I like the "dead eye" look for my skinks =) So I go with bleached bone and hi light it with some skull white. ex:
I paint them yellow, give them a watered-down wash of Baal Red, and then paint a slit of Chaos Black.
Wow, i think i'm the only one who paints them just like human eyes... my skinks are adeptus battlegrey with bloodred scales and royal blue shields. Their eyes I paint space wolf grey with a line of chaos black.
I paint them yellow and if the eye is not too small (like with some older minis) with a black stripe.
Mine I paint white then dot a bit of yellow and finished off with a black iris... <--- like my avatar over here.
I made some of mine with a sunburst yellow and 3 small black dots like that one guy off the cartoon serie Naruto (don't remember his name) but it takes time to do it that way so I decided to do it on the braves only....
I mentioned earlier how I do my Skink eyes, and here's a really old picture of the finished product. I think he's about the first Skink I ever painted, actually.