Development of an ADL instrument targeting elderly persons with age-related macular degeneration

Background : In order to estimate the needs of early intervention in a heal th education program, an ADL instrument measuring feelings of (in) security was needed. The instrument was intended to detect early signs of decline a nd to evaluate ADL performance among persons with AMD. An evaluative instru ment must have a high level of responsiveness, which is the ability to dete ct true changes over time but must also show a high level of intra-individu al agreement in a test-retest assessment. Purpose : The purpose of this study was to develop an ADL instrument for ev aluative purposes and to establish the reliability and the responsiveness o f the instrument. Method: The target group comprised all persons referred by an ophthalmologi st for low vision rehabilitation, 65 years and older, living at home, with aged-related macular degeneration as the primary diagnosis and with distanc e visual acuity of the better eye with best correction not lower than 0.1. A nonparametric statistical method that is developed for paired ordered par ametrical data was applied in order to measure the systematic and occasiona l intra-rater disagreement separately and to measure the responsiveness. Conclusion : The test-retest study showed that the ADL-instrument had a hig h level of test-retest stability, which is a condition for responsiveness. The instrument was found to be responsive. It could therefore detect true l ongitudinal changes and be used for evaluative purposes targeting elderly w ith AMD.