ERIC Number: ED118209
Record Type: Non-Journal
Publication Date: 1975-Apr
Reference Count: N/A
Infant Accommodation and Acuity Threshold as a Function of Viewing Distance.
Salapatek, Philip; And Others
This study investigated whether the acuity threshold for distant targets is elevated for infants ranging in age from 24 to 63 days. Using square wave gratings and a modified staircase procedure, acuity thresholds for each of 331 infants were determined for one or more of the distances 30 cm, 60 cm, 90 cm and 150 cm. Acuity threshold was defined as the finest grating toward which the infant directed a significant proportion of first fixations. Results indicate that these thresholds were centered around a modal grating-stripe width of 30 minutes of visual angle, regardless of the infant's age. The predominant threshold of 20 - 30 minutes of an arc was found for the 150 cm distance, and no general improvement in acuity threshold was found over the age range tested. These results are in agreement with other infant acuity studies, showing that 1- to 2-month-old infants are sensitive to gratings of 2 cycles per degree or coarser. This value was relatively constant across large distances, suggesting that the 1- to 2-month-old infant's lens does not accommodate as a function of target distance. This finding is compatible with the evidence to date that the low visual acuity of the infant does not vary with the distance of the pattern being viewed. (It is suggested that the young infant is sensitive only to low spatial frequencies, so that there is not effective stimulus for accommodation.) (GO)
Publication Type: Speeches/Meeting Papers
Education Level: N/A
Sponsor: Minnesota Univ., Minneapolis. Graduate School Research Fund.; National Science Foundation, Washington, DC.
Authoring Institution: Minnesota Univ., Minneapolis. Inst. of Child Development .