The Dry Eye dAily Life (DEAL) Questionnaire: Psychometric Validation of a New Instrument for Measuring the Impact of Dry Eye on Daily Life and Patient Satisfaction While Using Eye Drops.

PURPOSE: Dry eye disease (DED) significantly affects quality of life. Commonly used questionnaires such as the Ocular Surface Disease Index (OSDI) and Dry Eye Questionnaire (DEQ-5) have limitations: OSDI does not fully capture patient experience, and DEQ-5's one-month recall period may introduce bias. This study aimed to evaluate the psychometric properties of the Dry Eye dAily Life (DEAL), designed to assess a broader range of patient perceptions. MATERIALS AND METHODS: Baseline data from the TEARS cohort (Spain and UK) included 312 patients with DED who were treated with sodium hyaluronate and trehalose. In addition to the OSDI, DEQ-5, and a global satisfaction item, patients completed 19 questions (9 on the subject of DED impact and 10 on their satisfaction with eye drops) developed from a literature review. Items used 4- or 5-point Likert scales, and a 3-day recall period. RESULTS: The mean age of patients involved in the study was 57.9±15.2 years; 82.4% were women. Four of the questions were removed due to high inter-item correlation (3 items) or poor factor loading (1). Principal Component Analysis identified a stable 4-factor structure: 1/ impact on daily activities (6 items/questions); 2/ relief/being comfortable/duration with eye drops (4); 3/ mood/sleep impact (3); and 4/ ease of use (2). Cronbach's alpha ranged from 0.67 to 0.86. The review of logical correlations between the 4 dimensions with OSDI, DEQ-5, and global satisfaction supported the validity. The DEAL global score correlated only moderately with OSDI (r=0.44) suggesting additional patient-relevant information which is not addressed by OSDI alone. CONCLUSIONS: The 15-item, 4-dimension DEAL questionnaire shows promising preliminary psychometric properties and captures patient-relevant concepts not currently addressed by existing tools. The 4-dimension structure is internally coherent. Independent replication, assessment of responsiveness, and further work on the ease-of-use dimension and the optional contact-lens item are needed.