OBJECTIVES: Dry eye disease (DED) affects quality of life. Ocular Surface Disease Index (OSDI) and Dry Eye questionnaire (DEQ-5) are two frequently used tools. OSDI is psychometrically sound but its 12-item does not cover all the patient experience. DEQ-5 validity is questioned and the 1-month recall period may introduce a memorization bias. Aim of this study was to check the psychometrics properties of a new scale capturing a wider picture of patient perception.

METHODS: Baseline data were from the TEARS cohort (Spain and UK) of 312 DED patients treated by a combination of sodium hyaluronate + trehalose. Apart of OSDI, DEQ-5, and a global satisfaction, patients completed new questions (9 on DED impact, 10 on satisfaction with eye drops) identified through literature review and expert committee. These 19 items have a 4-to-5-point Likert answers, and recall period is the last 3 days.

RESULTS: Mean age of patients was 57.9±15.2 yrs., 82.4% were women. After iterative factorial analyses, 4 items were deleted (high inter-item correlation, or no factor loading). A 4-factor structure was found robust, ranked by their cumulative variance, and named by content analysis: 1/ DED impact on daily activities (n=6); 2/ perception of relief/being comfortable/duration with eye drops (n=4); 3/ DED impact on mood/sleep (n=3); 4/ easiness with eyes drops (n=2). Reliability of the dimensions was confirmed by Cronbach alpha ranging from 0.67 to 0.86. Scores were calculated (range: 0-100 worst), e.g. 35.8±20.6 for global score. Logical correlations between the 4 dimensions and OSDI, DEQ-5 and global satisfaction ranged from 0.088 (Easiness vs OSDI) and 0.715 (impact on daily activities vs DEQ-5). Correlation between global score vs OSDI was 0.440. 4 of the 5 DEQ-5 items were highly inter-correlated (> 0.8) challenging its validity.

CONCLUSIONS: This 15-item 4-dimension scale has robust psychometrics properties. The next step is to quantify its responsiveness to change.