Translation and validation of the Portuguese version of a dry eye disease symptom questionnaire

Purposes: A symptom questionnaire is an important tool used to quantify and qualify the impact of a disease on a patient's related quality of life and to estimate the prevalence of a certain condition within a population. Ophthalmologists frequently encounter patients with dry eye disease (DED), and therefore, evaluating the symptoms reported by these patients influences diagnosis, therapeutic monitoring, and evaluations of disease progression. The latest consensus on dry eye (Dry Eye Workshop, DEWS), published in 2007, led to the standardization of several questionnaires and a better understanding of the prevalence, severity, and overall effect of DED on the patient's quality of life. Methods: In this study, we translated into Portuguese a symptom questionnaire from DEWS that has already been used in several other population-based studies. For subsequent validation, the translated questionnaire was applied by two independent observers to a population of 30 subjects, and the results were compared in a concordance analysis. Results: The processes of translating to Portuguese and back translating the dry eye symptom questionnaire were conducted without difficulty. The high-correlation coefficients obtained when comparing the results of the initial application and the re-administration of this questionnaire to a sample of 30 individuals indicated excellent concordance with regard to results, repeatability, and reliability. Conclusions: This translated and validated questionnaire can be applied to a larger population with the intent to determine the prevalence of DED symptoms in the overall Brazilian population, as well as in distinct regions of the country.