How old are kittens when they have their permanent eye colour?

Question

I have two kittens at 12 weeks old. When i first got them they had bright blue eyes. Then they started changing. The ginger tabbys went grey then kind of grey green but still seem to be getting lighter, the other is black with ginger patches. Hers went bright green and now more of a yellow green and still getting more yellow. When will their eyes settle on the colour they will be? Would anyone like to guess what colours they'll end up?

Answer 1

Eye-colour is genetically linked to their coats. Unless a cat is white or pointed (or selectively bred down many generations for extreme eye colour) it's eyes will be greenish-yellow to gold.  

Answer 2

Their eyes will constantly change - my cats' eyes went really yellow then they each have been fading at different rates over time.  Now (at 16) they are both quite pale yellow.