Purpose: To examine the relationships between importance, satisfaction, visual acuity, and visual function in a sample of preoperative cataract patients and to derive and prospectively evaluate a shortened measure of visual function.
Setting: Day-stay cataract surgery unit at large private hospital and consulting rooms of metropolitan ophthalmologists.
Methods: Two independent samples of 111 and 121 patients were surveyed before and after surgery with regard to their visual satisfaction, trouble with vision, VF-14 visual function, overall satisfaction, and importance of factors affecting patient satisfaction. A 7-item scale of visual function derived from the first sample's results was prospectively tested against the second sample. Distance and reading acuities were recorded from the patients' charts.
Results: The 7-item measure of visual function strongly correlated with the VF-14 (r>0.9) and had predictive power equal to that of the VF-14 for satisfaction and trouble with vision. However, the 7 items differed somewhat from a version developed in Helsinki. Distance visual acuity was not significantly correlated with visual function, satisfaction, or trouble with vision, although reading acuity was significantly correlated with visual function and trouble with vision (r=0.31 and r=0.32, respectively).
Conclusions: A shortened measure of visual function that had a predictive value equal to that of the VF-14 can more practically be used in everyday practice. Furthermore, the study showed that regional factors matter and highlights the necessity of basing measurement scales on factors important to the population in question to ensure scale validity.