The Brazilian version of the 25-Item National Eye Institute Visual Function Questionnaire: translation, reliability and validity.

PURPOSE To develop and investigate the reliability and validity of a Brazilian version of the 25-Item National Eye Institute Visual Function Questionnaire. METHODS A Brazilian version of the questionnaire was developed and applied to patients with chronic eye diseases and healthy controls. Reliability was assessed by Cronbach's alpha coefficient, intraclass correlation coefficient and interrater reliability coefficient. Participants were submitted to the Medical Outcomes Study Short Form-36 Questionnaire. Validity was estimated by the correlation between the questionnaires and among the 12 subscales of the questionnaire, subscales scores and visual acuity, patients' and controls' subscales scores, and the factor analysis. Responsiveness of the questionnaire was assessed in a group of patients before and following cataract surgery. RESULTS Cronbach's alpha, intraclass correlation and interrater reliability coefficients were highly significant. Validity was well established in all tests. In patients who underwent cataract surgery, a better vision-related quality of life was observed following surgery. CONCLUSION The Brazilian version of the 25-Item National Eye Institute Visual Function Questionnaire has valid and reliable psychometric properties and can be applied to vision-related quality of life research.