This is actually pretty easy, but it can take a while, as it requires frame-by-frame work, (rotoscoping). Depending on the look you're going for, you could use a freehand Neon Light effect in the shape of the person's eyes, or a Grade Object with an inverted mask in the shape of the eyes. Whichever you do, just go frame-by-frame and line up the shape/mask with your actor's eyes. Then just experiment with the Neon Glow settings/Grade filters until you have a look you're happy with.
Also, if you haven't already, take a look at the video tutorials in the Support section. http://fxhome.com/support/vidtutes
They're really helpful, especially if you're just beginning with the program.
Hope that helps