Evaluation of the Intermittent Exotropia Questionnaire using Rasch analysis

JAMA Ophthalmol. 2015 Apr;133(4):461-5. doi: 10.1001/jamaophthalmol.2014.5622.


Importance: The Intermittent Exotropia Questionnaire (IXTQ) is a patient, proxy, and parental report of quality of life specific to children with intermittent exotropia. We refine the IXTQ using Rasch analysis to improve reliability and validity.

Observation: Rasch analysis was performed on responses of 575 patients with intermittent exotropia enrolled from May 15, 2008, through July 24, 2013, and their parents from each of the 4 IXTQ health-related quality-of-life questionnaires (child 5 through 7 years of age and child 8 through 17 years of age, proxy, and parent questionnaires). Questionnaire performance and structure were confirmed in a separate cohort of 379 patients with intermittent exotropia. One item was removed from the 12-item child and proxy questionnaires, and response options in the 8- to 17-year-old child IXTQ and proxy IXTQ were combined into 3 response options for both questionnaires. Targeting was relatively poor for the child and proxy questionnaires. For the parent questionnaire, 3 subscales (psychosocial, function, and surgery) were evident. One item was removed from the psychosocial subscale. Resulting subscales had appropriate targeting.

Conclusions and relevance: The Rasch-revised IXTQ may be a useful instrument for determining how intermittent exotropia affects health-related quality of life of children with intermittent exotropia and their parents, particularly for cohort studies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Exotropia / psychology*
  • Female
  • Health Status*
  • Humans
  • Infant
  • Male
  • Quality of Life / psychology*
  • Reproducibility of Results
  • Sickness Impact Profile*
  • Surveys and Questionnaires*