Abstract
OBJECTIVE: The purpose of this study was to determine if combining visual acuity (VA) and visual field (VF) measures in the manner proposed in the 1999 Guide for the Evaluation of Visual Impairment1and incorporated into the 5thEdition of AMA Guides for the Evaluation of Permanent Impairment2(Guide) would be more predictive of self-reported vision-targeted quality of life than standard vision measures of VA or VF alone. DESIGN: Visual function and quality of life (QOL) were assessed in 200 visually impaired individuals. Tests included visual acuities, visual fields, and vision specific QOL using the National Eye Institute Visual Function Questionnaire (NEI VFQ). Visual acuities and visual fields were scored in the usual manner and then rescored using methodology proposed in the Guide to derive measures of functional vision. Relationships among the visual function, functional vision and QOL outcomes variables were determined using correlation and stepwise regression analyses RESULTS: High correlations were found between standard VA scores and the functional acuity scores derived from the Guide (r = 0.94, p < 0.001) as well as between standard and functional field scores (r = 0.78, p < 0.001). Functional Vision Score (FVS) was the variable most highly correlated with NEI VFQ composite score (r = 0.61, p < 0.001), all NEI VFQ subscales except ocular pain, and could account for almost 40% of the variance in the NEI VFQ composite score. CONCLUSIONS: FVS, which combined visual acuities and visual fields into one measure, was a better predictor of self-reported vision-targeted quality of life than either VA or VF extent alone. These results provide empirical support for the functional vision scoring methods presented in the AMA Guides for rating vision disability.