one single factor explained 63.2% of the total variance (visual function). The scale showed a high degree of convergent validity (ICC = 0.857) with the VF-14. Visual acuity showed a moderate correlation with the DADV score (r = 0.366). The Rasch analysis showed a satisfactory model fit for the items. Although the DADV scale is a short questionnaire it showed high correlation with the VF-14 and moderate correlation with visual acuity. The results indicate that the scale has acceptable reliability and is valid to efficiently evaluate visual function.

► The DADV scale could be a useful tool for the assessment of visual function and for the early detection of difficulties in performing activities dependent on vision.
► Although the DADV scale is a short questionnaire it showed high correlation with the VF-14 and moderate correlation with visual acuity.
► The results indicate that the DADV scale has acceptable reliability and is valid to efficiently evaluate visual function.