Rescaling of the retinal map of visual space during growth of the kitten's eye.

We have measured the angle between the visual axis and the axis projected from the center of the optic disk in 35 cats ranging in age from two weeks to adulthood. Our results show that this angle, a, declines from around 27 degrees in very young kittens to about 16 degrees in adult cats, with most of the change occurring during the first 6 weeks after birth. We interpret this change as reflecting a progressive contraction of the area of object space projected onto the retina. For this to occur, the posterior nodal distance of the eye's optical system must increase by a larger factor than the transverse extent of the retina. This process undoubtedly contributes to maturation of the kitten's visual function, causing a reduction of the size of neuronal receptive fields and an enhancement of spatial resolution.