Near vision not so good as distant

Foster is 14, and in great shape... but I've noticed that although his distance vision is excellent (he can see the other dogs to play with on the other side of the park!), his near vision seems not to be quite so good. He can chase and catch tennis balls and bring them back no problem (if he's interested!), but sometimes he doesn't see something like a cat walking past his nose unless he's looking right at it. If he does see it he tries to catch and shred it, of course ;-)

I have no reason to think there's a problem, although there is a faint bluey white tinge to his pupils which I suspect are maybe cataracts starting, but I was wondering whether this sounds normal for a JRT this old? He's certainly not walking into things and his coordination is fine. Loads of energy too... more than me!!