The development of peripheral visual acuity in human infants. A preliminary study.

In 74 infants, we tested the resolution of gratings centered at 10 degrees in the peripheral visual field. The estimation of acuity was based on the direction of the first saccade from a fixation stimulus toward a peripheral grating stimulus. We also tested the development of the infants' "best acuity", using a method of forced-choice preferential looking (68 infants). Peripheral acuity developed dramatically in the first months of life and reached a plateau at about 4 months. By contrast, "best acuity" continued to increase significantly during the second half of the first year of age. At all ages, peripheral acuity was lower than the resolution evaluated with the same stimuli under free-viewing conditions. We conclude that, in spite of the known immaturity of the fovea in newborns (Abramov et al. 1982), even the youngest infants we tested (2 months old) showed a functional superiority of the central over the peripheral visual field.