Accommodation in infants as measured by photorefraction

Abstract

We developed a video camera photorefractive procedure that allows on-line monitoring of accommodation from a distance of 1-2m, and have used it to study accommodation in twenty-nine 2- to 10-month-old human infants. We presented square wave gratings and random checkerboard targets at 25, 33, 50, and 100 cm from the infant. All infants altered their accommodation in the appropriate direction for changing target distances. We also presented infants with a slowly rotating circular striped target. We did not observe any systematic change in accommodation of the astigmatic infants to the rotating striped target, nor any significant change in their accommodation to stationary targets as a function of target type. Measured speeds of accommodation in infants were at least 4.6 D/sec, comparable to that found for adults.