Development of a Quality-of-Life Questionnaire for Adults with Strabismus
Received 13 February 2008; received in revised form 15 August 2008; accepted 19 August 2008. published online 18 November 2008.
Purpose
We report the development of a patient-derived, health-related quality-of-life (HRQOL) questionnaire for adults with strabismus.
Design
Cross-sectional study.
Participants
Twenty-nine patients with strabismus in a first phase, and 32 patients with strabismus, 18 patients with other eye diseases, and 13 visually normal adults in a second phase.
Methods
Individual patient interviews generated 181 questionnaire items. For item reduction, we asked 29 patients with strabismus to complete the 181-item questionnaire, analyzed responses, and performed factor analysis. Two prominent factors were identified, and the 10 items with the highest correlation with each factor were selected. The final 20-item questionnaire (10 psychosocial items and 10 function items) was administered to an additional 32 patients with strabismus (22 with diplopia, 10 without diplopia), 13 visually normal adults, and 18 patients with other eye diseases. A 5-point Likert-type scale was used for responses (never = 100, rarely = 75, sometimes = 50, often = 25, and always = 0). Median overall questionnaire scores and psychosocial and function subscale scores, ranging from 0 (worst HRQOL) to 100 (best HRQOL), were compared across groups.
Main Outcome Measures
The HRQOL questionnaire response scores.
Results
Median overall scores were statistically significantly lower (worse quality of life) for patients with strabismus (56) compared with visually normal adults (95; P<0.001) and patients with other eye diseases (86; P<0.001). Median scores on the psychosocial subscale were significantly lower for strabismus patients (69) compared with visually normal adults (99; P<0.001) and patients with other eye diseases (94; P<0.001). For the function subscale, median scores were again significantly lower for strabismus patients (43) compared with visually normal adults (91; P<0.001) and patients with other eye diseases (78; P<0.001).
Conclusions
We have developed a 20-item, patient-derived, HRQOL questionnaire specific for adults with strabismus, with subscales to assess psychosocial and function concerns. This 20-item, condition-specific questionnaire will be useful for assessing HRQOL in individual strabismus patients and also as an outcome measure for clinical trials.
Financial Disclosure(s)
The authors have no proprietary or commercial interest in any materials discussed in this article.
Available online: November 13, 2008.
1Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota
2Department of Epidemiology, Johns Hopkins University, Baltimore, Maryland
Correspondence: Dr Jonathan M. Holmes, Ophthalmology W7, Mayo Clinic, Rochester, MN 55905. fax: (507) 284-8566
Manuscript no. 2008-210.
Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article.
Supported by National Institutes of Health Grants EY015799 (JMH), EY013844 (EAB), Research to Prevent Blindness, New York, NY (JMH as Olga Keith Weiss Scholar and an unrestricted grant to the Department of Ophthalmology, Mayo Clinic), and Mayo Foundation, Rochester, MN. None of the funding organizations had any role in the design or conduct of this research.
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