SELF-REPORTED ASSESSMENT OF DRY EYE IN A POPULATION-BASED SETTING

Purpose. To report on a subjective dry eye assessment method for use i n large-scale research, to evaluate its application in a population-ba sed study of dry eye among elderly persons in the United States, and t o apply novel techniques to improve simple questionnaire item summarie s. Methods, A dry eye questionnaire was administered to a population-b ased sample of 2520 volunteers ages 65 to 84 years in Salisbury, Maryl and. Individual symptoms and signs, counts of symptoms and signs, and latent class model summary of item responses were evaluated for validi ty and internal consistency. Results. Approximately 15% of participant s reported experiencing one or more of six dry eye symptoms often or a ll the time; 20% reported experiencing three or more symptoms sometime s, often or all the time. Four groups were derived on the basis of sym ptomatology, using latent class analysis. The groups exhibited face va lidity, revealed symptom patterns that added specificity to simple sym ptom counts, and were qualitatively similar when derived separately wi thin population subgroups, Internal consistency was moderate (Cronbach 's alpha = 0.61), indicating some variability in reporting. Conclusion s. Dry eye symptoms are commonly reported in a representative elderly population. Symptom data were moderately consistent, suggesting their usefulness for dry eye assessment if properly summarized. A latent cla ss summary revealed biologically meaningful summary patterns of sympto ms reported in this population and holds promise for use in risk facto r investigations and in clinical trials.