Technically, the idea that carotenoids may help protect your vision as you age isn't news. What is nice is to have more information as to why they're good for you.
Humans need to obtain these nutrients from the diet. Carotenoids have anti-oxidant properties, as does vitamin A. You can overdose on vitamin A either in supplement form or from the livers of arctic animals (So lay off the polar bear liver!). Plant-based carotenoids, however, are converted to vitamin A on an as needed basis, so eating high levels are not toxic (you can turn funny colors though).
The carotenoids lutein and zeaxanthin are yellow pigments contained in plants. These aren't precursors to vitamin A, but they are good for your vision just the same.
Macular degeneration occurs when light sensing cells in the macula stop working (see, a medical term that sounds like what it means!). Lutein in particular is found in the macula, and may protect against macular degeneration through its contribution to eye pigmentation.
You can get more carotenoids in your diet by eating plenty of carrots, corn, spinach, kale, and egg yolks.
http://lpi.oregonstate.edu/infocenter/phytochemicals/carotenoids/