Translation and validation of the contact lens dry eye questionnaire-8 (CLDEQ-8) to the Spanish language

Purpose: To present the process of cultural and psychometric adaptation, and clinical validation of a new version in the Spanish language of the Contact Lens Dry Eye Questionnaire-8 ( CLDEQ-8). Materials and methods: The translation-retro-translation method was applied to the CLDEQ-8 questionnaire. Two independent native Spanish-speaking translators adapted the questionnaire from English to Spanish, and then a committee of experienced clinicians ( CE) evaluated the semantic equivalence and designed a Spanish version of the CLDEQ-8 questionnaire. The resulting translated version was tested conducting a pilot study in contact lens users and assessing their perception and overall understanding of the terminology. The results were analyzed and a final version was designed. The final version was retro-translated to English by a native English-speaking translator and compared with the original CLDEQ-8 version to confirm there were no meaningful differences. To clinically validate the new instrument, a prospective study was conducted to apply the new Spanish CLDEQ-8 to 50 contact lens users. Results: Fifty patients were studied with an average age of 21.50 +/- 1.66 years. The average CLDEQ-8 score was 13.28 +/- 6.81 points ( range 1-31). The internal consistency ( Cronbach's alpha) was 0.89, with a corrected index of homogeneity > 0.50 for all evaluated items. Conclusions: The process of trans-cultural adaptation of the questionnaire CLDEQ-8 resulted in the elaboration of a reliable and much needed instrument capable of measuring frequency and intensity of dry eye symptoms in Spanish-speaking contact lens users.