Translation and validation of the 8-item contact lens dry eye questionnaire (CLDEQ-8) among Chinese soft contact lens wearers

Purpose: To develop a Chinese version of the 8-item Contact Lens Dry Eye Questionnaire (CLDEQ-8) with cross-cultural adaption and clinical validation among soft contact lens wearers (SCL) in China.

Methods: The translation and adaptation of the Chinese CLDEQ-8 (C-CLDEQ-8) followed a rigorous methodological process based on cross-cultural research guidelines consisting of three main phases: 1) forward and backward translation of original CLDEQ-8 into Chinese, 2) cross-cultural adaptation performed by medical advising committee, and 3) clinical validation and repeatability test of the translated questionnaire on Chinese SCL wearers. Rasch analysis was also performed to investigate the psychometric properties of C-CLDEQ-8.

Results: 134 experienced SCL wearers aged 18-45 completed the C-CLDEQ-8. C-CLDEQ-8 score was linearly related to the overall opinion of SCLs (beta = 2.16, p = 0.002), gestalt eye dryness response (beta = 2.90, p < 0.001), and sensitivity response (beta = 1.83, p = 0.001). The questionnaire showed excellent test-retest repeatability with an intra-class correlation coefficient (ICC) of 0.95 and great internal consistency with a Cronbach's alpha of 0.83. The corrected index of homogeneity for each item was more significant than 0.5. In Rasch analysis, the infit and outfit values for eight items were all within 0.6-1.4, suggesting a good fit for the Rasch model. Martin-Löf test result indicated that the Rasch model was unidimensional (p = 1.0). Item characteristics curves suggested combining categories 3-4 and 5-6 in item 5 of C-CLDEQ-8.

Conclusions: This study produced a Chinese version of CLDEQ-8 with great validity and reliability and proved capable of evaluating SCL-related symptoms.