The utility of visual function questionnaire in the assessment of the impact of diabetic retinopathy on vision-related quality of life

Aims To determine whether the Visual Function Questionnaire-25 (VFQ) is a more accurate instrument for assessing vision related quality of life (VRQOL) than visual acuity (VA) in patients with diabetic retinopathy. To compare VRQOL between patients with non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). Methods We administered the VFQ and Vision Preference Value Scale (VPVS) to 104 patients. With VPVS as the gold standard in our study, we used Pearson's correlation and multiple linear regression analysis to assess whether VFQ is a more accurate measure of VRQOL than VA. Spearman correlation coefficients were used to assess which VFQ subscales correlated strongly with VPVS. Patients with NPDR and PDR were compared using VFQ. Results The Pearson's correlation coefficient between VPVS and VFQ was 0.49 (P < 0.01) and between VPVS and VA was 0.33 (P < 0.01). In multivariable linear models, VFQ explained a higher proportion of the variance in VPVS than VA. The VFQ subscales with the strongest Spearman coefficients to VPVS scores were role differences, near activities, distance activities, mental function and dependence. In these subscales, patients with PDR vs NPDR suffered a 25-30 point loss (100-point scale). Conclusions VFQ is a superior measure of VRQOL for patients with diabetic retinopathy because it better captures mental and emotional aspects of the disease as well as visual function. Subjects with PDR vs NPDR suffer significant loss of VRQOL. Eye (2010) 24, 29-35; doi: 10.1038/eye.2009.56; published online 27 March 2009