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

In order to estimate the needs of early intervention in a health education program, an ADL instrument measuring feelings of (in)security was needed. The instrument was intended to detect early signs of decline and to evaluate ADL performance among persons with AMD. An evaluative instrument must have a high level of responsiveness, which is the ability to detect true changes over time but must also show a high level of intra-individual agreement in a test-retest assessment.

The purpose of this study was to develop an ADL instrument for evaluative purposes and to establish the reliability and the responsiveness of the instrument.

The target group comprised all persons referred by an ophthalmologist for low vision rehabilitation, 65 years and older, living at home, with aged-related macular degeneration as the primary diagnosis and with distance visual acuity of the better eye with best correction not lower than 0.1. A non-parametric statistical method that is developed for paired ordered parametrical data was applied in order to measure the systematic and occasional intra-rater disagreement separately and to measure the responsiveness.

The test-retest study showed that the ADL-instrument had a high level of test-retest stability, which is a condition for responsiveness. The instrument was found to be responsive. It could therefore detect true longitudinal changes and be used for evaluative purposes targeting elderly with AMD.