Abstract

The acuity card procedure¹ is a modified version of the forced-choice preferential looking procedure (FPL)² that has been used for the past fifteen years to measure grating acuity in individual infants in laboratory settings. In the FPL procedure, the observer's task is to watch the infant through a small peephole and to judge, based on the infant's eye and head movements, whether a black-and-white grating is located to the right or to the left of the peephole. After numerous presentations of at least four spatial frequencies of gratings, acuity is estimated as the (interpolated) spatial frequency that produced a score of 75 percent correct by the observer.

© 1990 Optical Society of America