Clinical experience with preferential looking acuity tests in infants and young children.

Early preferential looking methods for the assessment of infant visual acuity relied upon formal psychophysical procedures that were lengthy and only easily applicable to laboratory studies. Two clinically appropriate techniques evaluated in this study both maintain a forced-choice testing protocol and are administered by a single examiner. One method employs a specially constructed optical projection system to present gratings in a dark-room. The second method relies upon a commercially available acuity card test, used with good room lighting. Paediatric clinical patients and normal infants and young children were examined using both techniques. Findings demonstrate that suitably adapted preferential looking methods can provide rapid and valid estimates of visual acuity in infants and young children. The tests appear sufficiently robust to be appropriate for routine clinical use.