I hate to call it eyeliner, but it's really kind of what it is. Basically, while looking over eye reference images, I noticed that (regardless of gender) the majority of furries across a variety of artists had a noticeable outline around the eyes. Fairly expected for cartoonish drawings, true, but in looking over my reference images of real foxes, I noticed they also had such an outline! So, I figured I do some comparisons using eyeliner on the new eyelids.

I can't say that I like it a lot, but the more subtle variations do help a little, I guess. The full eyeliner is what you get when you apply directly to the polygon faces prior to smoothing; rather thick. With the thin variation, after smoothing I went back and removed a couple rows of the shader. The Alt color takes the plain black and replaces it with that grey-ish blue that shows up on the side of the nose in the Ambient Occlusion red body shader.