Reliability and validity of the Canadian-French ecological adaptation of the weighted version of the Melbourne low-vision ADL Index.

Background: The Mesure de l'impact de la déficience visuelle dans les activités quotidiennes (MIDVAQ) is the Canadian-French adaptation of the Melbourne Low-Vision ADL Index. It measures performance, personal importance and handicap situation in 16 instrumental activities requiring near vision (standardized material, part A) and in 9 self-care and domestic activities (self-report questionnaire, part B). This study aimed at measuring the MIDVAQ reliability and its relationship with measures of visual functions and functional vision.Methods: The MIDVAQ was administered twice to 100 visually impaired participants, at home, with their personal visual and non-visual aid. A second rater was present at T1. Two different versions of part A were used alternately at T1 and T2.Results: The total Handicap scale demonstrates good internal reliability (Cronbach's alpha coefficient = 0.82) and very high inter-rater and test-retest reliability (ICCs = 1.00 and 0.86). Part A alternative versions are highly comparable. Vision function measures are significantly correlated with total Handicap score, for which 48% of the variance is explained by functional vision estimates, age, and education.Conclusions: The MIDVAQ is highly valid and reliable. It can be useful to measure the functional impact of the visual impairment, its progression, and the outcomes of low vision rehabilitation services.Implications for rehabilitationEven if administered at home in an ecological way, this measure of the impact of the visual impairment in daily activities is very reliable.Given its good metric properties, this tool can be confidently used to assess the functional impact of visual impairment, outcomes of the low vision rehabilitation services, etc.This measurement tool provides complementary information to those obtained from clinical measures of visual functions, by reflecting the interaction between the functional abilities with the requirements of the environment.