Psychometric validation of the Chinese version of the dry eye-related quality-of-life score questionnaire.

Aim: To psychometrically validate the Chinese version of the dry eye-related quality-of-life score questionnaire (DEQS-CHN) among Chinese patients with dry eye.

Methods: This study involved 231 participants, including 191 with dry eye disease (DED) comprising the dry eye disease group, and 40 healthy participants forming the control group. Participants were required to complete the DEQS-CHN, and Chinese dry eye questionnaire and undergo clinical tests including the fluorescein breakup time (FBUT), corneal fluorescein staining (CFS), and Schirmer I test. To assess the internal consistency and retest reliability, Cronbach's and the intraclass correlation coefficient (ICC) were employed. Content validity was assessed by item-level content validity index (ICV) and an average scale-level content validity index (S-CVI/Ave). Construct validity was assessed by confirmatory factor analysis. The concurrent validity was assessed by calculating correlations between DEQS-CHN and Chinese dry eye questionnaire. Discriminative validity was evaluated through non-parametric tests, with receiver operating characteristic (ROC) curve serving as conclusive indicators of the questionnaire's distinguishing capability.

Results: The Cronbach's coefficients for frequency and degree of ocular symptoms, impact on daily life, and summary score were 0.736, 0.704, 0.811, 0.818, 0.861, and 0.860, respectively, and the ICC were 0.611, 0.677, 0.715, 0.769, 0.711, and 0.779, respectively. All I-CVI scores ranged from 0.833 to 1.000, with an S-CVI/Ave of 0.956. Confirmatory factor analysis results exhibited a well-fitting model consistent with the original questionnaire [ /=2.653, incremental fit index (IFI)=0.924, comparative fit index (CFI)=0.924, Tucker-Lewis index (TLI)=0.909, and root mean square error of approximation (RMSEA)=0.065]. There was a moderate positive correlation between the DEQS-CHN and the Chinese dry eye questionnaire ( =0.588). The dry eye group demonstrated significantly higher scores compared to the control group, and the area under the curve (AUC) value was 0.8092.

Conclusion: The DEQS-CHN has been demonstrated as a valid and reliable instrument for assessing the impact of dry eye disease on the quality of life among Chinese individuals with DED.