Development and evaluation of a Chinese version of the Adult Strabismus Questionnaire (AS-20)

The 20-item Adult Strabismus Quality of Life Questionnaire (AS-20) was developed in the United States to assess health-related quality of life (HRQOL) of adult patients with strabismus. At present, no questionnaire is available for assessing HRQOL specifically for adult patients with strabismus in China. A Chinese version of the AS-20 (CAS-20) was developed and its reliability and validity evaluated in adult patients with strabismus in China.

The AS-20 was translated into Chinese. A total of 102 adults with strabismus and 102 visually healthy adult controls were recruited to answer the 5-level Likert items of the CAS-20. Demographic (age and sex) and clinical data of the recruited subjects were documented. Internal consistency, test-retest reliability, correlations between items and their respective subscale, and construct validity were evaluated to assess questionnaire reliability and validity.

The number of responses for each item was calculated, as well as individual items' correlation with their respective subscale. Cronbach's α coefficient for the two subscales and the CAS-20 were satisfactory (0.846, 0.819, 0.883, respectively). The intra-class correlation coefficient for test-retest reliability was 0.723-0.862. Patients with strabismus had significantly lower scores on the CAS-20 than controls. Factor analysis identified six principal factors, and could be grouped into two subscales. The results supported the construct validity of the CAS-20.

The CAS-20 presented satisfactory reliability and validity in our study. It is suggested that the questionnaire can be applied in clinical trials or research for Chinese patients with strabismus.