Our ability to take in and respond to what we see depends as much on our brains as it does on our eyes. As we age, there is a degeneration in the speed, accuracy and strength with which the brain records visual information.
Visual cognition is very important in learning. A recent juggling study compared seniors with 20 year olds. Although, as you would expect, the younger group was faster to learn the new skill, there was no significant difference in the quantity of new brain cells grown.