Self-reported assessment of visual function in a population-based study: The SEE project

PURPOSE. To report on the usefulness of the Activities of Daily Vision Scal e ((ADVS) questionnaire for assessing visual functioning, a population-base d sample of elderly Americans. METHODS. The ADVS questionnaire was administered to a population-based samp le of 2520 community-dwelling individuals 65 to 84 years of age in Salisbur y, MD. Items and subscales were evaluated for internal consistency, item di scrimination, and content validity. Published subscale groupings and item a ssociations in our population were compared for coherence using correlation , factor, and cluster analyses. Whole-sample and race-and gender-specific a nalyses were conducted. External validity was explored by regressing ADVS s cores on standard psychophysical vision measures. RESULTS. ADVS scores were skewed to high visual functioning levels; approxi mately 60% of the population had function scores of 95 or better (of a poss ible 100). The overall night driving, and near vision scales were internall y consistent and had strong item-subscale associations; the cla) driving an d glare subscales were not acceptable regarding these properties. The far v ision subscale was acceptably scalable but only weakly differentiated from the other subscales. Overall, night driving, near vision? and far vision sc ores were all statistically and independently associated with multiple psyc hophysical vision measures. Findings were consistent across race and Sender subgroups. CONCLUSIONS. As assessed by the ADVS, reported visual functioning is high i n our representative older population. The overall scale and selected subsc ales effectively distinguish persons along a spectrum of ability. They corr elate with measures of visual impairment in a reasonable way and thus hold promise for risk factor investigations. The published da) driving and glare subscales should be examined for relevance and consistency before being ap plied in population-based settings. Methods specific to population-based se ttings should be investigated for their ability to better elicit additional visual function dimensions and early visual disability.