The development of visual acuity in very young kittens. A study with forced-choice preferential looking.

The development of visual acuity was studied longitudinally in young kittens, using a modification of the forced-choice preferential looking method (FPL) devised by Teller et al. [Vision Res. 14, 1433-1439 (1974)] for human infants. Acuity, defined as the spatial frequency which yields 70% correct responses by a naive observer, shows a 16-fold increase between 2 and 10 weeks of age. At comparable ages, acuity evaluated by this method falls short of the acuity values obtained with the mumping stand or with electrophysiological methods. FPL acuity estimated with a more lenient criterion (58%) comes close to the resolution of the highest-resolving single cells in the striate cortex. These results suggest that the preferential looking procedure provides a method that can be used in kittens over a wide age range, including ages at which it is impossible to use the jumping stand method.