According to KidsHealth.org, a human's eyes do continue to grow into adulthood. There is a common misconception that a person's eyes are full size at birth.
Dr. Ted Montgomery states that a human baby is born with an eyeball that is, on average, about 0.71 inches in diameter. This measure is the axial length, taken from the front of the eye to the back. As the infant grows, the eyeball increases just a little to measure approximately 0.78 inches in diameter. The eyeball slowly continues to grow until adulthood. It eventually measures about 1 inch in diameter. To compare, a ping pong ball is around 1 1/2 inches in diameter, which makes an adult eyeball about 2/3 the size of an average ping pong ball. The eyeball is encased in a bony, cone-shaped cavity called the "orbit" or the "socket." As the eyeball grows, this bony cavity increases in size as well.
According to the National Institute of Health, due to the growth of the eye, changes in vision may occur. Some of these changes are refractive changes, which means the shape of the eye prevents the light from focusing directly on the retina. These changes in the length of the eye also cause changes in the cornea. Since most of the eye growth occurs during childhood, these changes are the reason some children need corrective lenses to help improve their vision, as stated by KidsHealth.org.