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.