So, you want glowing eyes? As in, they emanate light? That I would do with thinned down paints carefully applied around the eyes in successive layers until it looks glowing. This is called Object Source Lighting (
OSL). Not a lot of tutorials on it and it is an advanced technique, so test it out first before committing to the final model.
Here is one tutorial I know might help:
http://www.coolminiornot.com/article/aid/288
If you mean you want the eyes themselves to glow, I question the scale of the model and the necessity of painting the eyes at all. At 25-28mm, I don't recommend eyes unless you want them wild-eyed or something very specific. Generally, scale-wise, you wouldn't see the eyes themselves.