Importance: A validated questionnaire that assesses symptoms and the effect of dry eye disease (DED) on the patient's daily life is needed to evaluate the condition.
Objective: To develop and validate the Dry Eye-Related Quality-of-Life Score (DEQS) questionnaire in Japan.
Design, setting, and participants: Development and evaluation of the DEQS questionnaire were conducted in 4 phases: (1) item generation, (2) pilot study to assess content and face validity, (3) preliminary psychometric validation study to examine factor structure and reduce the number of items, and (4) final psychometric validation with 224 participants (203 with DED and 21 serving as controls). Participants completed the DEQS questionnaire, the Short Form-8, and the National Eye Institute Visual Function Questionnaire-25. To evaluate reproducibility and responsiveness, individuals with DED completed the DEQS questionnaire twice.
Main outcomes and measures: Internal consistency, reproducibility, discriminant validity, concurrent validity, and responsiveness.
Results: Items were generated from a literature review, and 35 items were selected for the draft version. In the pilot study, 11 items were deleted; furthermore, 9 items were deleted based on the results of item analysis and factor analysis in the preliminary validation study. The final 15-item DEQS questionnaire consisted of an Overall Summary scale and 2 multi-item subscales: Impact on Daily Life and Bothersome Ocular Symptoms. The psychometric analysis revealed that the DEQS questionnaire has good internal consistency, test-retest reliability, discriminant validity, and responsiveness to change. The DEQS questionnaire correlated well with the mental component of the Short Form-8 and showed strong correlations with 4 subscales (Ocular Pain, Near Vision, Distance Vision, and Mental Health) of the National Eye Institute Visual Function Questionnaire-25.
Conclusions and relevance: The DEQS questionnaire is valid and reliable for evaluating the multifaceted effect of DED on the patient's daily life, including mental health, and it can be used easily in routine clinical practice.