Purpose:
No validated questionnaires exist that measure the effect of uncorrected refractive error and the impact of spectacle correction in a student population. The Student Refractive Error and Eyeglass Questionnaire (SREEQ) was developed by modifying the Pediatric Refractive Error Profile (Walline 2007). The purpose of this study was to assess the construct validity of the SREEQ.
Methods:
The SREEQ is a 4-point Likert type two part questionnaire. Part A addresses uncorrected vision (15 questions) and Part B relates to corrected vision and attitudes regarding eyeglasses (23 questions). After the SREEQ was evaluated for face and content validity by a multi-disciplinary research team, it was administered to students enrolled in a longitudinal study on refractive error who reported previous spectacle wear. Exploratory factor analysis (EFA) using principal components and quartimax rotation was conducted. Factors with Eigenvalues > 1.0 and questions loading >0.5 in one of the principal components were retained. Cronbach's alpha was conducted to determine internal consistency.
Results:
EFA identified 3 domains in Part A (Uncorrected Vision, Academics and Discomfort) into which all but 3 questions fit well, accounting for 69.9% of the variability in the responses. Internal consistency was good for all three domains (Cronbach’s alpha 0.79- 0.89). For Part B, EFA found 5 principal components responsible for 61.6% of the variability in the responses after excluding six questions that did not fit well into any domain. Internal consistency for these domains ranged from 0.63 to 0.82.
Conclusions:
Factor analysis showed SREEQ Part A to have good construct validity regarding the impact of uncorrected refractive error on the visual quality of life of children. The constructs in Part B on spectacle corrected vision were less clearly defined. Confirmatory Factor Analysis will be performed to further evaluate the SREEQ’s construct validity.
Keywords: visual development • quality of life • clinical research methodology