Abstract
Purpose: :
We report the development of a patient-derived, health related quality of life (HRQOL) questionnaire for adults with strabismus.
Methods: :
Individual patient interviews generated 181 questionnaire items. To identify the most pertinent 20 items for an easy-to-administer final questionnaire, we asked 29 adults with strabismus to complete the 181-item questionnaire. We then analyzed responses, performing factor analysis and redundancy analysis. Two prominent factors were identified, the first containing items relating to psycho-social well-being and the second, items relating to physical and emotional functioning. The 10 items with the highest loading in each factor were selected, to yield a final 20-item questionnaire (10 items constituting a ‘psycho-social’ subscale, 10 a ‘function’ subscale). The 20-item questionnaire was then administered to 22 patients with strabismus, 13 visually normal adults and 18 patients with other eye diseases (cataract (7), glaucoma (3), retinal disease (3), corneal disease (5)). A 5-point Likert scale was used for responses (‘never’=0, ‘rarely’=1, ‘sometimes’=2, ‘often’=3 and ‘always’=4). Overall questionnaire scores, and scores for each subscale, were averaged to give summary scores ranging from 0 to 4 (best to worst HRQOL). Overall and subscale scores were compared across all groups using ANOVA and between groups using paired t-tests.
Results: :
Mean overall scores for the final 20-item questionnaire were worse in strabismus patients (1.82 ±0.77) than visually normal adults (0.18 ±0.21;p<.0001) and patients with other eye diseases (0.56 ±0.37; p<.0001). For the psychosocial subscale, mean scores were worse for strabismus patients (1.2 ±0.98) than visually normal adults (0.02 ± 0.06; p<.0001) and patients with other eye diseases (0.23 ±0.44; p=0.0003). For the function subscale, mean scores were also worse in strabismus patients (2.44 ±0.90) than visually normal adults (0.35 ±0.40; p<.0001) and patients with other eye diseases (0.89 ±0.53; p<.0001).
Conclusions: :
We have developed a patient-derived 20-item HRQOL questionnaire specific for strabismus, with subscales to assess psychosocial and function concerns. This 20-item patient-derived HRQOL questionnaire is useful for assessing the impact of strabismus in individual patients and may be useful as an outcome measure for clinical trials.
Keywords: strabismus • quality of life • strabismus: diagnosis and detection