Visual fields of infants assessed with a new perimetric technique

The visual field of normal infants was assessed using a perimeter with LED stimuli and a forced-choice observation procedure. Central fixation was elicited by four central, pulsing LEDs and maintained with the aid of auditory stimuli. Field extent was derived from the four-alternative, forced-choice judgments of an adult who observed the infant's eye movements to peripherally illuminated LEDs. The binocular visual field of infants, ages 6-7 months, was similar to that of adults tested with the same apparatus. Area of the infants' binocular field was 93% that of the adults'. However, the infants' monocular fields were smaller than those of adults, averaging 74% of the adults' monocular field area. This may have been due to the distracting effect on infant behavior of the adhesive patch used for monocular testing. The visual fields of a young patient with hydrocephalus illustrate the potential clinical utility of this new perimetric technique for infants at risk of field defects.