Abstract
Abstract: :
Purpose: We investigated the measurement properties of the German version of the 25–item National Eye Institute Visual Function Questionnaire (NEI VFQ–25) in patients with age–related macular degeneration (AMD). Methods: This cross–sectional study included 187 patients who attended a clinic in Germany. Patients belonged to 1 of 3 severity classes: 1) early AMD in both eyes (n=35); 2) late stage AMD in 1 eye and early stage AMD in the other eye (n=111); and 3) late stage AMD in both eyes (n=41). Correlations of scores were calculated between NEI VFQ–25 and Snellen visual acuity. Mean scores on the NEI VFQ–25 were compared for different stages of severity using linear regression adjusting for age, gender, and number of comorbidities. Cronbach’s alpha was used for internal consistency reliability, and an intraclass correlation coefficient was used for test–retest (2 weeks apart) reliability. Results: For the better eye, visual acuity correlated strongly and significantly (P<0.0001) with NEI VFQ–25 domains on General Vision (r=0.63), Near Vision (r=0.70), Distance Vision (r=0.69), Driving (r=0.67), and with the Composite Score (r=0.66). Visual acuity correlated moderately and significantly with Peripheral Vision (r=0.44), Role Limitation (r=0.39), Dependency (r=0.55), Social Functioning (r=0.56), and Mental Health (r=0.44). For the worse eye, visual acuity scores were generally lower and remained moderate for most components. Discriminate validity was evidenced with significant differences (P<0.05) in mean scores among severity levels of AMD for most NEI VFQ–25 components. Cronbach’s alpha and intraclass correlations exceeded 0.70 on most components. Conclusion: The German version of the NEI VFQ–25 has demonstrated reliability and validity as a measure of vision–related quality of life in patients with AMD.
Keywords: age–related macular degeneration • quality of life • clinical (human) or epidemiologic studies: outcomes/complications