A new technique to measure contrast sensitivity in human infants

We used a new time-efficient procedure to obtain binocular contrast sensitivity functions (CSFs) from 80 infants aged 1-, 3-, 6-, and 12-months-old. The test consisted of 5 sets of large (50 by 28 cm) cards constructed by mounting a 7.2 degrees circular sine wave grating with 1 of 5 spatial frequencies (0.3, 0.6, 1.2, 2.4, and 3.6 cpd at 60 cm) onto light gray matteboard. Each card also contained a second 7.2 degrees unpatterned patch of equal space-average luminance. Depending upon the set, the contrast within the gratings ranged from approximately 25 to 0.5%. To judge the subject's detection of each grating we used a rapid version of preferential looking (PL) similar to that developed for the Teller Acuity Cards. Results showed that compared to previous techniques, the card procedure allows one to estimate an infant's CSF much more simply, rapidly, and inexpensively.