A COMPREHENSIVE SYSTEMATIC REVIEW OF THE PSYCHOMETRIC PROPERTIES OF VFQ-25 IN GLAUCOMA
Author(s)
Ejzykowicz F1, Gwadry-Sridhar F21University of Southern California, Los Angeles, CA, USA, 2University of Western Ontario, London, ON, Canada
Glaucoma can create visual impairment with ongoing morbidity. Having an instrument that assesses the progression of diseases of the eye and assesses treatment is necessary due to increased prevalence. OBJECTIVES Evaluate the psychometric properties (reliability, validity, responsiveness, and interpretability) of a short form of vision-specific instrument VFQ-25 for glaucoma and other eye chronic diseases., Compare the VFQ-25 to the generic SF-36. METHODS We conducted an extensive literature review using Medline, OVID, Google Scholar, Cochrane Library, ARVO and ISOQOL databases from the years 2000 to 2007. We included all articles that addressed the psychometric properties of VFQ-25. If no psychometric properties were assessed, we excluded the article RESULTS 8 articles and 2 abstracts relating to VFQ-25 met the inclusion criteria. Internal consistency reliability (Cronbach's alpha >0.70) was high for most of all subscales, except driving. Ceiling scores were observed in all studies included in this systematic review. However, no floor effect was detected. Discriminant and convergent validity were different for a few subscales (driving, social function and ocular pain), for others they ranged from 86%-100%. Scale-scale correlations between general health and other subscales were low (<0.3). In contrast, global score is moderately to highly correlated with other subscales (0.5-0.9). Compared to SF-36, VFQ-25 was low correlated. Responsiveness of VFQ-25 was not measured in patients with glaucoma. The effect sizes were small to moderate (0.07-0.51). CONCLUSIONS The results suggest that VFQ-25 is a reliable and valid measure of health-related quality of life in glaucoma patients and other chronic eye diseases. However, longitudinal studies should be done to assess responsiveness and interpretability of the questionnaire. Our findings suggest that VFQ-25 and SF-36 are capturing different dimensions of health.
Conference/Value in Health Info
2009-09, ISPOR Latin America 2009, Rio de Janeiro, Brazil
Value in Health, Vol. 12, No. 7 (October 2009)
Code
PSS3
Topic
Patient-Centered Research
Topic Subcategory
Patient-reported Outcomes & Quality of Life Outcomes
Disease
Sensory System Disorders