Validation, Reliability and Repeatability of the Ocular Surface Disease Index (OSDI) Questionnaire in a Sample of the Palestinian Population: The Pa-OSDI

Abstract PURPOSE To translate and validate a Palestinian dialect version of OSDI. METHODS The translation procedure included five stages; forward translation, revision of translation, backward translation, refinement of translation and finally test of the pre-final version. The final sets of questionnaires were constructed using an online JotForm platform. The online platform was chosen to automatically calculate the questionnaire's final overall score. Overall, 260 participants were instructed to fill out the English and the Pa-OSDI version twice to conduct the reliability of the translated version and repeatability evaluation. RESULTS The mean age of the participants was 33.45±11.74 years. Cronbach's alpha for all domains was greater than 0.80, except the ‘‘blurred vision’’ and ‘‘deteriorating vision’’ domains (0.77 and 0.74 respectively). The mean overall score difference between the OSDI and Pa-OSDI was 0.86 based on the Bland-Altman chart. For repeatability, no significant difference in the overall scores between the two repeats of the Pa-OSDI ( p =0.632). The outcome for the Pa-OSDI overall score (sessions 1 and 2) was a clinically difference (bias) of 0.21. By using the Varimax rotation method, only three factors (ocular symptoms, vision-related function, and environmental triggers) had eigenvalues greater than one in the structure of the Pa-OSDI. CONCLUSION The Pa-OSDI is an appropriate reliable and repeatable tool for the determination of dry eye symptoms, ocular discomfort and quality of life in the Palestinian dialect speaking population. This version could remove the language barrier in answering OSDI domains more easily.