The development of vernier acuity in the cat

The development of vernier acuity was assessed in nine kittens using offsets in a series of square-wave gratings as stimulus targets. The kittens were tested on a jumping stand in a two-choice simultaneous discrimination paradigm, and daily thresholds were tracked with a modified staircase procedure. Vernier acuity improved gradually from initial values of 13-57' arc and reached asymptote at 1.5-5.4' arc by 70-90 days of age. The developmental function for vernier acuity is discussed in relation to physiologic development of the kitten visual system and is related to published data on the development of stereoacuity and spatial resolution in the same species.