This paper discusses evidence for the development of ability in the physical, physiological and psychological phases of visual acuity. Visual acuity tests of various kinds were administered to 674 children between the first and sixth year of life and the results suggest that high levels of visual acuity are present at a very early age. The data show no development trend in the age groups beyond the third year of life. Apparent development prior to age three may be an artifact due to the inability of examiners to present comparable tests. Comparison of the present sample and a sample of older children shows the preschool sample to possess a higher level of visual efficiency. This suggests that growth and environment are effective in reducing efficiency earlier in life than was thought heretofore.