The VF-14. An index of functional impairment in patients with cataract.

OBJECTIVE: To describe the development and the performance of a brief questionnaire designed to measure functional impairment caused by cataract (the VF-14). DESIGN: Observational cross-sectional study. Patients were recruited between July 15 and December 15, 1991. SETTING: Patients were recruited from the practices of 70 ophthalmologists, located in Columbus, Ohio (N = 21), St Louis, Mo (N = 26), and Houston, Tex (N = 23). PATIENTS: Seven hundred sixty-six patients undergoing cataract surgery for the first time. MAIN OUTCOME MEASURES: Preoperative best corrected visual acuity in each eye; scores on the VF-14, a new index of functional impairment in patients with cataract; patient reports of overall trouble and satisfaction with their vision; and scores on the Sickness Impact Profile, a measure of general health status. RESULTS: The VF-14 has high internal consistency (Cronbach's alpha = .85) and correlates more strongly with the overall self-rating of the amount of trouble and satisfaction patients have with their vision than do several measures of visual acuity or the Sickness Impact Profile score. The VF-14 score is moderately correlated with visual acuity in the better eye. CONCLUSIONS: The VF-14 is a reliable and valid measure of functional impairment caused by cataract and provides information not conveyed by visual acuity or a general measure of health status.